The crew will pressurize the vestibule between the station and Dragon and will open the hatch that leads to the forward bulkhead of Dragon. Over the next two and a half weeks, the crew will unload Dragon’s payload and reload it with cargo that Dragon will bring back to Earth.
After its mission at the orbital laboratory is completed, newly arrived Expedition 33 Flight Engineer Kevin Ford, a retired United States Air Force Colonel and a NASA Astronaut, will use the Canadarm2 robotic arm to detach Dragon from Harmony, maneuver it out to the 15-meter release point, and release the vehicle. Dragon will then perform a series of three burns to place it on a trajectory away from the station. Mission Control Houston then will confirm that Dragon is on a safe path away from the complex. Approximately six hours after Dragon leaves the station, it will conduct a deorbit burn, which will last up to 10 minutes. Dragon’s trunk, which contains its solar arrays, is then jettisoned.
The landing is controlled by automatic firing of its Draco thrusters, which generate 400 newtons (90 pounds-force) of thrust using a mixture of monomethyl hydrazine fuel and nitrogen tetroxide oxidizer, during re entry, or the movement of human-made or natural objects as they enter the atmosphere of a celestial body from outer space–in the case of Earth from an altitude above the Karman Line (100 km). In a carefully timed sequence of events, dual drogue parachutes, or parachutes designed to be deployed from a rapidly moving object in order to slow the object, or to provide control and stability, or as a pilot parachute to deploy a larger parachute, deploy at 13,700 m (44,900 ft) to stabilize and slow the spacecraft. Full deployment of the drogues triggers the release of the three main parachutes, each 35 meters (116 feet) in diameter, at about 3,000 m (9,800 ft). While the drigues detach from the spacecraft, these main parachutes further slow the spacecraft’s descent to approximately 4.8 to 5.4 metres per second (16 to 18 ft/s). Even if Dragon were to lose one of its main parachutes, the two remaining chuites would still permit a safe landing. The Dragon capsule is expected to land in the Pacific Ocean, about 450 km (280 mi) off the coast of southern California. SpaceX will use a 100-foot boat equipped with an A-frame and an articulating crane, a 90-foot crew boat for telemetry operations, and two 24-foot rigid-hull inflatable boats to perform recovery operations. On board will be approximately a dozen SpaceX engineers and technicians as well as a four-person dive team. Once the Dragon capsule splashes down, the team will secure the vehicle and then place it on deck for the journey back to shore.