Photographers track space shuttle Endeavour as it lifts off from pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., Wednesday, July 15. Endeavour is on a mission to the International Space Station. AP / John Raoux

STS-127 Space Shuttle Endeavour launches from launch pad 39A at Kennedy Space Center July 15, in Cape Canaveral, Florida. After multiple delays due to hydrogen leaks and weather conditions, Endeavour is to deliver components of the Japan Aerospace Exploration Agency's Kibo laboratory to the International Space Station. Getty Images / Chip Somodevilla

Water vapor surrounds the US space shuttle Endeavour during liftoff on July 15, from Kennedy Space Center in Florida, its sixth bid in recent weeks to launch toward the orbiting International Space Station. The mission will feature five spacewalks and complete construction of the Japan Aerospace Exploration Agency's Kibo laboratory. Getty Images / Bruce Weaver

An STS-127 crew member aboard the Space Shuttle Endeavour recorded this image of the International Space Station as the two spacecfaft made their relative approaches July 17, in Space. NASA via Getty Images

Astronaut Doug Hurley, STS-127 pilot, looks through an overhead window on the aft flight deck of space shuttle Endeavour during flight day two activities, Thursday, July 16. NASA via AP

This view of the underside of the crew cabin of the space shuttle Endeavour was provided by an Expedition 20 crew member during a survey by the approaching STS-127 crew to the International Space Station, Friday, July 17. NASA via AP

A head-on view of the space shuttle Endeavour provided by an Expedition 20 crew member during a survey of the approaching vehicle prior to docking with the International Space Station, Friday, July 17. The image was photographed with a digital still camera, using a 800mm lens at a distance of about 600 feet (180 meters). NASA via AP

The underside of the crew cabin of the Space Shuttle Endeavour taken by an Expedition 20 crewmember during a survey of the approaching vehicle prior to docking with the International Space Station Friday July 17. NASA via AP

The exterior of the space shuttle Endeavour's crew cabin is one of a series of survey photos recorded by Expedition 20 crew members as the shuttle approached the International Space Station on Friday, July 17. NASA via AP

The Space Shuttle Endeavour during a survey of the approaching vehicle prior to docking with the International Space Station July 17, in Space. NASA via Getty Images

A partial view of space shuttle Endeavour's payload bay, vertical stabilizer and orbital maneuvering system (OMS) pods are featured in this image photographed by a STS-127 crew member from an aft flight deck window, Thursday, July 16. NASA via AP

The view of the space shuttle Endeavour was provided by an Expedition 20 crew member during a survey of the approaching vehicle prior to docking with the International Space Station, Friday July 17. NASA via AP

An STS-127 crew member aboard the Space Shuttle Endeavour recorded this image of the International Space Station as the two spacecfaft made their relative approaches July 17, in Space. NASA via Getty Images