NASA has admitted to a further $800 million increase in the International Space Station (ISS) budget overrun, which is now estimated to be $4.8 billion.

The agency concedes that some international partners may drop out of the project and that replacement parts for the ISS may be required earlier than anticipated, which could further increase the overspend to $5.4 billion.

Cost-cutting measures already in place have meant the ISS will have no US habitation or propulsion modules, a crew of three instead of six, no crew rescue vehicle and a 40% reduction in science.

The extra spending has been attributed to underestimating the original costs, new work on life support systems, extra manpower for ground support and repairs.

Funding hope has come from the US House of Representatives Appropriations Committee, however, which is proposing an additional $415 million to NASA's 2002 budget, including $275 million to restore the ISS Crew Return Vehicle. The request is an early step in the budget process and there is no guarantee it will be approved.

It has also been revealed that NASA did not comply with acquisition procedures to develop the original US Propulsion Module, according to the agency's Office of Inspector General (OIG). Requirements were not validated before a design review and, consequently, $97 million was wasted before the design was rejected. The OIG also says that NASA did not justify its selection of Boeing as sole-source contractor for the module.

The NASA Advisory Council has also criticised the agency's decision to cut 40% of the science to be conducted aboard the ISS in an effort to counteract the budget overrun. The decision is "totally unrealistic and undermines the primary rationale for the ISS in the first place", says the council.

Meanwhile, NASA has notified its main Space Shuttle programme contractors - United Space Alliance, Boeing, Lockheed Martin and Thiokol - to develop plans to cope with possible budget reductions of up to $300 million per year from 2003 to 2007.

Source: Flight International