After a days’ delay due to unfavorable conditions in the landing zone, ISS Mission Control in Houston issued the command to begin unberthing procedures at 3:10 AM CST today. At 5:56 AM, astronauts Tom Marshburn and Chris Hadfield, perched in the station’s own control tower in the cupola, pulled the trigger to release the Canadarm 2’s grip on the Dragon spacecraft. Moments later, as the station passed over Australia, once more under command from SpaceX headquarters in Hawthorne, California, the Dragon began the first of three burns to clear the vicinity of the station and rotate the craft 180 degrees to prepare for re-entry.
If there was any lingering hesitation remaining from first hours in orbit as SpaceX struggled with the Draco thrusters, it certainly didn’t show, and no doubt engineers will be particularly eager to inspect the craft at the first available opportunity. Also of interest in the landing to take place later this morning, is the effectiveness of changes made to an electrical compartment in the Dragon’s skirt. On the CRS-1 mission, water entering the compartment resulted in a loss of power to the GLACIER freezer contained within the capsule, but there was no harm to the experiments carried within the freezer. SpaceX noted at the pre-launch press conference that the Dragon being launched on the current mission contained modifications, with further upgrades being made to new production spacecraft.
The next major step, the de-orbit burn is scheduled to take place at 10:42 AM (CST)