PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov
Contact: Mary Beth Murrill
January 3, 1997
SOLAR SYSTEM'S BEST-OUTFITTED SPACECRAFT DONS ITS THERMAL CLOAK
Using tools and techniques more often associated with fine
tailoring than with space engineering, NASA technicians and
engineers spent part of the holiday season laboring over sewing
machines to clothe the Cassini spacecraft in the protective garb
it must wear to survive during its long journey to Saturn.
At NASA's Jet Propulsion Laboratory in Pasadena, CA, a
unique team of spacecraft shielding technicians are still
cutting, stitching and fitting shiny gold-colored and black
blankets onto the three-story-tall spacecraft in a clean room
near the Laboratory's testing facilities. The work requires a
unique combination of meticulous old-world skills and high-tech
materials to produce the finely sewn, super-strong and extremely
lightweight thermal blankets that will protect Cassini from the
extreme hot and cold of deep space.
Though it appears to be gold foil covering the spacecraft,
the shiny gold coloring of Cassini's blankets is due to the
combination of a transparent layer of amber-colored material on
top of a reflective aluminized fabric.
"Our blankets are built unlike any others," said Mark Duran,
supervisor of the "shield shop" that provides the space survival
gear for JPL's spacecraft and instruments. Using industrial
sewing machines, brown butcher paper patterns and large cutting
tables, Duran's team is working split shifts to finish the
blankets in preparation for Cassini's move into JPL's thermal
vacuum chamber next week. There, the finished spacecraft will be
tested in an artificial space environment.
Spacecraft blankets are built for long-term durability and
high thermal requirements. "Our goal in blanketing Cassini is to
keep temperatures onboard the spacecraft at room temperature,"
said Pamela Hoffman, a thermal requirements engineer who is
managing the blanketing of Cassini. In space, temperatures on
the unblanketed portions of the spacecraft will range from about
-220 to +250 degrees Celsius (about -364 to +482 degrees
Fahrenheit).
All the fabrics used in the blankets must stand up to the
extreme radiation environment of space and protect the spacecraft
for the duration of Cassini's 11-year mission. The blankets also
provide protection against micrometeoroids -- the dust grains of
rocky debris that litter space. Some of Cassini's blankets are
sewn with layers of a canvas-like, carbon-coated fabric called
beta cloth that is especially effective in protecting against
micrometeoroids.
For Cassini, the blankets consist of as many as 24 layers of
different fabrics, including aluminized Kapton, mylar, Dacron and
other special materials.
The blankets also have to meet tough electrical standards.
At both Earth and Saturn, Cassini will be traveling through
environments full of charged particles that could cause an
electrical arc to form across the blankets, Duran said, "so a lot
of work goes into making sure every single layer of each blanket
is electrically grounded." Thin, accordion-like strips of
aluminum are carefully sewn in to each blanket to prevent
electrical arcing.
Cassini, the most sophisticated planetary spacecraft ever
built, is scheduled to be launched October 6, 1997, on a Titan
IV-Centaur rocket from Cape Canaveral, FL. Its voyage to Saturn
will take nearly seven years. The spacecraft will fly a
trajectory that brings it twice around Venus, once past Earth and
once past Jupiter. These "swingby" maneuvers of other planets
will give Cassini the speed it needs to reach Saturn, more than a
billion kilometers away.
Once it reaches Saturn on July 1, 2004, Cassini will enter
orbit and study the planet, its rings and moons for four years.
It will also release a probe to parachute a payload of scientific
instruments through the atmosphere and to the surface of Titan,
Saturn's largest moon. Titan is believed to have large lakes of
liquid ethane on its surface. Chemical reactions in the
atmosphere create a variety of organic molecules that rain to the
surface below. The Titan probe, called Huygens, is provided by
the European Space Agency.
More information on the Cassini mission is available on its
Internet home page at:
http://www.jpl.nasa.gov/cassini
The Cassini mission is a joint project of NASA, the European
Space Agency and the Italian Space Agency. JPL manages the
mission for NASA's Office of Space Science, Washington, DC.
#####
Note to Editors: Images to illustrate this release are available
to news media by contacting JPL's Public Information Office at
(818) 354-5011 or the NASA Headquarters Imaging Branch at (202)
358-1900. A video file containing B-roll and interviews, is also
available to accompany this release. The video file will be
broadcast on NASA Television on Friday, January 3, at 9 a.m., 12
noon, 3 and 6 p.m. Pacific time. NASA Television is available
through the Spacenet 2 satellite on transponder 5, channel 9, 69
degrees west longitude, frequency 3880 MHz, audio subcarrier 6.8
MHz, horizontal polarization.
1-3-97 MBM
#9701
