However, a step in these planetary protection measures wasn't adhered to for NASA's Mars Science Laboratory rover Curiosity, now en route to the Red Planet, SPACE.com has learned.
The incident has become a lessons-learned example of miscommunication in assuring that planetary protection procedures are strictly adhered to.
The issue involves a set of drill bits carried by the Curiosity rover, which launched Nov. 26 to Mars. When project developers made an internal decision not to send the equipment through a final ultra-cleanliness step, it marked a deviation from the planetary protection plans scripted for the Mars Science Laboratory mission. [Photos: Watching the Mars Rover Curiosity Blast Off ]
That judgment, however, didn't reach NASA's chief protector of the planets until "very late in the game," said Catharine "Cassie" Conley, NASA's planetary protection officer. "They didn't submit the request for the deviation not to comply with their planetary protection plan until several months ago," she emphasized.
Conley told SPACE.com that the initial plan called for placing all three of the drill bits inside a sterile box. Then, after Curiosity landed, the box would be opened for access to the sterilized bits via the rover's robot arm, extracted one by one and fit onto a drill head as the mission progressed.
But in readying the rover for departure to Mars, the box was opened, with one drill bit affixed to the drill head, Conley said. Also, all of the bits were tested pre-launch to assess their level of organic contamination. While done within a very clean environment, that work strayed from earlier agreed-to protocols, she said.
"That's where the miscommunication happened," Conley said. "I will certainly expect to have a lessons-learned report that will indicate how future projects will not have this same process issue. I'm sure that the Mars exploration program doesn't want to have a similar process issue in the future. We need to make sure we do it right."
Conley said the deviation from protocol was reinforced by science and project officials concluding that Curiosity's target landing spot, Gale Crater, is free of potentially life-harboring ice — at least at depths that the drill bits would penetrate.
"That reinforced the reasonableness of not having the drill bits sterilized, because there's unlikely to be 'special regions' in the Gale Crater landing site," Conley said.
The $2.5 billion Mars Science Laboratory mission was designed to comply with a requirement to avoid going to any site on the Red Planet known to have water or water-ice within 3.3 feet (1 meter) of the surface.
Adhering to cleanliness standards is a way to make sure the mission does not transport Earth life to Mars. Doing so preserves the ability to study that world in its natural state and also avoids contamination that would obscure an ability to find native life on that planet, if it exists.