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The BBC's Rachael Payne reports
"No news was not good news"
 real 28k

Project Leader Dr Richard Cook
"Our expectations for the success of the mission are remote"
 real 28k

The BBC's Leo Enrigth
"The communications failure was a huge disappointment to controllers"
 real 28k

Tuesday, 7 December, 1999, 12:20 GMT
Mars probe silence signals failure
Richard Cook explains what should have happened in front of a model of the probe

The Mars Polar Lander (MPL) failed again early on Tuesday to communicate with Earth, signalling what may be the end of Nasa's latest Martian expedition mission.

You could say that our expectations for the success of the mission are remote
Richard Cook, MPL project manager
In what scientists at the Jet Propulsion Laboratory in Pasadena, California said was their "last best" opportunity to contact the spacecraft, a satellite orbiting Mars tried to contact the lander for 6 minutes at around 0800 GMT.

The satellite was met by a stony silence from the $165m lander.

This seventh attempt to contact the lander had been by the MPL project manager Richard Cook as the last attempt with any "high probability" of success.

One more try

At 0820 GMT Wednesday morning, Nasa will try yet again to communicate with the missing probe.

The Mars Global Surveyor satellite will pass almost directly over what should have been the touchdown point of the craft.

Martian MPL should have landed near the Martian south pole
It will be midday on Mars and the lander's solar batteries should be fully charged, allowing it to transmit at full power.

If that attempt fails, Nasa will resort to attempting to put the MPL's systems into neutral, or "safe mode", by sending a command via the satellite.

The scientists can then try to launch the probe's systems from safe mode.

HAVE YOUR SAY Mr Cook said that there was no great expectation that this last ditch attempt would succeed. He said Nasa would continue for a "couple of weeks" to listen for a signal from the MPL, and his "team is working on other possibilities".

Miniprobes also missing

The MPL has been out of contact with Earth since it turned its back on home and began the descent on to the Red Planet on Friday.

Artist drawing of MPL An artist's imnpression of the MPL landing safely on Mars
Possible causes for the communication failure run from the theory that the MPL was destroyed as it entered the Martian atmosphere to the possibility that it landed in difficult terrain, toppled over and is incapable of deploying or pointing its antenna.

Also of concern to Nasa is the lack of contact with the two mini-probes which comprised the $30m Deep Space Two project. These were released from the Polar Lander during entry.

They were designed to collect atmospheric data and analyse soil samples once they had smashed into the planet's surface.

Mars 'on the cheap'

The apparent failure of MPL comes just 10 weeks after the Mars Climate Orbiter was lost because of an embarrassing mix-up over metric and English units.

Already commentators are calling on Nasa to rethink its "cheaper, faster, better" policy of investing in low-cost Mars missions.

"It really looks like these missions haven't had enough money or people working on them so mistakes have crept in that have led to these failures," John Pike, Space Policy Director for the Federation of American Scientists (FAS), told the BBC.

"We've been trying to go Mars on the cheap - we've been trying to take a 15-gallon trip with just 10 gallons of gas in the tank."

Are Mars missions a waste of money?

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See also:
06 Dec 99 |  Sci/Tech
Mars: Mission impossible?
05 Dec 99 |  Sci/Tech
Mars probe stays silent
04 Dec 99 |  Sci/Tech
Nasa hopeful despite Mars silence
30 Nov 99 |  Sci/Tech
Polar lander ready for Mars
30 Nov 99 |  Sci/Tech
Martian mysteries under microscope
11 Nov 99 |  Sci/Tech
Orbiter loss blamed on 'silly mistakes'

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