NASA's Solar Sail
Propulsion Team and industry partners have successfully deployed
two 10-meter solar sails in a vacuum environment — a critical
milestone in development of the unique propulsion technology that
could enable future deep space missions. Solar sail propulsion uses
the Sun's energy to travel through space. The work is led by the
In-Space Propulsion Technology Projects Office at the Marshall
Center.
NASA engineers and their industry partners have successfully
deployed two solar sails — each nearly 33 feet in length
along one side — reaching a critical milestone in the
development of a unique propulsion technology that could enable
future deep space missions.
Solar sail propulsion uses the Sun's energy to travel through
space, much the way wind pushes sailboats across water. The
technology bounces a stream of solar energy particles called
photons off giant, reflective sails made of lightweight material 40
to 100 times thinner than a piece of writing paper. The continuous
pressure provides sufficient thrust to perform maneuvers, such as
hovering at a point in space and rotating the space vehicle's plane
of orbit, which would require too much propellant for conventional
rocket systems. Because the Sun provides the necessary propulsive
energy, solar sails also require no onboard propellant, thus
reducing payload mass.
In July, L'Garde, Inc., of Tustin, Calif., successfully deployed
a solar sail technology system. Earlier this year, Able Engineering
of Goleta, Calif., successfully completed testing of its own solar
sail design. The work of both contractors is led by the In-Space
Propulsion Technology Projects Office at NASA's Marshall Space
Flight Center in Huntsville, Ala.
"We are making the stuff of science fiction into reality," said
Les Johnson, manager of the In-Space Propulsion Technology Projects
Office at the Marshall Center. "It has been a tremendous
engineering challenge, and I'm pleased and proud of the teams that
have made it happen."
L'Garde's sail deployment was conducted in a 100-foot-diameter
vacuum chamber at NASA's Glenn Research Center Plum Brook Station
in Sandusky, Ohio. The tests included temperatures as cold as minus
112 degrees Fahrenheit to simulate the conditions of open
space.
The sail technology used an inflatable, thermally rigidized boom
system, which inflates and becomes stiff in space environment
conditions. The boom is the core of the support structure for the
thin, reflective solar sail itself — merely a fraction of the
thickness of a human hair -- and includes a stowage structure and
built-in deployment mechanism. Engineers used a computer-controlled
boom pressurization system to initiate deployment of the boom and
sail system.
In May, Able Engineering also successfully completed testing of
a solar sail design at NASA's Langley Research Center in Hampton,
Va. This sail employed a "coilable" graphite boom, which is
extended or uncoiled via remote control — much the way a
screw is rotated to remove it from an object. The boom supports the
lightweight sail, which is made of an aluminized,
temperature-resistant material called CP-1. Named NASA's 1999
Invention of the Year, CP-1 was invented by the Langley Research
Center and is produced under exclusive license by SRS Technologies
of Huntsville. The boom system also includes a central stowage
structure and deployment mechanism.
Tests of the coilable boom were conducted in a 50-foot-diameter
vacuum chamber. Engineers remotely initiated deployment of the boom
and sail in April, then spent the next five weeks studying its
shape and system dynamics — or how the solar sail functions
in relation to force, weight and tension.
Data from both tests will be used to make improvements to future
solar sail design and modeling. In March 2005, NASA plans a
laboratory deployment of a sail more than 65 feet in length.
Solar sail technology was selected for development in August
2002 by NASA's Office of Space Science in Washington. Along with
the sail system design projects by L'Garde and Able Engineering,
NASA's Jet Propulsion Laboratory in Pasadena, Calif., was tapped to
develop an integrated set of computer-based solar sail simulation
tools. These are just three of a number of efforts undertaken by
NASA Centers, industry and academia to develop solar sail
technology.
Solar sail technology is being developed by the In-Space
Propulsion Technologies Program, managed by NASA's Office of Space
Science and implemented by the In-Space Propulsion Technology
Projects Office at Marshall. The program's objective is to develop
in-space propulsion technologies that can enable or benefit near
and mid-term NASA space science missions by significantly reducing
cost, mass and travel times.