Squyres also is working on the Mars Express mission, the Mars Reconnaissance Orbiter's high-resolution imaging science experiment, the Mars Odyssey mission and the Cassini mission to Saturn, but the Mars rovers take up most of his time.
At Shippensburg, he will discuss how the golf cart-sized rovers were designed and built, the challenges in getting the rovers to Mars, how the solar-powered rovers work and the scientific discoveries and adventures they've experienced in their research about water on Mars.
Some of those adventures were misadventures, such as when Opportunity got stuck in a sand dune in the spring of 2005. It took almost three weeks to devise a plan to free Opportunity and three weeks to free the rover by having it move a few centimeters a day.
People all over the world sent Squyres "all sorts of goofy e-mails" with suggestions on how to get the robot unstuck, Squyres said in a recent phone interview from his office at Cornell University, where he teaches introductory astronomy.
Many people believed the rover could rock back and forth like a car to get out of the sand, but the rovers don't have enough power to do that.
The e-mails were indicative of a new interactive age with space exploration.
The rovers have sent back more than 100,000 photos, and the photos automatically go on the Internet, so there's the opportunity to see the photos before Squyres wakes up and looks. Check out the photos at http://marsrovers.jpl.nasa.gov/gallery.
Opportunity is exploring the edge of Victoria Crater, a crater half a mile in diameter, while Spirit is on the opposite side of the red planet exploring a plateau of layered rocks named HomePlate.
Because the rovers don't go anywhere quickly, it took Opportunity 952 Martian days (each 24 hours and 39 minutes long) to travel about 9 kilometers from its landing spot to the crater, arriving in September 2006. The rover's top speed is 6 centimeters per second because it doesn't have enough power to go faster, Squyres said. The rover moves in spurts, going a foot or two before stopping to investigate its surroundings - taking a variety of pictures such as infrared spectra and microscopic images and taking detailed analysis of rocks using a variety of instruments on its arm.
Also, cowardice and courage can be programmed into the rovers, Squyres said. Opportunity is cowardly these days while it's working near the top of a 6- to 8-meter-high cliff, and the team doesn't want it to be bold and take a tumble.
As dramatic a feat as getting to Victoria Crater was, some of the team's biggest challenges came in getting the rovers built and launched.
"The thing about launching to any planet, you have to wait for alignment of the planets," Squyres said. If the team had missed the launch window, it would have had to wait another 26 months for another opportunity and could possibly have faced the threat of the project getting canceled, he said.
Squyres said his team - spread across the U.S. and Europe - is very conscious of the mission's expense, which has reached $900 million so far.
The initial $800 million for the project included the cost of four rovers - two that remain on earth for testing, the rockets to take two rovers to Mars, software and the manpower to get it all done.
"We work very hard with that number always in mind, and we feel a deep sense of responsibility that the taxpayers that paid this get their 900 million dollars worth," Squyres said.
Beyond the scientific discoveries and research to help plan a potential trip for man to Mars, Squyres describes the mission's benefits to humanity as pointing to the fundamental question of whether there were ever life on Mars.
"We're motivated by questions like, 'Are we alone in the universe?' and, 'How does life first originate?'" Squyres said.
Through tectonic and volcanic activity, the record of the origin of life on earth has been destroyed, Squyres said. But, there are still rocks that are 4 billion years old on Mars.
If there were life on Mars, the mystery of how life first emerged could still be locked in the planet, he said.
If you go ...
WHAT: Lecture by Steven Squyres, principal investigator for the science instruments on the Mars Exploration Rover Project
WHEN: 8 p.m. Wednesday, April 4. Doors open at 7 p.m.