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, Science correspondent Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 21.

    Where can I get one of the batteries that will drive the Curiosity lander artound for 10 years?

  • rate this

    Comment number 20.

    "...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."
    Not according to a scientist interviewed on The Sky at Night. Engineering constraints rule a lot of Mars out as potential sites to visit (the poles for example).

  • rate this

    Comment number 19.

    Nice article. But you forgot to say what the status of the project was - I presumed from the article that the mission was about to land on mars. I searched and found the rocket launch is in fact a couple of days time. Lets hope all goes well. More details at

  • rate this

    Comment number 18.

    This is real hope, the real future, I do not think that it is impossible that one day we will have crops growing in space. Food production, energy, and new technology are all waiting out there. It is like we are in the middle ages and waiting for this second Renaissance. I have deep faith in our scientists and it is offers true inspiration, hope and opportunity for our children and rich rewards.

  • rate this

    Comment number 17.

    This is so profound and interesting it really blows my mind, its a shame people, short sighted though they are, cannot see it for the momentous accomplishment that it really is. Its another planet folks! Wakey wakey. I think most will only be interested when it offers them a job, a new home, or an intelligent species capable of saving us from ourselves. To them, the rest is all commentary.

  • rate this

    Comment number 16.

    I bet they find a shopping trolley up there.

  • rate this

    Comment number 15.

    Its good on one hand to see the rover there but on the other im wondering if theyre not looking for life are they instead trying to look in places that could be holding a small atmosphere like 3km down a crater that happens to get sunshine since its on the equator for left behind tech instead. If it was proven they found life they dont need to look for life and maybe were just not privy to this.

  • rate this

    Comment number 14.

    Let all hope that this time we do a well as spirit and opportunity and it keeps going for years to come. I am much happier spend cash on missions to Mars or the moon, than spending it on smashing atoms. I know which people can relate to more and give more for your £.

  • rate this

    Comment number 13.

    Curiosity? Not curious enough. Why isn't this probe searching for life? Don't believe the official story it's too difficult: the only experiment that worked on the 1970's Viking lander found signs of life and since then NASA has stopped looking. Curiosity is expensive, technically risky, and scientifically timid. Beagle 2 was better and could have found life. We should try again.

  • rate this

    Comment number 12.

    There is life on Mars. David Bowie said so.

  • rate this

    Comment number 11.

    Please add a link to the ridiculously awesome landing sequence;

    NASA and JPL have balls - that's for sure.

  • rate this

    Comment number 10.

    This is the future. the only way to slow down the self distruct button that our M.P's keep pressing for a quick fix.
    Phrases like, "Space is not a priority for our 4/5 years in power, let the next lot sort it"
    When will the idiots in power, not only governments but greedy corporations, realize that the planet is full.
    It's not rocket science, irony !!
    Exploration has never been more urgent.

  • rate this

    Comment number 9.

    Not to sound too pessimistic but wouldn't it be safer to send lots of smaller probes instead of a large one. Many eggs in one basket I think

  • rate this

    Comment number 8.

    My biggest worry is that I won't live long enough to see a Mars landing. The LHC is an intellectual frontier. This is the real thing. My neice (an actuary) tells me that 19 years is about what I've got so come on NASA and the rest of the world. I don't want to die not knowing...

  • rate this

    Comment number 7.

    At least they won't make the same mistake (I hope) of a previous joint Nasa/European Space agency mission, which converted a landing speed planned in units of feet per second into metres per second, which somewhat modified the lander bodywork.

  • rate this

    Comment number 6.

    It would be brilliant if it could find out what happened with the Beagle low-cost probe too.

  • rate this

    Comment number 5.

    Pity they're not going to have a more detailed look at the 'pyramids' at Cydonia. They do look like artefacts. Personally, I need more info than I have at the moment before I dismiss them as illusions.

    Show us what you've got, NASA!

  • rate this

    Comment number 4.

    All we need now is is planning permission, builders, a multi planetary space transport system, an atmosphere we can live with & "hey presto" World growth is saved & we can all spend again !

  • rate this

    Comment number 3.

    A really great use of some of our nuclear technology!!!

  • rate this

    Comment number 2.

    Best of luck for the launch, journey and landing. A lot of hardwork has gone into this and I look forward to hearing about it over the next few years.


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