The largest
heat shield ever built for a probe bound for Mars is ready for the new rover Curiosity,
a massive Martian robot the size of a car.
The immense heat
shield will shroud the Mars Science Laboratory rover, now named
Curiosity, to protect it during its deep space cruise to Mars and the searing
heat of entry into the Martian atmosphere. Lockheed Martin unveiled the heat
shield this week and delivered its conical backshell to NASA last year.
"The Mars Science
Laboratory aeroshell is the most complex capsule to fly to Mars," said Rich
Hund, program manager at Lockheed Martin Space Systems Co. "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."
Curiosity's
heat shield and conical backshell are the largest ever built for flight. Together
they make up the rover's 15-foot (4.5-meter) wide aero shell – larger than
those used with previous Mars
rovers and even than the shell used for NASA's Apollo spacecraft that
ferried astronauts back from the moon. The Mars rovers Spirit and Opportunity were
protected by shells measuring 8.5 feet (2.6 meters) and the Apollo capsule's
heat shield measured just under 13 feet (less than 4 meters).
As the
rover, which is about the size of a small car, descends over the red planet the
friction it creates with the thin Martian atmosphere could create temperatures
up to 3,800 degrees Fahrenheit (2,100 degrees Celsius) on the outside of the
shield. To withstand the heat, the shield is tiled with a material called a Phenolic
Impregnated Carbon Ablator. This will be the first time the heat shield type
has flown on a Mars mission.
Invented in
NASA's Ames Research Center, the material first flew as the heat shield for the
agency's Stardust sample return capsule, which collected particles from a comet
and returned
them to Earth in 2006.
NASA has an
intricate landing sequence planned for the new Curiosity rover. After entering
the Martian atmosphere, the rover will slow itself with a parachute and
jettison its heat shield and back shell before beginning a powered descent with
thrusters on a so-called "sky crane." The crane will lower the rover
to the ground on cables and then fly itself off and crash.
Curiosity
is scheduled to launch in the fall of 2011 to broaden NASA's exploration of
Mars and better understand the planet's watery. The evidence the rover gathers
may help answer questions about life on Mars and the planet's habitability in
the past or present. The rover should also assess Mars' climate and geology in
preparation for human exploration.
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