Two Penn State graduates were instrumental to the Curiosity rover’s successful landing on Mars last week.

Brian Schratz, 29, and Ray Baker, 35, both work for the Jet Propulsion Laboratory in Pasadena, Calif.

Schratz, a 2006 Penn State electrical engineering graduate who stayed to earn a master’s degree, was watching anxiously as the entry descent and landing communications lead.

He had the honor of uttering “Tango Delta nominal,” the signal that Curiosity was transmitting data on the Martian surface. Soon after, the operations chief announced “Touchdown confirmed” to the world, and the room erupted in shouts and tears.

“For a minute or two, we were not professional engineers,” he said. “We were kids in a candy store. Everything we wanted for Christmas we got.”

Baker, a JPL senior propulsion systems engineer, had been working for 11 years on the team that developed the Curiosity landing system’s eight braking engines.

“I think I was just on this big adrenaline rush,” said Baker, who earned an aerospace engineering degree from Penn State in 1998. “It was just a thrill to watch, but there were some hairy moments.”

Mars, of course, is very different from Earth. It’s a frigid desert constantly bombarded by radiation. There are geological signs that it was a warmer and wetter place once upon a time. One of the mission’s goals is to figure out how Mars transformed.

After sailing 352 million miles and eight months, Curiosity parked its six wheels near the Martian equator, where it will spend the next two years poking into rocks and soil in search of the chemical ingredients of life. It is the most expensive and ambitious mission yet to Mars.

Its ultimate destination is a mountain towering from the center of the crater floor. Preliminary estimates indicate Curiosity landed four miles away from the base of Mount Sharp, thought to contain intriguing signs of past water — a starting point to learning whether microbial life could exist.

Before the 1-ton, nuclear-powered Curiosity can start roving, it has to undergo several weeks of tedious but essential health checks.

Since it was too heavy to land using traditional air bags, it used a heat shield, parachute, rockets and cables. An orbiting spacecraft spotted the discarded spacecraft hardware, including the ballast weights that were shed soon after entry into the atmosphere.

Senior reporter Chris Rosenblum and The Associated Press contributed to this report.