DR. STEVEN Squyres took the long way to get to yesterday's lecture at the Science Leadership Academy.

He decided to visit Mars first.

Squyres, a Wenonah, N.J., native, is the principal investigator on the Mars Rovers Exploration Team, which sent a pair of rovers to Mars in April 2004.

His talk at the academy, a magnet school on Arch Street near 22nd sponsored by the Franklin Institute, came as he was awarded the 2007 Benjamin Franklin Medal in Earth & Environmental Science.

"Steve, as he said, was just one guy on this team, but talking to other people involved, he was the inspirational leader," said Dr. Philip Hammer, vice president of the Franklin Learning Center and the Franklin Institute Science Museum.

"He was the on-the-ground person, calling the shots on a day-to-day basis, keeping people going."

Squyres kept more than 150 students and faculty captivated with details of the NASA-funded, $900 million Mars project.

"We can experience Mars through the eyes" of the rovers, named Spirit and Opportunity, Squyres told the assembly. "We did two launches in 2004, and it took seven months for the rovers to get there. It was a terrifying ride."

The jovial Squyres, 51, studied geology at Cornell University, earning his bachelor's degree in 1978, and then his Ph.D. in planetary science in 1981.

Inspired by Voyager's mission to Mars in the '70s, Squyres spent three years analyzing imaging data from Voyager's encounters with Jupiter and Saturn.

In his talk, he had no problem connecting with students as he leavened hard-core science with humor.

"I thought he was very interesting; he made Mars exciting," said one student, a junior at the high school.

"His style was like an orchestra leader, arms moving all the time."

Squyres spoke of the wonderful colors of Mars, its harsh surface climate and environmental hazards.

"It's 60 degrees below zero, and very dry," Squyres said, as he showed photos of the planet. "It's a cold, dry desolate world. Very dusty."

The most amazing scientific pictures were of the atmosphere.

"It's pink during the day, blue at sunset," he said.

Squyres and his team sent the rovers to Mars in search of sedimentary deposits that would prove that water once existed on the planet.

He said the images "hint that Mars was warmer and wetter 4 1/2 billion years ago."

Squyres said more than 4,000 technicians worked on the MER project. The rovers were designed for a life span of 90 days, but he said yesterday marked the 1,177th day the two rovers have been on Mars.

"In 1987, I had the idea for the MER, and I have no idea when the program will end," said Squyres, who wrote a book about the endeavor, titled "Roving Mars."

Squyres said he was impressed by the students' enthusiasm.

"It's just great to see a school like this, really focused on science," he said. "The important thing is providing that type of inspiration." *