Fear of animal-rights protests played a key role in preventing UK scientists joining an international effort to put mice in space.
The student-led Mars gravity biosatellite programme will involve US and Australian experts. It will put 15 mice into orbit to explore the biomedical effects of Martian-level gravity - simulated by spinning spacecraft to generate centrifugal force - a crucial step in the preparation for a manned visit to the Red Planet.
Not one UK university took part in the Mars Society competition that spawned the mission.
Bo Maxwell, president of the Mars Society, said the initiative was launched at the height of the protests at Huntingdon Life Sciences, and experiments exploring the effects of artificial gravity on mice had met opposition.
"Some universities got cold feet," he said. "I strongly felt this was why we didn't get responses from the UK."
The Mars gravity biosatellite programme, unveiled last week, is independent of the Mars Society, although the three collaborating institutions - the Massachusetts Institute of Technology and the University of Washington at Seattle, in the US, and the University of Queensland in Australia - all took part in the competition.
Results from the £11 million programme will provide insights into fundamental biology as well as helping scientists devise ways to minimise health risks associated with manned missions to Mars.
Laurence Young of MIT said UK universities could get involved, so long as their scientific input could be matched by funding.