After a day’s delay due to bad weather, a partially reusable version of SpaceX’s Falcon 9V1.1 (dubbed the Falcon 9V1.1R) lifted off from the Cape Canaveral Air Station in Florida at 2010 GMT on 14 April 2015. Aboard was the Dragon CRS-6 on its NASA-paid-for commercial mission to deliver cargo to the International Space Station (ISS) including some live mice and, on ESA Italian astronaut Samantha Cristoforetti’s request, an Espresso coffee maker, later nicknamed ISSpresso.
Also on the flight as part of Dragon CRS-6’s cargo was the 3U-cubesat spacecraft Arkyd 3-R, which will be testing key technologies for the Arkyd-100 asteroid survey mission. In addition, it was carrying 14 3u-Cubesat-class spacecraft, part of the Flock 1E Earth observation constellation for PlanetLabs (Cosmogia Inc.), which will be released from the ISS. Also aboard was a test spacecraft called Centennial-1 carrying an imaging payload for the US Air Force Research Laboratory.
Dragon CRS-,with its cargo of spacecraft, was captured by robot arm at 1055 GMT on 17 April 2015 and subsequently berthed at the ISS Harmony module at 1329 GMT. (All times supplied by NASA via Jonathan McDowell.)
The launch also included another test flight of the reusable first stage which was supposed to make a powered approach and landing onto a landing pad vessel down range in the Atlantic. Unfortunately, just as the previous landing attempt had ended in a crash failure, so did this one, with the stage too badly damaged in the subsequent explosion to be used again.
Video footage shows that the stage appeared to approach too fast, ramping up its thrust too late to keep it fully controllable and upright. Although a touch down was achieved, the stage still had lateral motion and, after wobbling, it fell onto its side in a fiery explosion. The faulty landing was blamed on a sticking throttle valve, which reduced its response time.
Comment by David Todd: While this landing attempt of a reusable first stage was a second explosive failure, it was, once again, a close-run thing and it seems likely that the next attempt will work. If it can then repeat this on every mission, SpaceX will have a hugely competitive cost advantage.