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Published on January 9th, 2012 | by Carl Mundy


Curiosity Hasn’t Killed The Rover; Curse of the Red Planet and the Latest Mars Mission

Carl discusses the latest mission to Mars, the Mars Science Laboratory, and the historically unlucky journey to the red planet most recently highlighted by the failure of the Russian Phobos-Grunt Mars probe…

On Saturday the 26th November 2011, an amazing machine was launched atop an Atlas rocket and fired on a path towards the Red Planet. Approximately the same size as a Mini Cooper, this extraordinary machine is a mobile science laboratory and over fives times as massive as anything we have ever sent to roam the surface of Mars.

In just seven months the Mars Science Laboratory (MSL) will attempt the first precision Mars landing using an entirely new and unproven method, safely delivering arguably the most advanced scientific package ever sent to another world – a rover called Curiosity. It’s scientific mission? To determine if Mars is, or ever has been, able to support life.

The spacecraft is about to undergo an important manoeuvre which will involve a choreographed sequence of firings of eight thrusters over a period of around 3 hours. It will redirect the spacecraft more precisely toward Mars to land at Gale Crater. This operation is scheduled for January 11, 2012.

Curse of the Red Planet

The exploration of Mars has been a long and expensive process. Nearly two thirds of all missions sent to the Red Planet have failed before completing their mission. Although the success rate in modern missions is much greater, the chance of failure is still high; a fact highlighted by the recent launch and subsequent failure of the Russian Phobos-Grunt mission.

Phobos-Grunt was expected to bring a soil sample back from Mars’ moon Phobos, the first time a sample of a natural satellite would have been brought back to Earth since the Moon. Launched successfully into orbit around Earth, the engine burns that were to put it on course for Mars failed to occur. For the scientists and engineers staring intensely at computer screens here on Earth, it had to be a horrible feeling knowing the culmination of their hard work was going no where.

Precision Engineering

If the curse wasn’t enough of a risk to such a ground-breaking mission, MSL will attempt to safely place its precious payload, the rover Curiosity, down in an area nearly eight times smaller than previous attempts. Just how it intends to achieve this magnificent feat is quite unbelievable. Gather round…

The protective shell that cocoons the rover will position itself precisely before and during atmospheric entry. This positioning allows this precision landing to occur, ejecting ballast masses to ensure it stays on the correct path through the Martian atmosphere. At around 10km, the heat shield that protected the cocoon from the intense heat of atmospheric entry will separate and eject. Its massive 50 metre long, 16 metre diameter parachute can then be deployed to slow the craft down further.

Once the parachute has slowed the craft down to speeds just less than that of a bullet, Curiosity and the decent stage both drop out of their protective shell. Curiosity will be slowly lowered beneath the decent stage, connected by a new ‘sky crane’ system. This is all done while the decent stage uses its own thrusters to stabilise itself and slow itself down.

This new landing system will carry the rover to the landing site and gently place the rover on the surface of the Red Planet before small explosions cut the cables connecting the two machines and the decent stage flies away and crash lands, safe in the knowledge its duty has been fulfilled.

Curiosity Leads Us

When this car-sized rover safely reaches the surface of Mars, the real fun can begin. Curiosity is the biggest rover ever sent to Mars, or indeed any other body in our solar system. Some of the most advanced scientific instruments ever to leave Earth are packed into this mobile laboratory. For the next two years, Curiosity will rove the Red Planet’s dusty surface in search of clues to it’s habitability.

Curiosity is planned to touch down near Mars’ equator, in a region called Gale Crater. This strange site is unusual because in the middle of the crater is a mound of debris around a central peak. Rising 5km (3 miles) above the crater floor, this mound presents the opportunity to study a rock type never previously seen on Mars and will be the rover’s first target in its search for organic molecules.

A Bursting Suitcase

This rover didn’t pack light. Curiosity has a large suite of advanced scientific instruments that have been developed to search for organic molecules in the Martian rocks. Four cameras will image the rover’s decent to the surface, take microscopic images of Martian rocks and soil and provide colour images and spectra of anything that takes the rover’s fancy.

Accompanying these cameras is a suite of instruments called ChemCam. Part of this package is a laser-induced breakdown spectroscopy system. This amazing system fires a laser at a target up to seven meters away and vaporises it allowing the chemical make up of the target to be detected – different elements give off different coloured light. Never before sent to another planet, this is a first for the most unlucky planet within the solar system.

Curiosity also carries an X-ray spectrometer. This instrument will fire alpha particles (helium nuclei) at a target and observe the X-rays emitted to determine what the sample is made of. A host of other systems on the rover will allow it to avoid hazards that lurk on the surface, monitor the Martian weather and its immediate environment as well as provide it with the ability to detect water and ice on the Martian surface. This is one piece of intelligent and extremely expensive kit.

Humans Are Next

Curiosity will have another ability; one that is important in the planning of any future human trip to our red neighbour. It will monitor the harmful radiation that it may experience on the surface and guide scientists here on Earth in their research and planning for future manned missions to Mars. Radiation is the single biggest threat to any long-term manned mission into the solar system, both during transit and when on another planet or moon.

In November last year, the third stage of a unique experiment ended in which a group of volunteers spent 520 days together in the first full-length simulation of a human mission to our neighbouring planet. Mars500 was a joint venture between Europe, Russia and China in an effort to determine the problems, and any potential solutions, that may arise in a real mission. More efforts like these are vital to studying and understanding not only the technical challenges that may confront us, but also the challenges associated with the crew and their long term confinement.

Seven Months

If the craft survives its interplanetary journey to the red planet without any hiccups, if the craft performs all the necessary trajectory corrections, if every part separates as it should, if the sky crane performs its duty and if the rover still operates after its hopefully soft landing, Curiosity should provide us with our clearest picture of Mars’ history and indeed light the path for a future manned mission.

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About the Author

Astronomy PhD student from the UK with a passion for astronomy and science outreach projects. Involved with weekly science-based radio programme The Science Show on University Radio Nottingham (URN).

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