NASA - National Aeronautics and Space Administration

"The heights by great men reached and kept were not attained by sudden flight, but they, while their companions slept, were toiling upward in the night."
-- Henry Wadsworth Longfellow, 19th century American poet
When the Mars Science Laboratory mission, or MSL -- the latest entry in NASA's Mars Exploration Program -- reaches the red planet in summer 2012 to deliver an advanced new science rover, Curiosity, to the surface, NASA researchers also will be closely studying a complex instrumentation payload in the entry vehicle's heatshield. Its results could have significant long-term effects on how we send future robotic and human missions to Mars.

The MSL Entry, Descent, & Landing Instrument (MEDLI) Suite is a NASA Technology Demonstration Mission, a set of engineering sensors designed to measure the atmospheric conditions and performance of the entry vehicle's heatshield during atmospheric entry and descent. While not part of the core scientific payload of the Mars Science Laboratory, the instrument suite will provide important engineering data for the design of entry systems for future planetary missions. Its innovative Mars Entry Atmospheric Data System (MEADS) pressure sensors will gather information about the aerothermal and aerodynamic characteristics of the entry vehicle as it descends and study the Martian atmosphere itself. The MEDLI Integrated Sensor Plugs (MISP), comprised of thermocouples and recession sensors, will analyze the performance of the Mars Science Laboratory's thermal protection system.

Close analysis of this mission is vital to future NASA exploration of the red planet. The Mars Science Laboratory spacecraft will enter the Martian atmosphere traveling more than 3.5 miles per second -- the second fastest NASA entry to Mars to date, after the Pathfinder mission in 1997. The MSL vehicle's aeroshell also is much larger than Pathfinder’s, the craft itself is much heavier and its entry will include the first-ever guided lifting trajectory attempted there -- all conditions expected to result in the highest heat flux and shear stress ever faced by a vehicle's heatshield at Mars.

Because the Martian atmosphere is primarily composed of carbon dioxide, design and testing of the entry system to withstand such environments relies primarily on simulation tools. It is very difficult to conduct experiments on Earth that simulate all aspects of a Mars entry. As a consequence, the spacecraft had to be designed with large safety margins -- which come at the cost of payload mass. The results of the MEDLI experiment will help NASA dramatically reduce these margins on future missions, enabling more robust robotic studies and, in time, human journeys of discovery on Mars.

The MSL Entry, Descent, & Landing Instrument (MEDLI) Suite was designed and developed by NASA's Langley Research Center in Hampton, Va., in partnership with NASA's Ames Research Center in Moffett Field, Calif.

MEDLI will launch to space in late 2011 as part of the Mars Science Laboratory's onboard payload. It is expected to enter the red planet's atmosphere in August 2012. Researchers will analyze the results of the MEDLI project and make their final review by early 2013.