Slugger O'Toole

Curiosity: “We’re doing something completely novel, hanging it way out there”

Launched back in November 2011, Nasa’s mobile Mars Science Laboratory (MSL), the massive 900kg rover Curiosity, is scheduled to land on the red planet at 6.30am [BST] on Monday 6 August. [Image Credit: NASA/JPL-Caltech/ESA/DLR/FU Berlin/MSSS]

They’ve successfully repositioned the orbiting Mars Odyssey spacecraft to keep in touch with Curiosity as it descends into Gale Crater [pictured above] in a novel way.

To achieve the precision needed for landing safely inside Gale Crater, the spacecraft will fly like a wing in the upper atmosphere instead of dropping like a rock. To land the 1-ton rover, an airbag method used on previous Mars rovers will not work. Mission engineers at NASA’s Jet Propulsion Laboratory in Pasadena, Calif., designed a “sky crane” method for the final several seconds of the flight. A backpack with retro-rockets controlling descent speed will lower the rover on three nylon cords just before touchdown.

During a critical period lasting only about seven minutes, the Mars Science Laboratory spacecraft carrying Curiosity must decelerate from about 13,200 mph (about 5,900 meters per second) to allow the rover to land on the surface at about 1.7 mph (three-fourths of a meter per second). Curiosity is scheduled to land at approximately 10:31 p.m. PDT on Aug. 5 (1:31 a.m. EDT on Aug. 6).

“Those seven minutes are the most challenging part of this entire mission,” said Pete Theisinger, the mission’s project manager at JPL. “For the landing to succeed, hundreds of events will need to go right, many with split-second timing and all controlled autonomously by the spacecraft. We’ve done all we can think of to succeed. We expect to get Curiosity safely onto the ground, but there is no guarantee. The risks are real.”

A good science report by BBC spaceman Jonathon Amos explains why

Consider all the surface missions Nasa has sent to the Red Planet, from the Vikings in the 1970s to the Phoenix probe in 2008.

Each has had a more accurate landing system than its predecessor, but only with Curiosity’s EDL technology could you confidently attempt to get inside Gale Crater, one of the deepest holes on Mars.

“Scientists want to go to somewhere rough because that’s where the rocks are exposed. The engineers in the past wanted to go somewhere flat where their machines would be preserved,” explains Prof Sanjeev Gupta, a Imperial College London-UK researcher on the Curiosity science team.

“But we’ve now moved on to the next stage. Issues of life and habitability are really locked in the rock record, and to see those rocks you need to go to canyons and mountains – to get the chronology, to see the relationships and understand past climate changes.

“You won’t get that on flat plains.”

And the BBC’s recent Horizon: Mission to Mars, is still available to watch on the iPlayer.

Here’s Captain Kirk William Shatner on those seven minutes of terror and Curiosity’s “Grand Entrance”.

There’s also a Wil Wheaton version for Next Generation fans…