Seven minutes of dread in store as rover descends on Mars

IT HAS taken nine years and more than $2.3 billion to set it on its journey to Mars, but the fate of the most advanced space exploration rover ever built will be determined in just seven minutes when it finally reaches the red planet.

Engineers and scientists will face a tense wait in little over a week when NASA's Mars Science Laboratory rover, called Curiosity, begins its descent towards Mars at 21,243km/h in a landing that has been nicknamed ''seven minutes of terror''.

NASA has developed an entirely new landing system to get the van-sized wheeled robot, the largest ever sent to another planet, on to the Martian surface. It will be lowered the last 6 metres to the ground from a hovering spacecraft known as a ''sky crane''.

If that fails, the exploration of the Mars and the search for signs that the planet once supported life will come to a stop for at least five years and - in the current financial climate - could permanently set back NASA's ambitions to send humans to Mars.

Hanging in the balance are the careers of thousands of scientists from around the world who have been anticipating at least two years of new data to study as the rover explores the Martian surface, searching for signs of life.

Dr Stephen Lewis, a senior lecturer at the Open University who is a member of the entry, descent and landing team for the Curiosity mission, said: ''A mission like this probably only comes along once in a lifetime; there are going to be a lot of nervous people keeping their fingers crossed next Sunday.''


With an atmosphere up to 200 times thinner than Earth's, landing a one-tonne rover on Mars presents unique challenges as a parachute will not slow the spacecraft down enough to land safely. Curiosity will have travelled 566 million kilometres since it was launched in November by the time it reaches the edge of the Martian atmosphere. From there it will take just seven minutes to reach the ground.

The entry capsule will enter Mars' atmosphere 130 kilometres above the surface, slowing down as air resistance builds, causing its heat shield to reach temperatures of more than 2090 degrees as it descends.

Around 11 kilometres above the surface, a 15.5 metre-wide parachute will deploy, slowing it further until the parachute and outer capsule are detached entirely from the sky crane inside.

Booster rockets on the sky crane will then fire, slowing it to just 2.7km/h while on-board radar and computers will steer it towards the landing zone.

The rover will finally be lowered 6 metres from the crane on nylon cords to set it down gently on the surface. The sky crane will then detach and fly away.

However, with more than 247 million kilometres of space separating Mars from the Earth, it will take 14 minutes for signals from the spacecraft to reach the scientists back on Earth. It would take another 14 to send any instructions to the rover.

Telegraph, London