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Canadarm2 to Catch SpaceX’s Dragon on Its Maiden Voyage to the ISS
"Here, there be dragons”…the phrase used to designate the boundaries of the known world on historical maps seems fitting as the U.S. space program embarks upon a new frontier in space exploration with the launch of the first commercial demonstration flight to the International Space Station. However, rarely were the monsters of yore as eagerly anticipated as SpaceX’s Dragon, the first privately built cargo ship destined for the orbiting outpost.

Dragon represents a new era and a new NASA approach to space transportation systems. Since the retirement of the space shuttle, NASA has turned to the private sector to develop and operate safe, reliable and affordable commercial space transportation systems. Slated for liftoff on April 30, 2012, at 12:22 EDT from the Kennedy Space Center, the goal of Dragon’s planned 21-day mission will be to test the unpiloted capsule’s ability to rendezvous with the space station. Shortly after launch, Dragon will undergo a series of checkout procedures to test and prove its systems in advance of its docking with the station. It will approach from the Earth-facing (nadir) side, then hover at a distance of 2.5 kilometers so that its sensors and flight systems can be examined to ensure that it is safe to proceed. The spacecraft also will demonstrate its capability to abort the rendezvous.

Another Cosmic Catch for Canadarm2

As this computer animation shows, Dragon will approach the International Space Station, with Canadarm2 grappling the capsule in free flight and docking it to the station. Credit: Canadian Space Agency

Once Dragon is cleared for capture, Canadarm2 will perform a cosmic catch: it will grapple the capsule and install it on the space station. With NASA astronaut Don Pettit and European Space Agency astronaut Andre Kuipers at the helm, Canadarm2 will reach out to grasp Dragon at a distance of 8-10 meters below the station. Pettit will use the robotic arm to seize a grapple fixture located on the side of the capsule, and Kuipers will use Canadarm2 to install it on the Earth-facing side of the station’s Harmony node. Dragon will mark Canadarm2’s third successful capture and docking of a free-flying spacecraft.

Dextre and Canadarm2 lend a hand

During the 18 days that Dragon will spend docked to the International Space Station, the crew will unload its cargo of about half a ton of food and clothing packed inside the pressurized section. On flight day 6, Dextre and Canadarm2 will move in closer to inspect Dragon’s external surfaces and its “trunk”—the open, unpressurized section of the spacecraft that will later be used to transport a variety of payloads and science instruments on future missions.

At the end of its mission, Canadarm2 will undock release and release Dragon for its return to Earth, where it will then be retrieved and reused. Credit: Canadian Space Agency

At the end of the mission, Canadarm2 will detach Dragon from the station so that the reusable vehicle will return to Earth and be recovered and refurbished for its next mission.
Canadian Space Agency