THE International Space Station (ISS) will have more room for scientists if NASA鈥檚 plans for an 鈥渙rbital space plane鈥� succeed. The spaceplane will act as an escape capsule for the ISS, allowing a bigger crew to be housed aboard the station. But researchers who will need the extra manpower to run their experiments will have to wait until at least 2010 before the craft is ready.
NASA鈥檚 multibillion-dollar cost overruns on the ISS last year forced it to back away from earlier pledges to build a crew return vehicle for the ISS. As a result, the space station鈥檚 crew is currently limited to three, the most the Russian Soyuz capsules used as escape pods can carry.
America鈥檚 partners in the ISS complain that with such a small crew there will be hardly any time for science. And in July, an American review panel bluntly warned that unless the crew is expanded, 鈥淣ASA should cease to characterise ISS as a science-driven programme.鈥�
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The spaceplane was announced last week by NASA chief Sean O鈥橩eefe as part of an 鈥渋ntegrated space transportation plan鈥�. It would hold at least six people, possibly 10, making it possible for scientists to stay on board full-time. Too small to carry heavy freight, it will be launched atop massive new rockets called 鈥渆volved expendable launch vehicles鈥� such as the Delta 4. Like the shuttle, it will fly back to Earth unaided.
Beyond that, details of the plane remain vague. 鈥淚t is just a concept that we are going to sit down and spend the next year designing,鈥� a NASA spokesman told New Scientist.
NASA鈥檚 timetable still poses problems for space station operations. It plans to launch the first full-scale spaceplane in 2010, when an uncrewed rocket will deliver one to the ISS. The spaceplane would start carrying crews up to the station from 2012. But Russia鈥檚 agreement to supply Soyuz capsules for emergency escape expires in 2006. 鈥淣ASA has left the station with a gap of new return vehicles for at least four years,鈥� says Ralph Hall, the senior Democrat on the House Science Committee.
NASA has also pushed back plans for a full-scale shuttle replacement until at least 2015. To bridge the gap, it is planning upgrades to keep its four shuttles flying until then, and perhaps past 2020.
Even so, many doubt that NASA will have any replacement ready before time runs out for the ageing shuttle fleet. Its track record is not encouraging. In the mid-1990s, NASA pinned its hopes on commercial development and a single-stage craft called the X-33. When that programme foundered in 1999, NASA started exploring other launch technologies in the Space Launch Initiative. The latest shift allows the timetable for a 鈥渘ext generation鈥� launcher to slip yet again.