Which way is up? It’s a simple enough question for most of us – up is, well, up there, away from our feet and towards the stars. Unfortunately, for the astronauts on their way to another planet, or even floating in the International Space Station (ISS), the question of which way is up essentially has no meaning. Without any form of concrete directionality, up and down are useless pieces of information. Not only that, but the part of their brain responsible for determining directionality – the vestibular (balance) system – gets completely baffled by the unusual situation. Today, NASA has announced a new study designed to investigate the effect of very low (micro) gravity environments on the vestibular system.
Astronauts have previously reported feeling disorientated in microgravity environments. Perceptual illusions – the feeling of constantly switching between feeling like they are the right way up and upside down, for example – are common with spacefarers. Former shuttle astronaut Robert Parker once reported that, during his time on the ISS, he woke up expecting to be at home on Earth, and had to adjust his reference point to recall that, in space, the ceiling was directly above his head.
"My reference frame rotated clockwise until [the room] aligned with my own personal sense of up," he recalled to NASA. "The sensation was so definite and strong that I could almost feel myself [turning] counterclockwise."
Until artificial gravity systems are viable – as recently seen in "The Martian" on the Hermes spacecraft – astronauts will have to deal with the effect of having their vestibular system thrown completely off balance. The Spaceflight Effects on Neurocognitive Performance: Extent, Longevity, and Neural Basis study – currently without a snappy acronym – will use functional magnetic resonance imaging (fMRI) scans of the brain to look at the direct effect spaceflight has on the astronauts’ neurological systems, in particular the vestibular system.
This research will be combined with behavioral assessments in order to construct a fuller picture of the effects of microgravity on the occupants of the ISS. "We are looking at the volume of different structures in the brain and whether they change in size or shape during spaceflight," said principal investigator Rachael D. Seidler, director of the University of Michigan's Neuromotor Behavior Laboratory, in a statement.
By asking the subjects to perform tasks as the fMRI scans are carried out, scientists will be able to see – before, during and after their microgravity stint in low-Earth orbit – which parts of their brain they use. Astronauts will be asked to complete obstacle courses and will have their ability to mentally picture and manipulate a three-dimensional shape tested.
The brain is indeed very capable of adapting to new situations – a trait known as neuroplasticity – but the speed at which a brain can adapt between environments with wildly different gravitational field strengths is unknown. This is vital information: Space agencies will need to know how an astronaut that has spent many months in near-to-zero gravity will be able to adapt to landing on the Martian surface, where they will be expected to deal with complex mechanical tasks almost immediately.
At least astronauts already know which way to point their cameras in space: directly down at us, sending us beautiful photographs every single day.
