WASHINGTON — NASA is paying $7 million to add a high-definition 3-D camera to the already overbudget Mars Science Laboratory (MSL) mission at the urging of blockbuster filmmaker James Cameron.

In February, the U.S. space agency modified an existing $18 million contract with Malin Space Science Systems to restart work on a zoom-lens 3-D Mast Camera, or Mastcam, that NASA asked the San Diego-based company to set aside in 2007 in favor a Mastcam consisting of a pair of fixed-focal length 2-D cameras. Now that the cheaper, less-complicated cameras have been delivered to the Jet Propulsion Laboratory in Pasadena, Calif., for integration with the MSL rover, NASA has told Malin that it will fly the 3-D Mastcam instead if they can get it done by the end of the year.

MSL is slated to launch in October 2011, a two-year delay only marginally responsible for pushing the mission’s expected price tag past $2.3 billion, up from the $1.6 billion NASA estimated in 2008.

“There were some operational constraints that translated to cost growth, and we were told to delete the zoom lenses and come up with a new design,” Michael Ravine, Malin’s advanced projects director, said in a May 5 interview.

Cameron’s role in the project dates back to 2004, when NASA first chose Malin to lead MSL’s scientific camera team. As a Mastcam co-investigator, Cameron brings more to the project than the star power that goes along with having directed the two highest-grossing movies of all time (“Avatar” and “Titanic”). The former NASA Advisory Council member also is known for pioneering advances in cinematography in challenging environments, such as the lightweight 3-D camera he developed to film the underwater scenes in “Ghosts of the Abyss,” a 2003 documentary chronicling his diving expedition to the wreck of the RMS Titanic.

“Technically speaking, he has a lot of expertise that is applicable to what we are doing,” Ravine said, noting similarities between the 3-D Mastcam and the remote-controlled underwater camera Cameron developed for the Titanic documentary. “Separately from that, he has a demonstrated track record of using tools like this to get the public’s attention and keep them engaged.”

When NASA decided in 2008 to postpone MSL’s launch until 2011 to address a host of technical challenges, Ravine said he and Cameron saw an opportunity to restart work on the 3-D Mastcam.

With Cameron’s input, Malin put together a proposal to complete work on the high-definition zoom cameras and sent it to NASA  in early 2009. But the effort to revive the project did not gain traction until Cameron  met with NASA Administrator Charles Bolden this past January.

“He had a chat with the administrator and some other people … and at the end of that they didn’t see any obvious road blocks that would keep it from happening,” Ravine said. “If we are unable to deliver the zooms in time, or if they are unable to figure out how to get them on the spacecraft in a way that’s compatible with all the other thousands of things they have to do, then they’ll just fly the ones we’ve already given them.”

In addition to the $18 million the agency spent on the initial camera purchase — which covered three different sets of MSL cameras — NASA will pay Malin $5 million to complete production of the 3-D Mastcam and another $2 million for integration with the rover, said NASA spokesman Dwayne Brown. Regardless of which Mastcam ultimately flies, once on Mars they will serve the same scientific purpose.

“The cameras are used to look at the region around the rover and study the geology at a lot of different scales,” said Ashwin Vasavada, NASA’s deputy project scientist for MSL.

While any 3-D imagery MSL captures will be made publicly available through the normal channels, Vasavada said one of Cameron’s roles will involve using the imagery to engage the public.

“These aren’t the first stereo cameras we’ve had on Mars, but these will be the first stereo, zoom and [high-definition] set of cameras,” Vasavada said. “In order to see the color, it’s much better to do the kind of technologies that are in movie theaters and things like that. I expect we’ll try to do some of that.”