Stardust Sample Return:
NASA's Stardust spacecraft is
heading home with its one-of-a-kind cargo: The first-ever return of pristine
samples of comet material. The mission collected the samples in January 2004 as
it flew through the cloud of gas and dust surrounding comet Wild 2.
Earth Return 
After traveling more than 4.6
billion kilometers (more than 2.8 billion miles), Stardust will release a
return capsule from space in the pre-dawn hours of
If necessary, the Stardust team
can stop the entry procedure and direct the spacecraft into a backup orbit
around the sun. This maneuver would allow for another landing opportunity
3-and-a-half to 4 years later. .
About 15 minutes after letting go
of the capsule, Stardust will fire its thrusters in a maneuver that will put it
in orbit around the sun. The capsule will continue streaking toward Earth.
Four hours after separation, the
capsule will enter Earth's atmosphere, moving at 46,440 kilometers per hour
(28,860 miles per hour). This will be the fastest reentry of any human-made
object on record. Weather permitting, radar and range cameras at the Utah Test
and
Fifty-two seconds after entry, at
an altitude of 61 kilometers (200,000 feet), the capsule will reach its highest
temperature. The temperature on the exterior heat shield will spike to 2700
degrees Celsius (4900 Fahrenheit).
During the next 60 seconds, the
capsule will rapidly decelerate from 38 times the force of gravity (38 G's) to
3 G's and a small parachute, called a drogue chute, will deploy. At this point,
the capsule will be nearly over its landing zone.
About three minutes after
atmosphere entry, the capsule will begin its vertical descent over its landing
area. At an altitude of about 3 kilometers (10,000 feet), the capsule will cut
one of the lines holding the drogue chute. This will allow the drogue to pull
out a larger parachute. At the same time, the capsule will activate its UHF
locator beacon. Batteries powering the UHF can operate the beacon for 10 hours.
The sample return capsule will
touch down at about
*(
Minutes after the capsule touches
down, a helicopter will arrive at the landing site. The capsule will be
inspected, photographed and placed in a special handling fixture, then flown to
a temporary cleanroom. The sample canister will be
removed from the capsule and connected to a purge system that feeds it with a
constant flow of ultra-pure gaseous nitrogen. The image to the left is a
rehearsal.
A few days later, the capsule and
canister will be transported to NASA's
Photo Album
- Space Travel
Launch
http://www-pao.ksc.nasa.gov/kscpao/images/1999/feb/99pc0158.jpg
Passing by Home
Stardust's flight path took it
around the sun three times. During its first pass by Earth, the spacecraft used
Earth's gravity to set it on a path to rendezvous with comet Wild 2. At its
closest approach to Earth, Stardust was about 6,000 kilometers (more than 3,700
miles) away and viewable from high-powered telescopes.
Image courtesy:
http://stardust.jpl.nasa.gov/photo/ega1.jpg
Particle Collection
While traveling to Wild 2,
Stardust deployed its collector grid over two time periods to catch
interstellar particles flowing into our solar system. Scientists believe these
particles contain heavy chemical elements that originated in stars.
http://www.jpl.nasa.gov/images/spacecraft/stardust_solo_browse.jpg
Asteroid Annefrank
As a rehearsal for its comet
encounter, Stardust flew within 3,100 kilometers (1,927 miles) of asteroid Annefrank on
The false-color view (right)
emphasizes the variations in surface brightness, which result from different
angles of illumination from the sun, as well as from variations in the surface.
http://www.nasa.gov/mission_pages/stardust/multimedia/pia02885.html
http://photojournal.jpl.nasa.gov/catalog/PIA02886
- Instruments
Aerogel
Stardust used a substance called aerogel to capture and store the interstellar and cometary particles it collected.
Aerogel is a silicon-based solid with a porous
sponge-like structure in which 99 percent of the volume is empty space. It is
the lightest-weight, lowest-mass solid, and has been found to be ideal for
capturing tiny particles in space.
http://www.nasa.gov/mission_pages/stardust/multimedia/pia03186.html
Dust Collectors
The aerogel
was placed inside a grid of dust collectors that resemble a metal ice cube tray
set in an oversize tennis racket.
http://www.nasa.gov/mission_pages/stardust/multimedia/pia03188.html
Collection
The collector grid was extended
into the dust stream, exposing the blocks of aerogel
to the particles. When Stardust flew through comet Wild 2's coma, the impact
velocity of particles as they were captured was up to six times the speed of a
bullet fired from a high-powered rifle. After collecting samples, the collector
grid folded back down into the spacecraft.
Other Instruments
Stardust carries two other
dedicated science instruments. The comet and interstellar dust analyzer studied
the chemical composition of particle in the comet's coma. The dust flux monitor
measured the size and frequency of dust particles in the coma.
Top image: comet and interstellar dust analyzer
http://www.nasa.gov/images/content/137833main_dustanalyzer-browse.jpg
Bottom image:dust flux
monitor
http://stardust.jpl.nasa.gov/mission/dfm.html
- Comet Close-Up
Close Look
This close-up view of comet Wild
2, taken on
http://www.nasa.gov/mission_pages/stardust/multimedia/pia06285.html
Spewing Jets
This composite image was taken by
Stardust's navigation camera during the close approach to comet Wild 2 on
To create this image, a short
exposure image was overlain on a long exposure image taken just 10 seconds
later.
http://www.nasa.gov/mission_pages/stardust/multimedia/pia05578.html
One Dozen Views
This sequence, showing some of the
closest images of comet Wild 2, starts at the upper left and continues left to
right on the first three rows. The overexposed and out-of-sequence images at
the bottom are long exposures taken to help the spacecraft navigate during its
encounter. They also capture the best images of the comet's jets.
http://stardust.jpl.nasa.gov/highres/1097899fig1.jpg
If You Were There
This is an artist's concept
depicting a view of Wild 2 as seen from Stardust during its flyby of the comet
on
http://www.nasa.gov/mission_pages/stardust/multimedia/pia06283.html
- Time Capsules
Close-Up on Tempel 1
Scientists are interested in
studying comets because they are believed to be like time capsules from the
early formation of the solar system. The materials that make up a comet provide
a record of conditions when the planets were forming 4.6 billion years ago.
Several NASA missions have already
made close observations of comets. This image shows the view from Deep Impact's
probe 90 seconds before its planned collision with comet Tempel
1 in July 2005.
http://www.nasa.gov/mission_pages/deepimpact/multimedia/PIA02128.html
Tempel Alive With Light
This view of comet Tempel 1 was taken 67 seconds after the planned impact with
Deep Impact's probe. The image, taken by the mission's flyby spacecraft,
reveals topographic features including ridges, scalloped edges and possibly
impact craters formed long ago.
http://www.nasa.gov/mission_pages/deepimpact/multimedia/HRI-937.html
Comet Borrelly
Close-Up
This is the highest resolution
view of the icy, rocky nucleus of comet Borrelly,
taken just before NASA's Deep Space 1 made its closest approach to the comet in
September 2001. A variety of terrains, surface textures, mountains and fault
structures are visible. The image shows the 8-kilometer-long (5-mile) nucleus
from about 3417 kilometers (more than 2,000 miles) away.
http://photojournal.jpl.nasa.gov/catalog/PIA03500
Comet Borrelly
A false-color composite of images
from Deep Space 1 shows features of comet Borrelly's
nucleus, dust jets escaping the nucleus, and the cloud-like coma of dust and
gases surrounding the nucleus. Deep Space 1 took these images on
http://photojournal.jpl.nasa.gov/catalog/PIA03865