There were five Deep Space Network (DSN) tracking passes during the
past week. Commands were sent to the spacecraft to set the Command Loss
Timer back to its original value of nine days. The spacecraft, due to
interference from the Sun (solar conjunction), did not receive these
commands last week, and they were retransmitted. Other commands
were transmitted to the spacecraft to update the Small Forces, Earth
ephemeris and Sun ephemeris files. These files contained updated
information due to the trajectory and mass properties changes from the
Deep Space Maneuver in January. All subsystems onboard the spacecraft
are performing normally

The spacecraft transitioned back to Gyro Based Attitude Mode with the
Inertial Measurement Unit (IMU) powered on to provide high rate
attitude data during the aerogel grid deployment. Also six images were
taken with the Star Camera. These images will be analyzed to determine
the health of the Star Camera and provide information concerning why
the number of valid stars occasionally drops from 10 to 4 stars.

A historic milestone in planetary exploration was achieved by STARDUST this
week. The aerogel collector was successfully deployed to begin its
interstellar dust collection. The commanded timeline was followed
precisely with the heat shield on the Sample Return Capsule (SRC)
opening, followed by the shoulder motor moving the collector out of the
SRC and then finally the wrist motor extending the collector fully to
its collection position where it sticks above the spacecraft
dust shielding and into the interstellar dust stream.

The deployment was confirmed during deployment with small torques
detected by the attitude control system as well as the motors turning
for the proper time duration. The final confirmation came with the
shoulder and wrist microswitches being triggered when deployment was

In the spacecraft’s current orbit where it just came out of solar
conjuction, its inertial velocity direction is about 49 degrees away
from traveling directly with the interstellar dust stream. Over the
next few months as the spacecraft orbit curves around the sun, the
spacecraft motion will parallel the dust stream motion.

After the collector was fully deployed and all subsystems were verified
to be operating normally, a command was sent to move the collector 49
degrees in the direction of closing to position the collector surface area
normal to the interstellar dust stream flow. Every few weeks the wrist
motor will be commanded to change this angle by a few degrees to keep
the collector surface normal to the stream. Near the end of this first
interstellar collection period, the collector will be fully deployed
again. This historic collection will continue until 25 May 2000;
however we are currently exploring extending this period by a few
additional weeks.

There are no microswitches in between the full open and full close
shoulder and wrist positions to tell us the exact position of the
aerogel collector. Control and knowledge of this position during the
next few months is achieved by commanding the wrist motor for a fixed
length of time to provide the desired angle movement and then verify
this movement from telemetered wrist motor operating data. To reach
its current 49 deg offset angle, the wrist motor was power on for about
20 seconds, which was executed perfectly.

The collector has two sides of aerogel: side A for interstellar dust
collection and side B for cometary dust collection. We control which
side of the collector is exposed to a dust stream by orienting the
spacecraft in inertial space. Currently the spacecraft is oriented
with its dust shields pointing in the direction of its motion about the
sun and the interstellar dust particles hitting the back side (side A)
of the collector. The spacecraft orientation with be reversed relative
to the Comet Wild 2 particle stream so that the dust shields will
protect the spacecraft while the collector is extended above these
shields, into the oncoming dust stream.

As its name indicates, the interstellar particles to be collected now
are from outside of our solar system. There is a very tenuous dust
cloud within our galaxy, the Milky Way, which our solar system is
moving through. The direction of the interstellar dust is opposite to
the motion of the sun, which drags the planets with it, relative to the
particle media. Thus the dust motion is small relative to the solar
system motion that is controlling the direction of interstellar dust
passing through our solar system.

The interstellar dust stream was detected many years ago by earth
orbiting spacecraft and earlier Pioneer and Voyager spacecraft have
improved information on this stream. More recently the Ulysses and
Galileo spacecraft have confirmed the stream direction as well as
indicated that the density of particles in the stream is very low.=20
With the size of the STARDUST collector being only about 0.1 meter
square, on the order of 100 such particles are expected to be collected
during the 2 collection periods. The second collection period is in
about two years, when again the spacecraft is traveling in the
direction of the particle stream.

High praise goes to the spacecraft builder and flight operations team
at Lockheed Martin Astronautics in Denver, Colorado for this successful
deployment and the start of the sample collection. The interstellar
particles will be returned to earth with the Wild 2 particles for
detailed science analyses in 2006 after the SRC lands in the Utah Test
and Training Range.

Following the successful deployment, three images were taken with the
Navigation Camera. These images were taken through the
Optical Navigation filter (widest bandwidth) with the calibration lamp
on. Two images had an exposure time of 200 milliseconds and the third
had an exposure duration of 1 second. These images will be analyzed to
help determine the cause of the apparent decrease in Navigation Camera
sensitivity observed when the last star images were taken in October.

Also, after the aerogel collector deployment, the spacecraft transitioned
back to All Stellar attitude mode.

For more information on the STARDUST mission – the first ever
comet sample return mission – please visit the STARDUST home page: