Washington — The Mars Science Laboratory (MSL) is set for a landing on the Red Planet on August 5, after eight years of planning, design and construction and 570 million kilometers flown across the darkness of space.
Curiosity is the landing vehicle — the size of a compact car — that will actually descend to the surface. The rover represents a significant advance in NASA capabilities in robotics as the largest rover ever sent into space, and the smartest.
“This is the first roving, analytical laboratory we’ve sent to any planet,” said Michael Meyer, the lead scientist of the Mars Exploration Program, in a NASA briefing August 2. “It is a laboratory. It’s amazing that we can do chemistry and mineralology there on the surface.”
But first, the craft must reach the surface, and that maneuver will be unlike anything NASA has attempted before. Around the agency and at the Jet Propulsion Laboratory (JPL), where the mission is managed, they’ve come to call the MSL's entry through the Martian atmosphere to the surface “seven minutes of terror.”
The spacecraft will hit the Martian atmosphere traveling almost 22,000 kilometers per hour. NASA engineers and a staff that numbered in the thousands designed a system to slow the craft down to a gentle three-plus kilometers per hour when it reaches the surface.
The craft will deploy a parachute to slow itself, and will separate the rover from the landing craft with a specially designed “sky crane” that lowers and detaches Curiosity in a soft landing.
A complex series of discrete engineering operations all must be performed absolutely right to bring the rover to a predetermined landing site: Gale Crater. Through previous mapping and surveillance, this spot was determined to be a place with geologic features that may shed light on the Big Question that Curiosity is there to pursue: Has the Martian environment ever supported life?
Aerial observation of Gale Crater has revealed a couple of features very similar to ones on Earth that are left in rock by coursing water. That’s the prime place to begin a search for some sign of the existence of a life-form sometime in Mars’ history.
“That’s an exciting possibility,” said John Grotzinger, an MSL project scientist based at the California Institute of Technology, “because that already begins to sort of sniff a little bit like a potentially habitable environment that was very old.”
In the middle of Gale Crater is a more-than-four-kilometer-high feature the scientists have named Mount Sharp. Like a mountain on Earth, this surface formation, and the layers of different materials that form it, will tell a story about Mars' past, Grotzinger said.
Geologists will study the history of Mars, Grotzinger said, just as they have on Earth, “by taking hundreds of thousands of meters of stratigraphy as sort of a tape recorder of the way the planet changes to understand what happened.”
In addition to the surface formations and what they may reveal about Mars history and possible life-forms, the Curiosity mission will be tracking another critical environmental factor: the radiation levels on Mars. In fact, the spacecraft began that research not long after it launched, monitoring the level of radiation inside the space capsule as it traveled through the solar system, subjected to the unfiltered rays of the Sun.
Gauging the radiation levels that a Mars-bound astronaut might be subject to is a critical question looming over the possibility that a human crew might travel to Mars. Don Hassler, principal investigator of radiation levels for the mission, said they must calculate radiation exposure at three stages: the trip from Earth to Mars, a period on the planet surface, and the return trip to Earth, presumably a two- to three-year period, Hassler said.
“What we’ve learned is the contribution to an astronaut’s [lifetime] dose limit, which NASA has established, is a nontrivial fraction.” Hassler said. “It’s a significant fraction.” Hassler contributes to the MSL mission through the Southwest Research Institute, an independent, nonprofit research organization in San Antonio.
Gaining a high level of understanding about the radiation risk is, Meyer said, progress toward the ultimate goal of human exploration farther out in the solar system.
The lead scientist of Mars exploration said NASA has met and overcome tremendous engineering challenges in this mission that build the agency’s capabilities for human space flight. Creating a robotic rover of Curiosity’s size, equipped to serve as eyes and hands for scientists on Earth, is in itself a success. Carrying a metric ton of equipment 570 million kilometers, Meyer said, MSL will set an advanced robotic device on the surface equipped with 17 cameras, to give scientists back on Earth a view almost as good as being there.