HOUSTON Spacewalking is not as easy as it looks. It takes a lot of practice to learn how to turn a wrench on the space station or climb out the space shuttles airlock.

Since the early 1990s, the Johnson Space Center Virtual Reality (VR) lab has been the place to go to hone those not-so-intuitive skills of working in a microgravity environment where up may be down and a little too much thrust might send you spinning off into space.

The VR simulator looks like a high-tech computer game with gloves, video display helmet, chest pack and controller. That's where the crew of the upcoming Hubble Space Telescope mission has been practicing with "mass handling."

The simulator is an aluminum box currently set up to resemble one of the guidance sensors to be replaced on the Hubble. A system of computer-guided cables and pulleys allows an astronaut to get a feel for how the box will maneuver in space.

It takes practice to keep traveling in the right direction. Often spacewalkers look to the side and see their target, but are traveling in a different direction.

Hoblit said helicopter pilots sometimes understand better than fixed-wing pilots do that what theyre looking at may be not the direction they are heading.

One item spacewalkers have to master is the SAFER or simplified aid for EVA rescue. An astronaut would use the systems thrusters to maneuver to a safe place should he or she become untethered or escape from a foot restraint.

The lab also offers a simulator of the shuttles robotic arm used in almost every session so two astronauts can work together.

"Trainers bring the astronauts in here to help them develop good habits and train out the bad ones," Hoblit explained.

Trainers can watch the simulation from different perspectives on a nearby computer monitor.

The computer monitor replicates the window overlooking the payload bay and video monitors give views from different angles in the bay, just like in the shuttle.

In a twist of technology, Hoblit said the computer-generated graphics of the shuttles video cameras are better than the real thing.

"The images are too good," he said. "Since the real cameras are not that good, weve had to add some static to make it seem more real."