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.
