Launched from Florida on Tuesday, the Dragon spacecraft is carrying food and supplies for the Station crew. It is the first time a privately built spacecraft has been launched to the ISS.During the fly-under the ISS crew will send a test command to the Dragon spacecraft and receive a response, this is to make sure that they can communicate with each other in case other commands such as hold, retreat, or even abort, are needed during the rendezvous operations. The Dragon's relative GPS navigation will also be tested during the fly-under - this enables the spacecraft to navigate according to the position of the ISS and will be essential during tomorrow's complex approach.
Once the fly-under is finished Station managers will meet to review the performance of the spacecraft and give the go-ahead for tomorrow's rendezvous and berthing.
Dragon is scheduled to rendezvous with the ISS on Friday 25 May, when Expedition 31 crewmembers André Kuipers and Don Pettit will use the Station’s robotic arm Canadarm2 to grapple the spacecraft and manoeuvre it into position to mate with the Harmony module’s Earth-facing docking port.