The Remote Occulter (Orbiting Starshade) is a proposed 100-meter class starshade working with a ground-based telescope, designed for visible-band imaging and spectroscopy of temperate planets around sun-like stars. With advanced adaptive optics and the largest telescopes like the 39 m ELT, it would enable the study of planetary systems and a wide variety of exoplanets. In this paper, we describe the geometrical constraints and establish which parts of the sky are observable.
The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of Herschel, the largest telescope flown in space to date. After a 3 ½ year study, the Origins Science and Technology Definition Team will recommend to the Decadal Survey a concept for Origins with a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (MISC-T) will measure the spectra of transiting exoplanets in the 2.8 – 20 μm wavelength range and offer unprecedented sensitivity, enabling definitive biosignature detections. The Far-IR Imager Polarimeter (FIP) will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer (OSS) will cover wavelengths from 25 – 588 μm, make wide-area and deep spectroscopic surveys with spectral resolving power R ~ 300, and pointed observations at R ~ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The telescope has a Spitzer-like architecture and requires very few deployments after launch. The cryo-thermal system design leverages JWST technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural backgroundlimited sensitivity.
Planned for launch in 2019 on an Ariane 5 from French Guiana, JWST will observe at wavelengths from 0.6 to 28 µm with a full suite of imagers, spectrometers, and coronagraphs. JWST will extend the discoveries of the Hubble and Spitzer observatories in all areas from cosmology, galaxies, stars, and exoplanets to our own Solar System. With a 6.5 m primary mirror it has a collecting area 7 times that of Hubble and 50 times that of Spitzer. The image quality is diffraction limited at 2 µm with near IR camera pixels of only 0.03 arcsec. I will outline the planned observing program, showing how the instrument capabilities enable new discoveries in new territories. What were the first objects that formed in the expanding universe? How do the galaxies grow? How are black holes made, ranging from stellar mass to supermassive, over a billion solar masses, and what is their effect on the neighborhood? How are stars and planetary system formed? What governs the evolution of planetary systems, with the possibility of life? How did the Earth become so special? But the most important discoveries will be those we have not even imagined today.
The Space High Angular Resolution Probe for the Infrared (SHARP-IR) is a new mission currently under study. As part
of the preparation for the Decadal Survey, NASA is currently undertaking studies of four major missions, but interest
has also been shown in determining if there are feasible sub-$1B missions that could provide significant scientific return.
SHARP-IR is being designed as one such potential probe. In this talk, we will discuss some of the potential scientific
questions that could be addressed with the mission, the current design, and the path forward to concept maturation.
The IRMOS (Infrared Multiobject Spectrometer) is a multi-object imaging dispersive spectrometer for
astronomy, with a micromirror array to select desired objects. In standard operation, the mirrors are used to
select multiple compact sources such that their resulting spectra do not overlap on the detector. The IRMOS
can also be operated in a Hadamard mode, in which the spectra are allowed to overlap, but are modulated by
opening the mirrors in many combinations to enable deconvolution of the individual spectra. This mode
enables integral field spectroscopy with no penalty in sensitivity relative to the standard mode. There are
minor penalties in overhead and systematics if there are sky or instrumental drifts. We explain the concept and
discuss the benefits with an example observation of the Orion Trapezium using the 2.1 m telescope at Kitt
Peak National Observatory.
We report results of a recently-completed pre-Formulation Phase study of SPIRIT, a candidate NASA Origins Probe mission. SPIRIT is a spatial and spectral interferometer with an operating wavelength range 25 - 400 μm. SPIRIT will provide sub-arcsecond resolution images and spectra with resolution R = 3000 in a 1 arcmin field of view to accomplish three primary scientific objectives: (1) Learn how planetary systems form from protostellar disks, and how they acquire their chemical organization; (2) Characterize the family of extrasolar planetary systems by imaging the structure in debris disks to understand how and where planets form, and why some planets are ice giants and others are rocky; and (3) Learn how high-redshift galaxies formed and merged to form the present-day population of galaxies. Observations with SPIRIT will be complementary to those of the James Webb Space Telescope and the ground-based Atacama Large Millimeter Array. All three observatories could be operational contemporaneously.
The scientific capabilities of the James Webb Space Telescope (JWST) fall into four themes. The End of the Dark Ages:
First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization
history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas,
stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the
present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars,
from infall onto dust-enshrouded protostars, to the genesis of planetary systems. Planetary Systems and the Origins of
Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our
own, and investigate the potential for life in those systems. To enable these for science themes, JWST will be a large
(6.5m) cold (50K) telescope with four instruments, capable of imaging and spectroscopy from 0.6 to 29 microns wavelength.
The Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) is a space-based imaging and spectral ("double Fourier") interferometer with kilometer maximum baseline lengths for imaging. This NASA "vision mission" will provide spatial resolution in the far-IR and submillimeter spectral range comparable to that of the Hubble Space Telescope, enabling astrophysicists to extend the legacy of current and planned far-IR observatories. The astrophysical information uniquely available with SPECS and its pathfinder mission SPIRIT will be briefly described, but that is more the focus of a companion paper in the Proceedings of the Optical, Infrared, and Millimeter Space Telescopes conference. Here we present an updated design concept for SPECS and for the pathfinder interferometer SPIRIT (Space Infrared Interferometric Telescope) and focus on the engineering and technology requirements for far-IR double Fourier interferometry. We compare the SPECS optical system requirements with those of existing ground-based and other planned space-based interferometers, such as SIM and TPF-I/Darwin.
The Microlensing Planet Finder (MPF) is a proposed Discovery mission that will complete the first census of extrasolar planets with sensitivity to planets like those in our own solar system. MPF will employ a 1.1m aperture telescope, which images a 1.3 sq. deg. field-of-view in the near-IR, in order to detect extrasolar planets with the gravitational microlensing effect. MPF's sensitivity extends down to planets of 0.1 Earth masses, and MPF can detect Earth-like planets at all separations from 0.7AU to infinity. MPF's extrasolar planet census will provide critical information needed to understand the formation and frequency of extrasolar planetary systems similar to our own.
The scientific requirements of the James Webb Space Telescope fall into four themes. The End of the Dark Ages: First Light and Reionization seeks to identify the first luminous sources to form and to determine the ionization history of the Universe. The Assembly of Galaxies seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and active nuclei within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. Planetary Systems and the Origins of Life seeks to determine the physical and chemical properties of planetary systems including our own, and investigate the potential for life in those systems. These themes will guide the design and construction of the observatory.
Ultimately, after the Single Aperture Far-IR (SAFIR) telescope, astrophysicists will need a far-IR observatory that provides angular resolution comparable to that of the Hubble Space Telescope. At such resolution galaxies at high redshift, protostars, and nascent planetary systems will be resolved, and theoretical models for galaxy, star, and planet formation and evolution can be subjected to important observational tests. This paper updates information provided in a 2000 SPIE paper on the scientific motivation and design concepts for interferometric missions SPIRIT (the Space Infrared Interferometric Telescope) and SPECS (the Submillimeter Probe of the Evolution of Cosmic Structure). SPECS is a kilometer baseline far-IR/submillimeter imaging and spectral interferometer that depends on formation flying, and SPIRIT is a highly-capable pathfinder interferometer on a boom with a maximum baseline in the 30 - 50 m range. We describe recent community planning activities, remind readers of the scientific rationale for space-based far-infrared imaging interferometry, present updated design concepts for the SPIRIT and SPECS missions, and describe the main issues currently under study. The engineering and technology requirements for SPIRIT and SPECS, additional design details, recent technology developments, and technology roadmaps are given in a companion paper in the Proceedings of the conference on New Frontiers in Stellar Interferometry.
SAFIR is a large (10 m-class), cold (4-10 K) space telescope for wavelengths between 20 microns and 1 mm. It will provide sensitivity a factor of a hundred or more greater than that of Spitzer and Herschel, leveraging their capabilities and building on their scientific legacies. Covering this scientifically critical wavelength regime, it will complement the expected wavelength performance of the future flagship endeavors JWST and ALMA. This vision mission will probe the origin of stars and galaxies in the early universe, and explore the formation of solar systems around nearby young stars. Endorsed as a priority by the Decadal Study and successive OSS roadmaps, SAFIR represents a huge science need that is matched by promising and innovative technologies that will allow us to satisfy it. In exercising those technologies it will create the path for future infrared missions. This paper reviews the scientific goals of the mission and promising approaches for its architecture, and considers remaining technological hurdles. We review how SAFIR responds to the scientific challenges in the OSS Strategic Plan, and how the observatory can be brought within technological reach.
The Galactic Exoplanet Survey Telescope (GEST) will observe a 2 square degree field in the Galactic bulge to search for extra-solar planets using a gravitational lensing technique. This gravitational lensing technique is the only method employing currently available technology that can detect Earth-mass planets at high signal-to-noise, and can measure the abundance of terrestrial planets as a function of Galactic position. GEST's sensitivity extends down to the mass of Mars, and it can detect hundreds of terrestrial planets with semi-major axes ranging from 0.7 AU to infinity. GEST will be the first truly comprehensive survey of the Galaxy for planets like those in our own Solar System.
Far infrared interferometers in space would enable extraordinary measurements of the early universe, the formation of galaxies, stars, and planets, and would have great discovery potential. Since half the luminosity of the universe and 98% of the photons released since the Big Bang are now observable at far IR wavelengths (40 - 500 micrometers ), and the Earth's atmosphere prevents sensitive observations from the ground, this is one of the last unexplored frontiers of space astronomy. We present the engineering and technology requirements that stem from a set of compelling scientific goals and discuss possible configurations for two proposed NASA missions, the Space Infrared Interferometric Telescope and the Submillimeter Probe of the Evolution of Cosmic Structure.
The Next Generation Space Telescope, planned for launch in 2009, will be an 8-m class radiatively cooled infrared telescope at the Lagrange point L2. It will cover the wavelength range from 0.6 to 28 micrometers with cameras and spectrometers, to observe the first luminous objects after the Big Bang, and the formation, growth, clustering, and evolution of galaxies, stars, and protoplanetary clouds, leading to better understanding of our own Origins. It will seek evidence of the cosmic dark matter through its gravitational effects. With an aperture three times greater than the Hubble Space Telescope, it will provide extraordinary advances in capabilities and enable the discovery of many new phenomena. It is a joint project of the NASA, ESA, and CSA, and scientific operations will be provided by the Space Telescope Science Institute.
We discuss concepts for deploying direct-detection interferometers in space which are optimized for the wavelength range 40 micrometers to 500 micrometers . In particular, we introduce two missions in NASA's current strategic plan: SPIRIT (SPace InfraRed Interferometric Telescope) and SPECS (Submillimeter Probe of the Evolution of Cosmic Structure).
As part of NASA's Origins theme, the Next Generation Space Telescope will investigate the origin of galaxies, stars, and planets, using IR observations with a cooled telescope. Located at L2 or farther from the Earth, it will be protected from near-Earth hazards and will be radiatively cooled to allow background limited observations. The scientific goals were described in the 'HST and Beyond report,' and the proposed NGST approach in 'Visiting a Time When Galaxies Were Young.' It is clear that an 8m class telescope in deep space would be a tremendous tool that would lead to surprising discoveries. It will also require revolutionary changes in technology and management approaches, science budget must be small compared with Hubble Space Telescope. A major challenge is to develop a scientific performance metric that represents a consensus on the importance of various engineering parameters, like accuracy, field of view, sensitivity, spatial and spectral resolution, temperature, vibration, stability, and so forth. Such a metric could be used for choosing instrument or telescope configurations, or for selecting or paying a contractor in the performance based contracting approach now in vogue. Ideally, it could also be used for optimizing the cost of the mission, ensuring that effort is proportionate to benefit. The scientific, mathematical, and social aspects of our approach will be reported.
The Next Generation Space Telescope (NGST) Design Reference Mission (DRM) represents a suite of potential astronomical programs and targets along with their expected physical properties, and desired observation modes. This broad science program is being used to drive the observatory design in a way as fundamental as traditional engineering parameters. Astronomers use the DRM to communicate their desires in a quantitative fashion to the engineers who will eventually construct the observatory. The DRM is also the primary tool used to measure the relative value of NGST mission architectures and technological readiness of the program. Specifically, the fraction of the DRM completed by a given observatory configuration in a given time is, to first order, a measure of the value of the design. Those designs which complete a higher fraction of the observations listed below are more capable than those complete lesser fractions.
We present the preliminary results of a feasibility study performed by a team of scientists and engineers from NASA, academia and industrial concerns. The candidate concept is a deployable 8 meter diameter telescope optimized for the near infrared region (1 - 5 microns), but with instruments capable of observing from the visible all the way to 30 microns. The observatory is radiatively cooled to about 30 K and would be launched on an Atlas II-AS to the Lagrange Point L2.
The Cosmic Background Explorer (COBE) satellite carries three instruments to measure the diffuse infrared and microwave background radiation from the early universe, along with more recent diffuse sources. It was developed by NASA's Goddard Space Flight Center and launched by a Delta rocket on November 18, 1989. It has produced the first measurements of structure in the Big Bang and has shown that the primeval heat radiation has a blackbody spectrum to extraordinary accuracy. The three instruments include a Far Infrared Absolute Spectrophotometer (FIRAS) to cover the range from 100 micrometers to 1 cm wavelength with a 7 degree(s) resolution, a Diffuse Infrared Background Experiment (DIRBE) to map the sky from 1 to 300 micrometers with a 0.7 degree(s) resolution in 10 broad bands, and a Differential Microwave Radiometer (DMR) to map the sky at 31.5, 53, and 90 GHz with a 7 degree(s) resolution. The designs of the instruments and spacecraft are described, and the primary results ar summarized.
The Far InfraRed Absolute Spectrophotometer (FIRAS) was built to measure the spectrum of diffuse emission from 1 to 100 cm-1, with particular attention to possible differences between the spectrum of the cosmic microwave background radiation (CMBR) and a blackbody spectrum as small as 0.1% of the peak of the CMBR spectrum. The FIRAS has differential inputs and outputs, a full beam external calibrator, a controllable reference blackbody, and a polarizing Michelson interferometer with bolometer detectors. It is operated at a temperature of 1.5 K inside a liquid helium cryostat to suppress instrument emission and improve detector sensitivities. It has an intrinsic frequency resolution of the order of 0.7%, maximum path lengths of 1.2 and 5.9 cm, and a beamwidth of 7 degree(s), and achieved its goals for accuracy and rms sensitivity for νIν, which are better than 10-9 W/cm2sr over the frequency range from 2 to 20 cm-1.