Mission to Mars

Adam Stelzner has spent years working out how to land the rover on Mars. He will take control of the rover as it begins to enter the Martian atmosphere. He won’t be able to rely upon the systems that got the lunar rover down safely onto the surface of the moon.

Adam Stelzner “Mars is tough. The moon, where we landed lunar modules on the moon before, does not have any atmosphere and it makes the process of getting down to the surface kind of simple. You take a rocket engine, you turn it on and you slow yourself down until you touch down on the surface.”

Unlike the lunar rovers, Curiosity will have to battle an unpredictable atmosphere.

Adam Stelzner “Historically, Mars has been evil. You don’t know what the weather is going to be like, you don’t know whether the atmosphere is going to be dense or diffuse. Will be a hot day and not so dense, or a cold and dense day? If it’s cold and dense, you slow down faster, you end up shorter. If it’s hot and low density, you end up flying farther.”

The dangers of this unpredictable atmosphere are heightened by the speed the spacecraft has to travel at to get to Mars. It will arrive at 13,000 mph.

Adam Stelzner “We have enough energy of motion in the spacecraft that we could vaporise the spacecraft in the atmosphere of Mars just by slamming into that atmosphere and developing so much friction that the vehicle would burn up. So it’s a challenge.”

The rover will be tucked up inside spacecraft when it reaches the dangerous Martian atmosphere. Its first line of defence will be the world’s biggest heat shield. Next, the team have to stop it from crashing head-on into the Red Planet. So they have designed the biggest supersonic parachute ever made. In NASA’s giant wind tunnel near San Francisco, they put it to the test.

The parachute must be deployed at twice the speed of sound. The tests confirmed the huge canopy should survive the enormous forces it will encounter as it’s dragged through the Martian atmosphere. Finally, Curiosity’s engineers tested the most risky part of the rover landing procedure… A bizarre hovering crane that will have to lower the rover down the final 20 metres to the surface. The sky crane took the engineers years to perfect. It has never been used to land anything before. But although all of Curiosity’s individual landing stages passed their tests on Earth before launch, they have never been tested all together.

The Red Planet’s evil environment will be the first place the whole procedure is ever attempted.

Planning the journey was the first challenge for Joel Krajewski’s engineering team. As flight director, Joel’s colleague Brian Portock is, in effect, the mission’s quarterback. It’s Brian’s job to aim and throw the spacecraft across the solar system to a moving receiver… Mars.

Brian Portock “Everything is in motion in space. Mars is moving round the sun and the Earth is also moving round the sun, and their motion relative to each other is changing. Similar to a receiver running out for a pass is in motion… And the quarterback needs to stand back and throw a ball… So that the receiver and the ball meet at a point in space and time that is the correct one so that they can catch it. They need to figure out how far the ball needs to travel depending on where the receiver is. How fast the receiver’s running in that direction.”

Joel Krajewski “Most quarterbacks don’t sit down and calculate that on paper. It’s all done in their head, instinctively, without thinking about it. But spacecraft, we do it on paper, or these days, on computers.”

Brian Portock “The other thing a quarterback does is put spin on the ball. Spiral so that the ball flies in the correct trajectory. So we also are sending our spacecraft… So it maintains its attitude… And so that we can point the solar rays back at the sun and communicate back to the Earth. And so, the actual rotation of the ball is similar to the rotation of the spacecraft.”

They make it sound simple, but firing a spacecraft across the solar system involves some really complex ballistic calculations. The craft must escape the pull of the Earth’s gravity. It must contend with solar winds that could blow it off course… Cosmic radiation which can disrupt radio contact… And the craft is constantly being dragged from its course by the gravitational pull of other planets. Just a tiny error could result in Curiosity missing Mars altogether.

Joel Krajewski “To get the distance scales approximately similar, the quarterback here is throwing a pass 30 metres, 40 metres away. But Brian’s target of Mars is hundreds of millions of kilometres away. It’s similar to as if this quarterback here were throwing a football to a receiver in, say, London, and needing to hit his mark.”

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