Step 1: Launch
SpaceX's unmanned Dragon capsule is due to deliver food, supplies and science experiments to the orbiting laboratory as a test mission for NASA's Commercial Orbital Transportation Services (COTS) program, aimed at spurring development of replacement cargo ferries for the retired space shuttles.
Here's how the robotic mission will play out:
The Dragon capsule is set to lift off aboard SpaceX's Falcon 9 rocket from Cape Canaveral Air Force Station in Florida. SpaceX has use of the facility's Space Launch Complex 40. The initial ascent is powered by Falcon 9's first stage, consisting of nine SpaceX Merlin 1C rocket engines.
Step 2: Main Engine Cut Off/Stage Separation
Step 3: Payload Separation
Step 4: Orbital Checkouts
Teams on the ground will lead the vehicle through tests of its Absolute GPS (AGPS) system, which uses global positioning system satellites to determine its location in space. It will also demonstrate its performance in free drift phase, with thrusters inhibited. Finally, Dragon will test out its abort system to prove it can terminate its activities and move away from the space station if something goes wrong.
Step 5: Fly-Under
During the fly-under, Dragon will also test a secondary locator system called the relative GPS system, which uses the spacecraft's position relative to the space station to establish its coordinates.
While Dragon is flying under the station, the six-person crew inside the orbiting laboratory will be monitoring their new visitor. They will use a crew command panel onboard the station to communicate with the capsule and send it a command to turn on a strobe light.
After completing the fly-under, Dragon will loop out in front, above and then behind the space station to position itself for docking.
Step 6: Rendezvous
At this point, a series of final checkouts will be performed to make sure all of Dragon's location and navigation systems are accurate. If all looks good, Dragon's SpaceX control team on the ground will command the vehicle to approach the space station. When it reaches 720 feet (220 meters), the astronauts onboard the outpost will command the capsule to halt.
After another series of "go-no go" checks, Dragon will approach to 656 feet (200 meters), and then 98 feet (30 meters), and finally 32 feet (10 meters), the capture point.
Step 7: Docking
The next day, after more checkouts, the crew will open the hatch between Dragon and the station. Over the coming weeks, the astronauts will spend about 25 hours unpacking the 1,014 pounds (460 kilograms) of cargo that Dragon delivers. Though none of the cargo is critical (since this is a test flight), the capsule will arrive bearing food, water, clothing and supplies for the crew.