Payette, Endeavour crew check shuttle for damage

Endeavour performs a backflip before arriving at the space station last week, one of several procedures designed to inspect the shuttle's heat shield. The shuttle performed a similar manoeuvre upon departing the station Tuesday. (NASA)

Astronauts aboard the space shuttle Endeavour are set to inspect the spacecraft's heat shield one more time on Wednesday as they prepare for a Friday landing.

Endeavour's thermal protection system has already been cleared for landing based on an earlier review, but NASA wants to do one more check to ensure the shuttle's wings and nose were not damaged during the shuttle's time connected to the International Space Station.

As with an earlier inspection as Endeavour approaches the space station, Montreal-born Julie Payette will operate a 30-metre-long laser-tipped boom to inspect the shield for damage.

Both the laser and boom were made with technology developed in Canada: Ottawa technology firm Neptec designed and built the 3D laser camera, while the space robotics division of Canadarm-maker MacDonald, Dettwiler and Associates made the boom the sensor sits atop.

The shuttle undocked from the space station on Tuesday, completing an 11-day stay during which Endeavour's crew delivered and installed a porch-like structure used to conduct experiments exposed to the harsh conditions of outer space — the third major component to Japan's Kibo laboratory.

Endeavour is scheduled to return Friday at NASA's Kennedy Space Center in Florida.

The station took in another visitor on Wednesday, as an unmanned Russian cargo vessel carrying several tonnes of supplies docked. Commander Gennady Padalka manually guided the craft in after a problem with the cargo vessel's automatic system.