PUBLIC INFORMATION OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. TELEPHONE (818) 354-5011
http://www.jpl.nasa.gov

Mars Pathfinder Mission Status
July 11, 1997
2 p.m. Pacific Daylight Time
After determining Pathfinder's landing site coordinates yesterday, the Mars Pathfinder navigation team today reconstructed the spacecraft's novel entry, descent and landing at a 12 noon Pacific briefing. The team has been analyzing data acquired in the last week to come up with this preliminary landing profile.

Pathfinder was "right on the money," within a kilometer (6/10ths of a mile) of the target landing site, said Dr. Sam Thurman, one of the entry, descent and landing team members.

The spacecraft's terminal velocity as it parachuted to the ground was about 60 meters per second (134 miles per hour). An algorithm onboard the spacecraft that controlled the retro rockets recorded Pathfinder's speed at about 61.5 meters per second (140 miles per hour) at the time the RAD (rocket-assisted deceleration) rockets fired.

One issue of great importance to the Mars Global Surveyor team was Pathfinder's performance during descent, while it was subjected to the forces of the Martian environment. The Pathfinder navigation team reported that the spacecraft did indeed pick up some horizontal wind velocity on the order of about 13 meters per second (20 to 25 miles per hour), which was still well within the limits of the descent and landing design. That information will be very useful to the Mars Global Surveyor flight team when its spacecraft begins aerobraking through the upper atmosphere of Mars in order to circularize the spacecraft's orbit.

Pathfinder next fired its retro rockets at about 98 meters (321 feet) above the ground, just slightly higher than the 90-meter (295-foot) predicted elevation target, but also well within the parameters of the landing strategy. The 65-foot bridle was cut at about 21 meters (65 feet) above the ground, four seconds before impact.

Pathfinder's airbags – a new component of the spacecraft never before tested for a semi-hard landing -- hit the ground at a speed of about 18 meters per second (40 miles per hour) and bounced horizontally across the landscape at about 12.5 meters per second (28 miles per hour). Pathfinder bounced about 15 meters (50 feet) high after impact, then bounced about 14 or 15 times more before coming to a stop. In all, the spacecraft bounced and rolled for about 2.5 minutes and traveled about 1 kilometer (6/10ths of a mile) before coming to a halt.

Activities for Sol 8 of Pathfinder's nearly flawless mission will include a set of commands to drive Sojourner off the large boulder, named Yogi, that it began to climb yesterday before automatically stopping itself. The rover team will send the rover new commands to reposition itself near the rock and attempt to place the alpha proton X-ray spectrometer against the rock again. The imaging team, meanwhile, released the famous "monster pan" today, a full 360-degree, three-dimensional color panorama of the Ares Vallis landing site.

#####