He has asked the Defence Secretary, William Cohen, to supply him with an interim report in 90 days and a final report in six months on the causes and "actions required to ensure our future access to space."

Cohen will co-ordinate his investigation with CIA director, George Tenet, and Nasa chief, Dan Goldin.

Over the past nine months, six launch vehicles have either exploded on lift-off or delivered their expensive satellites into useless orbits.

'Corrective action'

The losses generated by the failures have totalled about $3.5bn. This represents nearly $3bn in lost government flight hardware, and more than $500 million in lost commercial satellites and rockets.

"It is vitally important that we fully understand the root causes behind the recent launch vehicle failures and take corrective action," Clinton said in a memo to Cohen.

Three of the failures involved military payloads carried on heavy-lift Titan IV rockets. Titan is the largest rocket in the US space programme.

Russian cruise missiles are now launching satellites

The other three failures were commercial payloads on small Delta III and Athena vehicles.

Putting satellites into orbit has become a highly competitive international business and the Americans need to sort out the problems very quickly.

The Russians have even started a payload delivery system based on their intercontinental ballistic missiles, due to be decommissioned under the Start nuclear disarmament treaty.

Hail damage

There is better news for Nasa on the next scheduled flight to the International Space Station (ISS). The launch of the space shuttle Discovery had been delayed for repairs to the vehicle's external fuel tank, which was damaged in a hail storm last week.

Nasa feared bad weather would further delay the launch but an improved forecast has allowed shuttle managers to set May 27 as the new launch date.