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Mars Science Laboratory Heat Shield
 
An artist's conception of MSL entering the Martian atmosphere.

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Ames' contributions page Ames MSL press kit
When the Mars Science Laboratory (MSL) spacecraft carrying the Curiosity rover hurtles through the Martian atmosphere, it will be protected from the hottest temperatures and heating ever experienced by a Mars mission payload and by the largest heat shield – 4.5 meters, or nearly 15 feet in diameter – to ever travel to another planet.

MSL Thermal Protection System

NASA Ames led the design, testing, and development of MSL’s thermal protection system (TPS), including the heat shield, backshell, and parachute close-outcone. Together with a team from NASA’s Langley Research Center, Hampton, Va., NASA’s Jet Propulsion Laboratory, Pasadena, Calif., and Lockheed Martin Space Systems, Littleton, Colorado, Ames’ engineers produced the protective packaging that will be the first TPS to endure the highest heating of any Mars entry. Due to MSL’s size, the atmospheric flow will change from a laminar (smooth and well-behaved) flow to a turbulent (rough and chaotic) flow over the heat shield, resulting in significantly higher heating. “This first-ever tiled ablative heat shield is the type of innovation that NASA Ames is known for throughout the aerospace community,” said Helen Hwang, MSL TPS project manager at Ames.
MSL Heatshield. Mars Science Laboratory Heat Shield NASA's Mars Science Laboratory rover, Curiosity, is being rotated for final closeout actions. Final Closeout Actions for Curiosity's Heat Shield and Back Shell
A cross-section of the MSL capsule. MSL Spacecraft with Thermal Protection System and Payload. Image Credit: NASA Connecting Curiosity's Heat Shield and Back Shell. Connecting Curiosity's Heat Shield and Back Shell

PICA

The Mars Science Laboratory spacecraft will be protected during the intense heating environment as it enters the Martian atmosphere by the Ames-developed Phenolic Impregnated Carbon Ablator (PICA) thermal protection material that won the 2007 NASA Invention of the Year. PICA is a heat shield material slightly more dense than balsa wood, designed to protect a spacecraft during fiery entry into planetary atmospheres. Prior to MSL, the Stardust sample return capsule used a PICA heat shield. Stardust brought back the first comet particles and interstellar dust samples to Earth in January 2006 and holds the record for the fastest Earth re-entry speed of any human-made object. When analysis and tests at Ames of the originally selected heat shield material revealed it would be unable to protect the payload at entry conditions, the final heat shield design using large PICA tiles was developed, tested, qualified, and built in only 18 months – record speed for engineering of this complexity. “The MSL PICA heat shield was designed to withstand more than five times the highest heating encountered anywhere on the space shuttle and we expect that it will perform beautifully,” said Robin Beck, the MSL TPS cognizant engineer at Ames. For more information about PICA, visit: http://www.nasa.gov/centers/ames/news/releases/2008/08_43AR.html
PICA heat shield material undergoing thermal testing. PICA being tested in the arc jet. The PICA material as seen in the Stardust heat shield. PICA material as used in the Stardust mission.

Arc Jet Testing

NASA Ames’ Arc Jet Complex reproduces heating and pressure conditions similar to the flight environment spacecraft experience during atmospheric re-entry. The Interaction Heating Facility (IHF) at Ames can heat air to temperatures above 14,000 degrees Fahrenheit - hotter than the surface of the sun - and accelerate the hot air to a hypersonic velocity of more than 11,000 miles per hour. Engineers at Ames analyzed anticipated entry conditions for the MSL Curiosity mission and conducted more than 100 arc jet tests to develop and qualify the thermal protection system materials used on the mission.
Testing of the MEDLI plug. The MEDLI instrument being tested in the arc jet at Ames. Medli plug being tested in the arc jet. Arc jet testing of the MEDLI plug.

MEDLI

In addition to protecting the payload, the MSL heat shield contains embedded sensors to measure actual atmospheric conditions on Mars and TPS performance during atmospheric entry. The MSL Entry, Descent, and Landing Instrument (MEDLI) suite contains seven MEDLI instrumented sensor plugs (MISPs) strategically installed on the heat shield to measure its performance during entry into Mars. These sensors were designed and built at Ames – an innovation that had not existed prior to the MSL mission. Each instrumented plug, containing temperature and ablation sensors, is designed to make measurements of the heating environment as the vehicle enters the atmosphere of Mars at a speed in excess of 12,000 miles per hour. The MEDLI sensors will return the most extensive flight data ever measured during a planetary entry and significantly improve our understanding of the heating environment and material performance during this crucial phase of entry. The data will assist engineers as they develop entry technologies for next generation Mars missions with advanced capabilities such as precision landing and heavier payload delivery. The MEDLI suite also contains seven pressure sensors that will enable a complete reconstruction of the guided flight trajectory of the entry vehicle as it descends towards the surface of Mars. For more information about MEDLI, visit: http://mars.jpl.nasa.gov/msl/mission/instruments/atmossensors/medli/
Heat shield being prepared for MSL spacecraft. Preparing Mars Science Laboratory Heat Shield The MEDLI system and the heat shield being prepared at Lockheed Martin Space Systems, Denver, in April 2011. Biggest-Ever Heat Shield Prepared for Mars Spacecraft
MEDLI Instrumented Sensor Plug (MISP) with multiple temperature and recession sensors. The MEDLI plug. MEDLI Plug

MEDLI video

Download the video here:
http://www.nasa.gov/multimedia/videogallery/index.html?media_id=149711171

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