Mars Pathfinder Mission Status - 4 February 1997

From: David S Dubov <> (by way of Jan Wee <>)
Subject: Mars Pathfinder Mission Status - 4 February 1997
Date: Tue, 04 Feb 1997 17:11:54 -0600

Dear discuss-lfm members,

FYI -- David just posted this news...



4 February 1997

The Mars Pathfinder spacecraft is currently 19 million km (11 million miles)
from Earth traveling at 30 km/s on its trajectory to Mars. All spacecraft
subsystems continue to operate as expected.

At 5:00 PM PST on February 3, we successfully completed our second Trajectory
Correction Maneuver. This maneuver was designed to correct errors in the first
TCM performed on January 9, and move us closer to our final trajectory. The
spacecraft will not be placed on a Mars atmospheric entry trajectory until after
TCM-3 (currently scheduled for May 5) because of planetary quarantine
requirements. The TCM-2 design team, led by Flight Engineer Guy Beutelschies,
developed a two part approach to perform the maneuver. In the first part, the
spacecraft fired two of its forward facing thrusters continuously for five
minutes. The change in velocity for this "axial" component was about 1.5 m/s.
The second part of the maneuver was a smaller velocity correction of 0.1 m/s
performed in the "lateral" mode. In this mode, the spacecraft pulses all four
thrusters on one side of the spacecraft for five seconds. This pulse causes a
small change in the spacecraft velocity in the direction perpendicular to the
spacecraft spin axis. This mode will be used for all future maneuvers, so TCM-2
was a good proof-of-concept test. Early analysis of tracking data from NASA's
Deep Space Network indicates that both components were completed successfully.

Upon completing the maneuver, the spacecraft's spin axis was turned 15 degrees
back toward Earth so that we can perform radio navigation more effectively. The
spacecraft is currently pointed about 5 degrees from Earth and 2 degrees from
the Sun. We will remain in this attitude until late March.

The spacecraft will remain in a relatively quiescent mode for the next two to
three months. The flight team is currently working hard to complete planning for
Mars entry and surface operations.

For more information, please visit our website at