Table of Contents

Space Life Science Experiments

SASSE (Space Adaptation Syndrome Supplemental Experiments)

This group of six experiments was designed to gather the information needed to develop the major experiment in this field. It deals with problems astronauts have encountered in adapting to living in the zero-gravity environment.

a) Vestibulo-ocular Reflex Gain:

The vestibulo-ocular reflex helps a person maintain a directed gaze in spite of head motion. For example, an outfielder chasing down a fly ball is able to keep his or her eyes focused on the ball despite the head bobbing. In the weightlessness of space, this reflex doesn't work as well, leading to a slip of the visual image on the eye's retina. A symptom of this condition can be motion sickness.

The experiment was designed to measure this reflex and the amount of image slip. It takes 10 minutes to do and Marc Garneau did it several times to see whether he was adapting to weightlessness as the mission went on.

Garneau first placed a cloth cross measuring about one meter by one meter (three feet by three feet) on the mid deck lockers. The arms of the cross were marked to indicate up, down, left and right and points along each arm were numbered from zero at the centre to 20 at the end. Zero was the cross-point.

Wearing a headband used to hold a pen-sized, narrow-beam flashlight, he will strapped himself into place in the middeck and faced the cross. He pointed the flashlight beam at the centre of the cross and concentrated on keeping his eyes fixed on that same point. He then shield his eyes with paper and made a quick head movement while trying to maintain the direction of his gaze towards the zero. When he removed the paper, he saw whether his eyes were still directed on the zero or had wandered. He also checked how far the flashlight beam and his head had moved. He recorded the results.

b) Proprioceptive Illusion Tests

During ground tests after the Spacelab I flight in 1983, some astronauts reported a bizarre illusion when asked to hop up and down. Even with their eyes open, they had the sensation that it was the floor that was moving up and down and not themselves. The prevailing theory is that these illusions occur because astronauts take time to re-adapt to Earth's gravity after getting used to the weightlessness of space.

This experiment was designed to study the occurrence and mechanisms of these illusions. It took 15-20 minutes to complete and was repeated during the mission and back on Earth.

First with eyes open, then with eyes closed, Marc Garneau performed a series of armbends and kneebends with his feet tied down to the floor. He reported whether it seemed as though he was moving, Challenger was moving or both were moving.

If, after doing the kneebends, Garneau sensed that Challenger, rather than he himself, was moving up and down, he repeated the test while holding onto a chair and, again, while wearing a belt attached to the floor by stretched rubber bands. This was to find out whether the sensation of holding onto a chair or the simulated weight sensation of wearing the belt eliminates any sensation that the orbiter is moving.

Keeping his head fixed, he then rapidly moved his eyes from one point to another and record whether the world seemed to be moving around him or whether he was moving just his eyes. Finally, he moved his hand and then a bare foot back and forth against a surface to see whether he felt the surface moving.

c) Sensory Function

Evidence suggests that sensory functions may gradually deteriorate in space. Astronauts have reported various sensory dysfunctions, including the feeling of pins and needles in the skin. There are two parts to this experiment which were designed to measure the effects of weightlessness on sensory function and examine the movement of various joints.

The first test took 15-20 minutes and was conducted with eyes open and, again, with eyes closed. It involved Marc Garneau's skin sensations when specially-ridged cubes are pressed against his index finger and his big toe by one of the other crew members. This was done before flight and during the mission. The tester pressed each set of ridges twice. Garneau had to report whether, in each of two tests, he felt the ridges to be different between the first and second test. Finer and finer sets of ridges were used to determine his ability to differentiate ridge spacing.

In the second part, which lasted 10 minutes, Marc Garneau and another crew member took turns performing the following test on each other. The subject was blindfolded. The crew member performing the test moves the outermost joint of the subject's middle finger and then, of the big toe, to see whether the subject was aware of movement. The tester then moved the subject's elbow joint and asked the subject to estimate the angle at which the joint was fixed. The test was repeated with the knee joint.

d) Awareness of Position

Reports from astronauts who have flown suggest that zero gravity (there is no up and down in space) and the absence of visual cues result in a loss of orientation. Astronauts have made large errors when attempting to point at targets when blindfolded. To investigate this disorientation, Marc Garneau conducted a test, taking about 10 minutes to complete, three times.

Garneau strapped himself at the hips in a seated position onto a place in the mid-deck and face the same cross as the one used during the vestibulo-ocular test. After memorizing where the target was, he was blindfolded by another crew member and asked to point to the centre of the cross with a hand-held flashlight. The crew member administering the test noted where the flashlight beam stroke the cross relative to the centre: left or right; up or down.

The crew member asked Garneau to say where he thought up and down were and why. For example, he could answer: "Down is here because it's towards my feet." The test also tried to find out whether there was a difference in Garneau's sense of up and down when his feet were attached to the floor, wall or ceiling of the mid-deck.

e) Space Motion Sickness

More than 40 per cent of all astronauts suffer to some extent from motion sickness when in space, particularly in the larger spacecraft. Motion sickness occurs mostly during Days 1, 2 and 3 of a mission. There are no reliable tests to predict who will be affected nor are the precise causes known. A better understanding of the phenomenon would not only benefit astronauts but could also benefit those who suffer motion sickness on Earth.

This experiment was designed to study the onset of symptoms and evaluate the effectiveness of various forms of treatment. There were three components -- observation of symptoms, susceptibility to motion and treatment. Marc Garneau used a checklist, a pocket mirror and a tape recorder to record any symptoms throughout the mission.

If mild nausea settled in, he strapped himself in a chair, keep his head very still, keep his eyes open and look at a fixed point and then record his symptoms every three minutes to see whether the immobilization was working.

Medication for nausea is a last resort because it would interfere with test results.

f) Taste in Space

Astronauts have reported that food tastes sweeter and less spicy in space but no formal experiments have been carried out on taste sensation. The change in taste may be caused by the upward shift of body fluids in space; or, it may be that weightlessness affects taste buds in some other way.

The experiment was designed to investigate changes in taste and smell during space flight and had possible application to astronaut diets. The test took about 10 minutes to complete and was done during Days 1, 3 and 7 of the mission to see whether results changed with time. Marc Garneau and other crew members were first be tested on Earth. During the mission, Garneau used a kit of 14 numbered solutions, each to be squeezed onto a cotton swab and applied to the tongue. The subject then said whether the solution was sour, sweet, bitter, salty or just plain water.

To test the sense of smell, the subject was asked to sniff different bottles each containing a gauze wetted with vanilla, lemon, spearmint or water and to record what he smelt.