Image credit: NASA

Let’s face it. Looking at all those “free-floaters” inside the multi-billion dollar International Space Station it must be a cool experience.

Unchained from the tug of Earth gravity, astronaut antics in microgravity are a way to take the edge off all those on-the-clock duties.

But now new research shows that space travelers, free from the pull of gravity, gain an uncanny ability to orient themselves and gauge distance travelled within the confines of their orbital home-away-from-home.

Image credit: NASA

Dozen astronauts

Björn Jörges of the Center for Vision Research at York University in Canada led the research work.

The findings of the study – “The effects of long-term exposure to microgravity and body orientation relative to gravity on perceived traveled distance” – has been published in the journal npj Microgravity. It was done in collaboration with a dozen ISS astronauts.

Written informed consent from all participants was acquired. The investigation was approved by the local ethics committee at York University as well as by the Canadian Space Agency (CSA), NASA, the Japan Aerospace Exploration Agency (JAXA), and the European Space Agency (ESA).

Image credit: NASA

Explicit goal of project

“As space flight programs start to move past some of their biases in astronaut recruitment — like the fact that NASA only selected young, white, male astronauts during its first 20 years — it becomes increasingly important that microgravity studies ensure representative participant samples,” states supplemental data attached to the primary research paper.

“As a small step in this direction, one of the explicit goals of the VECTION project, funded by the Canadian Space Agency, was to assess whether exposure to microgravity affected male and female astronauts differently.

Go to this video on the VECTION project at:


 The way people move about is more like flying, says co-investigator, Laurence Harris of York University, an expert on vision and the perception of motion. He also heads up the Multisensory Integration Lab and is the former director of the Center for Vision Research at York.

 “It has been repeatedly shown that the perception of gravity influences perceptual skill,” York explains in a university statement.

“The most profound way of looking at the influence of gravity is to take it away, which is why we took our research into space,” York added.

Image credit: NASA

Open question

It is an open question, the research paper points out, how exactly visual, vestibular and other cues are integrated to develop the perception of self-motion – particularly when self-motion is evoked purely by optic flow.

Based on research findings, York said that it seems as though humans are surprisingly able to compensate adequately for the lack of an Earth-normal environment using vision.

“People have previously anecdotally reported that they felt they were moving faster or further than they really were in space, so this provided some motivation to actually record this,” York explains.

The research explains that astronauts’ performance of their estimate of the distance of self-motion, either in terms of accuracy or precision, did not change significantly in response to microgravity exposure.

A screenshot from the hallway in which the post-flight participants were immersed. B The target is shown at the beginning of each trial.
Image credit: Jörges, B., et al

Crew safety

The study contrasted the performance of six men and six women before, during, and after their stints onboard the ISS.

It was found that the astronaut sense of how far they travelled remained largely intact. That has implications for crew safety in space and could potentially give clues to how aging affects people’s balance systems here on Earth.

“On a number of occasions during our experiment, the ISS had to perform evasive maneuvers,” Harris recalls. “Astronauts need to be able to go to safe places or escape hatches on the ISS quickly and efficiently in an emergency. So, it was very reassuring to find that they were actually able to do this quite precisely.”

Astronauts are unlikely to be exposed to dangers due to an unusual perception of traveled distance when in space, the paper points out, such as when sensitive equipment and machinery must be operated manually and in a visually guided fashion in the absence of gravity.

Image credit: Jörges, B., et al

First of three papers

The study, a decade in the making, represents the first of three papers that will emerge from investigating the effects of microgravity exposure on different perceptual skills including the estimation of body tilt, travelled distance, and object size.

York said that this newly published work finds that self-motion is largely unaffected, suggesting the balance issues that frequently come from old age may not be related to the vestibular system.

Image credit: NASA

“It suggests that the mechanism for the perception of movement in older people should be relatively unaffected, and that the issues involved in falling may not be so much in terms of the perception of how far they’ve moved, but perhaps more to do with how they’re able to convert that into a balance reflex,” York states in the university statement.

To view the full paper – “The effects of long-term exposure to microgravity and body orientation relative to gravity on perceived traveled distance” – go to:

Also, go to this tool used in the study at:


Leave a Reply