In 2014, Curiosity and MAVEN are slated to team up to help scientists unravel the mystery behind Mars' vanishing atmosphere: How did a wet, warm planet lose that thin layer that can preserve the building blocks of life?
When NASA's latest Mars rover Curiosity survived its "seven minutes of terror" plunge through the planet's atmosphere in early August and phoned home to say all was well, the mission's scientists and engineers were ecstatic. They had put themselves in a good position to see if their target, Gale Crater and its three-mile-high central summit, might at one time have hosted an environment suitable for life.
But the atmosphere through which Curiosity descended also plays a key role in determining the planet's hospitality. Engineers and technicians are now assembling MAVEN, an orbiter slated for launch in November 2013 that will unravel the mystery of Mars' vanishing atmosphere.
Combined with key measurements Curiosity will take at the surface, MAVEN's measurements at the top of Mars' atmosphere are expected to allow researchers to reconstruct a history of the atmosphere – including the rate at which the planet has lost water over its 4.6-billion-year history.
Water is a key ingredient for the emergence of organic life. One of the questions Curiosity will help answer: Did water ever collect in Gale Crater? MAVEN is asking: Where did any surface water ultimately go?
Moreover, a thick atmosphere is one line of defense against cosmic rays, as well as extreme forms of ultraviolet radiation and energetic particles, which stream from the sun as "solar wind" and flood Mars' immediate surroundings during powerful solar storms. These forms of radiation can make for a bad day at the office for organisms on a planet's surface or for the complex organic molecules on the surface that could give rise to simple forms of life.
Scientists have been interested in making MAVEN-like measurements at the red planet since the 1980s, says Bruce Jakosky, the mission's lead scientist.