Mars rover Curiosity on course to land Monday

PASADENA, Calif. — After a journey of 354 million miles to the outskirts of Mars, the Curiosity rover and its spacecraft are speeding up and coming under the influence of the planet’s gravity as it prepares for a dramatic landing early Monday.

NASA officials said early Sunday afternoon that the spacecraft was about 100,000 miles from Mars and remained in ideal shape. They also said its position in relation to the point selected to enter the atmosphere also is on target. The upcoming landing is one of the riskiest ever tried, with final descent that starts at 13,200 mph and ends after what NASA officials call “seven minutes of terror.”

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The Washington Post’s Marc Kaufman, author of “Mars Landing 2012: Inside NASA’s Curiosity Mission,” explains why the Curiosity mission to Mars is being hailed by NASA’s chief scientist as the “mission of the decade.”

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NASA’s Mars Curiosity: 11 things you may not know: A multibillion dollar gamble, a most scary landing and possibly learning whether Mars once could have supported life — briefly, that’s what’s at stake in NASA’s Mars Curiosity mission.

That landing is scheduled for 1:31 a.m., and officials said they could know almost immediately if the rover was safely on the ground. That tracking would come from the Odyssey orbiter circling Mars, if the spacecraft is able to get to the right location at the right time.

If not, the waiting time for a final answer on whether the rover was safely on the surface could range from two to eight hours. If no signal arrives from Curiosity via three Mars orbiters and the Deep Space Network after 18 hours, NASA officials said, then they would start to worry about its safety.

The final descent has been pre-programmed and the army of engineers and scientists at the Jet Propulsion Lab’s Mission Control have no control over it. “Our position will be identical to anyone at home,” said Adam Steltzner, lead of the Entry, Descent and Landing (EDL) team. “We’re all along for the ride.”

Speaking for the team as a whole, Steltzner said they were “Rationally confident, emotionally terrified and ready for EDL.”

Because the rover is so much larger, more complicated and more ambitious than earlier models, it has to land in a new and far more hazardous way. The landing, which could never be tested in full on Earth, includes a hovering rocket stage, a kind of sky crane, to lower it to the ground. NASA’s chief scientist John Grunsfeld has said that because of that heightened landing difficulty, in addition to the unprecedented sophistication of the instruments on board, Curiosity is “the most important NASA mission of the decade.”

Worldwide spectacle

The Curiosity landing is shaping up to be an international spectacle. Formal “landing” parties have been scheduled from South Australia to Rome, from Israel to Crete; and in the United States from Atlanta to Seattle, Milwaukee to Honolulu.

NASA also has helped organize a landing gathering in New York’s Times Square, which will feature a large screen that will beam the streaming news from atop a building and high above the crowd.

Reaching, orbiting and landing on Mars is notoriously hard. In addition to the European Space Agency, nations including the United States, the former Soviet Union, Russia, the European Space Agency, China and Japan have sent missions to Mars since the late 1960s, but only about one-third of them have succeeded.

The United States is the only nation to land a vehicle on Mars and complete its mission, having done it six out of seven tries.