Spacelab revisited

Helen E. Ross (Honorary Professor, University of Stirling) recalls an ‘out of this world’ research experience.

I was busy with research on divers in 1977 when a call came out from the European Space Agency. They were looking for simple experiments that astronauts could perform under microgravity in the first Spacelab Mission, scheduled for 1980.

This seemed like an interesting opportunity. One of the topics I had investigated with divers was how far they adapted to the reduction of weight in water caused by buoyancy, and how this affected their ability to judge the weight or mass of objects. It seemed an obvious step to investigate what would happen to judgements of heaviness under microgravity, when objects are weightless but still have mass. I wrote a short proposal for a discrimination experiment. The astronauts would be given a box of weighted tins, labelled randomly with letters of the alphabet, and cards containing lists of pairs to compare and decide which was heavier. The astronauts would be trained to do this on the ground. They would perform the test early and late in the mission, and again on return to Earth. The results would show how mass-discrimination under microgravity (near 0G) compared with weight-discrimination under normal gravity (1G), whether adaptation occurred during the mission, and whether there was an aftereffect on return.

I was delighted to hear that the proposal was accepted – one of six British experiments, amongst a total of 70 American and European experiments. I assumed that the experiment would cost very little and occupy only a few months of my time. The apparatus could be built at Stirling University, and I might have to travel a little to train the astronauts. In reality it was a step into the unknown, which unfolded to occupy at least the next ten years of my life and prove very expensive.

The first shock was receiving a lengthy Experiment Requirements Document. It was full of engineering jargon which I did not understand, and which did not seem to be relevant. So I ignored it. Then I was phoned and told that I must complete it and fax it to ESA the next day, or my experiment would be rejected. I stayed up half the night inventing answers, and faxed the document. My answers seemed to be OK, but it became clear that I was going to need some travel funds. All the Investigators were asked to attend many meetings, which were held at various locations in the USA and Europe.

I was unsure what range of weights to use, so the next step was to try it out in the microgravity phase of parabolic flight. I went to the Johnson Space Center at Houston, to take part in a series of parabolic flights. These flights use a KC-135 aircraft, which is a Boeing 707 with most of the seats taken out, and well-padded. During a parabola the aircraft accelerates upwards giving a force of up to 2G for about 20 seconds, then it goes over the top of the parabola giving microgravity for up to 20 seconds, then it accelerates downwards giving another period of high G before returning to straight and level flying. The flights usually entail 40 parabolas during one session. The aircraft is popularly known as the Vomit Comet.

Luckily I am not very susceptible to motion-sickness, and I enjoyed floating around under microgravity. It was a fascinating experience – like learning to swim for the first time. However, the flights are very expensive, so I spent most of the time testing participants. I used a box of weighted balls, which were tethered on strings to prevent them floating away. I presented the participants with one ball followed by another, and asked them to shake the balls and say which was heavier. The results showed that discrimination was about twice as bad under microgravity as under 1G, and was also impaired under high G: participants could discriminate a difference of about 5 grams from 54 grams under normal gravity, but needed a difference of 10 grams under 0G and 9 grams under 2G. I suspected astronauts would do better under the prolonged microgravity of Spacelab, because they would have time to adapt and the conditions would be less distracting. The parabolic flights were busy, with a lot of different experiments going on simultaneously. One day there was a group of Southern Baptist students sitting at the back, who sang ‘Nearer my God to Thee’. Despite all this my data were very useful, because they showed that the range of weights needed for Spacelab could be reduced. We settled on 24 balls ranging from 50-64 grams in 2 gram intervals, with duplicates of each weight.

It is easier to investigate the effects of high G than low G, because high G can be produced in the human centrifuge. I had a sabbatical visit in 1979 to the DFVLR Institute for Aerospace Medicine in Bonn, where I was able to run experiments in their human centrifuge. The results showed that estimates of weight were about half way between the weight of the object at 1G and the effective weight at 1.5, 2.0 and 2.5 G. Discrimination was also impaired at high G, but not as much as at 0G in parabolic flight.

Then we learned that the Spacelab mission had been postponed from 1980, probably till 1983. This was disappointing, but it gave the investigators more time to refine their experiments. Research at the DFVLR was fruitful and enjoyable, so I returned there from 1980-81.

By this time it was necessary to design the ‘space-qualified’ apparatus. There were stringent requirements on the materials and weight of apparatus in Spacelab, so the box to hold the weighted balls was built at ESTEC in the Netherlands. The balls were constructed at the Royal Aircraft Establishment at Farnborough, and were designed to have equal turning moments of inertia despite differences in mass. NASA approved the design, but disliked any mention of balls in space. So the balls were officially known as ‘isoinertial spheres’, but unofficially referred to as ‘Helen’s balls’ (or worse, ‘a balls-up in space’). I'm pictured with a home-built early version above.

The travel and apparatus requirements were expensive. The Medical Research Council normally funded my research, but they were unenthusiastic about funding research on astronauts. It was not Government policy to support human spaceflight, because their top advisors thought it was a waste of money. The MRC did provide funds for my apparatus and some travel, but kept cutting back my realistic estimates of travel costs. I had to keep on applying for small supplementary grants from various sources, occupying a large amount of time and effort both for me and for the people who process grants. Most other Investigators did not have these problems, as their countries provided guaranteed funds for space research.

The MRC became more generous in 1982 and provided a three-year grant to employ Eric Brodie as a research assistant and cover the costs of us both attending the Spacelab 1 mission in Houston. Spacelab eventually got off the ground in 1983, on the back of the Shuttle Columbia. It was necessary to have at least two people in a team for each experiment. Activities on Spacelab ran continuously, and the crew were divided into the Red Shift and the Blue Shift. Investigators were expected to man a consul at the Science Monitoring Area in Houston at all times, so I took the Red shift and Eric the Blue. We were supposed to listen in and keep a log of what was happening to our experiment. If the experiment was not run at the scheduled time, we could ask for it to be rescheduled. This was a Catch 22 situation. NASA ran a system of Negative Reporting, which meant that the astronauts only reported failures and negative incidents. We were supposed to assume that our experiment had been run unless we heard to the contrary. There was not a lot we could do about it.

My most exciting moment was when I was allowed to speak to one of the astronauts, Byron Lichtenberg, and he read out to me his results from the test card he had just completed. This reassured me that the experiments were running well. I then went to the Edwards Air Force Base in California, and watched the Shuttle land after a 10-day flight – another reassuring moment. There was a tight schedule of testing for the astronauts, with many investigators wanting them to repeat their experiments at the first possible opportunity. It was interesting to hear their accounts of how their bodies and clothes felt heavy for several days. One of the astronauts had brought back the precious record cards from the apparatus, so I was able to get the results without having to wait months for their official return. It turned out, as expected, that the crew had performed rather better than in parabolic flight, their discrimination threshold being raised by a factor of about 1.8 rather than 2.0. They also showed poor weight discrimination on return to earth for about three days. Unfortunately they had failed to perform the experiment early in the mission (without reporting the failure!), so there was no information on whether adaptation occurred during the flight. On the plus side I had some bonus data, because NASA had taken videos of some of the performances in flight. From these it was possible to calculate the accelerative forces used in shaking the balls. Those astronauts who gave the best discrimination used more vigorous shaking movements and applied higher accelerations to the balls. This was an interesting finding, and I got the opportunity to investigate it further in the D1 Spacelab mission in 1985, with my colleague Edwin Schwartz from the DFVLR as a co-investigator. For this experiment the astronauts used both high and low acceleration shakes. High acceleration shakes gave the best discrimination in space, but the worst discrimination on the ground. After the flight the astronauts gave unusual hand movements, and their discrimination was impaired for about three days.

I would have liked to have done more research on hand movements and mass-discrimination, but the general opinion was that this had little practical importance. I therefore proposed an experiment on motor skills for the Skynet mission in 1988, when the first official British astronaut was due to fly –- but the mission was cancelled after the Challenger accident. A new opportunity arose in the British-Soviet Juno space mission, but all British experiments were cancelled because of financial difficulties. The UK eventually increased its subscription to ESA to include human spaceflight, so Tim Peake was selected as the first official British ESA astronaut and joined the International Space Station in 2015. However, financial support for my space research fizzled out after about 1988, and I turned my attention to other matters.

I’m often asked whether it was worth so much effort for so little data. The answer has to be Yes. I collected a lot of data apart from that in Spacelab, and it was fascinating to be part of an international enterprise in the early days of space research.


Research publications

Ross, H.E. & Reschke, M.F. Mass estimation and discrimination during brief periods of zero gravity. Perception and Psychophysics, 1982, 31, 429-436.

Ross, H.E., Brodie, E.E. & Benson, A.J. Mass-discrimination in weightlessness and readaptation to earth’s gravity. Experimental Brain Research, 1986, 64, 358-366.

Ross, H.E., Schwartz, E. & Emmerson, P. The nature of sensorimotor adaptation to altered G-levels: Evidence from mass-discrimination. Aviation, Space and Environmental Medicine, 1987, 58 (9, Suppl.), A148-A152.

Ross, H.E. Motor skills under varied gravitoinertial force in parabolic flight. Acta Astronautica, 1991, 23, 85-95.

General publications

Ross, H.E. Through the nonsense barrier. The Guardian, October 20th, 1983, p.13. Reprinted in The Bedside Guardian 33, Ed. W.L.Webb, London: Collins, 1984, 70-73.

Ross, H.E. Was Spacelab a success? New Scientist, 1984, No. 1394, 37-38.

Ross, H.E. Dexterity is just a fumble in space. New Scientist, 1984, No. 1418, 16-17.

Ross, H.E. Astronauts’ perception of heaviness and limb position. The Bulletin. Scottish Branch of the British Psychological Society, 1997, Issue 24, 32-35.

BPS Members can discuss this article

Already a member? Or Create an account

Not a member? Find out about becoming a member or subscriber


As a psychology graduate from Stirling University in 1982 I vividly remember Helen's lectures and seminars on the space experiments. As an educational psychologist for the following thirty years I will be one of many students who benefitted from her example of applying a scientific approach to real life situations. Her efforts therefore had many wider benefits.