The SpaceX Dragon CRS-17 cargo freighter spacecraft, on a resupply mission for NASA, was successfully launched into low Earth orbit by a Falcon 9 at 0648 GMT on 4 May on its way to dock with the International Space Station (ISS). The Falcon 9 first stage landed on the drone ship “Of Course I Still Love You” in the Atlantic Ocean at approximately 0657 GMT. An electrical fault on the drone ship plus a helium umbilical fault on the launch tower had previously caused a one-day delay.

The reusable first stage of the Falcon 9v1.2FT Block 5 rocket had to be landed on a drone ship just off the coast of Cape Canaveral, rather than at the LZ-1 landing zone, due to the need to recover debris from the area following a test-stand explosive failure of the Crew Dragon DM-1 capsule.

Dragon CRS 17 was captured by the ISS remote arm at 1104 GMT on 6 May 2019 and was berthed with the nadir port of the Harmony module at 1333 GMT. The craft carried two payloads to be attached to the outside of the ISS: the OCO-3 (Orbiting Carbon Observatory-3) instrument to monitor carbon dioxide emissions and the military test payload package STP-H3.

During the grapple by the robot arm was discovered that an umbilical cable that should have separated from the Dragon CRS-17 craft at launch had remained attached. While this did not affect the later capture of the craft or its berthing – it could have presented a flight hazard, especially at lift-off, had it not snapped.

Dragon CRS-17 with its attached umbilical line (marked by red arrow). Courtesy: NASA