At 3:44am this past Tuesday, a rocket blasted off from Cape Caneveral, Florida on a historic mission to demonstrate the ability of a commercially developed and operated transportation system to safely deliver cargo to the International Space Station. This flight is only the third flight of the Falcon 9 rocket, developed by Elon Musk’s startup Space Exploration Technologies (SpaceX), and the second flight of their Dragon capsule, so the tension in the atmosphere at SpaceX was understandable. The first launch attempt, last Saturday morning, was scrubbed due to a leaky check valve in the central engine’s turbopump, which was fortunately caught by the Falcon 9’s flight computer, enabling a safe abort of the engines with only half a second to spare before the planned liftoff. SpaceX was able to diagnose and repair the problem over the weekend, and was ready to go again at the next launch window, on Tuesday morning. Fortunately, the Falcon 9 delivered a flawless performance, lifting the Dragon capsule safely to orbit a little over nine minutes after liftoff. I had literally been keeping my fingers and toes crossed for the whole flight while watching things from home (my past experience in rocket testing has made me somewhat superstitious). I choked up at the reaction of the SpaceX team when the Dragon’s solar panels finally deployed. If you need some inspiration, and haven’t seen the flight footage, I’d strongly suggest watching the unedited SpaceX broadcast (launch starts at ~44:40 mark).
While those initial thrilling moments were an excellent start to a historic mission which is the culmination of nearly six years of hard work at SpaceX and NASA, the most historic portion of this mission is about to begin tomorrow morning. Over the past two days since the launch, the Dragon capsule has been slowly catching up with the space station, while performing several tests to demonstrate to NASA the capsule’s ability to safely operate near the station. Earlier this morning, the Dragon performed a maneuver that allowed it to pass only 2.5km below the station, where the picture at the beginning of this post was taken by an astronaut on board the ISS (Don Pettit, the one who will be operating the robot arm for tomorrow’s “berthing” operation). This final test verified the ability of ISS crewmembers to send commands to the Dragon, and to test the inter-vehicle communication system. With the completion of today’s tests, SpaceX has actually fulfilled all the requirements they had originally planned for their second Dragon flight. However, over the past year, SpaceX has worked with NASA to gain permission to combine the second Dragon flight with the third and final Commercial Orbital Transportation Services (COTS) demonstration flight, where the Dragon capsule will ultimately berth with the station (using its robotic arm, controlled by astronauts on-board), cargo will be unloaded from inside the Dragon capsule, and a small amount of non-critical cargo will be loaded back into Dragon for the return flight. It is this final set of operations, which will start in the early morning hours tomorrow (around 7:30am on the east coast) and end with the hatch to the ISS being opened early Saturday morning, which will be the truly historic part of this mission—marking the beginning of service of the world’s first commercial space cargo delivery vehicle, completing SpaceX’s part in the COTS development program, and marking SpaceX’s transition into operational service as part of the Commercial Resupply Services program which it won flight contracts from at the end of 2008.