Mars Global Surveyor continues to perform excellently as it continues on a path that will reach the red planet just under two weeks from now. The spacecraft is currently 3.56 million kilometers from Mars and is closing that gap at rate of 247,000 km per day.
On Monday at 9:30 a.m. PDT, the onboard flight computer commanded Surveyor's small rocket thrusters to fire for twelve seconds. Eric Gratt of the navigation team reports that this tiny burn altered the spacecraft's velocity by 0.29 meters per second and was performed to make final, pre-arrival adjustments to Surveyor's flight path. Specifically, the maneuver altered the tilt of the spacecraft's flight path with respect to the Martian north pole by 3.3 degrees.
Monday's maneuver was the last in a series of four trajectory correction maneuvers designed to refine the spacecraft's flight path to Mars. The first maneuver occurred shortly after launch in November 1996, the second occurred in March 1997, and the third was canceled by chief navigator Dr. Pat Esposito because it was not needed.
Today, the flight team transmitted the T1 command sequence to Surveyor. This sequence will activate on Tuesday, September 2nd at 7:00 a.m. PDT, and contains commands that will ultimately control the spacecraft during the Mars orbit insertion burn on September 11th. In the unlikely event that communications is lost before arrival, Surveyor now possesses the ability to enter Mars orbit without any further instructions from mission control.
In other news, some of the long-range images of Mars obtained by the camera last week have been placed on the Surveyor web site. The camera team, led by Dr. Michael Malin, is currently processing the other images. These remaining images will be placed on the web site shortly after they are released at a press conference on Tuesday, September 9th. The URL to download the images is:
After a mission elapsed time of 295 days from launch, Surveyor is 240.69 million kilometers from the Earth and is moving in an orbit around the Sun with a velocity of 21.92 kilometers per second. This orbit will intercept Mars 13 days from now, slightly after 6:00 p.m. PDT on September 11th (01:00 UTC, September 12th). The spacecraft is currently executing the C11 command sequence, and all systems continue to be in excellent condition.
Status report prepared by:
Office of the Flight Operations Manager
Mars Surveyor Operations Project
NASA Jet Propulsion Laboratory
California Institute of Technology
Pasadena, CA 91109