Student playing role in Mars landing

ST. LOUIS -- As the spacecraft Phoenix heads for Mars, the success of the mission rests in part on the work of a 21-year-old St. Louis college student.

Weather permitting, NASA will launch its Phoenix Mission today, the first project of the space agency's Scout program, a lower-cost complement to more expensive Mars missions.

A team at Washington University in St. Louis led by Raymond Arvidson, chairman of the earth and planetary sciences department, played a key role in determining the landing spot -- no easy task on a planet known for its rocky terrain.

For senior Tabatha Heet of Jefferson City, Mo., the work wasn't as glamorous as it sounds. Her contribution largely involved counting rocks, a pivotal but painstaking duty.

"It was tedious," Heet said. "It involved staring at a computer screen for a really long time."

A rocky landing could cause the Phoenix to tilt or tip over. Also, large rocks could prevent the unfurling of the craft's solar panels. The instruments are solar-powered, so if the panels can't open, the mission can't succeed.

Starting last fall, Heet worked 20 hours a week for four months staring at grainy pictures and counting one rock after another.

"My end product was a color-coded map," Heet said. "Red was really bad -- you can't land there. Green was good -- go for it."

Heet's work was vital to the project, Arvidson said, allowing his team to "zero in on the safe havens."

Heet is confident the landing will be a smooth one.

"I can't wait," she said. "I'm pretty confident because NASA agrees with me, but there's also this part in the back of my mind that thinks, 'what if it crashes on a boulder and it will be my fault?"'