A strongback provides connections to the SpaceX Falcon 9 rocket as final preparations for launch are completed in Florida.

A strongback provides connections to the SpaceX Falcon 9 rocket as final preparations for launch are completed at Space Launch Complex-40 on Cape Canaveral Air Force Station in Florida.

Liftoff with the Dragon capsule on top is set for 4:55 a.m. EDT on May 19. The launch will be the company's second demonstration test flight for NASA's Commercial Orbital Transportation Services Program, or COTS. During the flight, the capsule will conduct a series of check-out procedures to test and prove its systems, including rendezvous and berthing with the International Space Station. If the capsule performs as planned, the cargo and experiments it is carrying will be transferred to the station. The cargo includes food, water and provisions for the station’s Expedition crews, such as clothing, batteries and computer equipment. Under COTS, NASA has partnered with two aerospace companies to deliver cargo to the station. For more information, visit http://www.nasa.gov/spacex. Photo credit: NASA/Ken Thornsley