Curiosity: Risky Landing on Mars

Curiosity: Searching for Life on Mars

The Curiosity rover, carried by the Mars Science Laboratory spacecraft, will be able to search for organic life on Mars.

Yes, if the high-risk landing on Mars on August 6, 2012, goes well. We will only know on Monday, August 6, 2012, at 05:31 UTC, or 14 minutes after the landing itself. This is the time it takes for signals to travel through space between Mars and Earth. Only 40% of the spacecraft sent to Mars have succeeded in landing.

Mars is the only planet whose surface we can see well from our terrestrial observations. The public, looking at the mysterious planet through a telescope, imagines they will see what they see in the best books reproducing magnificent glossy photographs. But it is only thanks to the robots that land on Mars that we can admire real images of the Martian surface. On August 6, 2012, Curiosity, the 900 kg technology robot, will make NASA astronomers anxious as it attempts to land in the Gale Crater region on Mars. It must land overnight from Sunday to Monday on the red planet, at the end of a long journey of more than eight months. "Mars is being kind to us, we will have good conditions for Sunday... a dust storm spotted a few days ago has dissipated, giving way to a fairly benign dust cloud," said scientist Ashwin Vasavada.

The $2.5 billion invested in Curiosity will allow us to answer an anxiety-inducing question: are we alone in the universe?

Indeed, the robot is tasked, over the next 2 years, with finding traces of past or present life on Mars.

If there are traces of life on another planet in the solar system, it means that life is everywhere and part of the matter of the universe.

Curiosity's landing is the most complex of the landings already carried out on Mars because the robot is too heavy for the impact to be cushioned with air-filled balloons.

To go from 21,243 km/h to 2.74 km/h in 7 minutes, engineers had to design an immense "parachute" about 20 meters in diameter, equipped with retro-rockets that will allow the robot to land like a feather. During these 7 minutes of terror, as NASA calls them, three probes in orbit around Mars will recover the signals sent by Curiosity to transmit them to the scientists in Pasadena.

It is only after this high-risk approach that Curiosity will begin its mission on Mars. Thanks to a nuclear generator, it will then set off, with the high-definition camera eyes wide open, in search of organic life.

A laser will allow it to avoid obstacles within seven meters. Many other high-tech instruments will help it search for traces of life in an apparently sterile environment.

Simple methane molecules will be enough to make scientists happy, as this gas is sought to detect the presence of life. To satisfy our curiosity, the robot will have to dig, spot, drill, sample, analyze the matter of the universe and, of course, send its observations back to us, poor humans. But after more than 8 months of "gestation," the duration of its space journey, it will have to overcome the risky step of its birth on the Red Planet (see the details of its exit on the image next to it).

Mars and Its Visitors: Exploration Probes

Image: The landing of the Curiosity rover is a real feat. To be convinced, just watch the little NASA film.

Since 1964, Mars has received visits from numerous probes and robots that have visited this planet with varying degrees of success.

• 1964: Soviet probe Mars 1 was the first to reach the red planet, but radio contact was lost before arrival.
• 1965: American probe Mariner 4 sent some photos and temperature and pressure data back to Earth.
• 1969: American probes Mariner 6 and Mariner 7 showed the south pole cap of Mars.
• 1972: Soviet probes Mars 2 and Mars 3, the first probes placed in orbit around the red planet. Mars 3 photographed Mars for nine months.
• 1972: American probe Mariner 9 photographed Mars for nearly a year, and Phobos, the Martian moon.
• 1974: Soviet probe Mars 5 sent the first data on the composition of the Martian soil.
• 1976: American probes Viking 1 and Viking 2, the first probes to land on Mars. They did not find traces of life but photographed the two Martian moons, Phobos and Deimos.
• 1989: Soviet probe Phobos 2 photographed Mars and Phobos. Failure of the orbiter that was to land a probe on Phobos.
• 1999: American probe Mars Global Surveyor completed the mapping of Mars. It detected crevasses dug by water.
• 1997: American probe Pathfinder and its motorized robot Sojourner discovered that Mars had liquid water and a denser atmosphere.
• 2002: American probe Mars Odyssey detected hydrogen and ice under the Martian poles.
• 2004: European probe Mars Express confirmed the presence of ice under the poles and methane in the atmosphere. The Beagle 2 probe, which was to land, was lost.
• 2004: American probe Mars Explorer Rover composed of two motorized robots, Spirit and Opportunity. They confirmed that Mars once had salty oceans.
• 2006: American probe Mars Reconnaissance Orbiter detected ice at the bottom of craters and several minerals associated with water.
• 2008: American probe Phoenix confirmed the presence of frozen water.
• 2012: American probe Mars Science Laboratory equipped with the famous motorized robot Curiosity.

Other missions are already planned to uncover the secrets of this mysterious planet.

Curiosity's Communications: A Permanent Relay with Mars

The Martian day is almost equal to the Earth day; it lasts 24 hours and 42 minutes. This allows JPL (Jet Propulsion Laboratory) engineers to communicate with Curiosity at the pace of an Earth day with the planet Mars.

They work during the Martian nights and send instructions to the robot in the early morning. Curiosity applies them during the day and transmits all its results in the evening. Communication with the Curiosity rover is via the three probes placed in orbit around Mars, which serve as transmission relays. Curiosity is thus always reachable from Earth. The robot is equipped with 3 specialized antennas of different powers to receive instructions and send the data collected by the probe to the orbiting relays. The transmission rate is apparently ridiculous but sufficient; the data is transmitted to the relays at a speed of 1.35 Mbits/s for transmission and 256 Kbits/s for reception. Under the robot, there are 8 Hazcams cameras that film the ground permanently in black and white and a 3D camera with a resolution of 1 Megapixel to avoid obstacles.

Two other Mastcams cameras located in the robot's head film in HD and 3D color with a resolution of 2 Megapixels.

Another small Mahli camera equipped with a flash can photograph microscopic objects of 12.5 microns. Its Chemcam laser allows it to target a rock and analyze the gas it releases to deduce its composition. Its 1.9-meter articulated arm is equipped with a drill, a brush, and a mini shovel to retrieve rocks and store the samples in two compartments inside the robot where they will be analyzed.

The engineers sought above all robustness; the robot's electronic brain should not have more than one failure in 15 years. It is equipped with a small 200 MHz processor, a PowerPc 750, like the old Apple Mac G3s, between 1997 and 2001. The RAM is 256 MB, and storage is on 2 GB of flash memory. The VxWorks operating system, published by an Intel subsidiary, is hosted in another flash memory updated by download from Earth. All these devices operate thanks to a nuclear generator that stores the electricity produced from the heat released by the natural disintegration of plutonium dioxide in two rechargeable lithium-ion batteries. The robot's autonomy is estimated at 687 days, or the duration of a Martian year.