NASA waits for Mars landing confirmation
Artist's concept of the Polar Lander on Mars
(CNN) -- If all went according to plan, history was made this afternoon as humankind landed its first spacecraft on the barren, windswept southern pole of Mars.
Confirmation of a successful landing, however, wouldn't reach Earth for at least 30 minutes and could take much longer -- perhaps even days.
Shortly after 3 p.m. EST, the Mars Polar Lander was scheduled to have parachuted through the thin martian atmosphere, deployed its lander legs, then fired its thrusters for a gentle, controlled descent to the frigid surface.
Scientists hope the $265 million project will reveal crucial information about the martian climate and possibly even signs of water ice buried beneath the planet's topsoil. The mission also is carrying the first microphone to Mars in hopes of letting Earth hear its neighbor for the first time.
Launched in January, the Mars Polar Lander marks humankind's first return to the surface of the red planet since 1996, when the Mars Pathfinder mission sent its rover crawling across the rocky martian landscape.
It also marks the culmination of months of work by NASA scientists, who were left smarting after human miscalculation caused the loss of another Mars project, the Climate Orbiter, in September.
At touchdown, the lander was expected to be going only about 5 miles per hour. Thurman said, "The lander would pass the typical bumper test used for most automobiles."
Full downlink could take days
Once successfully on the surface, attention was to shift to communications as the lander extends an antenna and begins trying to make contact with Earth. Richard Cook, project manager for operations, said the first signals could be relayed back as early as 3:39 p.m. EST.
But Cook added it could take up to several days for the lander to establish a fully functioning communications link.
"There is still a very real possibility that we may not hear anything during that whole period of time," Cook said, noting that even small variations in the lander's position on the ground could increase the time it takes to calibrate where Earth is and where to direct its signals.
Illustration of a Mars Microprobe (Click image for annotated graphic)
If something were to go seriously wrong with the lander's own antennae, the mission has a backup in the form of the orbiting Mars Global Surveyor, a satellite swinging around the planet which could be pulled into service as a communications relay for the lander on the ground.
"There are a lot of different paths that you can be on," Cook said of the difficulties in trying to predict exactly when the first Mars Polar transmission will come through. "We just have to wait to see which one."
The same question hangs over the two Deep Space 2 microprobes, mini-laboratories that will crash-land into the Martian surface. Dubbed Amundsen and Scott after the first explorers to reach the South Pole on Earth, the probes are technological experiments designed to examine the subsoil for signs of water.
Reuters contributed to this report.
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