Pioneer 10 Update 1 June 2000

Pioneer 10

(Launched 2 March 1972)
Distance from Sun (1 June 2000): 75.32 AU
Speed relative to the Sun: 12.24 km/sec (27,380 mph)
Distance from Earth: 11.41 billion kilometers (7.092 billion miles) Round-trip Light Time: 21 hours 08 minutes

 
From a recent tracking report:

Deep Space Station (DSS): 63 Madrid, Spain
Spacecraft: 23 [Pioneer 10]
Date of track: 3/21/00 Day of Year (DOY)=081
Beginning of Track (BOT) = 21:15 (Universal Coordinated Time)
End of Track (EOT) = 23:50
Spacecraft Health: Thermal, Power, RF, Science all nominal.

The Radioisotope Thermoelectric Generators (RTGs) continue to provide sufficient power to support the current spacecraft load of transmitter, receiver, command and data handling as well as the Geiger Tube Telescope (GTT) science instrument.

The RTGs are currently providing approximately 65 Watts of power (about 42% of the 155 Watts launch value).

The science and transmitter are turned off to provide enough power to fire the attitude control engines for the biannual spacecraft pointing maneuvers towards the Sun (the latest maneuver was executed on 2/11-12/00). The battery voltage is often discharged and charged. However, the battery does not support any of the load, being charged to only about 1 volt at its peak, down from its nominal value of 9 volts.

The Bus Voltage is at a steady 27 Volts with a Bus Current of about 1.3 Amps.

The platform temperature is still within acceptable limits at -41 degrees F (the nominal range is between -63 F to 180 F).

The Deep Space Network (DSN) continues to provide good data with the received signal strength of -178 dBm (only a few dBm from the receiver threshold of -180 dBm).

Although powerwise Pioneer 10 is operating OK with one science instrument on, the DSN may not be able to get good telemetry lock as the signal-to-noise ratio (SNR) continues to decrease. Even though in a year the DSN may still be able to get good telemetry lock, being this close to the receiver threshold and losing about 0.3 dBm/yr due to range, maintaining contact will be a challenge.

(From update report by Ric Campo, Pioneer Operations Supervisor)

Larry Lasher, Pioneer Project Manager llasher@mail.arc.nasa.gov