The First British Space Plant Experiment

In January 1992, Space Shuttle Discovery took the first-ever British plant experiment in microgravity into space.

STS-42 (22nd -30th January 1992) was no ordinary shuttle flight. Discovery carried the International Microgravity Laboratory-1 (IML-1), a pressurised Spacelab module packed with experiments exploring the complex effects of weightlessness on living organisms and materials processing.

The international crew included Canada’s first woman astronaut, Roberta Bondar, and West Germany’s first astronaut, Ulf Merbold. The crew split into two shifts to carry out as much science as possible during the eight-day mission.

While it was in orbit, the shuttle even adopted a special position, with its tail pointed towards the Earth. In this orientation, called a “gravity gradient attitude”, the shuttle’s position was primarily maintained by natural forces. This meant there was less need to fire the thrusters, giving the delicate experiments onboard a very smooth ride.

The British experiment looked at the roots of thale cress, Arabidopsis thaliana. On Earth, the wild strain (natural version) of Arabidopsis – just like other plants – grows roots downwards towards the gravitational pull and shoots upwards against it. However, the mutant strain aux-1 is agravitropic, meaning that it ignores gravity and sprouts in any direction.

The experiment was referred to as SHOOTS, although its full name was Genotype Control of Graviresponse, Cell Polarity and Morphological Development of Arabidopsis Thaliana in Microgravity. Principal investigators Greg Briarty (University of Nottingham) and Paddy Maher (the Open University in Edinburgh) wanted to know whether the wild strain would grow like aux-1 in microgravity and how the root tips, stems and