How a Vomit Comet Trains Astronauts

Find out how fixed-wing aircraft can simulate zero-gravity conditions for astronaut training.

When an aircraft follows a parabolic flight path, it creates a weightless period for several seconds. This is ideal for providing astronauts with the sensation of zero gravity and testing equipment for use in outer space. A typical three-hour training mission makes at least 30 parabolic flights. They can simulate zero-g for 25 seconds, one-sixth g (lunar-g) for 30 seconds or one-third g (martian-g) for 40 seconds.

In 1959, NASA used a Convair C-131 Samaritan aircraft to train the Mercury programme astronauts. It was quickly nicknamed the ‘vomit comet’, as one in three passengers became violently sick.

Most aircraft used for such flights are adapted versions of transport or commercial passenger aircraft. NASA currently uses a McDonnell Douglas C-9 and the European Space Agency uses an Airbus A300.

Since 2004, commercial companies started offering such flights to the public, and NASA offers a scheme for students to design and fly micro-gravity missions.

Vomit Comet Trains AstronautsAirbus A300

The French company Novespace operates the ‘zero-g’ Airbus A300 on behalf of the European Space Agency (ESA) from Bordeaux-Merignac Airport.

The Airbus was purchased in 1996 and was strengthened to deal with the demanding stresses of parabolic flight manoeuvres. Each flight carries five pilots, with three working in the cockpit at the same time.