MSL-Curiosity: Biggest Mars mission yet

Gale crater elevation model An elevation model of Gale crater made using data from Europe's Mars Express orbiter. MSL lands on the lower, nearside of the central peak, which rises more than 5km above the crater floor

The delivery of Nasa's Mars Science Laboratory rover, known as Curiosity, to the surface of the Red Planet is a mouth-watering prospect.

The $2.5bn robot is by far the most capable machine ever built to touch another world. Consider just the history of wheeled vehicles on Mars.

In 1997, the US space agency put the toy-sized Pathfinder-Sojourner rover on the surface. It weighed just over 10kg.

This was followed seven years later by the 170kg, twin rovers Opportunity and Spirit. Their instrument complement combined (5kg + 5kg) was equal to the total mass of Sojourner.

Now, we await Curiosity - a 900kg behemoth due for launch this Saturday. Its biggest instrument alone is nearly four times the mass of that teeny robot back in '97.

"It's the size of a Mini Cooper with the wheelbase of a Humvee," is how project scientist John Grotzinger describes the rover.

So, we're expecting great things from Curiosity. A big machine to address some big questions.

A roving laboratory for Mars

  • General equipment: MSL equipped with tools to remove dust from rock surfaces, drill into rocks, and to scoop up, sort and sieve samples
  • Mast Camera: will image rover's surroundings in high-res stereo and colour; wide angle and telephoto; can make high-def video movies
  • ChemCam: pulses infrared laser at rocks up to 7m away; carries a spectrometer to identify types of atoms excited in laser beam
  • Sample Analysis at Mars: inside body; will analyse rock, soil and atmospheric samples; would make all-important organics identification
  • Chemistry and Mineralogy: another interior instrument. Analyses powdered samples to quantify minerals present in rocks and soils
  • Mars Hand Lens Imager: mounted on arm toolkit; will take extreme close-ups of rocks, soil and any ice; details smaller than hair's width
  • Alpha Particle X-ray Spectrometer: Canadian arm contribution; will determine the relative abundances of different elements in samples
  • Radiation Assessment Detector: will characterize radiation environment at surface; key information for future human exploration
  • Mars Descent Imager: operates during landing sequence; high-def movie will tell controllers exactly where rover touched down
  • Rover Environmental Monitoring Station: Spanish weather station; measures pressure, temperature, humidity, winds, and UV levels
  • Dynamic Albedo of Neutrons: looks for sub-surface hydrogen; could indicate water buried in form of ice or bound in minerals

Mike Meyer is the lead scientist on Nasa's Mars exploration effort: "MSL plays a central role in a series of missions of looking at Mars and determining whether or not it has the potential for life. It is capable of going to a region and exploring that region, and telling us whether or not it has been, or may even still be today, a habitable place - something that could support microbial life."

Engineers have designed a new entry, descent and landing system they say can put the roving laboratory down on a button.

OK, so this button is 20km wide but the accuracy being promised is an order or magnitude better than previous technology, and it has allowed researchers essentially to go where their heart desired.

They've chosen a near-equatorial depression called Gale Crater. It's one of the deepest holes on Mars - deeper even than Valles Marineris, that great scar that tears across one quarter of the planet.

Scientists believe Gale will be the geological equivalent of a sweet shop - so enticing and varied are the delights it appears to offer.

"This crater is about 100 miles across and it has a central mound that's about three miles high," explains Grotzinger.

"The important thing is that the central mound is a series of layers that cut across the history of Mars covering over a billion years. So, not only do we have high-resolution images showing we have layers in this mound, but also because of the spectrometers we have in orbit flying around Mars, we can see minerals that have obviously interacted with water."

The intention is to put MSL-Curiosity down on the flat plain of the crater bottom. The vehicle will then drive up to the base of the peak.

In front of it, the rover should find abundant quantities of clay minerals (phyllosilicates) that will give a fresh insight into the very wet, early epoch of the Red Planet. Clays only form when rock spends a lot of time in contact with water.

Above the clays, a little further up the mountain, the rover should find sulphate salts, which relate to a time when Mars was still wet but beginning to dry out. Go higher still, and MSL will find mostly the "duststones" from the cold, desiccated world that Mars has now become.

But even before all this, MSL will land on what looks from orbit to be alluvial fan - a spread of sediment dumped by a stream of water flowing down the crater wall.

If the science on this fan proves productive, it could be many months before MSL gets to the base of the mountain.

The rover has time, though. Equipped with a plutonium battery, it has the power to keep rolling for more than 10 years - time enough to scout the crater floor and climb to the summit of the mountain.

Mars maps

"We are not a life detection mission," stresses Grotzinger.

"I know that many of you would like to know when we're going to get on with doing that. But the first and important step towards that is to try to understand where the good stuff may be. And in this case a habitable environment needs to be described.

"This is an environment that contains a source of water, which is essential for all life as we understand it on Earth; we need a source of energy, which is important for organisms to do metabolism; and we also need a source of carbon, which is essential to build the molecular structures that an organism is composed of."

You may be wondering why these sorts of missions don't look directly for life, and the reason is pretty straightforward. Those types of observations are actually quite difficult to make, and the truth is we don't really expect to find microbial communities thriving at the surface of present-day Mars. The conditions are simply too harsh.

Sojourner and the "Yogi" rock Little one: the Sojourner rover now looks like a toy compared to MSL

But go back further in time, and the situation may have been very different. It seems pretty clear now that when life was getting going on Earth more than three billion years ago, conditions on Mars were also warm and wet.

But the traces of those ancient lifeforms on our own planet are now very hard to read, and often require instruments that would fill a room. Not even a machine the scale of Curiosity could carry them.

So, MSL will restrict itself to the habitability question, and it will do this using a combination of 10 instruments.

The rover has instruments on a mast that can survey the surroundings and assess potential sampling targets from a distance. These include cameras and an infrared laser system that can excite the surface of a rock to betray some of its chemistry.

It's also got instruments on the end of a 2.1m-long arm for close-up inspections. These include a drill that can pull samples from up to 5cm inside a rock.

And MSL has two big lab kits inside its body to do detailed analysis of all the samples it takes from rocks, soils and even the atmosphere.

One eureka moment for this mission would be if it could definitively identify a range of complex organic (carbon-rich) molecules, such as amino acids.

Previous missions, notably the Viking landers in the 1970s, have hinted at the presence of organics. It would be good if Curiosity could bury all doubts. But it will be tough.

Even in Earth rocks where we know sediments have been laid down in proximity to biology, we still frequently find no organic traces. The evidence doesn't preserve well.

So, getting a positive result on Mars would be a triumph for the MSL team. Although, I guess one should make it clear - just finding complex organics does not indicate the presence of life because we know these carbon molecules can have non-biological origins, in meteorites, for example.

Nonetheless, it would help to build a case that at least the necessary preconditions have existed for life on the Red Planet at some point.

We can then think about how we might go about testing for life itself, although I think the only real solution will be to return rocks for analysis in those room-sized instruments here on Earth.

Jonathan Amos Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 101.

    I'm very relieved that the launch went well.

    Between now and next August when Curiosity lands it's probably a good idea to fix our money system otherwise a gaping black hole awaits us and all our endeavours might all be for nothing.

    Usury/interest must go and we need a resource-based economy and not a money-based one.

    We really do need a paradigm shift and soon. We can do it.

  • rate this

    Comment number 100.

    Robert Lucien and Powermeerkat,

    I wasn't belittling the Russians. My point was that many people complain about the cost of space science but don't realise the benefits that having a huge scientific and industrial base working on extremely difficult tasks brings. It isn't just Teflon and velcro. Glad the launch went well.

  • rate this

    Comment number 99.

    #94 powermeerkat
    , 56.Jones_the_Steve, Shift That Paradigm.

    Curiosity just lifted off on an Atlas 5 and the Atlas 5 is powered by Russian technology, specifically Buran technology, specifically the RD-180 rocket. A good thing since its about the most powerful and reliable rocket in current use (both Atlas and the RD-180). -

  • rate this

    Comment number 98.

    21.  Tom Ray 
    24TH NOVEMBER 2011 - 19:44
    Where can I get one of the batteries that will drive the Curiosity lander artound for 10 years?

    Personally, it will be fingers crossed that the rocket launch goes well. Otherwise the USA may suffer serious radiation contamination from the plutonium batteries on Curiosity.

  • rate this

    Comment number 97.

    Knights of Cydonia,now that is art

  • rate this

    Comment number 96.

  • rate this

    Comment number 95.

    Interfax said the signal was received at a Russian station at the Baikonur cosmodrome in Kazakhstan on Thursday afternoon.


    So what? Will it finally go to Mars now?

    Or American HAARP weapon (known so well to all people whose heads are protected by aluminum hats with propellers) will stop it?

  • rate this

    Comment number 94.

    Shift That Paradigm.

    Did you know that the US was forced to minituarise the electronic systems on its spacecraft to save weight as their boosters were not as powerful as the Soviets'.

    Don't belittle Russians; they still build the heaviest rockets and the biggest integrated circuits.

    While American michrochips are barely noticable.

    So 1:0 for Russians. ;-)

  • rate this

    Comment number 93.

    21.Tom Ray
    'Where can I get one of the batteries that will drive the Curiosity lander around for 10 years?"

    Its 14 yrs, actually. But you can't for PC folks on this planet have decided that all things nuclear are evil, and although they obviously can't tell a difference between plutonium 239 used in weapons and highly stable P- 238 they won't allow them to be sold.
    Although they could. :-(

  • rate this

    Comment number 92.

    Clay sulphate salts then duststones? No way, I had one earlier, its a thin layer of chocolate, then thick layer of soft fudge, thinish creamy caramel then very thin chocolate again.

    Seriously though it is a great mission lots of work and I hope they get time to rest and play.

  • rate this

    Comment number 91.

    #90 Shift That Paradigm, Laurie Kirby

    Don't worry its only plutonium. The shielding and casing and fuel of the battery are designed to survive just about anything. It can survive an explosion on the pad or even atmospheric re-entry. But even if it didn't the plutonium compound is designed to be chemically inert (i.e. safe).
    The safety of these NASA RTG's is exceptionally high.

  • rate this

    Comment number 90.

    @ 81. Laurie Kirby

    I concur.

    It would seem that the risk is acceptable to NASA and their funders. It is not acceptable to myself, however. Plutonium is far too dangerous to be transported by rockets through OUR biosphere.

  • rate this

    Comment number 89.

    It is interesting to see they are using Plutonium to power the Mars Rover They must be using radioisotope thermoelectric generators for power instead of solar panels.

  • rate this

    Comment number 88.

    good luck with the launch, and landing, but now that cydonia's lost its allure, id rather see whats on titan or europa, before heading beyond our solar system, but i guess we're still decades away from that.

    and, ok they are 10 years old, but for anyone interested who hasnt seen em yet, here's the hi-res nasa pics of cydonia

  • rate this

    Comment number 87.

    I notice that the article does not have a price tag ? Given the focus on American debt levels recently. I think that this project needs to be shelved until the U.S. tax-payer can afford it. Or are the Rothschild's actually going to use their own money? Dollar to a doughnut; any payout from the mission will be going directly into their pockets.

  • rate this

    Comment number 86.

    "Earth is too fragile a basket to keep all our eggs in " R.A.H.

    Another good step forward here.
    Also, hopefully the Russian probe can be reactivated.
    Why on earth (excuse the pun) don't they combine efforts.

  • rate this

    Comment number 85.

    A sky crane? Well that's going work given the history of Mars missions. $2.5b and they're not even testing for signs of life. Sorry. I just don't get it.

  • rate this

    Comment number 84.

    I'm stealing my nan's life savings because she is an even bigger luddite than me and wants to spend it all on food. She can't be trusted to make a sensible decision.

  • rate this

    Comment number 83.

    re82 redletter
    why are you stealing your nan's life savings?
    is this your luddite sentiment coming through?do you believe that if we scrapped the space programme and made everyone redundant that it would solve the worlds problems?lol I forgot humanity was perfect before statred expanding our horizons!

  • rate this

    Comment number 82.

    So, if I were to steal my old grandma's life savings then go downtown to Maplins and buy a Ferrari Alaplancha and drive off into the sunset, I take it you would all support my behaviour, as it is so glamorous and progressive. There is also some hope that I may find a nicely-shaped blonde at the end of the trip, and she would not be able to talk to me for at least three billion years.


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