Contrary to some press rpeorts, this announcement was not "rushed' at all. NASA HQ picked this press conference date a week ago and have been working up to it methodically with telecons and videocons since then. This is in sharp contrast to the situation in August 1996 when the White House leaked details of the ALH 84001 announcement and NASA scrambled to prepare with only 36 hours advance notice.

The briefing will originate from the James E. Webb Auditorium, 300 E St., S.W., Washington, and will be carried live on NASA TV with two-way question-and-answer capability for reporters covering the event from participating NASA centers.

Dr. Ed Weiler, Associate Administrator, Office of Space Science at NASA Headquarters, will make opening remarks. The panelists include:

• Professor Steve Squyres, Mars Exploration Rover (MER) Principal Investigator, Cornell University, Ithaca, N.Y.
• Professor John Grotzinger, MER science team geologist, Massachusetts Institute of Technology, Cambridge, Mass.
• Dr. Benton C. Clark III, MER science team member and Chief Scientist of Space Exploration, Lockheed Martin Space Systems Astronautics Operations, Denver
• Dr. Joy Crisp, MER Project Scientist, NASA's Jet Propulsion Laboratory, Pasadena, Calif.
• Dr. Jim Garvin, Lead Scientist for Mars and the Moon, NASA Headquarters

NASA Television is available on AMC-9, transponder 9C, C-Band, located at 85 degrees west longitude. The frequency is 3880.0 MHz. Polarization is vertical, and audio is monaural at 6.80 MHz. Audio of the broadcast will be available on voice circuit at the Kennedy Space Center on 321/867-1220.

For a live webcast of the briefing and information about NASA TV on the Internet, visit:

http://www.nasa.gov/ntv

More details to follow.

The following recent updates are rumored to be related to what will be announced on Tuesday. No specifics have been released, but the pervailing view is that the announcement has to do with the presence and abundance of water on Mars.