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Mars Science Laboratory
Heatshield Completed
June 19, 2009
Lockheed Martin has
completed production and testing of the heatshield for NASA’s Mars
Science Laboratory (MSL). The heatshield is half of the large and
sophisticated two-part aeroshell that will encapsulate and protect the
Curiosity rover during its deep space cruise to Mars, and from the
intense heat and friction that will be generated as the system descends
through the Martian atmosphere.
In October 2008, Lockheed Martin delivered the other half of the
aeroshell, the backshell, to NASA’s Jet Propulsion Laboratory in
Pasadena, Calif. where it is being integrated with other flight systems.
The heatshield will be stored at Lockheed Martin facilities near Denver,
Colo. until early 2011 when it will be shipped to Kennedy Space Center.
The aeroshell/heatshield is the largest ever built to be flown at 4.5
meters (nearly 15 feet) in diameter. In contrast, the aeroshells/heatshields
of the Spirit and Opportunity Mars Exploration Rovers measured 8.5 feet
and Apollo capsule heatshields measured just less than 13 feet.
Because of the unique entry trajectory profile that could create
external temperatures up to 3,800 degrees Fahrenheit, the heatshield
uses a tiled Phenolic Impregnated Carbon Ablator (PICA) thermal
protection system instead of the Mars heritage Super Lightweight Ablator
(SLA) 561V. This will be the first time PICA has flown on a Mars
mission. Invented by NASA Ames Research Center, PICA was first flown as
the thermal protection system on the heatshield of the Stardust Sample
Return Capsule that is now in the Smithsonian Air and Space Museum.
“The Mars Science Laboratory aeroshell is the most complex capsule to
fly to Mars,” said Rich Hund, MSL program manager at Lockheed Martin
Space Systems Company. “The design had to address the large size and
weight of the rover, the largest ever sent to Mars, and the requirement
for landing at a more-precise point on Mars.”
The
aeroshell has a steering capability that is produced by ejecting ballast
that off-sets the center-of-mass prior to entry into the atmosphere.
This off-set creates lift as it interacts with the thin Martian
atmosphere and allows roll control and autonomous steering through the
use of thrusters.
Prior to shipping to Kennedy Space Center, engineers will install the
MSL Entry Descent and Landing Instrumentation (MEDLI) suite on the
heatshield. Developed by NASA Langley Research Center, the MEDLI
instrumentation will measure heatshield temperatures and atmospheric
pressures as the aeroshell descends through the Martian atmosphere.
Scheduled for launch in the fall of 2011, the Curiosity rover – built by
the Jet Propulsion Laboratory – will support the Mars Exploration
Program’s strategy of “follow the water” and will have the science goals
of determining whether the planet was ever habitable, characterizing the
climate and geology of Mars, and preparing for human exploration. |