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August 6, 2012

'Curiosity' brings Purdue professor, alumni into Mars mission

NASA's Mars Science Laboratory Curiousity rover

Artist's concept of NASA's Mars Science Laboratory Curiousity rover (NASA/JPL-Caltech)
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WEST LAFAYETTE, Ind. — Three Purdue University alumni and a professor are part of NASA's Mars Science Laboratory mission, which early this morning landed the Curiosity rover on the planet's surface.

Purdue alumnus Douglas Adams, NASA's Mars Science Laboratory parachute cognizant engineer, helped design, build, test and deliver the parachute decelerator system on the Mars Science Laboratory, or MSL, spacecraft.

Testing of the parachute, which at 130 pounds is the largest ever used outside Earth's atmosphere, took place in the world's largest wind tunnel. The tunnel could hold a 737 jet, but couldn't quite contain the parachute, which peeked out one end of the tunnel, Adams said.

"Being next to something so massive that is moving so quickly gave me an understanding of how an ant must feel when a foot comes to step on it," he said. "The parachute had to be robust because it faced grueling conditions. Here on Earth, a parachute begins to slow an object as it is being deployed, but on Mars the entry vehicle hardly slowed at all until the parachute fully opened.  It had to hold up to a very sudden onset of tremendous force."

Mars Science Lab entry, desent and landing

Artist's concept of Mars Science Laboratory entry, descent and landing. (NASA/JPL-Caltech)
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The parachute was designed to generate up to 65,000 pounds of drag force, according to NASA's Jet Propulsion Laboratory.

Adams also helped develop the mortar deployment system, which he describes as basically an enormous cannon that shot out the parachute.

"The mortar had to fire very precisely as the spacecraft traveled at 900 mph, and any delay of even a half a second would have had a significant effect on targeting," he said. "As with many of the various teams' hardware and systems for MSL, if it had failed, it could have ended the mission. We only had one chance."

Adams said he nervously watched the data with other scientists at the Jet Propulsion Laboratory during the landing event.

"The tension in the room was palpable as every person there had invested a significant portion of their life in getting Curiosity to Mars," he said. "When the sky crane maneuver was completed and we got the 'Tango Delta Nominal' call, for touchdown nominal, the atmosphere changed to a chaos of jubilation. It was incredible. A once-in-a -lifetime experience."

Adams is a low-density supersonic decelerator parachute systems engineer and soil moisture active passive dynamics and systems engineer at the Jet Propulsion Laboratory in Pasadena, Calif. He earned his bachelor's, master's and doctoral degrees at Purdue in 1994, 1996 and 2001, respectively.

Purdue alumnus Eugene Bonfiglio, a NASA mission design engineer in the entry, descent and landing guidance and control system group, helped test and prepare the on-orbit contingency plan for the MSL that would have been enacted if a launch failure left the spacecraft orbiting Earth. Bonfiglio helped determine ways to control the spacecraft's fall back to Earth so that it would have landed safely in the Pacific Ocean. He also was involved in performing system tests that helped fine tune the software used to control the spacecraft during its entry, descent and landing.

Prior to this mission, most of Bonfiglio's work was related to trajectory and navigation and involved computer simulations. He said he is most looking forward to the measurements from MSL's actual entry, descent and landing.

"As hard as we try, any testing that we do here on Earth to understand aerodynamic interactions that occur during entry and landing will never perfectly simulate the conditions that are actually experienced when flying through the Martian atmosphere," Bonfiglio said. "Not only is this data priceless, but we will get more of it than ever before and it will go a long way in helping us better understand what is actually happening to the vehicle."

Bonfiglio earned his bachelor's and master's degrees from Purdue in 1997 and 1999, respectively.

Another Purdue alumnus, JPL senior technologist Behcet Acikmese, was responsible for developing and delivering algorithms vital for the flight guidance, navigation and control system's "fly-away phase" of the landing, where the sky crane was diverted from the rover after it touched down.

"My controller flew the sky crane about 650 meters away from the rover to a safe distance," said Acikmese, who will become an assistant professor at the University of Texas at Austin this fall.  

He earned a master's degree in mechanical engineering in 1996 and a doctoral degree in 2002 in aeronautics and astronautics, both from Purdue.

Both Adams and Bonfiglio earned degrees from Purdue's School of Aeronautics and Astronautics.

Steve Schneider, a Purdue professor of aeronautics and astronautics, evaluated the heat shield that protected the MSL spacecraft when it entered the Martian atmosphere. The heat shield is the largest ever built for a Mars mission. Schneider was on a review board for the thermal protection system. Input from the review led to a change in the heat shield material, he said.

"The heat generated on entry depends on the weight of an object relative to its size and this was the largest, heaviest probe ever landed on Mars," Schneider said. "This heat shield faced a very different scenario from past missions, and its engineering was quite complicated. This was the first Mars mission to use a heat shield made from PICA, which can handle a much higher temperature than previously used materials."

As the MSL plowed through the atmosphere of Mars, which is 100 times thinner than that of Earth, the heat shield was estimated to reach 2,900 degrees Fahrenheit, according to the Jet Propulsion Laboratory.

The Curiosity Mars rover will function as a mobile laboratory to investigate the current and past environment of Mars' Gale Crater to determine if it is or ever was capable of supporting life.  It is equipped with 10 science instruments and a robotic arm that can drill into rocks, scoop up soil and deliver samples to internal analytical instruments. More information about the mission is available at http://mars.jpl.nasa.gov/msl/

Writer: Elizabeth K. Gardner, 765-494-2081, ekgardner@purdue.edu

Additional media contact: Emil Venere, 765-494-4709, venere@purdue.edu

Douglas Adams, 301-460-2049, Douglas.S.Adams@jpl.nasa.gov

Eugene Bonfiglio, 818-354-9283, Eugene.Bonfiglio@jpl.nasa.gov

Steve Schneider, 765-494-3343, steves@purdue.edu

Behcet Acikmese, 626-318-1002, behcet@jpl.nasa.gov

Video: "Curiosity's Seven Minutes of Terror" (NASA/JPL-Caltech)