Lynx, one of four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, will provide leaps in capability over previous and planned X-ray missions, and will provide synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx will have orders of magnitude improvement in sensitivity, on-axis sub-arcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources. The Lynx architecture enables a broad range of unique and compelling science, to be carried out mainly through a General Observer Program. This Program is envisioned to include detecting the very first supermassive black holes, revealing the high-energy drivers of galaxy and structure formation, characterizing the mechanisms that govern stellar activity - including effects on planet habitability, and exploring the highest redshift galaxy clusters. An overview and status of the Lynx concept are summarized.
NASA's <i>Chandra</i> X-ray Observatory continues to provide an unparalleled means for exploring the high-energy universe. With its half-arcsecond angular resolution, <i>Chandra</i> studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, neutron stars, black holes, and solar system objects. As we look beyond <i>Chandra</i>, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address ever more demanding science questions—such as the formation and growth of black hole seeds at very high redshifts; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, we initiated a concept study for such a mission, dubbed <i>X-ray Surveyor</i>. The <i>X-ray Surveyor</i> strawman payload is comprised of a high-resolution mirror assembly and an instrument set, which may include an X-ray microcalorimeter, a high-definition imager, and a dispersive grating spectrometer and its readout. The mirror assembly will consist of highly nested, thin, grazing-incidence mirrors, for which a number of technical approaches are currently under development—including adjustable X-ray optics, differential deposition, and new polishing techniques applied to a variety of substrates. This study benefits from previous studies of large missions carried out over the past two decades and, in most areas, points to mission requirements no more stringent than those of <i>Chandra</i>.
Over the past 16 years, NASA's Chandra X-ray Observatory has provided an unparalleled means for exploring the high energy universe with its half-arcsecond angular resolution. Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, planets, and solar system objects addressing most, if not all, areas of current interest in astronomy and astrophysics. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address even more demanding science questions, such as the formation and subsequent growth of black hole seeds at very high redshift; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, NASA Marshall Space Flight Center, together with the Smithsonian Astrophysical Observatory, has initiated a concept study for such a mission now named the X-ray Surveyor. This concept study starts with a baseline payload consisting of a high resolution X-ray telescope and an instrument set which may include an X-ray calorimeter, a wide-field imager and a dispersive grating spectrometer and readout. The telescope would consist of highly nested thin shells, for which a number of technical approaches are currently under development, including adjustable X-ray optics, differential deposition, and modern polishing techniques applied to a variety of substrates. In many areas, the mission requirements would be no more stringent than those of Chandra, and the study takes advantage of similar studies for other large area missions carried out over the past two decades. Initial assessments indicate that such an X-ray mission is scientifically compelling, technically feasible, and worthy of a high prioritization by the next American National Academy of Sciences Decadal Survey for Astronomy and Astrophysics.
Addressing the astrophysical problems of the 2020’s requires sub-arcsecond x-ray imaging with square meter
effective area. Such requirements can be derived, for example, by considering deep x-ray surveys to find the
young black holes in the early universe (large redshifts) which will grow into the first super-massive black holes.
We have envisioned a mission, the Square Meter Arcsecond Resolution Telescope for X-rays (SMART-X), based
on adjustable x-ray optics technology, incorporating mirrors with the required small ratio of mass to collecting
area. We are pursuing technology which achieves sub-arcsecond resolution by on-orbit adjustment via thin film
piezoelectric “cells” deposited directly on the non-reflecting sides of thin, slumped glass. While SMART-X will
also incorporate state-of-the-art x-ray cameras, the remaining spacecraft systems have no requirements more
stringent than those which are well understood and proven on the current Chandra X-ray Observatory.
NASA's Chandra X-Ray Observatory, designed for three years of operation with a goal of five years, is now entering its 15-th year of operation. Thanks to its superb angular resolution, the Observatory continues to yield new and exciting results, many of which were totally unanticipated prior to launch. We discuss the current technical status, review some recent scientific highlights, indicate a few future directions, and present what we are the most important lessons learned from our experience of building and operating this great observatory.
2014 marks the crystal (15<sup>th</sup>) anniversary of the launch of the Chandra X-ray Observatory, which began its existence as the Advanced X-ray Astrophysics Facility (AXAF). This paper offers some of the major lessons learned by some of the key members of the Chandra Telescope team. We offer some of the lessons gleaned from our experiences developing, designing, building and testing the telescope and its subsystems, with 15 years of hindsight. Among the topics to be discussed are the early developmental tests, known as VETA-I and VETA-II, requirements derivation, the impact of late requirements and reflection on the conservatism in the design process.
We describe an X-ray Observatory mission with 0.5” angular resolution, comparable to the Chandra X-ray Observatory, but with 30 times more effective collecting area. The concept is based on developing the new technology of adjustable X-ray optics for ultra thin (0.4 mm), highly nested grazing incidence X-ray mirrors. Simulations to date indicate that the corrections for manufacturing and mounting can be determined on the ground and the effects of gravity release can be calculated to sufficient accuracy, so that all adjustments are applied only once on-orbit, without the need of any on-orbit determination of the required corrections. The mission concept is based on the Chandra Observatory, and takes advantage of the technology studies which have taken place over the past fifteen years developing large area, light weight mirrors.
The Constellation-X Observatory is currently planned as NASA's next major X-ray observatory to be launched towards
the end of the next decade. The driving science goals for the mission are to: 1) Trace the evolution of Black Holes with
cosmic time and determine their contribution to the energy output of the Universe; 2) Observe matter spiraling into
Black Holes to test the predictions of General Relativity; 3) Use galaxy clusters to trace the locations of Dark Matter and
follow the formation of structure as a function of distance; 4) Search for the missing baryonic matter; 5) Directly observe
the dynamics of Cosmic Feedback to test models for galaxy formation; 6) Observe the creation and dispersion of the
elements in supernovae; and 7) Precisely constrain the equation of state of neutron stars. To achieve these science goals
requires high resolution (R > 1250) X-ray spectroscopy with 100 times the throughput of the Chandra and XMMNewton.
The Constellation-X Observatory will achieve this requirement with a combination of four large X-ray
telescopes on a single satellite operating in the 0.25 to 10 keV range. These telescopes will feed X-ray micro-calorimeter
arrays and grating spectrometers. A hard X-ray telescope system will provide coverage up to at least 40 keV. We
describe the mission science drivers and the mission implementation approach.
The Constellation-X mission will address questions central to the NASA Beyond Einstein Program, using high
throughput X-ray spectroscopy to measure the effects of strong gravity close to the event horizon of black holes, study
the formation and evolution of clusters of galaxies to precisely determine cosmological parameter values, measure the
properties of the Warm-Hot Intergalactic Medium, and determine the equation of state of neutron stars. Achieving these
science goals requires a factor of ~100 increase in sensitivity for high resolution spectroscopy over current X-ray
observatories. This paper briefly describes the Constellation-X mission, summarizes its basic performance parameters
such as effective area and spectral resolution, and gives a general update on the mission. The details of the updated
mission configuration, compatible with a single Atlas-V 551 launch vehicle, are presented.
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 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.
The Constellation-X mission is a large collecting area X-ray facility, emphasizing observations at high spectral resolution (R ~ 300--3000) while covering a broad energy band (0.25-60 keV). By increasing the telescope aperture and utilizing efficient spectrometers the mission will achieve a factor of 25-100 increased sensitivity over current high resolution X-ray spectroscopy missions. Constellation-X is the X-ray astronomy equivalent of large ground-based optical telescopes such as the Keck and the VLT, complementing the high spatial resolution capabilities of Chandra. Key technologies under development for the mission include lightweight high throughput X-ray optics, multilayer coatings to enhance the hard X-ray performance of X-ray optics, micro-calorimeter spectrometer arrays, low power and low weight CCD arrays, lightweight gratings and hard X-ray detectors. Constellation-X will for the first time make high resolution X-ray spectroscopy of faint X-ray source populations a matter of routine. With its increased capabilities, Constellation-X will address many fundamental astrophysics questions such as observing the formation and evolution of clusters of galaxies, constraining the Baryon content of the Universe, observing the effects of strong gravity close to the event horizon of black holes and using these effects to determine the black hole rotation. The Constellation-X mission has received strong endorsements in two recent National Academy of Sciences reports: the Astronomy and Astrophysics Survey and the Committee on the Physics of the Universe.
The Chandra X-Ray Observatory, the x-ray component of NASA's Great Observatories, was launched early in the morning of 1999, July 23 by the Space Shuttle Columbia. The Shuttle launch was only the first step in placing the observatory in orbit. After release from the cargo bay, the Inertial Upper Stage performed two firings, and separated from the observatory as planned. Finally, after five firings of Chandra's own Integral Propulsion System--the last of which took place 15 days after launch--the observatory was placed in its highly elliptical orbit of approximately 140,000 km apogee and approximately 10,000 km perigee. After activation, the first x-rays focused by the telescope were observed on 1999, August 12. Beginning with these initial observations one could see that the telescope had survived the launch environment and was operating as expected. The month following the opening of the sun-shade door was spent adjusting the focus for each set of instrument configurations, determining the optical axis, calibrating the star camera, establishing the relative response functions, determining energy scales, and taking a series of `publicity' images. Each observation proved to be far more revealing than was expected. Finally, and despite an initial surprise and setback due to the discovery that the Chandra x-ray telescope was far more efficient for concentrating low-energy protons that had been anticipated, the observatory is performing well and is returning superb scientific data. Together with other space observations, most notably the recently activated XMM-Newton, it is clear that we are entering a new era of discovery in high-energy astrophysics.
The Constellation-X mission is a large collecting area x-ray facility, emphasizing observations at high spectral resolution while covering a broad energy band. By increasing the telescope aperture and utilizing efficient spectrometers the mission will achieve a factor of 100 increased sensitivity over current high resolution x-ray spectroscopy missions. The use of focusing optics across the 10-40 keV band will provide a similar factor of 100 increased sensitivity in this band. Key technologies under development for the mission include lightweight high throughput x-ray optics, multilayer coatings to enhance the hard x-ray performance of x-ray optics, micro-calorimeter spectrometer arrays with 2 eV resolution, low power and low weight CCD arrays, lightweight gratings and hard x-ray detectors. When observations commence towards the end of the next decade, Constellation-X will address many pressing questions concerning the extremes of gravity and the evolution of the Universe.
The High Throughput X-ray Spectroscopy (HTXS) mission is dedicated to observations at high spectral resolution. The HXTS mission represented a major advanced, providing as much as a factor of 100 increase in sensitivity over currently planned high resolution X-ray spectroscopy missions. This X- ray equivalent of the Keck Telescope will mark the start of a new era when high quality X-ray spectral will be obtained for all classes of X-ray sources, over a wide range of luminosity and distance. With its increased capabilities, HTXS will address many fundamental astrophysics questions such as the origin and distribution of the elements from carbon to zinc, the formation and evolution of clusters of galaxies, the validity of general relativity in the strong gravity limit, the evolution of supermassive black holes in active galactic nuclei, the details of supernova explosions and their aftermath, and the mechanisms involved in the heating of stellar coronae and driving of stellar winds.