The big Curiosity rover, on a US$2.5 billion science mission, will arrive on the red planet on Sunday evening PST, with a most audacious manoeuvre.
The final stage of Curiosity's descent to the surface of Mars will involve being slung on tethers below the spacecraft's landing stage.
The arrival of the Curiosity rover on Mars may well be the biggest, boldest extraterrestrial landing for NASA since Apollo 11 settled down on the moon on a summer's night in 1969.
Curiosity is scheduled to land in the red planet's Gale Crater today. Confirmation of the landing should come at about 5.31pm AEST, 5.01pm ACST and 3.31pm AWST. The rover will actually touch down before that, but there's a 14-minute communications time lag for signals travelling the 154 million miles from Mars.
The space agency will begin its live coverage today at 1.30pm (GMT +10 — Sydney, Brisbane, Melbourne, Hobart), 1.00pm (GMT +9.5 — Adelaide, Darwin) and 11.30am (GMT +8 — Perth) on the NASA TV site, and will also show the coverage via Ustream:
The US$2.5 billion Mars Science Laboratory mission has been in its spaceflight phase for about eight months, since a liftoff from the Kennedy Space Center in late November. But the centrepiece of the mission is only just about to begin — two Earth years of Curiosity roaming around 12 miles up a towering mound of sedimentary rock in Gale Crater, known as both Aeolis Mons and Mount Sharp.
The science instruments carried by Curiosity will be looking, among other things, for carbon compounds and signs of whether Mars is, or ever might have been, habitable. The rover's uphill climb will take it through eons of Mars' geological evolution.
"The really cool thing about the Gale stratigraphic succession to me is it's a tour through nearly the entire history of Mars, where we can begin to understand these major changes in the environmental history of the planet," project scientist John Grotzinger said in an interview with CNET.
But first, Curiosity has to survive its landing. Much larger than earlier Mars rovers Spirit and Opportunity — the 1-tonne machine is roughly the size of a very small car — Curiosity posed a significant challenge to the engineers tasked with getting it down through the Martian atmosphere and onto the soil of the red planet.
At an altitude of about 11.25 kilometres, and about seven minutes from the surface, a parachute will deploy to slow the spaceship's cruise stage from 21,243.3 kilometres per hour (km/h), first to 1448.41 km/h and eventually to 290 km/h. About 1.6km above the surface, the rocket-powered landing stage will take over, slowing things further to the walking-speed rate of 3.2km/h. At the very modest altitude of 22 metres, the rover will finally separate out, and this is where things get most interesting; Curiosity will be lowered the rest of the way to the surface on a bridle slung on three nylon tethers below the descent stage, with an umbilical providing a power and communication connection.
In the final few minutes, a high-definition camera will begin recording video. "It does 8 frames per second, high-definition-quality video from the back shell coming off [all the way] to the ground," said project manager Pete Theisinger. "So it's a lot of data; it'll take a long time to get it back. But it should be a tremendous movie when it does."