On Target

RSS

PASADENA, Calif. - NASA's Mars Science Laboratory is performing perfectly, and the weather on Mars is cooperating, for a landing in the planet's Gale Crater Sunday night at 1:31 a.m. EDT Aug. 6.

Controllers at the Jet Propulsion Laboratory cancelled a scheduled trajectory-correction manuever Saturday night when Deep Space Network tracking indicated the MLS spacecraft will hit its target atop the  planet's atmosphere.

"Our trajectory inbound to Mars has been right down the pipe," Arthur Amador, the MSL mission manager, told reporters here today.

If anything changes, there will be three more chances to tweak MSL's course before entry -- one today and two more tomorrow. Aside from that, the $2.5 billion spacecraft has been operating  autonomously since Monday, Amador said, and the only command definitely remaining to be uploaded is software for the  backup flight computer in case the prime fails before the long-awaited entry, descent and landing (EDL).

If the nuclear-powered Curiosity rover tucked in behind a 4.5-meter heat shield survives its "seven minutes of terror" -- slowing from 13,000 mph to 1.7 mph with atmospheric friction, parachutes, eight retrorockets and the untested "sky crane" descent to touchdown - the control room here may know as soon as radio signals make the 13.8-minute trip from Mars to Earth. "You'll see us celebrate," said Richard Cook, the MLS deputy project manger.

But that will depend on the Mars Odyssey orbiter, which will be in position to relay UHF signals from the rover to Earth in a "bent-pipe" setup. If there is a problem, and the signals aren't received, the seven minutes of terror could stretch into a day or more. Odyssey, the Mars Reconnaissance Orbiter (MRO), and Europe's Mars Express orbiter all will be receiving UHF signals from MSL as it lands. But only Odyssey will be able to reroute the signals immediately.

The MRO and Mars Express will record them for rebroadcast to Earth, and controllers will have several different chances to verify their spacecraft has landed safely in the hours after touchdown. If the silence stretches to 24 hours, Cook said, hope will begin to fade.

"There are certainly very credibly scenarios  by which those Odyssey and MRO passes might not happen in the firist 18 hours," Cook said. "Because of that, we might identify
ways in which we would have to wait untilo the next morning, for example, to hear the MRO  pass."

In addition to UHF broadcasts, the rover is set up to broadcast X-band "beeps" containing minimal  data. That would reassure controllers that the spacecraft is in one piece, even if the primary UHF radio fails for some reason. It would take several days for the backup UHF radio to activate itself, so if the rover isn't beeping when Mars swings it back into line of sight with Earth, it probably will mean trouble.

"Once we get past that first beep from the X-band system, if we haven't heard from it in any of those communications paths, including that one, then I think ... more likely than not that we would have a problem," Cook said. "It would take 24 hours."

                            

Please or Register to post comments.

What's On Space?

On Space

From The Archives

Aviation Week is approaching its 100th anniversary in 2016. In a series of blogs, our editors highlight editorial content from the magazine's long and rich history.

 

Aug 27, 2015
blog

Aviation Week Lifts Veil On Boeing B-52 Bomber (1952) 16

In 1952, Aviation Week provided the first details on the new Boeing B-52 bomber....More
Aug 14, 2015
blog

Bonanza Travel Pays 3

The legendary Beechcraft Bonanza has an impressive production record, so perhaps the marketers back in 1949 were onto something when they coined the phrase "Bonanza travel pays."...More
Aug 14, 2015
blog

Venerable Boeing 727 Prototype To Fly Again 28

The most famous 727, the prototype aircraft which would join United as N7001U, was delivered to the airline in October 1964 having served its time as a Boeing test aircraft....More
Aug 13, 2015
blog

Aviation Week And The Bomb

Aviation News did not predict how nuclear weapons would change the world. But neither did anyone else....More
Aug 13, 2015
blog

Collins Radar Takes The Ups And Downs Out Of Flying

Turbulence? Rockwell Collins had a solution for those bumpy rides in the early 80s with its WXR-700 Doppler Weather Radar....More
Blog Archive
Penton Corporate

Sponsored Introduction Continue on to (or wait seconds) ×