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Bodies In the Space Environment (BISE) - Which way is up in space?

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Bodies in the Space Environment (BISE) is an ongoing experiment that studies how astronauts distinguish up from down in a near-weightless environment. Sponsored by the Canadian Space Agency, BISE is a York University experiment led by Principal Investigator Dr. Laurence Harris. Canadian Space Agency Astronaut Bob Thirsk is one of 6 astronaut subjects for the experiment. Scientists will analyse data collected before, during, and after flight. BISE sessions on the International Space Station will be conducted throughout September 2009 and well into 2010.

For most people, telling up from down is so easy they hardly give it a second thought. But some people—those who find themselves in unusual, extreme environments or who suffer from certain medical disorders—find orienting themselves difficult and, as a result, they can make life-threatening mistakes.

One extreme environment where this can be a problem is space, where the brain no longer has gravity to help determine up and down. Astronauts must rely on other cues, such as their body position and what they see around them. If they get disoriented, it can lead to errors like flipping switches the wrong way or moving in the wrong direction during an emergency.

Principal Investigator Dr. Laurence Harris of York University. (Credit: CSA)

To learn more about how astronauts perceive up and down in microgravity, the Canadian Space Agency (CSA) is sponsoring a study called BISE (Bodies in the Space Environment) being led by a group of scientists from York University. It was partially conducted by Canadian astronaut Dr. Robert (Bob) Thirsk during Canada's Expedition 20/21. Launched in May 2009, this mission marked a milestone of Canada's Manned Space Program as Thirsk took part in the first-ever long-duration mission and research flight to the International Space Station (ISS).

The tests involved having subjects—including Thirsk—view a computer screen through a cylinder that blocks all other visual information. The astronauts were presented with background images with different orientations relative to their bodies. On top of these images were superimposed a letter that could be either a "p" or a "d" depending on its orientation.

They had to indicate which letter they saw and the scientists measured the transition points where the letters changed from a "p" to a "d" and back again. "The angle between those two is taken as the perceptual upright," notes psychologist Laurence Harris, principal investigator of the experiment. "We're able to alter that perceptual upright by changing body orientation or visual orientation." (In earth-based tests, they also change the relative position of gravity by having subjects lay on their sides.)

The researchers want to determine the relative importance of visual and body cues to the subjects' perception of up. Said Harris, "How the brain combines multiple pieces of information about the same thing and comes up with the right answer is a key question."

Studies done in special aircraft that produce brief periods of microgravity suggest that, in the absence of gravity, people rely more on body cues than on vision to tell them which way is up. The study will examine whether this also happens on the Space Station.

BISE experiment undergoes testing during parabolic flights in France. (Credit: Dr. Laurence Harris, York University)

According to Harris, their findings can help to create a safer work environment in space. He noted that the Station is "tricky" because its modules are not all in a straight line. "You often go through a right angle to go between one module and another, so whatever corresponds to the ground in one module won't necessarily match in another module."

This can cause disorientation that could have serious consequences in an emergency evacuation. Space station modules do have exit signs but "if you want to guid e people, you have to know what cues they're using and how effective they are—how effective a visual clue can be in that situation," Harris said.

Luchino Cohen, the CSA's mission scientist for the BISE experiment, noted that these issues also affect astronauts during spacewalks. "When you get outside the spacecraft, you have to adjust your orientation and use whatever visual cues you have." He said CSA supports this research because its mandate includes using the space environment to "improve the safety of space travel by understanding how the human brain adapts to microgravity."

According to Harris, the tools developed for this experiment can also help people on Earth who experience balancing problems or are prone to falling, including seniors and people with conditions like Parkinson's disease.

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