Mars lander communications successfully linked

NASA is one step closer to discovering whether life can exist on Mars, thanks in part to software installed on the Phoenix Mars Lander spacecraft, which touched down on the Red Planet on Sunday.

Comment on this article in the forum.Phoenix is a $420 million mission in NASA's Scout program, an initiative the agency developed to build smaller, lower-cost spacecraft designed to send data back from space to determine future exploration strategies. Phoenix successfully touched down on Mars Sunday evening and immediately began sending back photos of the planet's northern plains. Phoenix will scoop soil and ice from the Mars surface and evaluate the atmosphere using laser beams that can measure the height and thickness of clouds, wind speed and elevation temperatures. The analysis could help reveal the movement of water from air to soil so that scientists can use that information to determine whether the planet is habitable.

Much of the mission's success requires NASA to communicate with Phoenix directly from Earth, which required Lockheed Martin, the federal contractor that built Phoenix, to compile more than 100,000 lines of software code. A second, identical software application provides redundancy, should a system failure occur.

All data from the spacecraft is downlinked through the Lockheed-built Mars Odyssey or the Mars Reconnaissance orbiters, which NASA launched in 2001 and 2005, respectively. That data is then retransmitted to one of three ground-based antennas - known as the NASA Deep Space Network - which are strategically located worldwide to ensure one antenna is facing toward Mars at all times, regardless of the Earth's rotation. The data travels from the antennas into ground control computers at NASA's Jet Propulsion Laboratory and the University of Arizona. There, researchers decide what actions they want Phoenix to perform, and Lockheed sends commands and sequences back to the lander through the same communications channel. The commands take 15 minutes to travel to and from the spacecraft.

Phoenix had a controlled soft landing in which it had to slow from a 12,000 mph descent to 5 mph when it landed on the surface, using a parachute and then thrusters in the final seconds to control the descent. "Landing on the surface of Mars, and what we did with the power descent, is by far the hardest thing we do in robotics - period," said Ed Odell, Phoenix software lead at Lockheed. "There was no room for error."

Phoenix traveled a total of 422 million miles from Earth to land on Mars at a latitude equivalent to that of northern Alaska. A telescopic camera mounted on the Mars Reconnaissance orbiter caught a view of Phoenix, suspended from its parachute during landing.

"None of us thought it was possible," to get an image of the actual landing, said David Beaty, Mars chief scientist at the Jet Propulsion Laboratory. "It's sort of equivalent of taking a picture of a speeding bullet from a camera mounted on another speeding bullet."

After landing, the spacecraft waited 20 minutes for dust to settle before it deployed a stereo camera and a meteorology mast to collect atmospheric data, a robotic arm for digging and twin solar arrays. The camera took images of each 6-foot, 10-inch solar array, confirming that both were deployed to allow the spacecraft to generate its own power.

One glitch arose with a radio aboard the Mars Reconnaissance orbiter. While the problem encountered is still unclear, Odell said it "had a moment where it wasn't doing what it was supposed to, and instead went into safe mode and powered off." NASA then commanded the spacecraft to turn the radio signal back on the orbiter and lost one day of communicating, Odell said, but Odyssey continued to function and accept commands.