MEDIA RELATIONS 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 Polar Lander Mission Status
December 4, 1999 11:15 p.m.
       Mission controllers for NASA's Mars Polar Lander are proceeding with their checklist in a continuing attempt to communicate with the spacecraft.

       On Sunday, Dec. 5 from 10:50 to 11:00 a.m. Pacific Standard Time, they will try to hear the lander's signal by using NASA's currently-orbiting Mars Global Surveyor spacecraft as a relay system for the lander's UHF radio. Until this point, engineers have tried to reach the lander via its medium gain antenna.

       Controllers did not hear from the spacecraft during a communications opportunity on Saturday, Dec. 4 at 8:30 p.m. PST. They hoped to make contact during that window if, after landing, the spacecraft had successfully pointed its antenna toward Earth, then entered a safe, or standby mode.

       "Now we can cross that scenario off the list," said Mars Polar Lander project manager Richard Cook of JPL. "We're ready to move on to the next possibility on Sunday morning, which we hope will work if the spacecraft is not in safe mode, but has its antenna pointed incorrectly. We're sprouting ideas as we go along about how to contact the lander."

       If contact is not established during that attempt, additional attempts scheduled at this point will be made as follows:

      - Sunday, Dec. 5, from 10:10 to 11:10 p.m. using the lander's medium gain antenna scan if it is in safe mode but its antenna is not pointed correctly.
      - Tuesday, Dec. 7, at 12:20 a.m. PST using Mars Global Surveyor if Mars Polar Lander is in safe mode.

       Analysis of the landing site reveals the spacecraft would have touched down within 10 kilometers (6 miles) of the target site on the Martian south pole, according to Dr. Sam Thurman at JPL, the lander's flight operations manager. He said they see no surface features that would obstruct the lander's view of Earth and therefore hamper its communications capabilities.

       Engineers for the Deep Space 2 microprobes are continuing their attempts to communicate with the probes every two hours. The microprobes, designed to impact Mars about 60 kilometers (about 35 miles) north of the lander, will transmit data through Mars Global Surveyor.

       "The probes may have arrived in an area of high slopes, rough terrain or sand dunes," said Deep Space 2 project manager Sarah Gavit.

       Mission engineers believe the probes have entered a phase where they broadcast their data automatically for one minute out of every five. "It's also possible that the probes' batteries have not warmed sufficiently to power up the communications system. We're checking into all possibilities."

       Mars Polar Lander is part of a series of missions in a long- term program of Mars exploration managed by JPL for NASA's Office of Space Science, Washington, D.C. JPL's industrial partner is Lockheed Martin Astronautics, Denver. JPL is a division of the California Institute of Technology in Pasadena.

##### MEDIA RELATIONS 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 Polar Lander Mission Status
December 4, 1999, 5:45 p.m. PST
       Flight controllers for NASA's Mars Polar Lander have another opportunity to listen for a signal from the spacecraft beginning tonight at 8:30 p.m. PST. In a meeting late this afternoon they decided to listen for the lander during the first 30 minutes of the communications window, then they would transmit commands to the medium-gain antenna telling the spacecraft to search for Earth.

       One scenario that would explain why engineers have not yet heard from the lander is that the spacecraft entered standby, or "safe mode," about 20 minutes after landing shortly after 12 noon PST Friday, Dec. 3. If the lander entered safe mode at that time, it would not be able to receive any communication until it "wakes up" this evening. It would be preprogrammed by onboard software to start looking for Earth starting at noon on Mars, or about 8:30 p.m. PST. The communication window lasts until 10:45 p.m. PST.

       If contact has not been established by Sunday morning, Dec. 5, flight controllers will listen to see if the lander transmits via a UHF radio to the currently orbiting Mars Global Surveyor spacecraft. The lander would do that at about 10:50 a.m. PST Sunday if it did not receive commands from Earth telling it not to do so.

       Engineers working on NASA's Deep Space 2 microprobes have additional opportunities to hear from the probes this evening at about 5:30 p.m. and 7:30 p.m. PST through the Global Surveyor relay. The probes would automatically begin to transmit at those times if their radio receivers were unable to pick up commands from Global Surveyor.

       Mars Polar Lander is part of a series of missions in a long- term program of Mars exploration managed by JPL for NASA's Office of Space Science, Washington, D.C. JPL's industrial partner is Lockheed Martin Astronautics, Denver. JPL is a division of the California Institute of Technology in Pasadena.

##### MEDIA RELATIONS 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 Polar Lander Mission Status
December 4, 1999 4:15 a.m.
       Mission controllers for NASA's Mars Polar Lander and the accompanying Deep Space 2 microprobes will continue attempting to communicate with the lander and the probes throughout the weekend.

       Controllers did not hear from the spacecraft in their first few attempts to communicate with the lander and the probes during the first 12 hours after the scheduled landing time.

       The Deep Space 2 team will try to contact the probes approximately every two hours. The next opportunity for the Mars Polar Lander to contact Earth will be on Saturday evening, Dec. 4 at about 8:30 p.m. PST.

       "We're remaining upbeat," said Mars Polar Lander Project Manager Richard Cook at JPL. "We have prepared for various scenarios, and we're trying all the options."

       Cook pointed out that if the spacecraft entered a standby, or safe mode, about 20 minutes after landing at 12:15 p.m. PST on Fri., Dec. 3, it would not be able to receive any communications until it takes itself out of safe mode on Saturday evening.

       So far, mission controllers have been attempting to communicate with the lander by using its medium gain antenna. If contact has not been established by Sunday morning., Dec. 5, they will try to communicate with the lander by using NASA's currently-orbiting Mars Global Surveyor spacecraft as a relay system. In that scenario, the lander would automatically switch to its UHF radio.

       On Fri., Dec. 3, ground controllers attempted to "talk to" the lander at 6:27 p.m. PST. They tried to contact the Deep Space 2 microprobes at 7:30, 9:30, 11:30 p.m., 1:30 and 3:30 a.m. PST.

       The Deep Space 2 microprobes, which impacted Mars about 60 kilometers (about 35 miles) north of the lander, will transmit data through Mars Global Surveyor.

       "We know that the Mars Global Surveyor relay system is working," said Deep Space 2 Project Manager Sarah Gavit.

       Latest estimates indicate that Mars Polar Lander touched down on a gentle slope of about two degrees within an "amphitheater" near the edge of a ridge, according to Dr. David Paige of UCLA, principal investigator for the Mars Volatiles and Climate Surveyor science package on the lander.

       Mars Polar Lander is part of a series of missions in a long- term program of Mars exploration managed by JPL for NASA's Office of Space Science, Washington, D.C. JPL's industrial partner is Lockheed Martin Astronautics, Denver. JPL is a division of the California Institute of Technology in Pasadena.

      

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