The Jet Propulsion Laboratory's (JPL) Deep Space Network (DSN) provides two-way communications between the Stardust spacecraft and the mission operations team at JPL. Also, the DSN generates radio navigation data used to track and guide the spacecraft to its destination.

To assure continuous communication with spacecraft and compensate for Earth's rotation, three DSN complexes are located 120 degrees apart around the world - in Goldstone, California; Madrid, Spain; and Canberra, Australia. One complex always has Stardust within view. Data from Stardust, called telemetry, is received as a coded bitstream, then forwarded to the Deep Space Operations Center at JPL for processing and distribution to the mission managers and mission scientists.

By the time Stardust's radio signal reaches a DSN antenna, it can be of extremely low wattage. Separating the spacecraft's faint signal frombackground "noise" requires sophisticated techniques that involve both the use of "low-noise" receivers to amplify the signal and also telemetry coding to reduce signal distortion. DSN antennas have parabolic reflector dishes, some as large as 70 meters (230 ft.) in diameter, to capture the signal. Typically, Stardust signals are received on a 34-meter (112 ft) antenna.

The Mission Operations team generates commands for uplink to Stardust. A "packet" of data, called a "sequence" is pre-pared and forwarded by the Deep Space Operations Center to the appropriate complex for transmission to the spacecraft. The antenna is then pointed precisely at the spacecraft and the data are sent using powerful transmitters, the largest of which is capable of generating up to 400 kilowatts.

Additional information is available at

http://deepspace.jpl.nasa.gov/dsn