Maryland scientists vie for NASA missions

Proposals to win $425 million in funding include landing on a comet or in a Titan lake

  • Illustration of TiME spacecraft floating a sea on the Saturn moon Titan.
Illustration of TiME spacecraft floating a sea on the Saturn… (Courtesy of Lockheed Martin,…)
May 29, 2011|By Frank D. Roylance, The Baltimore Sun

One mission would parachute a floating science lab into a lake on Saturn's largest moon, Titan. The other would send a spacecraft to hop on and off a comet as it races toward the sun.

Both outer-space adventures would be led by Maryland scientists — two women who attended Brown University together, and once shared a room at a scientific conference. And both ventures would be managed by Maryland institutions.

But only one (or neither) will win the $425 million in NASA funding needed to get off the ground.

Competing for the money are the Titan Mare Explorer (TiME) mission, led by planetary geologist Ellen Stofan, of Proxemy Research in Gaithersburg; and Comet Hopper, led by geologist Jessica Sunshine, at the University of Maryland.

The spoiler in the race, the one that could elbow both Maryland bidders aside, is a third mission, designed to study Mars' interior geology. Called Geophysical Monitoring Station, or GEMS, it's led by Bruce Banerdt at the NASA Jet Propulsion Laboratory in California.

Each of the three was awarded $3 million last month by NASA to conduct design and feasibility studies. Next year, one of them will be selected for launch. The losers can regroup and apply in 2013 for the next round of funding under NASA's Discovery program.

"When I found out that Comet Hopper was competing against Ellen and TiME, we exchanged emails, and I noted this was competition in the best sense of the word," Sunshine said.

It's going to be a tough choice for the space agency, but the two Marylanders in the race both make fascinating pitches for their proposals.

For Stofan, the idea of exploring a lake on a frigid, alien world is irresistible.

"Imagine the first image," she said. "A grayish day and a bleak seascape, with some waves and clouds on the horizon. … And yet it's not Earth, but another planet on the other side of the solar system."

"That kind of exploration is something that appeals to me romantically," she confessed. "But our reasons for going there are scientific and so fundamental."

Stofan, 50, worked at NASA's Jet Propulsion Laboratory in California for 10 years, studying geological processes on Earth, Venus and Mars. She was also a member of the radar team on NASA's Cassini mission to Saturn, which dropped a probe called Huygens onto Titan's surface in 2005. This is her first time leading a mission as principal investigator.

She now works for Proxemy Research Inc. in Gaithersburg, a small firm that competes for NASA research grants. But planetary exploration is a rather exclusive club.

"I love Jessica; she's definitely a friend of mine," Stofan said. "And I am friends with Bruce Banerdt, who had an office down the hall at JPL."

In fact, she knows most of the 28 team leaders who competed for this round of NASA funding. It's a smart, competitive bunch. "You have to step up your game," she said. "Obviously, I hope to win, and that's my aim."

The competition began in 2007, when NASA issued a request for innovative missions that could make use of the space agency's new Advanced Stirling Radioisotope Generators. The devices could provide electrical power and heat on missions far from the sun, where solar panels can't do the job.

Stofan was approached by Lockheed Martin in 2007 to help write a proposal. The Johns Hopkins University's Applied Physics Lab, near Laurel, was enlisted later to manage the mission.

Sometime in 2023, if NASA selects it for funding, the TiME spacecraft, after a voyage of 71/2 years, would drop by parachute through Titan's dense atmosphere and splash into a frigid lake of liquid methane and ethane.

"Titan is a very benign place for descent and landing," said the mission's project scientist, Ralph Lorenz of APL. Titan's atmosphere is four times denser than Earth's, and it extends much higher above the surface — lots of cushion for a gentle splashdown.

TiME's target is the second-largest of Titan's known lakes, called Ligeia. About 150 miles by 250 miles, it's roughly the size of Lake Superior. That's big enough to be forgiving if NASA's aim is a bit off.

"Titan's lakes, to me, are … at once incredibly familiar, and at the same time incredibly alien," Stofan said.

Titan's lakes are filled with liquid hydrocarbons — methane and ethane. Even at minus-297 degrees Fahrenheit, Lorenz, said they remain liquid, behaving much like gasoline at room temperature. They evaporate, condense, fall as "rain," wash down off the land and collect in rivers and lakes, an analog of the water cycle on Earth.

There is water on Titan. But it is perpetually frozen, so cold it behaves like solid rock.

For now, Titan's lakes look "smooth as a millpond" to the orbiting Cassini spacecraft, he said. But there is evidence of wave action on the shores.

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