Ames' contributions pageAmes 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.
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
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.
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/