The far ultraviolet spectral region (roughly 900 - 1200 Å) is densely packed with strong atomic, ionic and molecular transitions of astrophysical importance. Many of these transitions provide unique access to the associated species. This spectral region is also technically challenging: optical reflectivities are limited, contamination control requirements are severe and detectors must be windowless. The Far Ultraviolet Spectroscopic Explorer (FUSE) covers the spectral region 905 -1187 Å with a resolution ~ 15 km s^-1. The mission, launched in June 1999 and now in its fifth year of science operations, has reaped a rich scientific harvest from this spectral region. This paper will examine the lessons learned from the FUSE mission with the perspective of looking ahead to possible future missions. In order to build on the scientific advances of the FUSE mission, such a mission would require both increased sensitivity and higher spectral resolution. We conclude that achieving these requirements will necessitate, among other advances, new approaches to far ultraviolet mirror coating technology. We also examine the possibility of accessing the far ultraviolet using an ultraviolet observatory designed for longer wavelength ultraviolet radiation.

We describe the Galaxy Evolution Explorer (GALEX) satellite that was launched in April 2003 specifically to accomplish far ultraviolet (FUV) and near ultraviolet (NUV) imaging and spectroscopic sky-surveys. GALEX is currently providing new and significant information on how galaxies form and evolve over a period that encompasses 80% of the history of the Universe. This is being accomplished by the precise measurement of the UV brightness of galaxies which is a direct measurement of their rate of star formation. We briefly describe the design of the GALEX mission followed by an overview of the instrumentation that comprises the science payload. We then focus on a description of the development of the UV sealed tube micro-channel plate detectors and provide data that describe their on-orbit performance. Finally, we provide a short overview of some of the science highlights obtained with GALEX.

The Chandra X-ray Observatory is the X-ray component of NASA's Great Observatory Program, which, in addition to Chandra, comprises the Hubble Space telescope and the Spitzer Infrared Telescope Facility. The Chandra X-ray Observatory provides scientific data to the international astronomical community in response to proposals for its use. Data becomes public at most one year after the observation. The Observatory is the result of the efforts of many organizations in the United States and Europe. NASA's Marshall Space Flight Center (MSFC) manages the Project and provides Project Science; NGST (formerly TRW) with the help of many outstanding subcontractors served as prime contractor responsible for providing the spacecraft, the telescope, and assembling and testing the observatory; and the Smithsonian Astrophysical Observatory (SAO) provides technical support and is responsible for ground operations including the Chandra X-ray Center (CXC).

INTEGRAL is an ESA space mission to study the sky at hard X-ray and soft gamma-ray energies. Its two main instruments SPI and IBIS cover the energy range 15 keV to 10 MeV, and are mainly devoted to high resolution spectroscopy (ΔE ~ 2,5 keV at 1 MeV) and fine source imaging (DJ ~ 12 arcmin), respectively. The 4 tons heavy payload was brought into an excentric orbit of 153.000 km apogee and 9.000 km perigee on October 17, 2002 by a Russian Proton rocket. After a successful performance and verification phase, the observational program started in late December 2002 by executing open-time proposals and guaranteed core-time observations. The observations concentrated mainly towards the galactic plane, and especially the inner Galaxy. Highlights from the first 18 months of the mission are results on nucleosynthesis and solar flare gamma-ray lines, on a survey of hard X-ray binary sources and their identification, on the origin of the "diffuse" galactic ridge emission, and on gamma-ray bursts. Whereas line measurements generally require deep exposures of several million seconds (1 month and more), results on compact objects can be obtained much easier - in most cases they require exposures of only one or a few days.

The AGILE gamma-ray mission is in its Phase C-D. The Engineering model of the Payload has been built and tested, and the construction of the flight model has started. We present here the status of the SuperAGILE experiment, the 15-40 keV imaging monitor, based on Silicon microstrip technology and equipped with one dimensional coded masks. We show the design of the experiment and the results of testing campaigns carried out on the engineering model of the experiment.

In various objects, it has been evident that non-thermal processes are playing important roles in high energy objects. They become outstanding above 10 keV and its total energy could be comparable to that of thermal components. In order to examine such non-thermal processes, we propose a hard X-ray imaging mission NeXT (New X-ray Telescope mission) together with the soft gamma ray detector and the high resolution spectrometer. Hard X-ray telescopes consist of multilayer coated high through put mirrors. The focal plane detectors are hybrid type imaging detectors to cover both soft and hard X-rays. Total performance in sensitivity for a point source reaches 100 times better than any currently scheduled missions in 10 - 60(80) keV range and 10 times better in soft gamma rays. It is planned to launch it in the time frame of 2011.

Monitor of All-sky X-ray Image (MAXI) is an X-ray all-sky monitor, which will be delivered to the International Space Station (ISS) in 2008, to scan almost the whole sky once every 96 minutes for a mission life of two years. The detection sensitivity will be 7~mCrab (5σ level) in one scan, and 1~mCrab for one-week accumulation. At previous SPIE meetings, we presented the development status of the MAXI payload, in particular its X-ray detectors. In this paper, we present the whole picture of the MAXI system, including the downlink path and the MAXI ground system. We also examine the MAXI system components other than X-ray detectors from the point of view of the overall performance of the mission. The engineering model test of the MAXI X-ray slit collimator shows that we can achieve the position determination accuracy of <0.1 degrees, required for the ease of follow-up observations. Assessing the downlink paths, we currently estimates that the MAXI ground system receive more than 50% of the observational data in "real time" (with time delay of a few to ten seconds), and the rest of data with delay of 20 minutes to a few hours from detection, depending on the timing of downlink. The data will be processed in easily-utilised formats, and made open to public users through the Internet.

Dark Energy dominates the mass-energy content of the universe (about 73%) but we do not understand it. Most of the remainder of the Universe consists of Dark Matter (23%), made of an unknown particle. The problem of the origin of Dark Energy has become the biggest problem in astrophysics and one of the biggest problems in all of science. The major extant X-ray observatories, the Chandra X-ray Observatory and XMM-Newton, do not have the ability to perform large-area surveys of the sky. But Dark Energy is smoothly distributed throughout the universe and the whole universe is needed to study it. There are two basic methods to explore the properties of Dark Energy, viz. geometrical tests (supernovae) and studies of the way in which Dark Energy has influenced the large scale structure of the universe and its evolution. DUO will use the latter method, employing the copious X-ray emission from clusters of galaxies. Clusters of galaxies offer an ideal probe of cosmology because they are the best tracers of Dark Matter and their distribution on very large scales is dominated by the Dark Energy. In order to take the next step in understanding Dark Energy, viz. the measurement of the 'equation of state' parameter 'w', an X-ray telescope following the design of ABRIXAS will be accommodated into a Small Explorer mission in lowearth orbit. The telescope will perform a scan of 6,000 sq. degs. in the area of sky covered by the Sloan Digital Sky Survey (North), together with a deeper, smaller survey in the Southern hemisphere. DUO will detect 10.000 clusters of galaxies, measure the number density of clusters as a function of cosmic time, and the power spectrum of density fluctuations out to a redshift exceeding one. When combined with the spectrum of density fluctuations in the Cosmic Microwave Background from a redshift of 1100, this will provide a powerful lever arm for the crucial measurement of cosmological parameters.

The mission ROSITA (ROentgen Survey with an Imaging Telescope Array) will perform the first imaging all-sky survey in the medium energy X-ray range up to 10 keV with an unprecedented spectral and angular resolution. Thus, ROSITA leads to an improved understanding of obscured black holes in Active Galactic Nuclei. In addition, ROSITA represents an important pathfinder for beyond 2015 space telescopes like XEUS and Constellation X. Targeting for a flight in 2008/2009 on one side ROSITA is considered as technology test bed for later X-ray cornerstone missions, on the other side the measurement data will form a good basis for later detailed surveys with the corresponding high resolution pointing systems.

The Lobster-ISS instrument is an X-ray all sky monitor proposed as an attached payload on the zenith platform exposed payload facility of the European Space Agency (ESA) Columbus module of the International Space Station (ISS). The basic instrument consists of six microchannel plate X-ray telescopes, collectively providing wide-angle (22.5 x 162 sq.degree) astronomical X-ray imaging in the 0.1 - 3.5 keV energy band. In this paper we describe computer modeling software underway at the University of Melbourne to provide an accurate simulation of the operation of the Lobster-ISS in its low Earth orbit environment. We exhibit some preliminary exposure maps and examples of the X-ray images that the instrument should produce given our simulation of its operation.

In March and April 2003, the Chandra X-ray Observatory carried out a series of 126 short observations (5 ksec each) covering a continuous area of the Bootes constellation to construct a large area shallow X-ray survey. These observations were carried out as collaboration of Guest Observer (C. Jones PI) and Guaranteed Time Observer (S. Murray PI) programs. We present here, in Paper I, an initial analysis of the survey data and the source detection process, showing the sky coverage, exposure map, and some of the collective properties of the resulting catalog of sources. The Bo\"otes area was selected to overlap a well studied region where optical, and radio data, to sufficient depth, have already been obtained making the identification of candidate counterparts straight forward. In 5 ksec, we reach a limiting flux of ≈10^-3ct s^-1 (corresponding to ≈10^-14 erg cm^-2s^-10.5-7.0 keV). We examine the spatial distribution of the sources in this ^~9.3 square degree survey region using several techniques to search for evidence of cosmic variance in the X-ray source density on scales as small as the ACIS-I field of view (^~16x16 arc minutes). With follow up optical spectroscopy using the MMT/Hectospec, we can obtain spectroscopic redshifts for about 1/3 - 1./2 of the X-ray sources, which can be used to look for evidence of large scale structures traced by AGN associated with the cosmic web.

The sensitivity of the Advanced CCD Imaging Spectrometer (ACIS) instrument on the Chandra X-ray Observatory (CXO) to low-energy X-rays (0.3 - 2.0 keV) has been declining throughout the mission. The most likely cause of this degradation is the growth of a contamination layer on the cold (-60 C) filter which attenuates visible and near-visible light incident on the CCDs. The contamination layer is still increasing 4 years after launch, but at a significantly lower rate than initially. We have determined that the contaminant is composed mostly of C with small amounts of O and F. We have conducted ground experiments to determine the thermal desorption properties of candidate materials for the contaminant. We have conducted experiments to determine the robustness of the thin filter to the thermal cycling necessary to remove the contaminant. We have modeled the migration of the contaminant during this bake-out process to ensure that the end result will be a reduction in the thickness of the contamination layer. We have considered various profiles for the bake-out consisting of different temperatures for the ACIS focal plane and detector housing and different dwell times at these temperatures. The largest uncertainty which affects our conclusions is the volatility of the unknown contaminants. We conclude that bakeout scenarios in which the focal plane temperature and the detector housing temperature are raised to +20~C are the most likely to produce a positive outcome.

XMM-Newton was launched into space on a highly eccentric 48 hour orbit on December 10th 1999. XMM-Newton is now in its fifth year of operation and has been an outstanding success, observing the Cosmos with imaging, spectroscopy and timing capabilities in the X-ray and optical wavebands. The EPIC-MOS CCD X-ray detectors comprise two out of three of the focal plane instruments on XMM-Newton. In this paper we discuss key aspects of the current status and performance history of the charge transfer ineffiency (CTI), energy resolution and spectral redistribution function (rmf) of EPIC-MOS in its fifth year of operation.

High resolution X-ray spectroscopy of optically thin sources is discussed. Based on a brief description of the general properties of highly ionized, optically thin sources and their spectra, and a set of specific examples drawn from the recent literature, I outline arguments for the importance of routine spectroscopy of faint sources as a science driver for future missions.

The Constellation-X mission will address the questions: "What happens to matter close to a black hole?" and "What is Dark Energy?" These questions are central to the NASA Beyond Einstein Program, where Constellation-X plays a central role. The mission will address these questions by using high throughput X-ray spectroscopy to observe the effects of strong gravity close to the event horizon of black holes, and to observe the formation and evolution of clusters of galaxies in order to precisely determine Cosmological parameters. To achieve these primary science goals requires a factor of 25-100 increase in sensitivity for high resolution spectroscopy. The mission will also perform routine high-resolution X-ray spectroscopy of faint and extended X-ray source populations. This will provide diagnostic information such as density, elemental abundances, velocity, and ionization state for a wide range of astrophysical problems. This has enormous potential for the discovery of new unexpected phenomena. The Constellation-X mission is a high priority in the National Academy of Sciences McKee-Taylor Astronomy and Astrophysics Survey of new Astrophysics Facilities for the first decade of the 21st century.

XEUS is the potential successor to ESA's XMM-Newton X-ray observatory. Novel light-weight optics with an effective area of 10 m² at 1 keV and 2-5" HEW spatial resolution together with advanced imaging detectors will provide a sensitivity around 200 times better than XMM-Newton as well as much improved high-energy coverage, and spectroscopic performance. This enormous improvement in scientific capability will open up new vistas in X-ray astronomy. It will allow the detection of massive black holes in the earliest AGN and estimates of their mass, spin and red-shift through their Fe-K line properties. XEUS will study the first gravitationally bound, Dark Matter dominated, systems small groups of galaxies and trace their evolution into today's massive clusters. High-resolution spectroscopy of the hot intra-cluster gas will be used to investigate the evolution of metal synthesis to the present epoch. The hot filamentary structure will be studied using absorption line spectroscopy allowing the mass, temperature and density of the intergalactic medium to be characterized. As well as these studies of the deep universe, the enormous low-energy collecting area will provide a unique capability to investigate bright nearby objects with dedicated high-throughput, polarimetric and time resolution detectors.

The Beyond Einstein Program in NASA's Office of Space Science Structure and Evolution of the Universe theme spells out the top level scientific requirements for a Black Hole Imager in its strategic plan. The MAXIM mission will provide better than one tenth of a microarcsecond imaging in the X-ray band in order to satisfy these requirements. We will overview the driving requirements to achieve these goals and ultimately resolve the event horizon of a supermassive black hole. We will present the current status of this effort that includes a study of a baseline design as well as two alternative approaches

The Constellation X-ray Mission is a high-throughput X-ray facility emphasizing observations at high spectral resolution (R ~ 300-3000) while covering a broad energy band (0.25-60 keV). The mission is intended to achieve a factor of 25-100 increase in sensitivity over current high resolution X-ray spectroscopy missions. Constellation-X is the X-ray astronomy equivalent of the Keck and the VLT, complementing the high spatial resolution capabilities of Changra. Constellation-X achieves its high-throughput and reduces mission risk by dividing the collecting area across four separate spacecraft launched two at a time into an L2 orbit. We describe the overall mission concept and also present a brief overview of alternate concepts which are under consideration. We discuss recent progress on the key technologies, including: lightweight, high-throughput X-ray optics, micro-caloriment spectrometer arrays, low-power and low-weight CCD arrays, lightweight gratings, multilayer coatings to enhance the hard X-ray performance of X-ray optics, and hard X-ray detectors.

The status of technology development for the Constellation-X Spectroscopy X-ray Telescope (SXT) mirror is presented. The SXT mirror combines a large (1.6 m) aperture with modest (12 arc sec half power diameter) angular resolution and low mass (750 kg). The overall collecting area, larger than 9,600 square cm at 0.25 keV, requires high throughput, and thus nesting of a substantial number of thin reflectors. A phased development program is underway to develop reflectors, mounting and alignment approaches, and metrology techniques for components and the mirror has a whole. The latest results in all these areas are summarized, along with an overview of results of optical testing of reflector performance.

The Reflection Grating Spectrometer of the Constellation-X mission has two strong candidate configurations. The first configuration, the in-plane grating (IPG), is a set of reflection gratings similar to those flown on XMM-Newton and has grooves perpendicular to the direction of incident light. In the second configuration, the off-plane grating (OPG), the grooves are closer to being parallel to the incident light, and diffract along a cone. It has advantages of higher packing density, and higher reflectivity. Confinement of these gratings to sub-apertures of the optic allow high spectral resolution. We have developed a raytrace model and analysis technique for the off-plane grating configuration. Initial estimates indicate that first order resolving powers in excess of 1000 (defined with half-energy width) are achievable for sufficiently long wavelengths (λ ≥ 12Å), provided separate accommodation is made for gratings in the subaperture region farther from the zeroth order location.

The Xeus mission is designed to explore the X-ray emission from objects in the Universe at high redshifts, and these science requirements necessitate a very large effective area. We describe a completely revised mission scenario that mitigates previous concerns about the deployable mass and use of the ISS. New mirror technology with lightweight optics enables a direct launch to a L2 operational orbit, and we describe the outline of the Mirror and Detector Spacecraft that are deployed in formation flying to achieve the 50m focal distance separation.

The XEUS (X-ray Evolving Universe Spectroscopy) mission is designed to explore the X-ray emission from objects in the Universe at high red shifts. A package of instruments has been defined in some detail that allows the scientific goals of the mission to be met. It comprises narrow field imaging spectrometers of both Transition Edge Sensor (TES) and Superconducting Tunnel Junction (STJ) designs, and a Wide Field Imager with novel Silicon Active - Pixel sensing elements. We discuss the utilisation of the largest yet conceived mirror collecting area that facilitates secondary science such as high time resolution, polarimetry and extensions to high energies >10keV, and briefly mention some future trade-off studies that must be addressed.

Compton telescope is a promising technology to achieve very high sensitivity in the soft gamma-ray band (0.1-10 MeV) by utilizing Compton kinematics. Compton kinematics also enables polarization measurement which will open new windows to study gamma-ray production mechanism in the universe. CdTe and Si semiconductor technologies are key technologies to realize the Compton telescope in which their high energy resolution is crucial for high angular resolution and background rejection capability. We have assembled a prototype module using a double-sided silicon strip detector and CdTe pixel detectors. In this paper, we present expected polarization performance of a proposed mission (NeXT/SGD). We also report results from polarization measurements using polarized synchrotron light and validation of EGS4 MC simulation.

The NeXT mission has been proposed to study high-energy non-thermal phenomena in the universe. The high-energy response of the super mirror will enable us to perform the first sensitive imaging observations up to 80 keV. The focal plane detector, which combines a fully depleted X-ray CCD and a pixelated CdTe detector, will provide spectra and images in the wide energy range from 0.5 keV to 80 keV. In the soft gamma-ray band upto ~1 MeV, a narrow field-of-view Compton gamma-ray telescope utilizing several tens of layers of thin Si or CdTe detector will provide precise spectra with much higher sensitivity than present instruments. The continuum sensitivity will reach several x 10^-8 photons/s/keV/cm² in the hard X-ray region and a few x 10^-7 photons/s/keV/cm² in the soft gamma-ray region.

The new frontier in astrophysics is the study of the very first stars, galaxies and black holes in the early Universe. These objects are beyond the grasp of the current generation of X-ray telescopes such as Chandra, and so the Generation-X Vision Mission has been proposed as an X-ray observatory which will be capable of detecting these earliest objects. Xray imaging and spectroscopy of such distant objects will require an X-ray telescope with large collecting area and high angular resolution. The Generation-X concept has 100 m2 collecting area at 1 keV (1000 times larger than Chandra) and 0.1 arcsecond angular resolution (several times better than Chandra and 50 times better than the resolution goal for Constellation-X). The baseline mission involves four 8 m diameter telescopes operating at Sun-Earth L2. Such large telescopes will require either robotic or human-assisted in-flight assembly. To achieve the required effective area with launchable mass, very lightweight grazing incidence X-ray optics must be developed, having an areal density 100 times lower than in Chandra, with perhaps 0.1 mm thick mirrors requiring on-orbit figure control. The suite of available detectors for Generation-X should include a large-area high resolution imager, a cryogenic imaging spectrometer and a grating spectrometer.

X-ray interferometry has the potential to provide imaging at ultra high angular resolutions of 100 micro arc seconds or better. However, designing a practical interferometer which fits within a reasonable envelope and that has sufficient collecting area to deliver such a performance is a challenge. A simple system which can be built using current X-ray optics capabilities and existing detector technology is described. The complete instrument would be ~20 m long and ~2 m in diameter. Simulations demonstrate that it has the sensitivity to provide high quality X-ray interferometric imaging of a large number of available targets.

The proposed Micro-Arcsecond X-ray Imaging Mission (MAXIM) uses an array of spacecraft containing grazing incidence optics to create and acquire an image on a distant detector spacecraft. Among the technical challenges facing the mission, maintaining an acceptably small wavefront error in the optical system is addressed in this paper. Starting with a performance model for the observatory and both analytically- and raytrace-based optical sensitivities to misalignment and figure error, an error budget is constructed that includes the effects of the individual optical surfaces, the alignment of the optical elements within the 4-mirror periscope sub-assemblies, and the relative alignment of the many periscopes that make up the MAXIM optical imaging system. At this stage of conceptual development, the allocations to different sub-systems that affect wavefront error is based on the philosophy of "spreading the pain" associated with performance requirements of the contributing elements. The performance model and error budget become tools with which to explore different architectures and requirements allocations as the mission concept develops.

We present new schemes for a next-generation X-ray telescope for the energy range between approximately 1 and 10 keV providing an angular resolution of at least 1 milli-arcsec. Its technology will be based on diffractive transmission optics, e.g. Fresnel zone plates and their derivatives. Beside near-diffraction limited imaging, these devices hold the potential of a large collecting area well beyond 10 square meters at a simple and lightweight construction, compared to conventional mirror telescopes. However, there are drawbacks. Firstly the intrinsically long focal lengths do require separation and precise formation flight of lens and detector spacecraft. Accordingly, techniques will be discussed for relative stabilization on the one hand and possibilities to reduce focal length and thus lever arm on the other hand. For this purpose, large arrays of small, independent lenses might offer a notable perspective. Secondly, diffractive optics feature severe focal length dispersion which has to be accepted using narrow-band spectral selection or-better-should be corrected over a practicable wide energy range. In the hard X-ray regime, hybrid lens devices made of beryllium, lithium or plastics like polycarbonate will be an appropriate solution for a fixed energy, while tunable systems with variable correction lenses possess-in principle-the capability for dispersion compensation in the soft X-ray region, too. An overview on the science case of milli-arcsec X-ray imaging will conclude the contribution. We show that significant new insights in astrophysical processes are expected just at and beyond this angular scale and give examples from X-ray binaries over AGN's up to gamma-ray bursts.

The large collecting area of XMM-Newton combined with the good energy resolution of the EPIC-pn CCDs allows the study, with unprecedented detail, of accretion processes onto neutron stars and black holes. The EPIC-pn CCD camera in Timing mode, in which data are read out continuously, is among the fastest X-ray CCD camera available; however, telemetry constraints do not allow full use of these capabilities for many sources because currently randomly distributed data gaps are introduced by the on-board data handling electronics. As an alternative, we have proposed to implement a modification of the Timing mode in which data from soft X-ray events are not transmitted to Earth. Here we discuss the properties of this modified Timing mode, which will first be used in simultaneous XMM-Newton, RXTE, and INTEGRAL observations of the Galactic black hole binary Cygnus X-1 in autumn 2004. We discuss the predicted performance of this new mode based upon laboratory measurements, Monte Carlo simulations, and data from existing Timing mode observations.

Constellation-X is NASA's next major X-ray astronomical observatory. Its salient features are its very large effective X-ray collecting area (about 30,000 cm2 at 1 keV) and high resolution gratings and cryogenic detector systems. The large mirror effective area presents unique and unprecedented challenges in optical fabrication and metrology. In this paper we report on the development of very lightweight X-ray mirrors that address these challenges. We use a two-step mirror fabrication process: (1) slumping thin (0.4mm) flat glass sheets to generate high quality substrates that may have mid-frequency figure errors, and (2) reducing or eliminating the mid-frequency errors using an epoxy replication process. We discuss problems and the potential associated with each of these two steps. Based on our work to date, we expect that this technology to be able to meet the baseline Constellation-X requirements, i.e, 15" HPD (half-power diameter) at the observatory level. In the next few years, we will further advance this technology and expect it to reach the Constellation-X goal: 5" HPD at the observatory level.

The success of the XEUS mission depends critically on the deployment of a 10 square metre class telescope system in a suitable orbit for science observations. The minimisation of the telescope mass and volume becomes of critical importance for such a large facility. We describe developments of novel light weight optics that enable a reduction in mass per unit area of more than an order of magnitude, compared with traditional replication optics technology. With such a large collection area, image confusion limits become a scientific driver as well, demanding arcsecond class resolution. We describe measurements that demonstrate the improvement in resolution that gives very high confidence that these requirements can be met.

What is the nature of the Dark Energy that is driving the universe apart? Clusters of galaxies offer an ideal probe of cosmology because they are the best tracers of Dark Matter and their distribution on very large scales which is dominated by the Dark Energy. DUO will measure 10.000 clusters of galaxies, the power spectrum of density fluctuations of clusters and their number density as a function of cosmic time. Although designed long before the existence of Dark Energy was claimed, the ABRIXAS type X-ray telescope turns out to be ideally suited for this task: DUO is, in essence, a re-flight of the ABRIXAS X-ray telescope which some modifications of the focal plane instrumentation. First of all, we will use new CCDs which are improved versions of the pn-CCDs successfully flown on XMM-Newton. A modular concept having seven individual cameras in the foci of the seven mirror systems allows us to design the orientation of the seven telescopes with respect to each other matching the scientific needs of the DUO mission. Details of the concept including mechanical, electrical and thermal aspects are given.

Recent development of cryogenic detectors enabled high resolution diagnostics of emission line and absorption line/edge structures. These studies are quite important to investigate physics of interstellar/intergalactic plasma and dynamics of matters around black holes, for example. Soft X-ray telescopes for such purpose, sensitive up to 10 keV, are usually designed using Au, Pt, or Ir for their large electron density and large critical angle. However in fact, these materials are not very suitable in a few to 8 keV region, because they have wide and deep M-shell absorption edge structures in 2--4 keV region. Considering absorption edges and also thin-film characteristics, C or Ni can be alternatives. However, these materials alone cannot be a good mirror, again from absorption edges in the energy region of interest (0.1-10 keV). We designed composite structure consisting of C, Ni and Pt with thickness of 30 to 300 A, to get smooth and high reflectivity all across the energy region. Test fabrication showed interfacial roughness is as low as expected, indicating match of materials is also good. We applied this result to the baseline design of NeXT/Soft X-ray Telescope, by substituting current material (Au) with C-Ni-Pt composite, and obtained 20% larger effective area in 2-8 keV region.

Focusing optics are now poised to dramatically improve the sensitivity and angular resolution at energies above 10 keV to levels that were previously unachievable by the past generation of background limited collimated and coded-aperture instruments. Active balloon programs (HEFT), possible Explorer-class satellites (NuSTAR - currently under Phase A study), and major X-ray observatories (Con-X HXT) using focusing optics will play a major role in future observations of a wide range of objects including young supernova remnants, active galactic nuclei, and galaxy clusters. These instruments call for low cost, grazing incidence optics coated with depth-graded multilayer films that can be nested to achieve large collecting areas. Our approach to building such instruments is to mount segmented mirror shells with our novel error-compensating, monolithic assembly and alignment (EMAAL) procedure. This process involves constraining the mirror segments to successive layers of graphite rods that are precisely machined to the required conic-approximation Wolter-I geometry. We present results of our continued development of thermally formed glass substrates that have been used to build three HEFT telescopes and are proposed for NuSTAR. We demonstrate how our experience in manufacturing complete HEFT telescopes, as well as our experience developing higher performance prototype optics, will lead to the successful production of telescopes that meet the NuSTAR design goals.

We report on innovative X-ray mirror technologies with focus on requirements of future X-ray astronomy space projects. Various future projects in X-ray astronomy and astrophysics will require large light-weight but highly accurate segments with multiple thin shells or foils. The large Wolter 1 grazing incidence multiple mirror arrays, the Kirkpatrick-Baez modules, as well as the large Lobster-Eye X-ray telescope modules in Schmidt arrangement may serve as examples. All these space projects will require high quality and light segmented shells (shaped, bent or flat foils) with high X-ray reflectivity and excellent mechanical stability.

Ultraviolet astronomy is an important tool for the study of the interplanetary medium, comets, planetary upper atmospheres, and the near space environments planets and satellites. In addition to brightness distributions, emission line profiles offer insight into winds, atmospheric escape, energy balance, currents, and plasma properties. Unfortunately, the faintness of many target emissions and the volume limitations of small spacecraft and remote probes limit the opportunities for incorporating a high spectral resolution capability. An emerging technique to address this uses an all-reflective form of the spatial heterodyne spectrometer (SHS) that combines very high (R >105) spectral resolution and large étendue in a package small enough to fly as a component instrument on small spacecraft. The large étendue of SHS instruments makes them ideally suited for observations of extended, low surface brightness, isolated emission line sources, while their intrinsically high spectral resolution enables the study of the dynamical and spectral characteristics described above. We are developing three forms of the reflective SHS to observe single line shapes, multiple lines via bandpass scanning, and precision spectro-polarimetry. We describe the basic SHS approach, the three variations under development and their scientific potential for the exploration of the solar system and other faint extended targets.

We present the optical design of the spectrometer for imaging spectroscopy in the extreme-ultraviolet (EUV) spectral region for the Solar Orbiter mission. The instrument consists of a telescope making an image of the Sun on an entrance slit of a grating spectrometer. Two different optical designs are presented: a) a normal-incidence off-axis paraboloid telescope feeding a normal-incidence spectrometer and b) a grazing-incidence Wolter-type telescope feeding a normal-incidence spectrometer. The spectral region of operation is the 58-63 nm region, with the possibility of extending the range to the 116-126 nm region. The two designs are discussed in terms of optical performance, effective area and thermal load.

We have measured the topography and near-normal incidence EUV efficiency of five flat multilayer-coated polymer-overcoated blazed ion-etched holographic test gratings. Blaze angles were in the range 2.0-4.1°. All gratings had a surface roughness <3 Å rms (20-4000 Å). The best grating had a measured efficiency of 29.9% in the second order at 157.9 Å and a derived groove efficiency of 53.0%. At the shortest wavelength investigated (100.0 Å) another grating produced a measured efficiency in the first order of 12.9% and a derived groove efficiency of 33.6%. In third order another grating produced a measured efficiency at 137.8 Å of 13.4% and a derived groove efficiency of 21.8%. To the best of our knowledge these values exceed previous published results. Some issues remain that may be associated with modification of the groove profile by the multilayer coating.

A very significant fraction of the baryonic matter in the local universe is predicted to form a Warm Hot Intergalactic Medium (WHIM) of very low density, moderately hot gas, tracing the cosmic web. Its X-ray emission is dominated by metal features, but is weak (< 0.01 photons/cm²/s/sr) and potentially hard to separate from the galactic component. However, a mission capable of directly mapping this component of the large scale structure of the universe, via a small number of well chosen emission lines, is now within reach due to recent improvements in cryogenic X-ray detector energy resolution. To map the WHIM, the energy resolution and grasp are optimized. A number of missions have been proposed to map the missing baryons including MBE (US/SMEX program) and DIOS (Japan). The design of the mirror and detector have still room for improvements which will be discussed. With these improvements it is feasible to map a 10 x 10 degree area of the sky in 2 years out to z = 0.2 with sufficient sensitivity to directly detect WHIM structure, such as filaments connecting clusters of galaxies. This structure is predicted by the current Cold Dark Matter paradigm which thus far appears to provide a good description of the distribution of matter as traced by galaxies.

While the energy density of the Cosmic X-ray Background (CXB) provides a statistical estimate of the super massive black hole (SMBH) growth and mass density in the Universe, the lack, so far, of focusing instrument in the 20-60 keV (where the CXB energy density peaks), frustrates our effort to obtain a comprehensive picture of the SMBH evolutionary properties. HEXIT-SAT (High Energy X-ray Imaging Telescope SATellite) is a mission concept capable of exploring the hard X-ray sky with focusing/imaging instrumentation, to obtain an unbiased census of accreting SMBH up to the redshifts where galaxy formation peaks, and on extremely wide luminosity ranges. This will represent a leap forward comparable to that achieved in the soft X-rays by the Einstein Observatory in the late 70'. In addition to accreting SMBH, and very much like the Einstein Observatory, this mission would also have the capabilities of investigating almost any type of the celestial X-ray sources. HEXIT-SAT is based on high throughput (>400 cm2 @ 30 keV; >1200 cm2 @ 1 keV), high quality (15 arcsec Half Power Diameter) multi-layer optics, coupled with focal plane detectors with high efficiency in the full 0.5-70keV range. Building on the BeppoSAX experience, a low-Earth, equatorial orbit, will assure a low and stable particle background, and thus an extremely good sensitivity for faint hard X-ray sources. At the flux limits of 1/10 microCrab (10-30 keV) and 1/3 microCrab (20-40 keV) (reachable in one Msec observation) we should detect ~100 and ~40 sources in the 15 arcmin FWHM Field of View respectively, thus resolving >80% and ~65% of the CXB where its energy density peaks.

The primary scientific mission of the Black Hole Finder Probe (BHFP), part of the NASA Beyond Einstein program, is to survey the local Universe for black holes over a wide range of mass and accretion rate. One approach to such a survey is a hard X-ray coded-aperture imaging mission operating in the 10-600 keV energy band, a spectral range that is considered to be especially useful in the detection of black hole sources. The development of new inorganic scintillator materials provides improved performance (for example, with regards to energy resolution and timing) that is well suited to the BHFP science requirements. Detection planes formed with these materials coupled with a new generation of readout devices represent a major advancement in the performance capabilities of scintillator-based gamma cameras. Here, we discuss the Coded Aperture Survey Telescope for Energetic Radiation (CASTER), a concept that represents a BHFP based on the use of the latest scintillator technology.

Monitor e Imageador de RAios-X (MIRAX) is a Brazilian high energy astronomy mission dedicated to monitoring the central 1000 sq. deg. of the Galactic plane to observe unpredictable transient phenomena from compact objects in the 2-200 keV range through nearly continuous imaging with good spatial/temporal/energy resolution. The strength of MIRAX lies in the departure of its observing strategy from traditional pointed programs and scanning monitors. MIRAX will achieve two major advantages over previous and existing missions. First, it will detect, localize, and study transient phenomena, which last on all timescales from milliseconds to years, and are very likely to be missed by traditional observing strategies. Second, MIRAX will study longer lived phenomena in exquisite detail. The mission elements and science will be presented.

We propose a university-class micro-satellite "Hu-ring" to localize and study gamma-ray bursts. The primary mission of "Hu-ring" is to localize gamma-ray bursts with an 10 arcmin accuracy in real time, and transmit promptly the coordinates to the ground. Although many of its mission concepts are modeled after HETE-2, use of avalanche photodiodes (APDs), innovative photon detector device, make it possible to further reduce the size and the mass of the satellite. We designed "Hu-ring" within a size of 50 cm cube and a weight limit of 50 kg, so that it can be launched as a piggy-back payload of the Japanese H-IIA Launch Vehicle. The satellite is spin-stabilized, and has a half-sky field of view centered on the anti-sun direction. A set of scintillation counters equipped with rotation modulation collimators are employed for localization of GRBs. We also measure the soft/medium X-ray spectra of GRBs using APDs as a direct X-ray photon detectors. These two kinds of instruments cover the 0.5--200 keV energy range. The satellite bus is designed mostly with commercially available components in order to reduce the cost and the lead time. Following the HETE-2 model, in order to receive the prompt burst alerts it is designed to rely on a global network of receive-only low-cost ground stations, which may be hosted at research instutions with a small footprint. We performed analyses in many aspects: mechanical and thermal design of the satellite bus, attitude control simulations, power budget, ground contact schedule and downlink capacity, etc. We verified that the mission goal can be achieved with this proposed design philosophy.

The MEGA mission would enable a sensitive all-sky survey of the medium-energy ?-ray sky (0.3-50 MeV). This mission will bridge the huge sensitivity gap between the COMPTEL and OSSE experiments on the Compton Gamma Ray Observatory, the SPI and IBIS instruments on INTEGRAL and the visionary ACT mission. It will, among other things, serve to compile a much larger catalog of sources in this energy range, perform far deeper searches for supernovae, better measure the galactic continuum emission as well as identify the components of the cosmic diffuse emission. The large field of view will allow MEGA to continuously monitor the sky for transient and variable sources. It will accomplish these goals with a stack of Si-strip detector (SSD) planes surrounded by a dense high-Z calorimeter. At lower photon energies (below ~30 MeV), the design is sensitive to Compton interactions, with the SSD system serving as a scattering medium that also detects and measures the Compton recoil energy deposit. If the energy of the recoil electron is sufficiently high (> 2 MeV), the track of the recoil electron can also be defined. At higher photon energies (above ~10 MeV), the design is sensitive to pair production events, with the SSD system measuring the tracks of the electron and positron. We will discuss the various types of event signatures in detail and describe the advantages of this design over previous Compton telescope designs. Effective area, sensitivity and resolving power estimates are also presented along with simulations of expected scientific results and beam calibration results from the prototype instrument.

The Chandra Low Energy Transmission Grating Spectrometer (LETGS) is comprised of 3 micro-channel plate (MCP) segments and is primarily used with the High Resolution Camera spectroscopic array (HRC-S). In-flight calibration data observed with the LETG+HRC-S show that there are non-linear deviations in the positions of some lines by as much as 0.1 Å. These deviations are thought to be caused by spatial non-linearities in the imaging characteristics of the HRC-S detector. Here, we present the methods we used to characterize the non-linearities of the dispersion relation across the central plate of the HRC-S, and empirical corrections which greatly reduce the observed non-linearities by a factor of 2 or more on the central MCP.

High quantum efficiency over a broad spectral range is one of the main properties of the EPIC pn camera on-board XMM-Newton. The quantum efficiency rises from ~75% at 0.2 keV to ~100% at 1 keV, stays close to 100% until 8 keV, and is still ~90% at 10 keV. The EPIC pn camera is attached to an X-ray telescope which has the highest collecting area currently available, in particular at low energies (more than 1400 cm2 between 0.1 and 2.0 keV). Thus, this instrument is very sensitive to the low-energy X-ray emission. However, X-ray data at energies below ~0.2 keV are considerably affected by detector effects, which become more and more important towards the lowest transmitted energies. In addition to that, pixels which have received incorrect offsets during the calculation of the offset map at the beginning of each observation, show up as bright patches in low-energy images. Here we describe a method which is not only capable of suppressing the contaminations found at low energies, but which also improves the data quality throughout the whole EPIC pn spectral range. This method is then applied to data from the Vela supernova remnant.

We present the current status of soft X-ray calibration of X-ray CCD cameras, X-ray Imaging Spectrometer (XIS), onboard Astro-E2. We perform soft X-ray calibration of four front illuminated (FI) CCD cameras and two back illuminated (BI) CCD cameras, among which four cameras will be selected to be installed on the satellite. The calibration aims to measure the quantum efficiency and re-distribution function of the CCDs as a function of incident X-ray energy. A soft X-ray spectrometer is used to measure these items. In addition, we employ a gas proportional counter and an XIS engineering unit as reference detectors for the quantum efficiency measurement. We describe how we calibrate the absolute quantum efficiency of the XIS using these instruments. We show some of the preliminary results of the calibration including quick look results of BI CCD cameras.

We report a ground-based X-ray calibration of the Astro-E2 X-ray telescope at the PANTER test facility. Astro-E2, to be launched in February 2005, has five X-Ray Telescopes (XRTs). Four of them focus on the X-Ray Imaging Spectrometers (XIS) while the other on the X-Ray Spectrometer (XRS). They are designed with a conical approximation of Wolter-I type optics, nested with thin foil mirrors to enhance their throughput. A calibration test of the first Astro-E2 flight XRT for XIS was carried out at the PANTER facility in August 2003. This facility has an 130 meter long diverging beam from X-ray generator to XRT. Owing to the small X-ray spot size of about 2 mm dia., we verified that the focal position of each quadrant unit converged within 10 arcsec. The energy band around Au-M edge structures was scanned with a graphite crystal. The edge energy (Au M5) is consistent with that listed in Henke et al. 1997. Owing to the large area coverage of the PSPC detector which is a spare of the ROSAT satellite, off-axis images including stray lights at large off-axis angle (up to 6 degree) were obtained with a large field of view. We also compared the results with those measured with the parallel pencil beam at ISAS which is in detail reported in our companion paper by Itoh A. et al..

We present X-ray characteristics of X-ray telescopes (XRTs) onboard the Astro-E2 satellite. It is scheduled to be launched in February 2005. We have been performed X-ray characterization measurements of XRTs at Institute of Space and Astronautical Science (ISAS) since January 2003. We adopted a raster scan method with a narrow X-ray pencil beam. Angular resolution of the Quadrants composed of the Astro-E2 XRT was evaluated to be 1'.6-2'.2 (HPD; Half Power Diameter), irrespective of the X-ray energy, while those of the Astro-E XRT was 2'.0-2'.2. The effective area of a telescope is approximately 450, 330, 250, and 170 [cm²] at energies of 1.49, 4.51, 8.04, and 9.44 keV, respectively. The field of view (FOV) of the XRTs which is defined as Full Width Half Maximum (FWHM) of the vignetting function is ≈18' at 4.51 keV. We summarize these characters of the XRTs.

ESA's large X-ray space observatory XMM-Newton is in its fifth year of operations. We give a general overview of the status of calibration of the five X-ray instruments and the Optical Monitor. A main point of interest in the last year became the cross-calibration between the instruments. A cross-calibration campaign started at the XMM-Newton Science Operation Centre at the European Space Astronomy Centre in collaboration with the Instrument Principle Investigators provides a first systematic comparison of the X-ray instruments EPIC and RGS for various kind of sources making also an initial assessment in cross calibration with other X-ray observatories.

The HRC-S is a microchannel plate detector on board Chandra and is primarily used for spectroscopic observations with the Low Energy Transmission Grating Spectrometer (LETGS) in place. Photons are detected via signals read out from evenly spaced wires underneath the plates and positions are computed by centroiding around the strongest amplifier signals. This process leads to gaps in between the taps where no events are placed. A deterministic correction is then made during ground processing to these event locations to remove the gaps. We have now developed a new, empirical degap corrections from flight data. We describe the procedure we use, present comparisons between the new degap and lab-data based degap, and investigate the temporal stability of the degap corrections.

We report on the results of the ground calibration of Astro-E2/XIS with front-illuminated (FI) chips. The sensors have basically the same performance as that of Astro-E/XIS. However, there are some improved points: (1) A 55Fe radio isotope is equipped on a door, and (2) a charge injection (CI)capability (described below) is added. The FI sensors have been calibrated at Kyoto University, Osaka University, and MIT. At Kyoto University we focus on the high energy range (>1.5 keV). We measured the gain, energy resolution, and quantum efficiency as the function of energy by using characteristic X-rays for each sensor. An energy resolution of 130 eV@5.9 keV (FWHM) and a quantum efficiency of 82%@6.4 keV are achieved. After XIS is launched, the Charge Transfer Inefficiency (CTI) increases due to the radiation damage by cosmic rays. Then XIS equips the CI capability to calibrate and compensate the increase of the CTI. In order to utilize the CI capability, the amount of charge injected into the CCDs is expected to be kept constant. The time variability of the amount of the injected charge is estimated.

We present progress in the development of a new sounding rocket payload that will perform high resolution (R~100) x-ray spectroscopy of diffuse celestial x-ray sources. The instrument features a new geometry that allows for high resolution along with high throughput. A wire-grid focuser constrains light from diffuse sources into a converging beam that feeds an array of diffraction gratings in the extreme off-plane mount. Starting with launch in 2006 we can obtain physical diagnostics of supernova remnants such as the Cygnus Loop and ultimately the hot phase of the interstellar medium.

NeXT is Japan's 6th X-ray astronomical observatory following to ASTRO-E2. The launch is currently scheduled in 2010. One of the main goal of NeXT is to explore the hard X-ray Universe with newly developed hard X-ray telescope. The hard X-ray telescope utilizes multilayer-supermirror and high-throughput thin-foil optics technology. Performance of the hard X-ray telescope has been demonstrated through InFOCuS balloon experiment. This paper describes principle, design, and technology background of the Hard X-ray Telescope on board NeXT.

The XMM-Newton observatory, with its high throughput in combination with the EPIC CCD-cameras, is an ideal instrument to study extended sources like clusters of galaxies. Very deep observations of galaxy clusters reveal substructure on different levels: structure associated with bright galaxies, faint galaxies, or structure consistent with the merger of groups with the main cluster. Another indication of substructure is the deviation of the temperature of the intra-cluster gas from isothermality. We present XMM-Newton mosaic observations of the nearby clusters A3667 and A754. These clusters are good representatives of the different evolution stages that all clusters experience as they grow from mergers of smaller groups. Hence they show merging at different phases, which is also reflected in the different appearance of their temperature maps, pressure maps and entropy maps.

We present the metrology requirements and metrology implementation necessary to optically characterize the reflector technology for the Constellation-X (C-X) spectroscopy x-ray telescope (SXT). This segmented, 1.6m diameter highly nested telescope presents many metrology and alignment challenges. In particular, these mirrors have a stringent imaging error budget as compared to their intrinsic stiffness. The low stiffness is seen to be implied by the required effective area and the required weight. The low mirror stiffness has implications for the metrology that can be used. A variety of contact and non-contact optical profiling and interferometric methods are combined to test the formed glass substrates before replication and the replicated reflector segments. The reflectors are tested both stand-alone and in-situ in an alignment tower. Some of these methods have not been used on prior x-ray telescopes and some are feasible only because of the segmented approach used on the SXT. Methods to be discussed include high precision coordinate measurement machines using very low force or optical probes, axial interferometric profiling, azimuthal circularity profiling, and use of advanced null optics such as conical computer generated hologram (CGHs).

The Reflection Grating Spectrometer (RGS) on Constellation-X is designed to supply astronomers with high spectral resolution in the soft x-ray band from 0.25 to 2 keV. High resolution, large collecting area and low mass at grazing incidence require very flat and thin grating substrates, or thin-foil optics. Thin foils typically have a diameter-to-thickness ratio of 200 or higher and as a result very low stiffness. This poses a number of technological challenges in the areas of shaping, handling, positioning, and mounting of such optics. The most minute forces (gravity sag, friction, thermal mismatch with optic mount, etc.) can lead to intolerable deformations and limit figure metrology repeatability. We present results of our efforts in the manipulation and metrology of suitable grating substrates, utilizing a novel low-stress foil holder with friction-reducing flexures. A large number of reflection gratings is needed to achieve the required collecting area. We have employed nanoimprint lithography (NIL) - which uses imprint films as thin as 100 nm or less - for the high-fidelity and low-stress replication from 100 mm diameter saw-tooth grating masters.

We describe the principles of operation of the STJ spectrometer baselined for XEUS (X-ray Evolving Universe Spectroscopy mission), and describe some of the practical implementation issues that are being developed or trade-offs that are still being studied actively. The instrument is to be optimized for good energy resolution (<2eV FWHM) in the energy range between 0.1 - 3keV. The field of view should be maximized to allow spectroscopic mapping of modestly extended objects (e.g. cluster cores) and to maximize the number of point source objects analysed. This remains the greatest challenge for the instrument design.

High groove density reflection gratings placed at grazing incidence in the extreme off-plane mount offer improved performance over conventional in-plane mounts in the x-ray. We present test results from the grating evaluation facility at the University of Colorado for gratings optimized for use in the off-plane configuration. The gratings tested are produce via holographic lithography. Gratings tested have radial groove patterns and include both blazed and sinusoidal groove profiles. We present efficiency and sub-aperture resolution results.

Hard X-ray focusing observation is important to reveal non-thermal emission mechanism and origin in active galaxies and clusters of galaxies. We have carried out the hard X-ray observation throughout the ¥infocus program, which is an international balloon-borne experiment in collaboration with NASA/GSFC and Nagoya University. The telescope is conical approximation of Wolter-I optics with 8 m focal length and 40 cm diameter. It consists of 255 nested thin (0.17 mm thickness) reflectors with incidence angles of 0.10° to 0.36°. Reflectors are coated with depth-graded platinum-carbon (Pt/C) multilayers, so-called supermirrors, with periodic length of 2.6 to 13 nm and bi-layer number of 28 to 79, depending on incidence angles. We are now continuously fabricating advanced next hard X-ray telescope for the second ¥infocus flight in 2004. Compared with the first telescope, the following improvements have been made on the second one. Supermirror reflectors have wider sensitivity in energy band of 20-60 keV adopting optimum supermirror design for balloon observation, and smaller interfacial roughness owing to complete replication technique. For upgrading of the image quality, we then adopted stiffer reflector substrate, selected replication mandrel with better shape, and the modified telescope housing with higher alignment accuracy for reflectors. The performance of the new hard X-ray telescope was measured in X-ray beamline facility in ISAS/JAXA and synchrotron radiation facility SPring-8. The effective area and image quality are obtained to be 45 cm² at 30 keV and 23 cm² at 40 keV, and 2.5 arcmin in half power diameter, respectively. In this paper we report our development of the upgraded hard X-ray telescope for the second balloon flight experiment.

Large collecting area x-ray telescopes are designed to study the early Universe, trace the evolution of black holes, stars and galaxies, study the chemical evolution of the Universe, and study matter in extreme environments. The Constellation-X mission (Con-X), planned for launch in 2016, will provide ~ 10⁴ cm² collecting area with 15 arc-sec resolution, with a goal of 5 arc-sec. Future missions require larger collecting area and finer resolution. Generation-X (Gen-X), a NASA Visions Mission, will achieve 100 m² effective area at 1 keV and angular resolution of 0.1 arc-sec, half power diameter. We briefly describe the Con-X flowdown of imaging requirements to reflector figure error. To meet requirements beyond Con-X, Gen-X optics will be thinner and more accurately shaped than has ever been accomplished. To meet these challenging goals, we incorporate for the first time active figure control with grazing incidence optics. Piezoelectric material will be deposited in discrete cells directly on the back surface of the optical segments, with the strain directions oriented parallel to the surface. Differential strain between the two layers of the mirror causes localized bending in two directions, enabling local figure control. Adjusting figure on-orbit eases fabrication and metrology. The ability to make changes to mirror figure adds margin by mitigating risk due to launch-induced deformations and/or on-orbit degradation. We flowdown the Gen-X requirements to mirror figure and four telescope designs, and discuss various trades between the designs.

High groove density reflection gratings placed at grazing incidence in the extreme off-plane mount offer increased performance over conventional in-plane mounts in the x-ray. We are developing an off-plane approach to the Reflection Grating Spectrometer of the Constellation-X Mission. In this paper we discuss the geometry of the off-plane mount and present formulae for the key tolerances of the grating array.

X-ray timing with musec time resolution can be used to probe strong gravity fields around collapsed objects and to constrain the equation of state of dense matter in neutron stars. With its large collecting area, XEUS will be ideally suited for very high signal to noise studies of such objects. An instrument dedicated to X-ray timing of bright Galactic sources has thus been foreseen as part of the XEUS instrumentation. In this contribution we present numerical simulations for silicon based detectors (silicon drift detectors and pixel based sensors) for a variety of astrophysical sources such as neutron star power spectra (including kHz quasi-periodic oscillations) and black hole lightcurves to illustrate the expected scientific capabilities of the fast timing mode instrument.

We are studying on a press forming of a 0.3-mm-thick foil in order to make advanced thin-foil substrates with a two-stage reflector for large X-ray telescopes. We press-formed one sheet of aluminum foil using a stamping die with high accuracy, and then obtained a two-stage reflector with a length of 100 mm/stage. The accuracy of its shape along the axial direction reached to 10 μm. Since long substrate has an advantage for fabrication of large X-ray telescopes, we are making a two-stage reflector with a stage 200 mm long. The stamping die for the long substrate was processed by the ELID method. We will perform a press-forming in this summer. In order to evaluate the press-formed substrate, we have made a surface measurement system. It is possible to response to a fabrication of the substrate quickly.

The X-Ray Telescope (XRT) experiment on-board the Japanese satellite SOLAR-B (launch in 2006) aimed at providing full Sun field of view at ~ 1.5" angular resolution, will be equipped with two wheels of focal-plane filters to select spectral features of X-ray emission from the Solar corona, and a front-end filter to significantly reduce the visible light contamination. We present the results of the X-ray calibrations of the XRT flight filters performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. We describe the instrumental set-up, the adopted measurement technique, and present the transmission vs. energy and position measurements.

The X-Ray Telescope (XRT) experiment on-board the Japanese satellite SOLAR-B (launch in 2006) is equipped with a modified Wolter I grazing incidence X-ray telescope (focal length 2700 mm) to image the full Sun at ~ 1.5" angular resolution onto a 2048 x 2048 back illuminated CCD focal plane detector. The X-ray telescope consisting of one single reflecting shell is coated with ion beam sputtered Iridium over a binding layer of Chromium to provide nearly 5 square centimetres effective area at 60 Å. We present preliminary results of X-ray calibrations of the XRT flat mirror samples performed at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF-OAPA. We describe the instrumental set-up, the adopted measurement technique, and present the measured reflectivity vs. angle of incidence at few energies.

We describe and discuss astronomical LOBSTER EYE X-ray telescopes based on Multi Foil Optics including recent results of the development and tests of advanced laboratory samples. An alternative proposal for a space experiment based on this optics - Lobster All Sky Monitor - is also briefly presented and discussed.

We are developing an ultra high precision soft X-ray telescope. The design of the telescope is a normal incident one for 13.5nm band using Mo/Si multilayers. Two ideas are introduced. One is the optical measurement system in order to monitor the precision of the optics system. The other is the adaptive optics system with a deformable mirror. Using an X-ray-optical separation filter, we can always monitor the deformation of the optics by optical light. With this information, we can control the deformable mirror to compensate the system distortion as a closed loop system. The telescope system is now integrating and checking by optical light. The shape of the primary mirror is an off-axis paraboloid with a focal length of 2m and an effective diameter of 80mm. This primary mirror was coated by Mo/Si multilayers. The reflectivity of the primary mirror at 13.5nm was ranging from 30 to 50 %. The secondary mirror is a basically flat mirror but actually an deformable mirror with 31 piezo-actuators. The detector is now a wave front sensor (shack-hartmann type). The closed loop control has been performed and factor of 2.4 improvement of the wave front shape has been performed comparing to the un-control case.

Very lightweight X-ray optics are being developed by ESA and its industrial partners, for a number of X-ray astronomy and planetary missions. These developments could significantly improve the performance of future X-ray timing instrumentation. Based on Micro-Channel Plate (MCP) technology, the novel optics effectively reduce the mirror thickness by almost two orders of magnitude, and therefore also the mass of the telescope optics. Very large collecting areas become feasible for space implementation, especially as required for X-ray timing observations. Furthermore this technology leads to much reduced detector sizes due to the use of imaging X-ray optics. This dramatically improves the detected signal-to-noise ratios, as well as introducing photon collection areas sufficiently large as to study temporal phenomena on the millisecond time scale. This is particularly important to improve the studies of compact X-ray sources, both for improving the signal to noise ratios in temporal bins so that spectral or fluctuation analyses are improved, and for extending the range of measurements to fainter classes of objects. We present a brief overview of the MCP micro-pore optics technology and a possible design for an X-ray timing mission based on this technology and we analyze the performance of such mission.

UVISS is a square aperture Ritchey-Chretien telescope of 45x45 cm designed for accommodation on the International Space Station. The designed field corrector can give a corrected field of view larger than that required by the project; the optical surface of the corrector will be figured using the ion beam figuring technique, with an expected extremely good optics quality. UVISS will employ multilayer coatings for imaging in the near UV (130 - 260 nm) and possibly also far UV (90 - 115 nm) bands.

A number of X-ray astronomical missions of near future will make use of hard X-ray optics with broad-band multilayer coatings. However multilayer mirrors can be also useful to enhance the effective area of a given X-ray telescope in the "classical" low energy X-ray band (0.1 - 10 keV), the window where X-ray spectroscopy provides very useful plasma diagnostics) with a consistent gain with respect to usual single-layer reflectors. Multilayers for soft X-rays are based on stacks with constant d-spacing (in order to minimize the loss due to the photoelectric effect). A further gain in reflectivity (however only restricted to the energy range between 0.5 and 4 keV) can be achieved by using a low density material as a first external layer of the film, with the role of reducing the photoelectric absorption effect when the mirror acts in total external reflection regime (Carbon is the most performing material for this specific scope). In this paper the impact of using soft X-ray multilayer mirrors in future X-ray telescopes is discussed, and soft X-ray reflectivity tests performed on prototype samples presented.

Astro-E2 will be the fifth in a series of X-ray observatory of Institute of Space and Astronautical Science (ISAS) of Japan Aerospace Exploration Agency (JAXA) and is being developed by international collaboration lead by ISAS/JAXA and NASA. The main features of the mission are high-sensitivity broadband and high-resolution X-ray spectroscopy. The spacecraft, the scientific payloads, and expected in-orbit performance and science output are described with emphasis on the high resolution X-ray spectrometer, XRS.

NASA's Strategic Plan for Space Sciences currently envisions a mission capable of resolving the event horizons of supermassive black holes, with imaging-spectroscopy capabilities at angular resolutions better than 0.1 microarcsecond. To achieve this goal, the Micro-Arcsecond X-ray Imaging Mission (MAXIM), a broadband X-ray interferometer, is currently under study. Ground-based proof-of-concept efforts include experiments to demonstrate the feasibility of X-ray interferometry with simple optics. We describe here recent advances in laboratory testbeds, at the University of Colorado and at NASA's Goddard Space Flight Center, that essentially replicate Young's double-slit experiment at X-ray energies. A typical apparatus employs four flat mirrors arranged in periscope pairs, with each pair illuminated at grazing incidence by a slit. We discuss the salient features of these experiments, technical hurdles such as metrology and line-of-sight issues, the successful detection of fringes at wavelengths as short as the Al Kalpha line at 8.35 Angstroms, and future upgrades of our facilities.

This paper presents a first look at a telescope level error budget for the Generation-X telescope. This alignment budget is presented in terms of the allowable intermodule alignment as a function of the intrinsic optical performance degradation of perfectly aligned modules. This intrinsic optical performance is quantified by the image half-power diameter of a point source. Sets of misalignment parameters are used in a Monte Carlo calculation to determine the distribution of outcomes. The distribution is, then, integrated to give the cumulative probability that the defined set of tolerances will yield a certain optical performance. This cumulative probability is, then, used to generate a confidence level for achieving a specific level of telescope performance, expressed as a multiplier to the intrinsic optical performance.

The most powerful diagnostics of hot gas in the universe are well understood, but there are few instruments capable of making measurements at the wavelengths of the most important lines (103 nm, 123 nm, and 155 nm, the lithium-like series of O, N, and C). No complete survey has been done with moderate spatial resolution in emission even though virtually all measurements capable of detecting the presence of lithium-like oxygen do so. We present a type of imaging spectrograph that takes advantage of the large, well-corrected field of view from a three-mirror anastigmat (TMA) in conjunction with aberration-corrected holography applied to the tertiary. The combination of a TMA and aberration-corrected holography allows a large well-corrected field of view in diffracted light, potentially providing an excellent basis for an instrument capable of the first large scale survey from 100 nm to 150 nm.

We have repaired and reflown an existing sounding rocket payload to observe the OVI 1032 Å, 1038 Å emission doublet from a non-radiative shock in the NE section of the Cygnus Loop supernova remnant. We will analyze the images to determine the distance between the OVI-emitting gas and the shock front in visible light, as well as measuring the morphology of OVI across the shock. This will provide a measure of the temperature equilibration length, which can then be used to constrain models of the physical processes causing temperature equilibrium of charged particles in the hot shocked gas of the interstellar medium.

The XAA1.2 chip is a low noise, self-triggered, data-driven and sparse readout ASIC chip with 128 input channels designed as a front-end electronic circuit for silicon-microstrip detectors and manufactured by Ideas ASA (Norway). The XAA1.2 has been selected as the front-end electronic circuit of the SuperAGILE experiment on-board the AGILE satellite mission. This chip underwent to extensive laboratory tests to evaluate its scientific performances. Particularly we have measured the electronic noise and threshold voltage in both configurations stand alone and bonded to a silicon microstrip detector and we have tested the chip thermal stability and radiation damage. In this paper we describe the measurements and we discuss the results.

SuperAGILE, the X-ray stage of AGILE, is a position sensitive X-ray detector. It can be schematised as a horizontal floor of silicon microstrips, collimated by vertical walls of tungsten and roofed by a flat linear coded mask. Since the direction of the incoming photons is reconstructed thanks to the parallelism of microstrips and mask slits, exact shadows on the strips are requested. The width of the microstrips is rather small (121 μm), therefore a satisfactory alignment among all the strips and all the mask slits along the detector size (40 cm) is rather demanding. To date the Engineering Model of SuperAGILE has already been built; in this article we show the techniques developed to assemble and align the detector properly.

AGILE is an ASI (Italian Space Agency) Small Space Mission for high energy astrophysics in the range 30 MeV - 50 GeV which is planned to be launched in 2005. The AGILE payload complement consists of a Tungsten-Silicon Tracker, a CsI Minicalorimeter, an anticoincidence system and a X-Ray detector sensitive in the 10-40 KeV range. The Minicalorimeter detector shall contribute to the determination of the energy interacting gamma-rays and will allow the detection of Gamma Ray Burst and other impulsive events from around 300 KeV. The MCAL Science Console software is part of the test equipment which provides support to the integration, verification and calibration of the Minicalorimeter from the Simplified Electrical Model (SEM) to the Protoflight model (PFM). We describe here the software version we have developed for the SEM test equipment, and which has been used during the functional, performance and calibration test campaign carried out in 2003 on the SEM Minicalorimeter model. In particular we address the performance and architectural issues in view of the next release to be procured for the Minicalorimeter PFM

The Space Telescope European Coordinating Facility's (ST-ECF) lamp project, funded directly by the European Space Agency (ESA), is dedicated to the study of hollow cathode calibration lamps as they are used onboard the Hubble Space Telescope (HST). There are two main objectives: First, we have measured the spectra of Pt/Cr-Ne lamps in order to obtain accurate and reliable wavelengths for all emission lines between 115 and 320 nm. This wavelength range corresponds to the coverage provided by the Space Telescope Imaging Spectrograph (STIS) Echelle modes. Extensive laboratory measurements were performed at the National Institute of Standard and Technology (NIST) using their 10.7 m normal incidence spectrograph and a Fourier Transform Spectrograph. Until now no good laboratory wavelengths for Cr had been available and their addition has a major impact on the wavelength calibration, in particular in the near UV. The new line list is being used in conjunction with the physical instrument model of STIS which is employed to derive an improved wavelength calibration as part of the STIS Calibration Enhancement (STIS-CE) effort. Second, we attempt to gain a better understanding of the performance of such lamps and the physical processes involved in their long term operations. Among the issues studied are the change of the spectrum as a function of current, its change as a function of time and the tolerances of alignment. The bulk of the measurements were performed on flight spares from STIS and on new space qualified lamps for the accelerated aging test. The original flight lamps from the Faint Object Spectrograph (FOS) and the Goddard High Resolution Spectrograph (GHRS) are the only lamps ever to be measured after their return from space. Together with the spectra archived from six years of on-orbit operations they provide a unique data set for studying ageing effects in these lamps. The new Pt/Cr-Ne line list has been successfully applied in the STIS-CE effort. Thereby the ST-ECF's lamp project directly leads to an improvement in the quality of scientific observations of existing HST spectrographs. Our findings also constitute important lessons for the design and operations of future UV and optical spectrographs in space.

If sensitive enough, future missions for nuclear astrophysics will be a great help in the understanding of supernovae explosions. In comparison to coded-mask instruments, both crystal diffraction lenses and grazing angle mirrors offer a possibility to construct a more sensitive instrument to detect gamma-ray lines in supernovae. We report on possible implementations of grazing angle mirrors and simulations carried out to determine the performance. In this study we differentiate between single and multilayer mirrors. Moreover we discuss the possibilities of double reflection implementations.

AGILE is an Italian Space Agency (ASI) space mission for high energy astrophysics in the gamma ray energy range 30MeV-50GeV, and in the X-ray band 10keV-40keV. AGILE is composed of three detecting systems: a Tungsten-Silicon Tracker, a CsI(Tl) Mini-Calorimeter and a Silicon based X-ray detector (Super-Agile), plus an anticoincidence system for background rejection. The satellite will have good imaging performances (with angular resolution of a few arc-minutes in the gamma ray band), good timing resolution and a large field of view (about 1/5 of the sky). AGILE detection principle is based on the pair production process that arises from the interaction of high energy photons with the Tungsten layers of the Silicon Tracker. The Silicon Tracker determines the direction of the incoming radiation, while the Mini-Calorimeter contributes to the evaluation of the interacting photons' energy. The Mini-Calorimeter can also work as a stand-alone gamma ray detector in the energy range 250keV-250MeV, with no imaging capabilities, for the detection of transients and gamma ray burst events (in cooperation with Super-Agile) and for the evaluation of gamma ray background fluctuations. We report the status and the result of the latest tests on the Mini-Calorimeter models already realized.

Shull et al. have asserted that the contribution of stars, relative to quasars, to the metagalactic background radiation that ionizes most of the baryons in the universe remains almost completely unknown at all epochs. The potential to directly quantify this contribution at low redshift has recently become possible with the identification by GALEX of large numbers of sparsely distributed faint ultraviolet galaxies. Neither STIS nor FUSE nor GALEX have the ability to efficiently survey these sparse fields and directly measure the Lyman continuum radiation that may leak into the low redshift (z < 0.4) intergalactic medium. We present here a design for a new type of far ultraviolet spectrograph, one that is more sensitive, covers wider fields, and can provide spectra and images of a large number of objects simultaneously, called the Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS). We intend to use a sounding rocket flight to validate the new instrument with a simple long-slit observation of the starburst populations in the galaxy M83. If however, the long-slit were replaced with microshutter array, this design could isolate the chains of blue galaxies found by GALEX over an ~30' diameter field-of-view and directly address the Lyman continuum problem in a long duration orbital mission. Thus, our development of the sounding rocket instrument is a pathfinder to a new wide field spectroscopic technology for enabling the potential discovery of the long hypothesized but elusive Lyman continuum radiation that is thought to leak from low redshift galaxies and contribute to the ionization of the universe.

In this paper we describe the instrumentation and the software tools we developed to test the SuperAGILE Front-End Electronics (SAFEE) and Interface Electronics (SAIE). The SAFEE is based on twelve XAA1.2 ASICs (produced by IDE-AS). The Test Equipment hardware is composed of commercial VME modules and laboratory developed boards. Commercial VME boards were used for data acquisition and SAFEE handling. Laboratory developed boards provide signal conditioning, pulse generation, trigger system and timing. The VME based architecture assured a stable system for a period of years and a very high acquisition rate. The choice of 'laboratory-developed' boards allowed an easy and cost effective continuous improvement of the system. Two Linux running PC were used, one for the "System Control" and data acquisition, the other one for data reduction and archiving. The s/w for DAQ, data-reduction, and analysis also was laboratory-developed and based on well-known tools.

The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite has been in orbit and collecting scientific data since mid-1999. The FUSE detector system contains two large-format microchannel plate detectors with double delay line anodes. Both detectors have performed well since the beginning of the mission, but as they have aged their gain characteristics have changed. Variations in the amount of charge extracted as a function of position on the detector has caused time- and wavelength-dependent changes to the detector performance; corrections for these effects must be applied to the data in the science data pipeline in order to minimize the introduction of artifacts into the calibrated spectra. The gain characteristics of the detectors and the ways in which they have changed since launch are discussed, as are mitigation strategies in both the use of the detectors and the interpretation of the data.

The IBIS instrument launched on board the ESA INTEGRAL observatory on October 2002 is a coded mask telescope composed by two position sensitive detection planes, one with 16384 Cadmium Telluride pixels (ISGRI) and the other with 4096 Caesium Iodide pixels (PICsIT). Events detected in coincidence in the two detector layers are flagged as generated by Compton scattered photons and can be then processed and filtered using the Compton kinematic equations. The analysis of these data is, however, quite complex, mainly due to the presence of a great number of fake events generated by random coincidences between uncorrelated ISGRI and PICsIT events; if this component is not subtracted with great accuracy, false source detections can be produced. In this work, we present the performance (spectral and imaging) obtainable from the IBIS Compton data, by analyzing ground calibration acquisitions. We also analyze the IBIS Compton flight data relative to the Crab observation, to determine its scientific capabilities.

Observation of diffuse soft X-rays with very low surface brightness can provide us cosmologically important information which is related to the missing baryon problem, large scale structure, etc. Diffuse Intergalactic Oxygen Surveyor(DIOS) mission is planned to observe such source, which may be originated by Warm Hot Intergalactic Medium(WHIM). For this purpose, the X-ray optical system designed under the condition of limited resource of the satellite, such as weight and size. Remarkable characteristic of this sysytem is to four time reflection to fit their observational instrument to the small satellite. Numerical simulations were performed to evaluate X-ray observational performance such as grasp, angular resolution, field of view. In addition to the promissing way of mirror fabrication, aluminum foil based epoxy replication method, it will also be described that the present status of four-stage full shell mirror development.

Imaging spectroscopy at wavelengths below 2000 Å offers an especially powerful method for studying many extended high-temperature astronomical objects, like the Sun and its outer layers. But the technology to make such measurements is also especially challenging, because of the poor reflectance of all standard materials at these wavelengths, and because the observation must be made from above the absorbing effects of the Earth's atmosphere. To solve these problems, single-reflection stigmatic spectrographs for XUV wavelengths have bee flown on several space missions based on designs with toroidal uniform line-space (TULS) or spherical varied line-space (SVLS) gratings that operate at near normal-incidence. More recently, three solar EUV/UV instruments have been selected that use toroidal varied line-space (TVLS) gratings; these are SUMI and RAISE, both sounding rocket payloads, and NEXUS, a SMEX satellite-mission. The next logical extension to such designs is the use of elliptical surfaces for varied line-space (EVLS) rulings. In fact, EVLS designs are found to provide superior imaging even at very large spectrograph magnifications and beam-speeds, permitting extremely high-quality performance in remarkably compact instrument packages. In some cases, such designs may be optimized even further by using a hyperbolic surface for the feeding telescope. The optical characteristics of two solar EUV spectrometers based on these concepts are described: EUS and EUI, both being developed as possible instruments for ESA's Solar Orbiter mission by consortia led by RAL and by MSSL, respectively.

The next large NASA mission in the field of gamma-ray astronomy, GLAST, is scheduled for launch in 2007. Aside from the main instrument LAT (Large-Area Telescope), a gamma-ray telescope for the energy range between 20 MeV and > 100GeV, a secondary instrument, the GLAST burst monitor (GBM), is foreseen. With this monitor one of the key scientific objectives of the mission, the determination of the high-energy behaviour of gamma-ray bursts and transients can be ensured. Its task is to increase the detection rate of gamma-ray bursts for the LAT and to extend the energy range to lower energies (from ~10 keV to ~30 MeV). It will provide real-time burst locations over a wide FoV with sufficient accuracy to allow repointing the GLAST spacecraft. Time-resolved spectra of many bursts recorded with LAT and the burst monitor will allow the investigation of the relation between the keV and the MeV-GeV emission from GRBs over unprecedented seven decades of energy. This will help to advance our understanding of the mechanisms by which gamma-rays are generated in gamma-ray bursts

AGILE is an ASI (Italian Space Agency) Small Space Mission for high energy astrophysics in the range 30 MeV - 50 GeV which is planned to be launched in 2005. Mechanical equipments are required for the Assembly, Integration and Verification (AIV) of the various subsystems together, forming the Payload complement. Furthermore, the calibration of the AGILE's performances requires to test with a beam line and with discrete X and γ ray sources the instrument response as a function of the energy of the incoming photons and particles and of their inclination with respect to the instrument axis. These AIV and Calibration activities lead to require an ad hoc Mechanical Ground Support Equipment (MGSE) which is able to move the instrument up and down, left and right as well as to rotate the instrument around the vertical axes and to tilt it by an angle between 0 and 180° with reference to the direction of the beam. We present here the MGSE we have designed in order to provide these functionalities with the required performances, and taking into account the working environment of the AIV and calibration sites.

Without an additional Hubble Space Telescope (HST) Servicing Mission (SM4), the HST Project will face numerous challenges to keep the telescope operating for as long as possible. As part of SM4, the HST Project planned to install various upgrades to the telescope including the installation of new batteries and new rate integrating gyros. Without these upgrades, reliability analyses and trend projections indicate that the spacecraft will lose the capability to conduct science operations later this decade. The HST team is being challenged to maximize the telescope's remaining operational lifetime, and also maximize its science output and quality. The two biggest areas of concern are the age and condition of the batteries and gyros. Together they comprise the largest risk to telescope productivity and safety and present the biggest challenges to the HST team. The six nickel-hydrogen (NiH2) batteries on HST are the original batteries from launch. With fourteen years of operational life, these batteries have -lasted longer than those on any comparable mission. Yet as with all batteries, their capacity has been declining. Engineers are examining various methods to prolong the life of these mission critical batteries, and retard the rate of degradation. In addition to the batteries, the National Aeronautics and Space Administration (NASA) scheduled all six gyros to be replaced on SM4. Two of the six gyros have already failed, leaving four available for operational use. To be able to conduct science operations, the telescope currently needs three gyros. Efforts are underway to enable a guiding mode that will require only two gyros. In this mode, however, science target scheduling will be strongly driven by new factors (such as star tracker availability), which may ultimately reduce science gathering efficiency. The status on this effort and its potential impact on science operations will be discussed. This paper will focus on these and other efforts to prolong the life of the HST, thus enabling it to remain a world-class observatory for as long as possible.

Objectives for the next generation of UV microchannel plate astronomical detectors include development of efficient photocathodes, including gallium nitride (GaN), and diamond, and optimization of silicon based MCPs. Goals include the development of GaN photocathodes in sealed tube and open detectors with >50% DQE in the UV (>110nm), with tunable cutoffs around 400nm. Activated diamond photocathodes with >40% DQE @ >110nm, cutoffs >200nm, and their application to Si MCPs are also of interest. GaN photocathodes have been developed with efficiencies >60% and cutoffs of ~380nm. Diamond photocathodes with ~40% efficiency at 40nm have been achieved, and Cs activation shows promise for high efficiencies (>20% at 180nm). Silicon based MCPs have qualities that make them preferable to glass MCPs (very low intrinsic background, low fixed pattern noise). Large 8cm Si MCPs have been fabricated with large open area ratio, good lifetest data has been obtained, and techniques for coating high temperature/robust photocathode layers have been explored. We also report on a novel MCP imaging readout scheme, the Cross Strip (XS). This anode uses charge division, and centroiding, of microchannel plate charge signals detected on two orthogonal layers of sense strips to encode event X-Y positions, time tags and signal amplitudes. The XS anode is fabricated as a multilayer ceramic/metal structure that can be implemented in a footprint that is not much larger than the active area, and may accommodate formats up to 10cm x 10cm. To date the XS scheme has been tested with a 32 mm x 32 mm prototype anode and customized electronics. This has demonstrated excellent resolution (<7μm FWHM, ~5k x 5k resolution elements (limited by the MCP pore size)) using low MCP gain (~4 x 10⁵), with anode & electronics resolution of ~3μm FWHM.

Constellation-X, NASA's next major X-ray observatory, is planned to be launched in 2012/2013. Each of the four identical spacecraft contains a large diameter, spectroscopic X-ray telescope (SXT). The mirror assembly is compsed of many densely nested Wolter type 1 mirror reflectors, having segment angles of 30 or 60 degrees. The reflectors will be made of thin, accurately shaped glass sheets, onto which the reflective mirror surface is replicated from high precision, super polished Zerodur mandrels. One key issue for high-performance mirrors is the exact shape of the glass substrates. They are produced at NASA/GSFC by a dedicated hot forming process (slumping) from precision forming mandrels. The hot forming process requires special materials for the glass substrates and the forming mandrels. In this paper we report on figuring (precision machining), polishing, metrology and performance analyses of Wolter type 1 forming mandrels. The mandrels are characterized by the following features: Mandrel dimensions: 450 x 640 mm²; radius of curvature: ~800 mm; segment angle: ~40 deg; shape: hyperboloid or paraboloid; material: Zerodur K20 (Keatite) or fused silica (quartz).

This paper will describe the objectives of the Marshall Space Flight Center (MSFC) Solar Ultraviolet Magnetograph Investigation (SUMI) and the optical components that have been developed to meet those objectives. In order to test the scientific feasibility of measuring magnetic fields in the UV, a sounding rocket payload is being developed. This paper will discuss: (1) the scientific measurements that will be made by the SUMI sounding rocket program, (2) how the optics have been optimized for simultaneous measurements of two magnetic lines CIV (1550Å) and MgII (2800Å), and (3) the optical, reflectance, transmission and polarization measurements that have been made on the SUMI telescope mirrors and polarimeter.

A number of X-ray astronomical missions of near future (XEUS, Constellation-X, SIMBOL-X, HEXIT-SAT, NEXT) will make use of hard X-ray (10-100 keV) optics with broad-band multilayer coatings. To this aim we are developing a multilayer deposition technique for large substrates based on the e-beam deposition technique, improved by the implementation of an ion beam assistance device, in order to reduce the interfacial roughness and improve the reflectivity. The e-beam deposition with ion assistance keeps the film smoothness at a good level and takes the advantage of a reduction of the interlayer stresses. This approach is well suited for the manufacturing of high-reflectance multilayer mirrors for hard X-rays space telescopes where, in addition to a high quality of the deposited films, a volume production is also requested. Moreover, we are also up-grading the replication technique by nickel electroforming, already successfully used for the gold coated soft X-ray mirrors of Beppo-SAX, XMM, JET-X/SWIFT missions, to the case of multilayer coated mirrors. In this paper we will present the technique under development and the implemented deposition facility. Some preliminary, very encouraging, results achieved with the X-ray (8.05 and 17.4 keV) and topographic characterization on flat samples will be discussed.

The Swift Gamma Ray Burst Explorer, chosen in October 1999 as NASA's next MIDEX mission, is now scheduled for launch in October 2004. SWIFT carries three complementary instruments. The Burst Alert Telescope (BAT) identifies gamma-ray bursts (GRBs) and determines their location on the sky to within a few arc-minutes. Rapid slew by the fast-acting SWIFT spacecraft points the two narrow field instruments, an X-ray Telescope (XRT) and an Ultraviolet/Optical Telescope (UVOT), to within the BAT error circle within 70 seconds of a BAT detection. The XRT can determine burst locations to within 5 arc-seconds and measure X-ray spectra and photon flux, whilst the UVOT has a sensitivity down to 24th magnitude and sub arc-second positional accuracy in the optical/uv band. The three instruments combine to make a powerful multi-wavelength observatory with the capability for rapid determination of GRB positions to arc-second accuracy within a minute or so of their discovery, and the ability to measure light-curves and red-shifts of the bursts and after-glows. The paper summarises the mission's readiness for October's launch and operations.

The next generation astronomical X-ray telescopes (e.g. XEUS) require extremely large collecting area (10 m2) in combination with good angular resolution (5 arcsec). The existing technologies such as polished glass, nickel electroforming and foil optics would lead to excessively heavy and expensive optics, and/or are not able to produce the required large area or resolution. We have developed an entirely novel technology for producing X-ray optics which results in very light, stiff and modular optics which can be assembled into almost arbitrarily large apertures, and which are perfectly suited for XEUS. The technology makes use of commercially available silicon wafers from the semiconductor industry. The latest generation silicon wafers have a surface roughness that is sufficiently low for X-ray reflection, are planparallel to better than a micrometer, have almost perfect mechanical properties and are considerably cheaper than other high-quality optical materials. The wafers are bent into an accurate cone and assembled to form a light and stiff pore structure with pores of the order of a millimeter. The resulting modules form a small segment of a Wolter-I optic, and are easily assembled into an optic with large collecting area. We present the production principle of these silicon pore optics, the facilities that have been set up to produce these modules and experimental results showing the excellent performance of the first modules that have been produced. With further improvement we expect to be able to match the XEUS requirements for imaging resolution and mass.