Earth awaits signal from Mars

Mars Polar Lander was to have arrived on Red Planet on Friday afternoon.

By ROBERT LEE HOTZ

Los Angeles Times

PASADENA, Calif. --- Anxious space engineers strained Friday for any signal from an errant spacecraft on Mars, hopeful it had landed safely near the Martian South Pole but fearful they may have lost their second mission to the Red Planet since September.

Despite repeated attempts, flight operations engineers at the Jet Propulsion Laboratory in Pasadena were unable to establish contact with the $165 million Mars Polar Lander, which they believe reached the Martian surface at 2:15 p.m. Topeka time Friday.

High resolution images of the landing site suggest that if the spacecraft landed safely, it may have touched down in an area crisscrossed by ravines and potholes caused by frost heaves that could have left the lander askew, one mission scientist said. A second mission scientist speculated the craft may have settled off- kilter, with one of its spindly support struts stuck in a small crater. A third suggested that the surface itself may be so soft --- like baby powder --- that 1,270-pound lander broke through into an underlying crust.

"The spacecraft may just have settled in a little differently than planned," said Dan McCleese, JPL's chief scientist for Mars exploration.

In any of those scenarios, the craft's medium-gain antenna that links it to Earth would point in the wrong direction, preventing it from carrying out its mission. It is quite possible that the spacecraft is functioning normally but transmitting its data uselessly into space, JPL engineers said.

"I am a little bit tense at the moment, but I am still optimistic that we will hear from it," said JPL meteorologist David Crisp, who is in charge of an advanced weather station aboard the lander. "I have worked about 10 years on those instruments. We are holding on to any chance to get this data."

In September, its sister spacecraft --- the $125 million Mars Climate Orbiter --- disappeared as it began to orbit the planet to study weather and look for signs of water. Investigators blamed that loss on an arithmetic error --- the failure to convert English-style measurements of space flight forces into the metric system.

On Friday, flight operations engineers last heard from the Mars Polar Lander at 2:03 p.m. Topeka time when the spacecraft, beginning its automated landing sequence, turned itself away from Earth as programmed so its protective heat shield was aimed toward the Red Planet.

NASA's Deep Space Network at the Goldstone Deep Space Network station couldn't detect any transmission from the lander during two communications sessions Friday, but NASA officials held out hope that contact would be established with the lander sometime in the next few days. To achieve contact, mission managers are playing out a series of emergency options, based on contingency plans drawn up months before the craft ever left Earth.

So far, however, the National Aeronautics and Space Administration has no direct evidence that the three-legged spacecraft actually survived its fiery descent.

As best NASA and JPL can tell, the lander entered the Martian atmosphere traveling at 15,400 miles per hour, with spacecraft temperatures reaching 3,000 degrees Fahrenheit from the friction of the thin tenuous shell of gases. Navigation data suggested that it may have entered the atmosphere on a slightly more shallow flight path than originally planned, but it still appeared to be well within design margins.

Flight operations managers at JPL believe the lander made it to the surface intact because the spacecraft headed into Mars with "extraordinary accuracy," with all its systems in good shape.

As the Polar Lander entered the Martian atmosphere it jettisoned the two $29.2 million microprobes, called Deep Space 2, which are designed to slam like hypersonic hypodermic needles into the planet's soil.

While researchers involved with the lander craft fought off discouragement late Friday, the scientists working on the Deep Space 2 probes were optimistic they would hear as planned from their two tiny probes sometime in the next few days.

If the armored probes survived their hard fall from space, they were expected to begin reporting back to Earth as soon as late Friday.

Their data on subsurface soil conditions, water content and soil conductivity will be relayed to Earth by the Mars Global Surveyor, a satellite that has been orbiting Mars for the past two years.

For the Deep Space 2 researchers, the most important experiment involving the probes centers on their survival. They are essentially technology experiments designed to test new ways of building hardy probes that can function without the expensive and fragile safety nets of parachutes, landing systems or guidance computers.

For the DS2 probes, the most crucial test is one of simple survival.

"If we are capable of getting any signal from the probe, we would be able to validate most of the technology," said DS2 project manager Sarah Gavit. "We would even be very happy to just get a (basic radio wave) signal" even it carried no data at all because that would show the probes survived the smash with Mars.

Mars

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