The shuttle’s planned landing has already been delayed by 24 hours after the discovery of the object, which may have come off the shuttle.
Shuttle program manager Wayne Hale said the six-member crew will wake up especially to use the shuttle's robotic arm and inspect the underside of the vehicle.
He says the five-hour survey "is to get a general sense to make sure we are not missing any large pieces of the (shuttle's) thermal protection system."
"We don't think we are but this is to make sure."
If a closer inspection is warranted, a boom sensor system, a 15-metre arm extension with lasers and a high-definition camera, will then be deployed.
If the results are still not satisfactory, Atlantis' return to Earth could
be delayed a few days, he said.
"We have the capabilities to stay in orbit until Saturday. We have the tools to go off and make sure we are safe for re-entry," Hale said.
NASA has strived to avoid damage to the orbiter's heat shield since a crack in shuttle Columbia's protective skin caused it to disintegrate as it returned to Earth in February 2003, killing seven astronauts.
Atlantis is capping a successful mission to install the International Space Station's first addition in nearly four years.