Aug. 4, 2012 at 3:02 PM ET
One day before a multibillion-dollar landing, NASA's Mars Science Laboratory spacecraft is almost perfectly on track to deposit its Curiosity rover in one of the deepest holes on Mars, mission managers said today. Even the weather is looking up.
"Mars appears to be cooperating very nicely with us," Ashwin Vasavada, the $2.5 billion mission's deputy project scientist, told reporters today at NASA's Jet Propulsion Laboratory in Pasadena, Calif. A worrisome dust storm in the vicinity of the landing site has evolved into a "fairly harmless cloud of dust," he said — and the presence of water-ice clouds in the Red Planet's thin atmosphere suggests that conditions will be cold and relatively dust-free.
Meanwhile, the 15-foot-wide (4.5-meter-wide) spacecraft is coming "right down the pipe," mission manager Arthur Amador said — so close to the desired track that a scheduled course correction was canceled. The probe is now less than a half-million miles from Mars and speeding up due to the influence of the planet's gravitational field.
That's not to say that all the worries are over. The trickiest part of the mission still lies ahead, on Sunday night. There'll be a nail-biting descent through the atmosphere. As the probe decelerates from a speed of 13,200 mph (5,900 meters per second), the heat shield will have to protect the rover from temperatures ranging up to 3,800 degrees Fahrenheit (2,150 degrees Celsius).
The climax of the "seven minutes of terror" comes in the form of a never-tried-before "sky crane" maneuver to put Curiosity to the surface. A rocket-powered platform is expected to hover tens of yards (meters) above the ground, lower the one-ton, car-sized rover on three cables, cut the cables loose and then fly itself out of the way.
The landing plan may sound crazy, but the rover is so heavy that it's impossible to use the kind of airbag-cushioned landing that came into play for NASA's earlier rover landings in 1997 and 2004. And if it were put on a legged lander, the rover would be unstable and prone to fall over, said Adam Steltzner, the NASA engineer in charge of the landing team. That makes the sky-crane method the "least crazy" plan NASA was able to come up with, he said.
Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters, compared the maneuver to Olympic-level gymnastics.
"Can we do this? I think we can do this. ... But that risk still exists. It's going to be tough," he said.
Live pictures can't be broadcast from the spacecraft, but NASA TV is due to air coverage from the Jet Propulsion Laboratory. Steve Sell, a member of the team in charge of Curiosity's landing sequence, said we'll be able to see a "cool animation" based on the sparse telemetry being relayed back to Earth. The live broadcast will also show the reactions from scores of scientists, engineers and VIPs gathered in JPL's mission control room.
If everything works right, Curiosity will basically send a text message from the surface, which will be relayed by NASA's Mars Odyssey orbiter and received back on Earth at 10:31 p.m. PT Sunday (1:31 a.m. ET Monday). How will the world find out about success? "You'll probably be able to tell by [seeing] us celebrating," said Richard Cook, the mission's deputy project manager.
If the crucial text message doesn't come through immediately, the Mars Science Laboratory team — and the rest of us — might have to wait hours longer for data to be relayed by Mars Odyssey, NASA's Mars Reconnaissance Orbiter or the European Space Agency's Mars Express. The rover itself isn't due to send its first beep directly back to Earth until Monday afternoon, Cook said.
If nothing is heard by then, it would be "more likely than not that we've had a problem," Cook said.
There's a lot riding on this mission: Curiosity is the last probe NASA is due to put on the Martian surface for the foreseeable future, due to budgetary constraints. The space agency is in the midst of retooling its Mars exploration program to fit an era of tighter spending. If the landing fails, that would deepen the already-serious questions about the future.
On the flip side, success would usher in two years of exploration in one of the most geologically interesting spots on Mars — a crater called Gale that features a 3-mile-high (5-kilometer-high) mountain in the middle. The various layers of rock on the mountainside could reveal a geological record encompassing billions of years, bridging the gap between Mars' warmer, wetter past and its cold, dry present.
After the landing, it'll take several days for Curiosity to get all its instruments up and running. Its first six-wheeled drive away from the touchdown site isn't due to take place until early September.
Search for organic chemicals
Curiosity's prime task is to look for special types of carbon compounds that could tell scientists whether Mars was potentially habitable in the ancient past, and even whether the conditions are right for microbes to endure on the planet today. The rover's 10 scientific instruments are not designed to detect life directly, but findings from this mission could lay the groundwork for life-detecting missions to come.
Because the rover is powered by radioisotope generators, it's not dependent on solar arrays, as NASA's Opportunity rover is. Opportunity is still going strong in a different spot on Mars, more than eight and a half years after its landing in 2004. John Grotzinger, a Caltech professor who serves as Curiosity's project scientist, hoped that this rover would last even longer.
"Maybe this rover will still be going when humans finally make it to Mars," he told an audience during a talk at a Mars Society conference in Pasadena on Friday.
That line got the biggest applause of all.
More about the Mars mission:
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.