During cruise, most of the downlinks have excessive noise in the temperature signal. The source is electronic interference from the Propulsion Drive Electronics, PDE. Conducted and/or radiated electrical noise from the PDE is picked up by the thermocouple system. The peak to peak variability of the temperature signal without this interference, is on the order of 0.06 degrees Celsius. This can be seen clearly on the January 30, 1997 downlink when meteorology health checks were scheduled to study this effect prior to and after the PDE was turned back on. The excess noise, of no consequence during cruise, will cease after the cruise stage is separated from the entry stage in preparation for Entry, Descent and Landing (EDL).
|Data and calibration provided by:
Mars Pathfinder Program
NASA, Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109
Dr. John T. Schofield
James E. Tillman, Research Prof.
and Neal C. Johnson
Department of Atmospheric Sciences, Box 351640
University of Washington
Seattle, WA 98195-1640