FOR IMMEDIATE RELEASE                        September 23, 1999

NASA'S MARS CLIMATE ORBITER BELIEVED TO BE LOST

     NASA's Mars Climate Orbiter is believed to be lost due to a 
suspected navigation error.

     Early this morning at about 2 a.m. Pacific Daylight Time the 
orbiter fired its main engine to go into orbit around the planet. 
All the information coming from the spacecraft leading up to that 
point looked normal.  The engine burn began as planned five 
minutes before the spacecraft passed behind the planet as seen 
from Earth.  Flight controllers did not detect a signal when the 
spacecraft was expected to come out from behind the planet. 

     "We had planned to approach the planet at an altitude of 
about 150 kilometers (93 miles). We thought we were doing that, 
but upon review of the last six to eight hours of data leading up 
to arrival, we saw indications that the actual approach altitude 
had been much lower.  It appears that the actual altitude was 
about 60 kilometers (37 miles). We are still trying to figure out 
why that happened," said Richard Cook, project manager for the 
Mars Surveyor Operations Project at NASA's Jet Propulsion 
Laboratory.  "We believe that the minimum survivable altitude for 
the spacecraft would have been 85 kilometers (53 miles)."

     "If in fact we have lost the spacecraft it is very serious, 
but it is not devastating to the Mars Surveyor Program as a 
whole.  The program is flexible enough to allow us to recover the 
science return of Mars Climate Orbiter on a future mission. This 
is not necessarily science lost; it is science delayed," said Dr. 
Carl Pilcher, science director for Solar System Exploration at 
NASA Headquarters, Washington, D.C. "We have a robust program to 
explore Mars that involves launching on average one mission per 
year for at least a decade. It began with the launch of Mars 
Pathfinder and Mars Global Surveyor in 1996, continued with Mars 
Climate Orbiter and Mars Polar Lander and will be followed by 
more missions in 2001, 2003 and 2005. In fact, Mars Polar Lander 
will arrive in just over two months and its mission is completely 
independent of the Mars Climate Orbiter.  The science return of 
that mission won't be affected."

     Flight controllers at NASA's Jet Propulsion Laboratory in 
Pasadena, CA and Lockheed Martin Astronautics in Denver, CO will 
continue their efforts to locate the spacecraft through the Deep 
Space Network during the next several hours.  A special 
investigation team has been formed by JPL to further assess the 
situation.

     Mars Climate Orbiter is one of a series of missions in a 
long-term program of Mars exploration known as the Mars Surveyor 
Program that is managed by the Jet Propulsion Laboratory for 
NASA's Office of Space Science, Washington, DC.  JPL is a 
division of the California Institute of Technology, Pasadena, CA.

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