Nasa satellite struggles in space

An artist's impression of how the satellite should look

By Dr David Whitehouse BBC News Online science editor

One of the most sophisticated satellites launched into space has floundered on its way to its designated orbit.

We detected a problem with the supply of propellant from one of the satellite's four tanks

Boeing spokesman

Engineers are struggling to rescue the data relay station called TDRS-I (Tracking and Data Relay Satellite), which is one of three such satellites built in a $825m project led by the US aerospace giant Boeing.

TDRS-I was launched into space on 8 March by an Atlas rocket from Cape Canaveral in Florida.

Having reached its first orbit successfully, it was to have spent two weeks being raised to a higher altitude that would keep it in the same position above the Earth's equator. But a malfunction in one of the satellite's four fuel tanks has now put that in jeopardy.

At the moment, it is uncertain whether the satellite can be saved.

'Switchboard' in the sky

TDRS-I is one of the most sophisticated and powerful satellites put into space. It was to have acted as a "switchboard" in the sky, communicating with the space shuttle, the International Space Station, the Hubble Space Telescope and other satellites.

The satellite is crucial for Nasa's space communications

Its twin, 15-feet unfoldable antennae are capable of transferring information to and from the Earth 5,000 times faster than an average modem.

The satellite can also receive signals from five other spacecraft and transmit to one of them.

TDRS-I is one of three second-generation data relay satellites. The original set was launched from the space shuttle in the 1980's, although one was destroyed in the 1986 Challenger accident.

Possible options

Because the original series was getting old, the US space agency (Nasa) ordered three higher-performance replacements.

The first of these was launched in 2000 and the final one was set to go up at the end of this year.

A spokesman for Boeing told BBC News Online: "We detected a problem with the supply of propellant from one of the satellite's four tanks. Nasa was immediately informed."

Under the terms of the contract, Nasa does not accept delivery of the satellite until it is in its final orbit. If it gets there, Nasa will redesignate it TDRS-9.