NASA is developing a wide range of instrument and sensing technologies for future space science and earth science missions. NASA has committed a significant effort over the last several years to develop advanced technologies including focal plane arrays, cryogenics, precision structures, metrology, and lightweight optics. In 1994 NASA increased the effort in infrared astronomy, responding to the high priority placed on this area by the Office of Space Science (OSS). This investment has paid off with benefits for ground-based, airborne, and space astronomy missions. The following are some examples from ground-based, airborne, and space astronomy:
Scientists
from the
Near Infrared Astronomy Group
at the University of Rochester have taken
spectacular images in the
1.2 to 3.3 micron range, including
images of
Jupiter after the comet Shoemaker-Levy 9 impact.
They used their 58x62 and 256x256 indium antimonide
(InSb)
Infrared Array Cameras to take images from the
Mt. Lemmon Observing Facility and the
Wyoming
InfraRed Observatory.
The NASA core technology and
the space science research programs jointly sponsored this university group to test
and evaluate these arrays, and the National Science Foundation
(NSF) sponsored the incorporation of these arrays into
cameras and spectrometers for astronomical research.
Scientists
from the
Department of Astronomy at
Cornell University have taken
unprecedented, spectacular images of the
Orion nebula at 37 microns. They used an
antimony-doped silicon
(Si:Sb)
Rockwell International
array in an astronomical demonstration on the Kuiper Airborne Observatory
(KAO).
The NASA core technology and
the space science research programs
jointly developed this 128x128 array, which demonstrated excellent sensitivity and uniformity.
Click here for summary graphic.
The Wide-Field Infrared Explorer
(WIRE)
will measure infrared sources 500 times fainter than those in the Faint Source Catalog from
the Infrared Astronomical Satellite
(IRAS).
The improvement is due mainly to the improved sensitivity of new 128x128 arsenic-doped-silicon
(Si:As)
impurity band conduction (IBC) focal plane arrays. This joint
NASA
core technology and space science research program development
made the WIRE
mission possible, leveraging earlier investments by the Department of Defense
(DOD).
In addition to the Si:As impurity band conduction arrays, the WIRE baseline mission includes
core technology developed gamma-alumina Dewar support straps.
They have a very high strength-to-thermal-conductivity ratio over the entire
temperature range below room temperature. Their performance exceeds that of fiberglass
epoxy and graphite epoxy supports. In WIRE the use of alumina rather than fiberglass
epoxy supports will extend the mission life by 34 percent (from 3.5 months to 4.7 months).
Gravity Probe-B
(GP-B)
will also use this technology for its neck tube and supports, as will the
Space Infrared Telescope Facility
(SIRTF)
for its supports.
A major improvement in technology for infrared astronomy is the development of
1.5 kelvin cryogenic readouts for the Space Infrared Telescope Facility
(SIRTF).
This breakthrough will enable the readout electronics to operate at
the same temperature as the focal plane for the far-infrared photometer instrument.
These new devices clearly meet the performance objectives for SIRTF.
The SIRTF project has already factored them into the 100 micron focal plane design,
simplifying the design, improving the efficiency, and reducing the overall cost.
The previous baseline required that the readouts operate at 20 kelvins in
close proximity to the 1.5 kelvin detectors. This complicated the thermal
design, increased the load on the cryogenic system, and shortened the mission life.
In addition to simplifying the thermal design, the new silicon
CMOS
cryogenic readout electronics achieved improved stability and a four-fold
reduction in noise, using a 32-channel, multiplexed format. The NASA core technology
program funded all of this development effort.
Bill Irace of the SIRTF project has written a
"thank
you" letter acknowledging this contribution.
This technology will also be useful to
SOFIA,
SAM/FIRST,
and others.
Click here for a
chart
showing progress in Infrared Detectors
for Astronomy since 1983, jointly supported by the core technology and
the space science research programs.
For more information see the the following sources:
Created March 13, 1995. Last update: April 23, 1997. Please see my Disclaimer and Web Policy page. Maintained by Gordon Johnston.
Gordon.Johnston@hq.nasa.govThe world wide web uniform resource locator (URL) for this page is:
http://ranier.hq.nasa.gov/Sensors_page/DD/DDAccomp/AstronIRAcc.html
