Nasa's Curiosity Mars rover set for high risk landing

Mission control Mission control is ready for the descent. Note the pot of peanuts at front-centre - a landing tradition

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One of the most daring space missions ever undertaken is nearing Mars.

Nasa will attempt to land its one-tonne Curiosity rover on the Red Planet to study the possibility that this world may once have hosted microbial life.

The vehicle is packed with scientific instruments, including a laser that can zap rocks to determine their make-up.

Curiosity is currently hurtling through space, close to the end of a 570 million km journey from Earth.

Engineers describe its trajectory as near-perfect and they have passed up the last two opportunities to make course corrections.

The rover, tucked inside a protective shell, is due to begin its descent to the surface at 05:24 GMT, Monday (06:24 BST; 22:24 PDT, Sun).

A signal confirming it has landed inside a deep depression known as Gale Crater is expected on Earth about seven minutes later, at 05:31 GMT.

But getting this audacious exploration project safely down will be a colossal challenge.

Two-thirds of all missions sent to the Red Planet have failed, a good many lost on entry into the thin but unforgiving Martian atmosphere.

Curiosity - Mars Science Laboratory

Rover (Nasa)
  • Mission goal is to determine whether Mars has ever had the conditions to support life
  • Project costed at $2.5bn; will see initial surface operations lasting two Earth years
  • Onboard plutonium generators will deliver heat and electricity for at least 14 years
  • 75kg science payload more than 10 times as massive as those of earlier US Mars rovers
  • Equipped with tools to brush and drill into rocks, to scoop up, sort and sieve samples
  • Variety of analytical techniques to discern chemistry in rocks, soil and atmosphere
  • Will try to make first definitive identification of organic (carbon rich) compounds
  • Even carries a laser to zap rocks; beam will identify atomic elements in rocks

And yet, the US space agency has high confidence that the high-risk descent strategy its engineers have devised will deliver an intact vehicle to the surface.

This strategy will use a sequence of fully automated manoeuvres to slow the fall from an initial 20,000km/h at the top of the atmosphere to less than 1m/s at the moment of touch-down.

The last stage in the sequence will see a hovering, rocket-powered crane lower the rover to the ground on nylon cords.

The manoeuvres have raised eyebrows because of their complexity, but the entry, descent and landing (EDL) team leader, Adam Steltzner, has emphasised the amount of "reasoned engineering" that has informed the design.

"I slept better last night than I have in years, and I think that's because it's done - whatever's going to happen is going to happen," he said.

Nasa will be monitoring the drama from the Jet Propulsion Laboratory (JPL) in Pasadena, California.

It is here that mission control will receive the telemetry from Curiosity that has been bounced to Earth by the overflying satellite known as Odyssey.

Engineers can only watch and wait, however. The 250 million km between Mars and Earth right now means there is a 13-minute lag in communications.

The mission team knows that when it gets that first signal to say the rover has entered the planet's atmosphere, the vehicle will in reality have already landed or been destroyed some seven minutes previously.

Step by step: How the Curiosity rover will land on Mars

Aeroshell separates from cruise stage As the rover, tucked inside its protective capsule, heads to Mars, it dumps the disc-shaped cruise stage that has shepherded it from Earth.
Thrusters fired from MSL entry capsule The capsule hits the top of the atmosphere at 20,000km/h. It ejects ballast blocks and fires thrusters to control the trajectory of the descent.
Heat shield Most of the entry vehicle's energy is dissipated in the plunge through the atmosphere. The front shield heats up to more than 2,000C
Parachute deployment The parachute deploys when the capsule is about 11km above the ground but still moving at supersonic speed.
Parachute deployed above rover A key event is the dropping of the heat shield. This permits imaging and radar instruments to monitor the approaching surface.
Final moments before touchdown At about 1.5km above the ground and still moving at 80m/s, the rover and its sky crane drop away from the parachute and capsule backshell
Rover finally touches down Rockets on the sky crane slow the descent to 1m/s. Cords spool the rover to the surface. The cords are then cut and the crane flies away to a safe distance
Rover on the surface The rover is equipped with a nuclear battery and should have ample power to keep rolling across the Martian surface for many years.

"It will be really exciting; it always is. It's electrifying but it's tense," Doug McCuistion, the director of Nasa's Mars programme, told BBC News.

"Everybody white-knuckles through these 'seven minutes of terror', and it's named that for a good reason."

This is the fourth rover Nasa has attempted to put on the surface of Mars since 1997.

But Curiosity - also known as the Mars Science laboratory (MSL) - dwarfs those previous efforts in size and sophistication.

The rover will sample rocks for signs that Mars was once favourable to life

Assuming the robot lands safely, it will spend 98 (Earth) weeks scouring Martian soils and rocks for any signs that current or past environments on the planet could have supported microbial life.

Gale Crater was chosen as the landing site because satellite pictures had spied sediments in the depression that looked as though they were laid down in the presence of abundant water.

"We see a lot of evidence that water was on Mars in the distant past and flowed across the surface for maybe millions of years," explained Ashwin Vasavada, the MSL-Curiosity deputy project scientist.

"This mission goes one step further by trying to understand whether the environments in which the water persisted were habitable. Were there basic ingredients for life there? We're going to understand what the conditions were like when life was most likely in Mars' ancient history."

The rover is equipped with 10 advanced instruments. It also has a plutonium battery and so should have ample power to keep rolling for more than a decade.

Landing  ellipses
  • Engineers define an ellipse in which they can confidently land
  • Successive landings have become ever more accurate
  • Viking's ellipse was 300km across - wider than Gale Crater itself
  • Phoenix (100km by 20km) could not confidently fit in Gale
  • Curiosity's landing system allows it to target the crater floor
  • The rover's projected landing ellipse is just 7km by 20km
Mars rover (Nasa)
  • (A) Curiosity will trundle around its landing site looking for interesting rock features to study. Its top speed is about 4cm/s
  • (B) This mission has 17 cameras. They will identify particular targets, and a laser will zap those rocks to probe their chemistry
  • (C) If the signal is significant, Curiosity will swing over instruments on its arm for close-up investigation. These include a microscope
  • (D) Samples drilled from rock, or scooped from the soil, can be delivered to two hi-tech analysis labs inside the rover body
  • (E) The results are sent to Earth through antennas on the rover deck. Return commands tell the rover where it should drive next and follow me on Twitter


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  • rate this

    Comment number 143.

    Everyone in NASA is a US citizen. It's a requirement, as it's a government agency.
    Utter rubbish, you do not have to be a US citizen to work for a US government Agency. I am not American, but I have worked as a federal employee for Uncle Sam. The work involved growing and handling human pathogens. The only thing you can't be in the US is president if you weren't born there.

  • rate this

    Comment number 142.


    Well done on a successful landing. Best news all week :)

  • rate this

    Comment number 141.

    Nice try. Only 10-15% of the total post grad students in the US are foreigners. Stop claiming.
    I was a post-doc, the others were post-docs too.

  • rate this

    Comment number 140.

    A superb achievement for the US.
    But just remember who was your founding Father.
    One Mr Von Brown.Extracted from Germany I think.

  • rate this

    Comment number 139.

    $2.5bn diverted from space exploration won't solve world hunger. Praying to your favourite magic fairy won't solve world hunger. A second wave of British imperialism and governance in place of corrupt political regimes might go some way though.

  • rate this

    Comment number 138.

    I think its wonderful - man reaches for the stars (or a neighbouring planet) and knowledge about other planets - after all we have ruined this one, in the not too distant future we are probably going to need to new one - we now need to learn how to handle all that deadly cosmic radiation.

  • rate this

    Comment number 137.

    Of course the other great achievement that starts this week may be attributed to the BBC. Finally we have important global news taking priority over sports results in the headline banner. Could this be the start of the doubtless long recovery to normality ? So congratulations to the US for this maginificent achievement & to the BEEB too for allowing us to come up for air.

  • rate this

    Comment number 136.

    6. penguin337
    I will pray for the success of this mission
    (It might help)

    It doesn't for heart surgery, in fact it's bad for you! See below!

  • rate this

    Comment number 135.

    These are the times when one realises that we are one human race. Good luck NASA, money can always be spent in multiple ways but this is important too.

  • rate this

    Comment number 134.

    129. Macro
    What a magnificent achievement! What really does annoy me is comments from ignorant people such as, "what's the point", or "waste of money". If everyone thought like that we would all still be living in mud huts using candles as light.Making comments like that just shows how ignorant you are.
    Do you ever wonder if we have come too far, too fast?

  • rate this

    Comment number 133.

    Such another magnificent scientific but human endeavour by the US completely eclipses the Oplympics; Triple Gold for NASA. Of course the politics of envy will generate a great deal of negative comment; indeed this posting will attract negative ratings from those enslaved to the fashion of bashing America. Just like an Olympic Gold this is a fantastic achievement for such a young nation.

  • rate this

    Comment number 132.

    For all those commenting about money wasted!

    I suggest you turn off your computers now and dig out your abacus's!

    Yes the world has problems, but the amount spent on this project pales into insignificance compared to the money held in offshore accounts by the truly rich and greedy.

    "To boldly go...etc"

  • rate this

    Comment number 131.

    Mike from Brum: "I lived and worked in the USA when I was younger. It was a university research post, none of my colleagues were American"

    I don't believe you. This is a myth that people make up to rob the US of credit for its accomplishments. Only 4% of students in institutions of higher learning in the US are foreign, that's lower than the rate of foreigners in the US general population.

  • rate this

    Comment number 130.


    Paragraph 3 says "... 570 million km journey from Earth..." and further down you say "... The 250 million km between Mars and Earth..." Which is it???"

    Here's a clue - the distance varies. The distance now is not the same distance travelled by the CR. It is somewhat misleading though I agree.

  • rate this

    Comment number 129.

    What a magnificent achievement! What really does annoy me is comments from ignorant people such as, "what's the point", or "waste of money". If everyone thought like that we would all still be living in mud huts using candles as light.Making comments like that just shows how ignorant you are.

  • rate this

    Comment number 128.

    Kent: And why does the US gets blame for all the world's problems but can't take pride in the achievements of its natl space agency?
    The U.S. only gets blamed for the "wold's problems" from the POV of Americans that are are exceptionally thin skinned.

    This achievement speaks for itself. You pounding your chest re: a project you did no work on adds nothing.

  • rate this

    Comment number 127.

    Well done Curiosity for avoiding the BBC coverage of the Olympics

  • rate this

    Comment number 126.

    You're obviously not paying attention and/or just don't care to know the reality. If you take a brief moment and actually watch the news conference, the director of the mission just thanked the 7 countries who helped contribute in the building of the rover. If you're implication is that all 3,500 people who worked on the mission is a US citizen; you're wrong. It's OK to be wrong btw.

  • rate this

    Comment number 125.

    GO NASA!!! "And among His Signs is the creation of the heavens (celestial bodies) and the earth, and the living creatures that He has scattered through them: and He has power to gather them together when He wills. Quran 42:29"

  • rate this

    Comment number 124.

    Dear all
    I may be wrong. but what about cloud in the background ?? Because I heard still have to prove there is water on the mars ! So, Think about those pictures.


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