Dragon spacecraft being grappled with CanadArm2 robotic arm at the station. Credit: NASA
This weekend, SpaceX added to its list of firsts when the Dragon cargo spacecraft docked with the International Space Station. To begin with, the rocket was the new Falcon 9 "Full Thrust" version which replaces all Falcon 9 launches now. The modified thrusters enable the second stage to fire longer, allowing SpaceX engineers to attempt more first stage recovery attempts.
Dragon CRS-8 with aerodynamic fairings ready for launch. Credit: SpaceX.
Liftoff occurred at 4:43p.m. EDT from the Launch Complex 40 at Cape Canaveral Air Force Station, Florida. The flight went very well, with clear visibility and great telescopic views of the stage separation. The previous Falcon 9 and Dragon launch ended in disaster, as the Dragon spacecraft was lost and the returning first stage was destroyed in a landing attempt.
Liftoff from LC-40, the same launch pad that saw dozens of Titan 3 and Titan 4 rockets lift off, including a flight of the Cassini probe to Saturn. Credit: SpaceX.
SpaceX has tried four times previously to land the first stage of the rocket on a barge out at sea, with all four being losses of the rockets and damage to the barge. This fifth experiment was a total success, as having delivered the second stage and Dragon into an orbital trajectory, the first stage fell to its designated landing location, then re-ignited the engine for a controlled descent. It was obvious on the monitors that the seas were somewhat choppy and that there was a good cross-wind blowing (for this rocket, any wind is a cross-wind!).
View from the observer aircraft as the Falcon first stage descends towards the tiny landing barge. Credit: SpaceX.
The Falcon stands successfully on the pad with the engine deactivated and legs completely deployed. Credit: SpaceX
Although the commercial company Blue Origins was the first to successfully land its Alan Shephard rocket upright after a test flight in Texas (and they've done it 3 times now!), SpaceX had the harder task as the Falcon flies higher and faster to place its spacecraft into an orbital trajectory. And to land the stage in a moving, choppy sea on a tiny barge is just outright fantastic flying.
Dragon approaches the ISS. Credit: NASA.
Meanwhile, in space, the Dragon cargo spacecraft reached orbit and began its chase to rendezvous withe the International Space Station. Over a two day period, the Dragon re-ignited its engine to change altitude and maneuver closer to the station. Eventually on Sunday morning, the spacecraft came within range for astronauts Tim Peake and Jeff Williams to extend the CanadArm2 robotic arm and grapple the craft, guiding it to berth at the Harmony module.
Dragon at left is seen in the same view with the Cygnus spacecraft (middle) and a Soyuz spacecraft (on the far right). Credit: NASA.
With the Dragon docked, it also set a first as the first time it has been docked to the ISS at the same time as the Cygnus cargo spacecraft! Together with the Russian Progress robotic spacecraft, the three ships are able to bring quite a tonnage of supplies and equipment to the ISS. Of the three craft, however, only the SpaceX Dragon can safely return materials and experiments to the surface of the Earth.