Dragon appears as a faint dot just below the Earth's limb in this view from the International Space Station early Thursday. Image Credit: NASA TV
The SpaceX Dragon wrapped up a successful "fly under" of the International Space Station Space early Thursday.
The freighter sailed 1.5 miles below the six-person orbiting science lab just before 7:30 a.m., EDT, before swinging out in a loop that will take Dragon in front, above and eventually well behind the station.
The unpiloted Dragon will return to the station early Friday, if all goes well, propelling itself close enough for station astronauts Don Pettit, Andre Kuipers and Joe Acaba to grapple it with Canadarm2, a 58-foot long robot arm. The capture is scheduled for shortly after 8 a.m., EDT.
The "track and capture" would lead to a scheduled berthing of Dragon to the station's U. S. segment just after 11 a.m, EDT.
During Thursday's "fly under," the station and Dragon established a crucial relative GPS link, assuring flight control teams the spacecraft can maneuver safely in relation to one another. The station astronauts also established a UHF link that allowed them to command a Dragon strobe light.
The strobe assures the safety of the station, demonstrating Pettit and his colleagues can command the capsule to pause in its approach to the outpost or even fly away if there is a collision threat.
If all goes well, the astronauts plan to open Dragon on Saturday, retrieving food, computer equipment and other supplies.
The capsule would remain docked until May 31. After departing, Dragon will re-enter the Earth's atmosphere, splashing down in the Pacific Ocean off the southern California coast just before noon, EDT.
SpaceX teams will be prepared to recover the reusable spacecraft and its return cargo -- about 1,400 pounds of research equipment, station hardware and space suit gear.