NASA to Instrument Mars Science Laboratory Heat Shield for Aerodynamics Data

NASA's exploration, science and aeronautics directorates have joined forces to instrument the heat shield for the upcoming Mars Science Laboratory (MSL) mission to gather aerodynamics data that could help eventually land human astronauts on the red planet. Set to launch in the fall of 2009 and arri ve the following summer, the 1- metric ton MSL will be the largest payload ever landed on Mars.

Ordinarily, NASA's science directorate wouldn't have bothered instrumenting the heat shield due to the expense involved, according to Scott Horowitz, head of NASA's Exploration Systems Mission Directorate (ESMD). But both ESMD and the Aeronautics Research Mission Directorate (ARMD) saw MSL as an opportunity to gather needed data. "Aeronautics is very interested in the basic science of aero and how good are their models at predicting how the heat shield works on Mars," Horowitz said. And "it's obviously very useful engineering information for us as we start developing the heat shield for the future, because we're going to eventually go to Mars."

Every mission NASA has landed on Mars has used versions of the parachute system originally developed and qualified for the Viking landings of the 1970s, according to Peter Coen, principal investigator for the ARMD supersonics project. MSL "will be the absolute limit of what that parachute system can safely land," Coen told The DAILY. For anything larger, "we're going to need a different kind of system."

The estimated landing mass for a human mission to Mars is 20 metric tons. The Apollo Earth re-entry approach of heat shields and parachutes took advantage of Earth's denser atmosphere, but similar systems wouldn't provide enough deceleration at Mars. Martian landings have used an aeroshell for hypersonic (i.e., greater than Mach 5) deceleration, followed by parachutes for supersonic deceleration. Possible higher-mass concepts include a larger aeroshell that could handle both hypersonic and supersonic deceleration.

NASA has up to this point worked these problems separately, "knowing all along that what we really need to do is solve that problem together" with a single system, Coen said. So the hypersonics and supersonics researchers at ARMD have joined forces to look at tool and concept development. The team is looking at parachute-derived concepts for a 2-metric ton landing, and inflatable decelerators or aeroshells with the potential for supersonic propulsive deceleration as potential solutions at the 20-metric ton level.

At this early stage, ARMD is focusing on refining its analytical tools rather than developing specific concepts for Mars entry systems, which will be driven by ESMD requirements that won't be finalized for many years. When ESMD is ready, ARMD plans to deliver to them a computational toolkit along with some "preferred concepts," Coen said.

- Jefferson Morris

			Mars Science Laboratory is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the red planet. + Read More