Dave Steitz
NASA Headquarters
(Phone: 202/358-1730)

Allen Kenitzer
Goddard Space Flight Center
Greenbelt, Md. 20771
(Phone: 301/286-2806)

Terra STATUS REPORT #7
Tuesday, Feb. 1, 2000
10:00 a.m. EST

The Terra Mission operations are going well as instrument activation and outgassing continue after more than six weeks in orbit.

During the week of Jan. 24, while most of the Washington area was shut down for two days because of the snowstorm, operations in the Terra Control Center continued. "It is fortunate that even this recent blizzard did not impede this Team," said Kevin Grady, Terra project manager at NASA's Goddard Space Flight Center, Greenbelt, Md. "The commitment of individuals on this Team remains phenomenal."

Last week began with the MODIS instrument opening its space view door and configuring into science mode. Both of these activities were completed as planned. The first recorder dump of MODIS science data executed as planned and the data were routed to the DAAC and the MODIS Science Team for analysis. The nadir (Earth-viewing) aperture door on MODIS is still closed and it will remain in that state until the first engineering image is taken sometime in late February.

In the middle of the snowstorm, the ASTER instrument also took the opportunity to perform two pointing checks. Both of these movements were successful.

In recent weeks, the Terra Team has been focusing on the spacecraft's orbit ascent maneuvers. During the attempt of the first long ascent maneuver in early January, Terra's flight computer detected a roll attitude anomaly and properly aborted the maneuver approximately one minute into the burn. The data regarding the roll anomaly have now been analyzed and a strategy is ready for completing an ascent sequence. Four firings will take place over the next week to prepare for the ascent sequence, and eliminate (or establish) anomalous thruster performance as one of the contributing factors. The first two firings are planned for this week.

Controllers plan to perform a series of burns, which will place Terra in its operational orbit in formation with Landsat 7. "It is a challenging plan, but safety is always first and foremost when the maneuvering of Terra is planned," Grady added.

Just as the blizzard started last Tuesday morning, controllers were confronted with a data recorder anomaly on Terra. During a routine housekeeping recorder playback, the solid state recorder playback hung up. This housekeeping playback operation followed a successful MODIS science playback and replay on the previous orbit. A number of diagnostics were run on the recorder in the hung state, and finally the recorder was reset to clear the anomaly. Housekeeping and science data recording and playback are now working nominally. Analysis and simulation are in process to determine the cause for this hang up.

High gain antenna radiation hits have been occurring periodically. Controllers are now seeing them on the descending passes through the South Atlantic Anomaly. The telemetry monitor continues to successfully restart the antenna after each of these events.

Terra was launched from Vandenberg Air Force Base, Calif., on Dec. 18, 1999, at 1:57 p.m. EST, and is the "flagship" in the Earth Observing System series of satellites, part of a precedent setting program designed to provide daily information on the health of the planet.

The primary objective of the Terra Mission is to simultaneously study clouds, water vapor, small particles in the atmosphere (called "aerosol" particles), trace gases, land surface and oceanic properties, as well as the interaction between them and their effect on the Earth's energy budget and climate.

Terra is managed by NASA's Goddard Space Flight Center, Greenbelt, Md., for NASA's Office of Earth Science, Washington, D.C. A goal of the Earth Science Enterprise is to expand knowledge of the Earth System from the unique vantage point of space. Earth Science Enterprise data, which will be distributed to researchers worldwide at the cost of reproduction, are essential to people making informed decisions about their environment.

For additional information on the Terra mission, call the Goddard Newsroom at (301) 286-8955. The next Terra status report will be issued during the week of Feb. 7, 2000.

See Terra Status Reports Index.

For more information:

About Terra
Terra Animations
Terra Web Site

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