Original URL: http://www.theregister.co.uk/2011/11/25/mars_rover_curiosity/

NASA's nuclear laser tank will hunt down any life on Mars

Seriously though: How excellent if there was some

By Brid-Aine Parnell

Posted in Science, 25th November 2011 16:15 GMT

While tales of UFOs and alien abductions are still being greeted with snorts of derision, NASA really is searching the skies for signs of extraterrestrial life, though it's not little green (or grey) men the agency is looking for, it's signs of life - most probably not above the microbial level - on Mars.

The Red Planet has been an enticing option for life outside of this planet for both scientists and popular culture. Its proximity and similarity to Earth has led to all sorts of speculations, from Marvin the Martian to the famous 'Face on Mars' photo taken by the Viking 1 orbiter in 1976.

Now, the American space agency is sending its biggest and best Mars rover to try to discover if there was, is, or could be the potential for microbial life on the planet.

The Mars Science Laboratory (MSL) mission will carry Curiosity, a rover five times as large as, and carrying 10 times more scientific instruments than, the previous Mars rovers Spirit or Opportunity.

The space truck is the size of a small SUV, has its very own fancy propulsive launcher to land it on the planet and carries cameras, a robotic arm, a drill and a laser capable of vaporising rock.

In fact, there's so much gear on the rover that it can't be powered by solar panels, oh no, it needs a plutonium-powered 'space battery' to run all its gizmos and gadgets.

NASA is launching the MSL on an Atlas V booster on November 26, a day later than originally intended, but Curiosity won't reach the surface of Mars until sometime in August next year after a journey of around 354 million miles.

On arrival at Mars the complex "aeroshell" - the round space tin in which the rover and its rocket-skycrane landercraft are packaged - will make a screaming entry into the thin atmosphere of the red planet, during which it will scrub off velocity using "S-curve" manoeuvres much as space shuttles used to do when plunging down through Earth's atmosphere. The aeroshell will slow itself further in the final minutes using a parachute, then release the rover and its "upper stage" lander, a sort of flying rocket bedstead which will use retro thrust to bring itself down to a hover above the surface and lower the rover down on cables in "sky crane" mode the last few metres. Lines detached, the sky-crane upper stage will then use the last of its fuel to take itself off somewhere and crash safely away from Curiosity's landing point.

Where there was a well, that's the way

Even during the descent, the mission will already be gathering data at a furious rate. The Entry, Descent and Landing Instrument Suite will record every detail of the plunge through the atmosphere in order to make planning of future missions - perhaps manned - easier, and during the final minutes of the plunge hi-def video of the region surrounding the landing site will be filmed, allowing supervising boffins to subsequently direct the rover to promising features.

Following landing, Curiosity will trundle about the Gale Crater area of Mars for a primary mission time of one Martian year (98 Earth weeks), though on past form for NASA probes and rovers it will probably carry on much longer provided that it manages to arrive fully operational. The landing site has been chosen because observations from Mars orbit have given the region the first tick on the checklist of life's requirements - it was once wet.

Evidence for water on Mars' Endurance crater

"Researchers have used NASA’s Mars Reconnaissance Orbiter to map the area’s mineralogy, finding exposures of clay minerals. Clays, other phyllosilicates and sulfates form under conditions with adequate liquid water in a life-supporting, medium range between very acidic and very alkaline," NASA's launch statement (PDF) for the MSL reads.

In other words, it has mud and it couldn't have mud if it didn't once have water, even if that was more than three billion years ago. Curiosity's job will be to find more evidence for water and search for the two other signs of possible life – chemicals like oxygen, nitrogen, phosphorus and sulfur used by life and a source of energy.

Clays on Mars

As well as looking into the past, Curiosity is also equipped to look to the future, specifically a manned mission to Mars.

The rover is carrying a weather station, an instrument for monitoring natural high-energy radiation and an instrument that can detect soil moisture and water-containing minerals in the ground beneath it. Samples scooped or drilled by the rover's arm, or vaped by its laser, can be probed and analysed in all kinds of cunning ways.

"Selection of Curiosity's landing site was not based on traits favouring present-day habitability. However, much of the information this mission contributes about the modern environment will enhance our general understanding of Mars," the mission statement says.

"For example, can organic compounds delivered by meteorites persist in the soil close to the surface? How does the modern atmosphere affect the ultraviolet and high-energy radiation that reaches the surface, posing a hazard to life and to preservation of organics? How might we better estimate levels in the past?

"The rover’s monitoring of radiation levels from cosmic rays and the sun also is designed to address astronaut safety on eventual human missions to Mars," NASA added.

And of course, as much as the agency may want to play down the possibility, all that research will also tell space boffins if there's microscopic life on the planet right now, or there could be in the future.

NASA is touting this mission as the "prospecting stage" in the process of getting a "definitive answer about whether life has existed on Mars", but most space enthusiasts can't help but wonder if this is the one that finds microscopic Marvin the Martian. ®