NASA's Mars rover may not phone home right away
PASADENA, California - NASA cheekily calls the Mars Science Lab's risky approach and landing attempt the "seven minutes of terror." In reality, the anxiety at mission control could last much longer.
The robotic lander dubbed Curiosity, a $2.5 billion mission to search for life-friendly habitats on the Red Planet, was on autopilot for touchdown at 10:31 p.m. PDT Sunday (1:31 a.m. EDT Monday/0531 GMT).
If all goes as planned, NASA will heave a big sigh of relief immediately. But word of whether Curiosity survives may not come for hours.
Because Earth sets over the Martian horizon minutes before Curiosity is due to land, direct communication with the lander will be cut off. Scientists tracking the craft from the Jet Propulsion Laboratory in California will depend on three other spacecraft in orbit around Mars to transmit information about the rover's fate.
One of those orbiters, nicknamed Odyssey, can potentially relay Curiosity's descent and landing signals in real time. But NASA won't know if this satellite can be properly positioned for live coverage until about 15 minutes before Curiosity hits the Martian atmosphere.
The Odyssey orbiter, flying about 250 miles (400 km) over Mars, lost one of its steering wheels in June, and flight controllers have had to learn how to maneuver it with a spare.
All communications between Curiosity and Earth, whether directly with the probe or relayed via the Mars orbiters, are sent and received by NASA through its Deep Space Network, a collection of satellite dishes arrayed in California, Spain and Australia.
Once direct communication with Curiosity is cut off, it will be another day before Earth and Mars are properly aligned again for a "line-of-sight" linkup.
If proper alignment of Odyssey fails, that leaves NASA to seek data from two other orbiters to confirm whether Curiosity safely touched down or crashed.
Like Odyssey, both the Mars Reconnaissance Orbiter and Europe's Mars Express will be flying overhead during Curiosity's descent and landing and should be recording the event. But getting those signals back to Earth and deciphered will take eight hours or more.
Moreover, there is no guarantee that the Reconnaissance Orbiter or Mars Express would succeed in their first attempts at relaying landing data to NASA.
"If we get past 24 hours, it's more likely than not that we had a problem," deputy project manager Richard Cook said.
"Tonight's it's the Super Bowl of planet exploration. One yard line, one play left. That play is about twelve hours from now. We score and win," NASA's Mars exploration program director Doug McCuistion said.
Curiosity, the first full-fledged mobile science laboratory ever sent to a distant world, is scheduled to touch down inside a vast, ancient impact crater on Sunday at 10:31 p.m. Pacific time (1:31 a.m. EDT on Monday/0531 GMT on Monday).
Mission control engineers at the Jet Propulsion Laboratory (JPL)near Los Angeles acknowledge that delivering the one-ton, six-wheeled, nuclear-powered vehicle in one piece is a highly risky proposition, with zero margin for error.
"We're about to land a rover that is ten times heavier than the Spirit or Opportunity with fifteen times the payload. Pretty incredible feat we're about to attempt. So we may not be successful," McCuistion said.
But on the eve of Curiosity's rendezvous with Mars, JPL's team said the spacecraft and its systems were functioning flawlessly, and forecasts called for favorable Martian weather over the landing zone.
After a journey from Earth of more than 350 million miles (567 million km), engineers said they were hopeful the rover, the size of a small sports car, will land precisely as planned near the foot of a tall mountain rising from the floor of Gale Crater in Mars' southern hemisphere.
Facing deep cuts in its science budget and struggling to regain its footing after cancellation of the space shuttle program - NASA's centerpiece for 30 years - the agency has much at stake in the outcome of the $2.5 billion mission.
"If we are successful getting to the ground and we are successful with Odyssey information coming back we are going to have the opportunity for untold discoveries," McCuistion said, "It would be one of the greatest feats in planetary exploration ever not to mention just this decade. I think it shows the leadership the United States has had in the exploration of Mars."
Mars is the chief component of NASA's long-term deep space exploration plans. Curiosity, the space agency's first astrobiology mission since the 1970s-era Viking probes, is designed primarily to search for evidence that the planet most similar to Earth may have once have harbored ingredients necessary for microbial life to evolve. — Reuters
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