How They Work: “The Mars Curiosity Rover (Part II)

MAYBE because it was named out of the human nature’s perception of Mars; many a people have been very curious about the “Red” Planet with talks about its “Green” inhabitants, not green as in raw though!

Friday, August 17, 2012

MAYBE because it was named out of the human nature’s perception of Mars; many a people have been very curious about the "Red” Planet with talks about its "Green” inhabitants, not green as in raw though!  The launch system aimed not for where Mars was, but for where it would be when the craft arrived.

NASA planned that gamble, and the rover reached its round and red receiver more than 250 days later, and touched down on Sunday, Aug. 6, 2012, fantastic indeed! However, NASA did not "throw” MSL from Earth’s surface; the agency launched it from planetary orbit. Here’s how: Once the lifting vehicle reached space from Cape Canaveral, its nose cone, or fairing, opened like a clamshell and fell away, along with the rocket’s first stage, which cut off and plummeted to the Atlantic Ocean.

The second stage, a Centaur engine, then kicked in, placing the craft into a parking orbit. Once everything was properly lined up, the rocket kicked off a second burn, propelling the craft toward Mars. About 44 minutes after launch, MSL separated from its rocket and began communicating with Earth. As it continued on its way, it made occasional planned course corrections. Once it hit the Martian atmosphere, the fun really began. Within Mars, stands a sediment mountain 5 kilometres high. Composed of layers of minerals and soils including clays and sulphates, which point to a watery history, these layers will provide an invaluable map of Martian geological history. Past water would have flowed toward and collected in Gale’s lowlands, making it a likely repository for the remains of streams, pools and lakes, and therefore an ideal place to find evidence of Mars’s past habitability. 

Curiosity will one day soon stand isolated on a promontory, sending back data from which its mission controllers will decide "how to explore the vacant vast surrounding.” Its spidery resemblance does not end with poetic license or even its spindly, jointed legs, however; it extends to the spiderlike way the rover landed on the Martian surface. When the spacecraft carrying Curiosity swung into the Martian atmosphere 125 kilometres above the ground, it steered and braked through a series of S-curves like those used by the space shuttles. During the minutes before touchdown, at around 11 kilometres up, the craft popped a parachute to slow its 1,448 kph descent. It then ejected its heat shield from the bottom of the cone, creating an exit for Curiosity.  The rover, with its upper stage clamped to its back like a turtle shell, fell clear of the cone.

A few moments later, the upper stage’s rim-mounted retro rockets blasted to life, stabilizing the pair into a hovering position about 20 meters above the surface; from here, the upper stage acted as a sky crane, lowering Curiosity like a spider on silk. Once the rover was safely on the ground, its tether was cut, and Curiosity set off on its journey.Shortly before touchdown, the Mars Descent Imager took high-definition color video of the landing zone. The footage aided with landing and provided a bird’s-eye-view of the exploration area for researchers and mission specialists back home. Another array of instruments, the Mars Science Laboratory Entry, Descent and Landing Instrument Suite, that are designed to measure atmospheric conditions and spacecraft performance. NASA will use this data when planning and designing future missions. The superb landing system was more complicated, but also more precisely controlled, than any before, enabling mission planners to bull’s-eye the long-desired target of Gale Crater.

Landing within Curiosity’s 20-kilometer target area within the crater would have been impossible for Spirit and Opportunity, which needed five times as much area when bouncing down in their space-age bubble wrap. This success opened up a number of desirable sites, including steep-walled craters previously off-limits due to their tricky terrain.