Washington

Up in the air: limiting the ISS's crew to three would leave onboard science struggling for resources. Credit: NASA

The scaled-down International Space Station (ISS) currently proposed by NASA — with only three astronauts on board and very limited resources — would be able to do very little high-priority science, according to a review of research planned for it.

If the curtailed design is not enhanced, “NASA should cease to characterize the ISS as a science-driven programme”, charges the Research Maximization and Prioritization (REMAP) task force, which presented the outcome of its four-month assessment to NASA's Advisory Council on 10 July.

Startled members of the council warned that the assessment could lead to the abandonment of the lumbering, 18-year-old project. “If I were in the White House,” says council member Tom Young, a retired aerospace executive, “I would take this as a recommendation to terminate the existing space station.”

But most political observers say that it is too late for that, and that some version of the station will be completed. The White House budget office last year ordered NASA to plan for a three-member station crew, instead of a more capable six- or seven-person version, unless it can manage the project — currently at least $5 billion over budget — more tightly (see Nature 410, 399; 200110.1038/35068684). The decision drew protests from scientists and from the station's international partners, including the European and Japanese space agencies.

Commissioned by NASA and chaired by Columbia University biopsychologist Rae Silver, REMAP was asked to set research priorities for the agency's Office of Biological and Physical Research (OBPR), which sponsors most of the station's planned experiments.

Surveying the broad portfolio of physics and biology research sponsored by the OBPR, the 20 members of REMAP gave “highest priority” ranking to more than a dozen subdisciplines, including studies of radiation health, crew behaviour and advanced life support. These were deemed either to have intrinsic scientific merit or to offer help for enabling future human space travel. Lower priority was given to experiments in protein-crystal growth, which have been criticized by other review groups (see Nature 404, 114; 200010.1038/35004728).

After determining the rankings, REMAP worked with the OBPR on an implementation plan — with discouraging results. By NASA's own estimates, a three-person crew could handle only a small fraction of the 'high-priority' research. Key resources, such as electrically powered 'lockers' for experiments, would be in critically short supply. Limiting the space shuttle to four flights a year, which has been proposed as a money-saving move, would leave almost no room for science equipment on station resupply missions. And two key pieces of lab hardware — a centrifuge for varying g-forces, and a holding facility for animals and plants — are in danger of being delayed or scrapped.

This has led REMAP to conclude that the scaled-down station would not be the lab that NASA originally envisioned. Some high-priority science could still be done on board, Silver says, but the station could no longer count research as its primary function.

Former astronaut and US senator John Glenn, a member of the advisory council, says he is worried that the report will “be used as material to kill the whole programme”.

But Silver is hopeful that policy-makers will respond to the assessment by improving the specification of the station so that it can be used for valuable science. She says she is encouraged by the fact that NASA's administrator, Sean O'Keefe, has repeatedly encouraged her task force to identify the best science that could potentially be done on board the station, without worrying about the constraints that the scaled-down design would impose.