Weightless in virtual reality

Test subjects in a parabolic flight conducting "The Influence of Gravity on the Perception of Self-Motion SMUG (Self-Motion Under Gravity)" experiment. It was a difficult campaign to organise, but the scientific results are some of the best ever. In November 2020 over 60 researchers run 11 experiments in an Airbus aircraft with no less than three pilots. This was no ordinary flight: the A310 'Air Zero G' flew in parabolic arcs, repeatedly free-falling 600m up and back down again, providing weightlessness for all passengers and their experiments, 20 seconds at a time.

With flights prepared and operated by contractor Novespace, ESA runs regular parabolic campaigns to conduct scientific research and to test hardware for future space missions.

ESA's 73rd parabolic flight campaign was relocated to Padeborn-Lippstadt airport in Germany to minimise risk of COVID-19 infection.

As in all human spaceflight, safety is paramount and many measures were taken to ensure COVID-19 was kept at bay. All participants were tested before leaving high-risk areas, temperatures were checked regularly, strict social distancing was in place in the hangar where experiments were prepared, masks were obligatory at all times, only a limited number of experimenters were allowed on the aircraft, and the plane’s seating arrangement was changed to ensure social distancing.

The diverse experiments focused on how humans perceive motion without gravity as reference, how our brains manage to process information during weightlessness, new ways of extracting oxygen from lunar soil, techniques for better cooling and heat transfer in space, and zero-g 3D-printing.

The experiment shown here investigates how humans generate a perception of their motion by integrating a range of different cues. Vision and vestibular cues are particularly important in this process. Humans have evolved and adapted to an environment where a constant gravity pulling “down” is ever-present. When this pull is disrupted such as in space or in a parabolic flight, the integration process must adapt to avoid severe disorientation or even sickness. A key question for finding solutions to this problem is whether we can we modify the visual environment to counteract the effects of the loss of a constant 1 g. Results from the SMUG project will allow the development of a model of how gravity affects the processing of visual information that is able to evoke self-motion – a model that will predict astronauts’ perception of motion in space.