The viability of the entire international human space flight enterprise is being undermined by a loss of confidence in Nasa's ability to exercise adequate management and cost discipline

Charles Kennel, advisory council chair

The US space agency's (Nasa) Advisory Council has endorsed the idea of scaling back the project, saying the huge cost overruns - which run into billions of dollars - "cannot be excused and must not be ignored".

The council's recommendations are not binding on Nasa executives, but as the standing body of experts set up to offer guidance to the space agency, its views carry great weight.

Only last month, another report from an independent task force that looked into the ISS project suggested to Nasa ways in which costs could be reduced.

These included lowering the number of people working on the station, the number of shuttle flights to the platform, and a reorganisation of the station management.

'Loss of confidence'

The advisory council suggests the ISS carry no more than three residents at any one time (the number there now but four short of the intended, regular crew size).

It is suggested shuttle visits be cut back

"The viability of the entire international human space flight enterprise is being undermined by a loss of confidence in Nasa's ability to exercise adequate management and cost discipline," the council's chairman, Charles Kennel, wrote in a letter to Nasa.

The council said the agency had failed to make its scientific priorities clear and should do so immediately.

"Given this lack of clarity," Mr Kennel wrote, "it is not surprising that there is little public understanding of why the United States is building" the station.

Uncompromising criticism

The council has issued its opinions after studying the results of the International Space Station Management and Cost Evaluation (IMCE) Task Force.

The IMCE was asked to perform an independent external review of the space station programme.

The panel was uncompromising in its criticism of what it said were serious flaws in the agency's management.

"The existing deficiencies in management structure, institutional culture, cost estimating and programme control must be acknowledged and corrected for the programme to move forward in a credible fashion," it said.

Nasa said it would have no formal comment on the council's findings until the administrator and senior agency management had had an opportunity to do a comprehensive assessment of the advisory council's recommendations.

The final outcome? The biggest project ever undertaken in space