Just a few days after Canadian astronaut David Saint-Jacques
launched to the International Space Station on Dec. 3, the
first-time space flyer faced a considerable challenge: learning how
his perception is altered by spaceflight.
Scientists know that astronauts in microgravity often feel like
they’re moving if they see another object moving, even when
they’re immobile, which is a phenomenon that makes depth
perception more difficult. This would especially be a problem when
capturing a cargo spacecraft using the robotic Canadarm2. While the
track record for successful astronaut captures is pretty much
flawless, scientists are working on minimizing any complications.
After all, crews need cargo to keep functioning in space.
This is where Saint-Jacques’ experimental challenge came in.
Saint-Jacques spent a half hour participating in Vection, a
virtual reality experience that will help scientists learn more
about how astronauts estimate the size and motion of objects in
space. He donned a VR headset and took part in three experiments:
estimating the size of an object, “moving” in the virtual world
to where he thought the object was placed in a hallway, and
determining how he perceives tilt and visual acceleration.
The results of the experiment could be used to enhance the safety
of operations aboard the ISS, and also help future astronaut crews
working on the moon or on Mars.
“By understanding errors in self-motion and distance perception,
and how they may change during time in space, we may be able to
inform tasks that involve either of these judgments,” explained
principal investigator Laurence Harris, of Toronto’s York
University, in an email to Seeker.
When using Vection, the astronauts are
guided through three tasks via a head-mounted display. In the
first, they are accelerated “sideways” along a virtual
corridor, triggering a sense of motion even though in reality they
“We then assess whether any of that visual acceleration may be
interpreted as acceleration due to gravity by asking them to
indicate the new angle of the floor, which should appear tilted if
they regard their previous direction of motion as ‘up’,”
In the second experiment, astronauts view a target in the same
corridor. The target disappears as the astronauts virtually
“move” along the corridor, and they press a button when they
reach the position where they think that the target was
“This tells us about how powerful visual motion is in space: how
far visual motion makes you feel you have moved,” Harris
The third experiment asks astronauts to compare the size of an
object in the virtual corridor with a reference object they have in
their hands. “The only way they can assess an object’s size is
by knowing how far away it is and therefore this allows us to
measure their perceived depth,” Harris added.
This work not only has implications for the ISS, but any future
spaceflight activity – including NASA’s desire to establish the
Lunar Orbital Platform-Gateway space station near the moon in the
2020s, and to move crews to Mars in the decades that follow.
Knowing depth perception in space can help astronauts improve their
ability to reach emergency hatches, dock a spacecraft, or control
Credit: York University
There are applications on Earth as well, such as better controlling
moving vehicles or assisting people who have trouble with balance,
such as the elderly.
“A major aim is to understand how our brains process self-motion
cues in general,” Harris noted, “and to provide a quantitative
model for how sensory information is combined together to do
Each participating astronaut will be tested five times.
Saint-Jacques has already gone through two tests – one on the
ground, and another one in the days after his arrival on the ISS.
His next three measurements will happen when he’s fully adapted
to space (between days 80 and 100), when he’s adjusting to life
back on Earth (four to six days after landing), and when he has
made a full recovery from space (50 to 70 days after landing).
But we’ll have to be patient while awaiting results from the
Vection experiment. There are only small crews on the ISS, and at
least seven astronauts need to participate. A final report
summarizing the data is expected to be published by 2023, just a
year before the scheduled completion of the space station
Source: FS – All – Science – News 2
Vection is a VR experience that's helping scientists learn more about how astronauts estimate the size and motion of objects in space.