NASA officials said the Mars Phoenix Lander has completed its 296-day, 422 million-mile journey Sunday, with only about a 50-50 chance of a successful touchdown on the arctic plains.
“There’s nothing else to do but watch,” said Phoenix project manager Barry Goldstein of NASA’s Jet Propulsion Lab in Pasadena, California.
Goldstein’s teams decided to waive an opportunity to tweak the Phoenix flight path, saying that the spacecraft was on the right track.
The mission of the Phoenix is to analyze the soils and permafrost of Mars’ arctic tundra for signs of life, either past or present.
Seven minutes is all it took for the spacecraft traveling nearly 13,000 mph to hit the Red Planet atmosphere while hitting the brakes to make touchdown. During that time, onboard computers will be working at a manic pace as the spacecraft deployed its parachute while its thrusters prepared the lander for a soft landing.
“We always have to be scared to death,” said Barry Goldstein, project manager. “The minute we lose fear is the minute that we stop looking for the next problem.”
NASA has not successfully landed a probe on Mars using landing legs and stabilizing thrusters since the Viking missions in the late 1970s. The other three successful Mars landings — Pathfinder in 1997 and the Spirit and Opportunity rovers in 2004 — used massive airbags that inflated around the landing craft just before landing to cushion the impact.
“I love airbags,” said Weiler. “We got three success stories with airbags, but you don’t invent science by continuing to do what you know how to do.”
The Phoenix doesn’t have airbags because the lander is too big and heavy for them to work properly. NASA will have to figure out how to land reliably with thrusters and landing legs in order to fly even larger spacecraft in the future.
“We landed on Mars with rockets and legs twice with Viking. It’s not impossible by definition, we have proof of it,” Weiler said. “Humans will have to land on landing legs. Eventually, we want to send humans there, obviously.”
The Phoenix landing site is at the far nothern plains of Mars, near the northern polar ice cap. Data from the Mars Odyssey spacecraft suggests large quantities of ice there, probably in the form of permafrost, either on the surface or just barely underground.
Phoenix is equipped with a robotic arm capable of scooping up ice and dirt to look for organic evidence that life once existed there, or even exists now.