With the seats tilted forward in launch position, the flight simulator lifts back at a perfect 90 degree angle. The mock shuttle shakes abruptly. Booming sounds of a launch in progress surround the walls and voices from mission control are heard through headsets.

"Copy that Houston; let’s go for config four," says Megan McArthur, mission specialist for the STS-125 astronaut crew into her microphone.

Moments later, following orbit, the crew prepares for landing. The simulator points downward and landing gear is activated. The shuttle shudders for a quick second as it touches ground. A voice from mission control pierces the silence, "Houston to Atlantis, welcome to Spain."

"Thank you, Houston; it feels great to be back," responds Scott Altman, commander for the STS-125 astronaut crew.

This process is repeated at least four to five times a day with crews preparing for upcoming missions. In between each trial, the crew takes a break to debrief with members of the Mission Control Center and Shuttle Mission Simulator team to discuss what went smoothly along with any technical anomalies needing to be corrected and how to better communicate with each other.

"They would be in the spacecraft simulator and we were in the control center and it worked just like a real mission," said Charles Lewis, a retired flight director. "You really felt like you were in the actual mission environment."

The flight simulator, also known as the Shuttle Mission Simulator, is an apparatus used to mock the feel of an actual mission. Mission Control and the Shuttle Mission Simulator team will often test out the crew’s response to an emergency situation, preparing for the unexpected.

Training in the flight simulator is simply one aspect of the overall training process astronaut crews go through to practice for future missions.

"Depending on the mission, they generally will spend about a year training," said Tom Hanson, Shuttle Mission Simulator team lead.

The crew undergoes instruction on how to work in an environment without gravity through underwater training in the Neutral Buoyancy Laboratory, which contains a 100-foot mock-up portion of the International Space Station.

"This is definitely one job you just can’t afford to have any mistakes," said Hanson. "Things need to run perfectly or you put others at risk."

The STS-125 crew consists of seven members: Gregory Johnson, pilot; Scott Altman, commander; Michael Massimino, Michael Good, Megan McArthur, John M. Grunsfeld and Andrew J. Feustel, all mission specialists. The members are currently preparing for their shuttle mission to make repairs to the Hubble Space Telescope. They expect to launch in February 2009.

For more information on the flight simulator at NASA Johnson Space Center, visit academy.grc.nasa.gov/2007/tour-summaries/shuttle-mission-simulator/