NASA's make-or-break Mars mission has entered its landing phase on Monday morning. While the Curiosity rover attempts to land using a never-attempted sky crane, engineers back on Earth have no control over the pre-programmed sequence.
The touchdown is scheduled for 5:31 GMT.
NASA engineers will have to wait at least 14 minutes before learning the fate of Curiosity. That is if the Odyssey orbiter circling Mars is at the right spot in the sky to catch the rover’s signal. If not, it could take up to eight hours to get the final answer on the rover’s fate.
The $2.5 billion Mars Science Laboratory "could arguably be the most important event in the history of planetary exploration," said Doug McCuistion, director of Mars exploration at NASA’s headquarters in Washington, DC.
The trickiest part of the mission, currently on its 8 months since launching in 2011, is the landing. Not only does it involve delivering the NASA’s largest-ever one-ton payload safely to the Martian surface, it will also attempt a new kind of landing sequence involving a guided entry, a supersonic 16-meter parachute, firing eight rocket thrusters during the descent and, finally, the sky crane.
A crane hovering some seven meters in the sky after touchdown will lower Curiosity to the surface of Mars. The approach was chosen over a traditional lander or inflatable cushioning due to the size of the rover. The sky crane trick avoids risks like tilting the platform, or mechanical damage from the clouds of dust and debris kicked up by rocket engines. But the sky crane technology couldn’t be fully field-tested on Earth, since it was designed for the atmosphere and gravity of Mars.
The landing will be carried out automatically. Due to the distance between Earth and Mars, it will take almost 14 minutes for a radio signal to reach NASA – mission control won't know if the landing was a success or failure until it’s long over. If the rover makes a smooth landing, it may still take hours or even days before a communication link to the rover is established through the Mars Odyssey satellite orbiting the planet, NASA officials warned.
Curiosity will be in operation for at least one Martian year, or 687 Earth days, during which it will cover a distance of at least 20 kilometers. Its findings could potentially outshine previous rover missions Spirit and Opportunity.
"It's an order of magnitude more capable than anything we have ever launched to any planet in the solar system. It will go longer, it will discover more than we can possibly imagine," senior NASA manager Colleen Hartman said before launch.
The rover is the size of a small car, and about twice as long as its predecessors. It carries 80 kilograms of scientific equipment, compared to the 5 kilograms of equipment carried by Spirit and Opportunity. Curiosity also contains a plutonium-powered generator, and is not dependent on the Sun for electricity.
Curiosity’s mission will focus on a geological study of the Gale Crater, which scientists speculate may once have been a lake. The rover will climb Aeolis Mons, a 5.5-kilometer-high mountain near the center of the crater that is believed to contain eroded sedimentary layers, which would offer a glimpse at some 2 billion years of Martian history.
With its robotic arm, high-res cameras and 10 scientific instruments, the rover will conduct a geological survey of the area. The mission’s main goal is to determine whether Mars was once capable of supporting life. It will be looking for biosignatures: the carbon-based building-blocks of living organisms.
A Russian-made device called Dynamic Albedo of Neutrons will be deployed to search for spots with high concentrations of underground water and ice. “Such places are of greatest interest when you are looking for signs of life,” said the instrument’s manufacturers at Russia’s Space Research Institute.
The mission comes at a crucial time when NASA faces budgetary restrains. The fiscal year 2013 budget cut $300 million from the agency’s planetary science programs, most of it related to Mars missions. NASA had to withdraw from an agreement with the European Space Agency on the ExoMars program, which called for launch of a planetary orbiter in 2016 and two rovers in 2018.
The Mars Science Laboratory is NASA’s only remaining flagship mission for the planet. The launch was initially scheduled for 2009, but was postponed for two years to test the rover’s mobility system and robotic arm.