NASA’s mission to repair the Hubble telescope faces a higher than usual risk of being smashed by space junk.

Shuttle program manager John Shannon says a mission to the International Space Station comes with a 1 in 300 chance of a catastrophic debris strike. For the Hubble mission the odds are 1 in 185 (Reuters).

“It’s worse for Hubble because we fly higher. We’ve had some vehicle breakups on orbit, and they have made the (debris) environment worse,” says Shannon (Space.com / USA Today).

Both Reuters and the USA Today point the finger at a Russian spy satellite’s self-destructing and a Chinese satellite-killer missile test for much of the debris.

Showing how seriously the risk is being taken, NASA has another Shuttle – Endeavour – on standby in case it has to launch a rescue mission. “It’s just nice extra insurance to have since we’re in a position that we can have a vehicle on the pad ready to go launch. … We don’t expect to use it, but if we do, we feel very confident we could,” says Shannon (Florida Today).

Atlantis commander Scott Altman told USA Today, “That comes with the mission. Hubble is where it is. … We’ve got to go where the work is.”

Image: rollout Atlantis viewed from inside the Launch Control Center / NASA Kim Shiflett