ExoPlanets & Stellar Astrophysics Programs/Missions
Current
Space Telescope Imaging Spectrograph (STIS)
Dr. Bruce Woodgate is the Principal investigator for the Space
Telescope Imaging Spectrograph (STIS) currently
onboard the Hubble Space Telescope. STIS provides medium and high
spectral resolution imaging in the ultraviolet and visible wavelength
bands. In addition to co-investigators Heap and Gull, Drs. Kimble and
Bowers are team members. Throughout its life, since installation on
HST in 1997, STIS has observed the interstellar and intergalactic
medium and recently made possible observations of the "transiting
extra-solar planet" (HD 209458b). Recently, STIS suffered a power
supply failure, and is not operational. A study of the feasibility of
repairing STIS during Servicing Mission 4 (SM4) in 2008 is underway.
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Infrared Array Camera (IRAC)
IRAC is a camera onboard the Spitzer Space Telescope (aka SIRTF),
a cryogenically cooled IR telescope and the last of the Great Observatories.
It was launched in August 2003, and is working as well or better than
designed. The picture to the right is a true color (3.6, 4.5, 5.8,
8 micron) image of the galaxy M81 obtained with IRAC and released in December 2003 [image credit:
NASA/JPL-Caltech/Willner (Harvard-Smithsonian Center for Astrophysics)].
IRAC was built at GSFC; Harvey Moseley is the Instrument Scientist. G. Fazio at Harvard is the
P.I. IRAC contains 2 InSb arrays (1-5.5 microns), and 2 HgCdTe arrays (2-
28 microns).
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Fizeau Interferometry Testbed (FIT)
An overview of the Phase I FIT, with baffles removed to show the optical elements clearly.
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The Fizeau Interferometry Testbed is a ground-based testbed located in the GSFC Instrument Development Lab and under development by K.
Carpenter (PI), R. Lyon, A. Liu, and K. Hartman at GSFC, in collaboration with D. Mozurkewich (Seabrook Eng.), and J. Marzouk, P. Petrone, P.
Dogoda, and P. Liiva (Sigma Space). FIT is being used to develop and test algorithms for closed-loop control of actuated multi-element (7-20)
sparse aperture systems, using feedback from Phase Diversity analysis of the combined beams - a critical technology for future long-baseline Fizeau
Interferometers and Sparse Aperture Telescopes, such as the Stellar Imager (SI) mission. The FIT
currently uses 7 articulated mirrors each having tip, tilt and piston that are automatically controlled to demonstrate closed-loop control and keep
the beams phased to simulate a 7-element formation-flying interferometer. Plans are in place to increase the number of elements to 15-20 for FIT
Phase II.
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Future
Terrestrial Planet Finder (TPF)
The Terrestrial Planet Finder (TPF) is a series of two missions to detect and
characterize earth-like planets around nearby stars. The TPF optical
coronagraph (TPF-C) will be the first to fly, followed by an
infrared interferometer (TPF-I) about five years later. The launch schedule is under
review at present, with a TPF-C launch expected no earlier than about 2016. Goddard
is collaborating on TPF with JPL, which is the lead Center for TPF. Goddard's primary
role is to build the telescopes for TPF-C and TPF-I. In addition, scientists in the
Exoplanet Lab are studying a number of technologies relevant to TPF (masks,
visible nulling coronagraphy, interferometry, mirror coatings, and spectrographs).
Sally Heap and Chuck Bowers are the Telescope and Deputy Telescope Scientists,
respectively, for TPF-C. Bill Danchi is the Telescope Scientist for TPF-I, and is
the TPF Project Liaison with ESA's Darwin Project. For further info, also visit
JPL's TPF site.
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Stellar Imager (SI)
K. Carpenter is leading the development of the Stellar Imager (SI), a UV-Optical, Space-Based Interferometer designed to enable 0.1 milli-arcsecond
(mas) spectral imaging of stellar surfaces and stellar interiors (via asteroseismology) and of the Universe in general. Its spectral imaging
capability is designed to enable an improved understanding of: 1) Solar and Stellar Magnetic Activity and Its Impact on Space Weather, Planetary
Climates, and Life and 2) Magnetic Processes, the Origin and Evolution of Structure, and the Transport of Matter Throughout the Universe. SI is
included as a "Flagship and Landmark Discovery Mission" in the 2005 Sun Solar System Connection (SSSC) Roadmap and as a candidate for a "Pathways to
Life Observatory" in the Exploration of the Universe Division (EUD) Roadmap (May, 2005). The ultra-sharp images of the Stellar Imager will
revolutionize our view of many dynamic astrophysical processes: The 0.1 mas resolution of this deep-space telescope will transform point sources
into extended sources, and snapshots into evolving views. SI's science focuses on the role of magnetism in the Universe, particularly on magnetic
activity on the surfaces of stars like the Sun. SI's prime goal is to enable long-term forecasting of solar activity and the space weather that it
drives in support of the "Living With a Star" program in the Exploration Era. SI will also revolutionize our understanding of the formation of
planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the
Universe. This "Vision Mission" concept is being developed by GSFC in collaboration with a broad variety of industrial, academic, and astronomical
science institute partners, as well as an international group of science and technical advisors. Please see the Stellar Imager Homepage for further information.
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EPIC (Extrasolar Planet Imaging Coronagraph)
M. Clampin is the Principal Investigator
for EPIC, a Discovery Mission
concept. EPIC is designed to directly image and characterize extrasolar gas
giant planets (EGPs) at typical distances of 2 to 20 AU from the parent star,
and will therefore find solar-system analogs - those most likely to
harbor earth-like planets. Such systems will be the primary targets
for NASA's subsequent planet searches with the Terrestrial Planet
Finder (TPF). EPIC's direct planet discovery capabilities are
complemented by its unique ability to image the dust disks and very
low-mass companions close in to stars. The EPIC concept employs a
visible nulling coronagraph and a 1.5-m aperture telescope. GSFC team members
include Dan Gezari and Rick Lyon.
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Fourier Kelvin Stellar Interferometer (FKSI)
W. Danchi is leading the development of the Fourier-Kelvin Stellar
Interferometer (FKSI), with Drs. D. Benford, D. Leisawitz, D. Gezari,
S. Rinehart, J. Rajagopal, D. Deming and M. Mumma at GSFC, together with
numerous members of the community. FKSI is a mission concept for a
nulling interferometer for the near to mid infrared spectral region
(3-8 microns). FKSI is conceived as a scientific and technological
precursor to the Terrestrial Planet Finder (TPF) mission. The
scientific emphasis of the mission is on the evolution of protostellar
systems, from just after the collapse of the precursor molecular cloud
core, through the formation of the disk surrounding the protostar, the
formation of planets in the disk, and eventual dispersal of the disk
material. FKSI will address key questions about exosolar planets: (1)
what are the characteristics of exosolar giant planets? (2) what are the
characteristics of exosolar zodiacal clouds around nearby stars? and (3)
are there giant planets around classes of stars other than those already
studied? In the past year, a detailed design study for FKSI was undertaken at
GSFC. Using a nulling interferometer configuration, the optical system
consists of two 0.5m telescopes on a 12.5m boom feeding a Mach-Zender
beam combiner with a fiber wavefront error reducer to produce a 0.01%
null of the central starlight. With this system, planets around nearby
stars can be detected and characterized using a combination of spectral
and spatial resolution. For further information, check out this
recent poster on FKSI from the ESO Garching conference (Oct 2005):
PPT file.
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Microlensing Planet Finder (MPF)
MPF (formerly known as the Galactic Exoplanet Survey Telescope (GEST)), is a proposed Discovery-class
mission concept headed by P.I. David Bennett (U. Notre Dame) to discover planets by their
microlensing effects on background stars. The MPF would observe 100 million stars in the
Galactic bulge and could detect a planet roughly every day, and an
Earth-like planet every few weeks. Goddard co-investigators include J.
Mather, M. Greenhouse, R. Kimble, M. Niedner and B. Rauscher.
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James Webb Space Telescope (JWST) Development
EUD is home to the scientists developing
JWST. John Mather is Senior Project
Scientist, Jon Gardner is Deputy Senior Project Scientist, Mark Clampin
is the Observatory Project Scientist, Matt Greenhouse
is Project Scientist for the Integrated Science Instrument Module (ISIM),
Bernie Rauscher is Deputy ISIM Project Scientist for detector
development, and George Sonneborn is Operations Project Scientist.
Programmable transmissive microshutter arrays are being developed using
MEMS technology for the JWST Near Infrared Spectrograph
(NIRSpec) by Moseley, Silverberg, Kutyrev, and Woodgate.
Each shutter is individually controllable (open or closed).
The transmissive design allows high contrast, compared to reflective micro-
mirror approaches. To date, a 256x256 pixel array has been constructed and
tested at cryogenic temperatures. Both the NIRCam (near-IR) and MIRI (mid-IR)
cameras contain coronagraphs, and the study of debris disks and Extrasolar Giant
Planets (EGPs) is one of the primary scientific goals of JWST.
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Wide Field Camera 3 (WFC3)
WFC3 is planned for installation on the Hubble Space
Telescope in Servicing Mission 4 in 2008, subject to a successful return to flight
of the Space Shuttle. This panchromatic camera
offers imaging from 200nm to 1.7 microns. The Instrument Scientist is
Randy Kimble. The characteristics of the CCDs and Rockwell
HgCdTe IR arrays have been tested at GSFC in the Detector
Characterization Lab, which is jointly operated by the EUD and the GSFC
engineering directorate. The picture of WFC3 (right) was taken during
assembly at Ball Aerospace.
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Next Generation UV detectors
Woodgate, Kimble, Norton,
Hilton (SSAI) are developing high QE detectors for use in the UV, based on
new photocathode materials such as AlGaN for deposition on silicon-based
microchannel plates. Recent results show improvements in Quantum efficiency
in the Near-UV (180 nm) to almost 50%.
Kimble, Norton, Haas and B. Pain (JPL)
are developing an Active Pixel Sensor (APS) for eventual use in a UV
camera together with the high QE microchannel plate.
Tim Norton is shown at left in the detector processing lab in B21 at Goddard.
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