Cygnus spacecraft returns to Earth

The Cygnus CRS OA-6 spacecraft has returned to Earth after supplying 3.5 tonnes of cargo to the International Space Station (ISS).

Cygnus was launched on 23 March from Cape Canaveral by an Atlas V rocket, and berthed three days later at the ISS as it circled the Earth at an altitude of 400 km. After delivering its cargo — which included food, filters, spacesuit spare parts, and computer and camera equipment — the spacecraft was released from its docking station on 14 June.

The Cygnus Shallow Re-entry Observation Campaign was designed to record the spacecraft’s re-entry and give scientists detailed information about how spacecraft disintegrate during their descent through the atmosphere. The campaign saw a team of 13 scientists from Australia, Germany and the United States charter a Bombardier Global Express plane from Sydney Airport to observe the re-entry.

Using a range of instruments and cameras that recorded fragmentation of the spacecraft and emissions from the fireball, the team captured the final leg of the Cygnus journey before it crashed into the South Pacific, east of New Zealand. Data and images gathered by the instruments made it possible to determine how hot some parts of the spacecraft got and how others scattered during re-entry.

University of Southern Queensland (USQ) radiation-flow expert Professor David Buttsworth was one of the scientists lucky enough to take part in the campaign. He spent his time on the flight in control of an instrument for near-UV spectroscopy, as well as two smaller cameras for recording near-IR emissions.

“The instruments that we used on the aircraft are designed to split the components of the light emitted from the spacecraft into different wavelengths,” said Professor Buttsworth. “This gives much more information than we can get from the overall brightness of the light.”

The campaign will help scientists better understand the physics of the end-of-life ISS de-orbit and the physics of shallow uncontrolled re-entries.

Image caption: Professor David Buttsworth on the campaign flight.