Stardust Status Report
May 2, 2003
There were two periods of communications with the Stardust spacecraft
in the past week. Telemetry relayed from the spacecraft indicates it is
healthy and all subsystems continue to operate normally.
Commands were successfully transmitted to the spacecraft to redefine
the battery 100 percent state of charge definition as the spacecraft
continues to move closer to the Sun back to Earth's orbit,
resulting in the solar panels producing more power. The battery
performance, as expected, has degraded over time and with it a
reduction in the maximum voltage supplied by the battery. These
commands will increase the battery maximum voltage to approximately
32.5 volts. The battery state of charge is determined by battery
pressure, which has now been redefined as 800 psi, increased from 740
psi. In early February a test was performed on the battery to
determine its full value. The battery reached 900 psi before
entering its exothermic region where battery temperature increases
instead of charging. After the Comet Wild 2 encounter in January 2004,
we anticipate raising the 100 percent value again to ensure there will be
sufficient power during the third aphelion when the spacecraft will
reach 2.8 AU from the Sun.
Testing for the Comet Wild 2 encounter under nominal conditions
continues in the Spacecraft Test Laboratory (STL). These tests are
being used to establish a nominal baseline that will ensure a
faster turn-around when the off-nominal tests are performed.
Earth-based telescopic observations of Comet Wild 2 are being taken as
approaches its perihelion passage (its closest distance from the Sun)
on September 25 of this year.
Information on the present position and orbits of the Stardust spacecraft
and Comet Wild 2 may be found on the "Where Is Stardust Right Now?"
web page located at:
http://stardust.jpl.nasa.gov/mission/scnow.html
For more information on the Stardust mission -- the first ever comet
sample return mission -- please visit the Stardust home page:
http://stardust.jpl.nasa.gov
