FEATURE
Goddard Technologists to Lead
Three ST-9 Concept Definition Studies
Three
Goddard technologists will lead year long concept
studies to define space experiments that demonstrate
and validate advanced technology for future science
missions.
The effort is a part of the New Millennium Program’s
Space Technology-9 (ST-9) project, which is testing
system-level technologies in five technical concept
areas for a total project cost of $5 million. By the
end of August 2006, the teams will submit study reports
describing a technology-validation experiment and
its rationale, a development schedule, and cost plan.
The Science Mission Directorate will then evaluate
the proposals to select the concept area that will
proceed into “formulation refinement”
as the ST-9 mission. A flight is scheduled for 2010.
The concept areas to be led by Goddard technologists
include system technologies for solar sails (Tim Van
Sant, Code 460), precision formation flying (Jesse
Leitner, Code 591), and large space telescopes (Chris
Schwartz, Code 502). Technologists from the Jet Propulsion
Laboratory (JPL), meanwhile, will lead similar efforts
for a terrain-guided automatic landing system for
spacecraft and an aerocapture system technology for
planetary exploration.
Joining all five team leads are 11 recently selected
technology providers who will conduct studies and
gather data needed to support the proposals. The technology
providers represent both NASA Centers and private
industry. A kick-off meeting is scheduled for late
August. After that point, Van Sant, Leitner, and Schwartz
said they are allowed to begin their studies.
Solar
Sail Technology
In the area of solar sails, Van Sant will work with
the L’Garde, Inc. of Tustin , CA , studying
a flight experiment that would deploy and operate
a steerable solar sail. Solar sails are made of very
thin, reflective membranes (about 1/50 th of the thickness
of a human hair). They are deployed and supported
by ultra-lightweight booms or masts.
The reflective membrane exchanges momentum with reflected
solar light, providing a small but continuous force
that can accelerate a spacecraft through space —
without the use of fuel. Solar photon pressure provides
enough thrust to allow a spacecraft to hover at a
fixed point in space or to change its orbital inclination
— moves that would require prohibitive amounts
of fuel for conventional propulsion systems.
In addition, Van Sant said the concept shows great
promise in placing spacecraft in otherwise inaccessible
orbits and has advanced well beyond mere concept and
the limited ground tests of the past. The technology
would be ideal for three possible missions: Heliostorm,
which would alert scientists of solar storms that
could wreak havoc on Earth-based communication systems;
the Solar-Polar Imager, which could potentially be
the first mission to image the Sun’s Polar Regions
; and the Interstellar Probe, which would travel well
beyond the influence of the Sun into interstellar
space.
Formation
Flying
Leitner, a renowned expert in formation flying, will
work with two JPL researchers and one from the Arizona-based
General Dynamics Decision Systems, to study technologies
that will continuously and collaboratively control
multiple spacecraft flying in formation. In particular,
Leitner’s team will examine advanced inter-satellite
communication and sensor technologies.
Formation flying offers the scientific community a
many orders-of-magnitude improvement in angular resolution
over the current state of the art. With this technique,
scientists would be able to image black holes and
planets in other solar systems by flying many spacecraft
in close collaboration and tight control to effectively
create a distributed segmented telescope or interferometer.
According to Leitner, the technology is ideal for
the Magnetospheric MultiScale Mission, the Terrestrial
Planet Finder-Interferometer, the Stellar Imager,
MAXIM, the Solar Imaging Radio Array and the Submillimeter
Probe of the Evolution of the Cosmic Structure.
Large
Telescopes
Working with researchers from Northrop Grumman Space
Technology, Lockheed Martin Space Systems, and systems
engineers from Goddard and JPL, Schwartz will examine
the technologies required to build large, deployable,
actively cooled sunshields and cryogenically cooled
telescopes — technologies that are critical
for detecting and analyzing the composition of planets
in orbit around nearby stars, and studying the formation
of the first galaxies and the birth of stars and planetary
systems.
From the study, Schwartz and his team will create
a plan to develop a fully instrumented cryogenically
cooled engineering model of a telescope that will
be cooled to temperatures as low as –452 °
Fahrenheit (4 Kelvin). If the directorate chooses
the proposal to proceed to the phase, Goddard and
JPL systems engineers will develop predictive models,
which the ST-9 flight will validate.
Schwartz also said the team is especially interested
in technologies needed to create a silicon-carbide
mirror equipped with a simple thermal interface to
the cooling system.
Modeling is a very important aspect of the study,
Schwartz added. It will pull together all the data
and allow mission planners to develop future cryogenically
cooled missions, like Single Aperture Far-Infrared
Observatory (SAFIR) and Cosmic Background Polarization
(CMBPol) experiment. “We take data and feed
it into our models to predict what telescopes will
do under specific conditions, which is important in
the development of any large telescope system,”
he said.
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