Table of Contents

CANEX-2

Space Vision System Experiment (SVS)
Principal Investigator: Dr. H.F. Lloyd Pinkney, National Research Council of Canada, Ottawa, Ontario.

Space is a difficult visual environment with few reference points and frequent periods of extremely dark or bright lighting conditions. Astronauts working in space find it difficult to gauge the distance and speed of objects such as satellites. The development of the Space Vision System (SVS). a machine vision system for robotic devices such as the Canadarm. was undertaken to enhance human vision in the unfavourable viewing conditions of space. The SVS can provide information on the exact location, orientation and motion of a specified object. Dr. MacLean evaluated an experimental Space Vision System for use in the Space Shuttle and in the construction of Space Station Freedom.

The Space Vision System uses a shuttle TV camera to monitor a pattern of target dots of known spacing arranged on an object to be tracked. As the object moves, the SVS computer measures the changing position of the dots, and provides a realtime TV display of the location and orientation of the object. This displayed information helps an operator to guide the Canadarm or the Mobile Servicing System (MSS) when berthing or deploying satellites.

For the CANEX-2 experiments, target dots were placed on the Canadian Assembly (CTA), a small satellite carried in the Space Shuttle's cargo bay. During the flight, a mission specialist used the Canadarm to deploy the CTA and take it through a series of manoeuvres using the information displayed by the SVS, while Dr. MacLean evaluated SVS performance and investigated details that needed to be considered to design a production model of the system.

Beyond its application as a computerized eye for the Space Shuttle, the Space Vision System will be used to help construct and maintain the Space Station. In another application, an SVS-based system guides small, remotely operated space vehicles for satellite retrieval and servicing. On Earth, advances in machine vision leads to improvements in the manufacturing of products, in auto plants for example, and to applications involving work in environments such as mines or nuclear reactors.

Materials Exposure in Low Earth Orbit (MELEO)
Principal Investigator: Dr. David G. Zimcik, Canadian Space Agency, Ottawa, Ontario.

Plastics and composite materials used on the external surfaces of spacecraft have been found to degrade in the harsh environment of space. Evidence suggests that this degradation is caused by the interaction with atomic oxygen which induces damaging chemical and physical reactions. The result is a loss in mass, strength, stiffness and stability of size and shape.

The MELEO experiment was an extension of work performed by the Canadian Space Agency which began with the Advanced Composite Materials Experiment (ACOMEX) flown on Dr. Marc Garneau's 1984 mission. For STS-52, researchers wanted to extend the valuable baseline data obtained to further investigate the deterioration process, try new protective coatings, and test materials designed for use on specific space hardware such as the Mobile Servicing System (.MSS) for the Space Station Freedom and RADARSAT, the Canadian remote sensing satellite which was launched in early 1995.

The MELEO experiment exposed approximately 350 material specimens which were mounted on "witness plates" on the Canadarm and analyzed after the mission. Typical spacecraft materials were tested along with new developments in protective measures against atomic oxygen. The specimens were exposed in the flight direction for at least 30 hours. Dr. MacLean periodically photographed the specimens to record the stages of erosion. All materials were returned to Earth for detailed examination after the flight.

The MELEO experiment used active elements called Quartz Crystal Micro-balances (QCM's), attached to the end of the Canadarm, to measure the erosion of material with a very high degree of accuracy. Their electrical functions were regulated by a controller located on the aft flight-deck of the shuttle orbiter. Data were recorded using the on-board Payload General Service Computer (PGSC). This enabled the Canadian payload specialist to have real-time readout of the erosion data during the mission.

The MELEO experiment provided data on the performance of new materials exposed to the true space environment and provided information used in the development of effective ground-based space simulation facilities capable of testing and screening spacecraft materials in the laboratory.

Orbiter Glow-2 (OGLOW-2)
Principal Investigator: Dr. E.J. (Ted) Llewellyn, University of Saskatchewan, Saskatoon, Saskatchewan.

Photographs taken by astronauts have revealed a glow which emanates from surfaces of the shuttle facing the direction of motion. This phenomenon is thought to be caused by the impact of high-velocity atoms and the effect of the orbiter's surface temperature.

In the first OGLOW experiment, Dr. Marc Garneau successfully photographed the glow phenomenon. Computer analysis of these photographs and of corresponding video recordings revealed the bright areas to be concentrated around the shuttle's tail section instead of around the entire shuttle, as had been expected. Additional data, obtained when Dr. Garneau took several photographs while the shuttle's thrusters were firing, led to the need for an OGLOW-2 experiment. This experiment explored in greater detail the gaseous reactions caused by the orbiter thrusters through the post-flight analysis of the thruster-induced glow spectrum. Photographs of the shuttle's tail, primarily while the thrusters are firing, were taken. Onboard TV cameras were used to obtain corresponding video recordings. The OGLOW-2 experiment also determined whether optical measurements taken from the shuttle were adversely affected by the glow. To carry out part of the experiment, Dr. Steve MacLean used newly developed equipment to photograph the Canadian Target Assembly (CTA) with its different material surfaces.

The OGLOW-2 experiment also studied the glow from the Earth' upper atmosphere.

Queen's University Experiment in Liquid-Metal Diffusion (QUELD)
Principal Investigator: Prof. Reginald W. Smith, Queen's University, Kingston, Ontario.

Atoms of any substance, whether liquid or solid, are in constant motion. Knowledge of the rate at which atoms move around and in between each other (diffusion) is important for a variety of industrial processes. On Earth, the effects of convection make it difficult to measure the actual degree of diffusion which is taking place within a substance. In space, where convection is eliminated, it is possible to obtain more accurate information.

The QUELD experiment allowed measurements of the diffusion coefficients of a number of metals in the liquid state. The QUELD apparatus contained two small electric furnaces in which over 40 specimens were heated in tiny graphite crucibles until the test metals in them were molten. They were allowed to diffuse for 30 minutes or more and then rapidly cooled to solidify the metals for post-flight analysis upon return to the university.

The researchers used the data to help develop a general theory that will make it possible to predict the rate of diffusion for any metal in the liquid state, as well as provide some fundamental information about the structure of liquid metals. This is expected to lead to the creation of better crystals for use in the fabrication of computer microchips and radiation sensors, and to the development of special alloys which cannot be made on Earth.

SunPhotoSpectrometer Earth Atmosphere Measurement (SPEAM-2)
Principal Investigator: Dr. David I. Wardle, Environment Canada, Toronto, Ontario.

The measurement of atmospheric structure and composition using space-based instruments has provided a vast new capability for environmental monitoring. SPEAM-2 added to an expanding body of information about the stratosphere, the part of the upper atmosphere that contains most of the Earth's protective ozone layer.

The SPEAM-2 experiment comprised two measuring instruments and a control computer. All three were developed by the Atmospheric Environment Service of Environment Canada. The SunPhotoSpectrometer (SPS) made multispectral measurements of ozone and of the nitrogen compounds which play an important role in controlling ozone balance especially in the presence of chlorine. Atmospheric transmission, or the degree to which light is absorbed in the Earth s atmosphere, waa also measured in the visible and near-infrared parts of the solar spectrum. This hand-held instrument was aimed at the sun by Dr. MacLean during several sunset and sunrise periods. The Airglow Imaging Radiometer (AIR) observed atmospheric airglow from atmospheric molecular oxygen in several regions of the electromagnetic spectrum and possibly from OH radicals, highly reactive molecules composed of oxygen and hydrogen, which affect the ozone concentration in the stratosphere.

These measurements provided information about the chemical processes which take place in the stratosphere and affect the protective ozone layer. SPEAM-2 data complemented other measurements including those from NASA's Solar Aerosol and Gas Experiment (SAGE) and other ground-based observations.

The SPEAM-2 experiment provided extremely useful information about the upper atmosphere and the capabilities of the new instruments. The engineering data and experience gathered enabled Canadian atmospheric scientists to make more effective use of future space platforms such as research satellites and Space Station Freedom.

Phase Partitioning in Liquids (PARLIQ)
Principal Investigator: Dr. Donald E, Brooks, Department of Pathology and Chemistry, University or British Columbia, Vancouver, British Columbia.

Phase partitioning was studied as a way of separating, from complex substances, different kinds of cells which differ only subtly in their surface properties.

The process used two types of polymers (compounds formed by repeated units of similar but not identical molecules) which were dissolved together in water. They formed two solutions, called "phases", which reacted to one another like oil and vinegar, one floating up to lie on top of the other once they had been mixed and left to stand. When mixtures of small particles such as cells were added to the liquids, some were attracted to one of the phases, some to the other. Consequently, the liquids separated the cell types.

The astronaut shook a container which holded a number of chambers with solutions containing different mixtures of model cells visible through windows. The container was then observed and photographed at short intervals as partitioning occurs. At the end of the experiment, the separated phases containing their cells were isolated and returned to Earth. The effects of applying an electric field on the separation process was also studied.

The ultimate objective was to increase the purity of the separated cells. On Earth, it is difficult to separate substances and achieve maximum purity using this process because of gravity-induced fluid flow. In microgravity, the combined forces acting on the liquids and the cells are entirely different from those on Earth and the physics of the process can be better understood.

A phase partitioning experiment using the same apparatus was performed by Dr. Roberta Bondar and other crew members during her January 1992 mission. This investigation was itself an extension of an experiment carried out in 1985 on Mission 51-D in which test solutions separated in a way that had not been observed previously. The results of .this experiment can be of interest to medical researchers because they apply to the separation and purification of cells involved in transplants and treatment of disease.

Space Adaptation Tests and Observations (SATO)
Principal Investigator: Dr. Alan Mortimer, Canadian Space Agency, Ottawa, Ontario.

Every flight by a Canadian astronaut includes research into human adaptation to spaceflight. Dr. MacLean's mission was no exception. The data obtained supplemented the results of similar experiments performed during the missions of Drs. Marc Garneau and Roberta Bondar. What follows are descriptions of the investigations which made up the SATO group of experiments.

Vestibular-Ocular Reflex Check
Investigator: Dr. Doug Watt, McGill University, Montreal, Quebec.

An experiment performed by Marc Garneau in October 1984 investigated the effect of weightlessness on the vestibulo-ocular reflex, an automatic response triggered by the vestibular system that keeps the eyes focused on a given object despite head motion. Although researchers expected at Ieast a slight deterioration in the functioning of this reflex, systematic testing revealed no change.

Since these unexpected results were obtained with testing several hours after launch time during which considerable adaptation could have occurred, it was necessary to test the vestibulo-ocular reflex at the time of entry into microgravity.

Dr. MacLean used a hand-held target and, by routing the head back and forth, determined the ability of the eyes to track correctly.

Body Water Changes in Microgravity
Investigators: Dr. Howard Parsons, Dr. Jayne Thirsk, and Dr. Roy Krouse, University of Calgary, Calgary, Alberta..

In the absence of gravity there is a shift of body fluids towards the head which leads to the "puffy face" syndrome that can be observed in astronauts after several days of spaceflight. There is also a loss of water from the body early in a spaceflight and preliminary results from Dr. Roberta Bondar's IML-1 mission indicate that there may be significant dehydration occurring in astronauts.

This test determined the changes in total body water throughout the spaceflight. Dr. MacLean ingested a sample of heavy water at the beginning and end of the mission and saliva samples were collected daily. Upon return, the samples were analyzed to determine total body water.

The results of this experiment were of importance in developing nutritional protocols for long duration spaceflight, and contributed to the development of countermeasures that are used during re-entry.

Assessment of Back Pain in Astronauts
Investigator: Dr. Peter C. Wing, Head, Department of Orthopedic Surgery, University of British Columbia, University Hospital, Vancouver, British Columbia.

More than two thirds of astronauts have reported experiencing back pain during spaceflight. The pain seems to be worst during the first few days in space, and may be due to the astronauts' total height increase of up to 7,4 cm documented during Dr. Roberta Bondar's IML-1 mission.

The height increase in the absence of gravity results from 1 the lengthening of the spinal column and the flattening of the normal spinal curves, probably as a result of an increase in the water content and thus the height of the discs between the vertebrae of the spine. This in turn may result in an increase in the distance between the vertebrae, and may cause pain from tension on soft tissue such as muscle, nerves and ligaments.

This experiment continued the investigation of the causes of back pain in space, which began during the IML-1 mission. The ultimate goal was to develop techniques to be used either before or during spaceflight to alleviate its effects. During the mission, Dr. Steve MacLean measured his height and used a special diagram to record the precise location and intensity of any back pain.

The results of this experiment led to an increased understanding of back pain on Earth.

Illusions During Movement
Investigator: Dr. Doug Watt, McGill University, Montreal, Quebec.

While performing deep knee bends in space and after return to Earth, astronauts have experienced the disconcerting illusion that the floor is moving up and down.

The objective of this test was to determine when these illusions occur and to investigate how visual and tactile inputs affect such illusions. For example, Dr. MacLean holded on to a fixed object such as a seat while doing knee bends to see if that altered the illusion of the floor moving.

Canadarm

The Canadarm is an integral pare of Mission STS-52. An experimental machine vision system, called the Space Vision System (SVS), will be evaluated by Canadian payload specialist Dr. Steve MacLean during the mission. Developed by the National Research Council of Canada, Spar Aerospace Limited, and the Canadian Space Agency, the SVS uses a video camera to monitor a pattern of target dots of known spacing arranged on an object to be tracked. As the object moves, the SVS computer measures the changing position of the dots, and provides information on the location and orientation of the object. This information will help guide the Canadamm in berthing or deploying satellites. It is expected that the SVS will be adapted for use on board Space Station Freedom.

For CANEX-2, the set of CANadian EXperiments to be conducted during STS-52, a target satellite called the Canadian Target Assembly (CTA) which was specifically developed for the SVS evaluation will be carried in the cargo bay. During the flight, a mission specialist will use the Canadarm to deploy the CTA and take it through a series of manoeuvres so that Dr. McLean can evaluate the performance of the SVS.