A space mission to service the Hubble telescope 350 miles (570km) above Earth has been postponed after it suffered a breakdown that threatens its future.

Astronauts were to have headed into orbit aboard the shuttle Atlantis on October 14 to capture the giant observatory as it circled the planet at 17,500mph (28,100km/h) and perform five complicated spacewalks to upgrade and service its instruments. But a hardware failure led to the telescope shutting itself down at the weekend, cutting off the flow of spectacular deep-space images that it has beamed back to Earth for 18 years.

The telescope will be switched to its back-up system later this week - a procedure that relies on equipment that has not been turned on since 1990 - but that will be only a stop-gap. Any further problems could mean a permanent shutdown.

Delaying the $1.5 billion (£843m) Atlantis mission while it prepares the necessary replacement part - and the astronauts are trained to fit it - will cost Nasa $10 million a month and will further complicate the space agency’s already tight timetable for completing all shuttle missions before retiring the ageing fleet in 2010.

But managers, who will spend Nasa’s 50th anniversary today brainstorming the challenge, say that the cost of abandoning Hubble would be far greater in terms of lost knowledge. “I don’t see us throwing in the towel all because we’ve got to spend a few more tens of millions,” Preston Burch, the manager of the Hubble programme at the Goddard Space Flight Centre in Maryland, said.

Hubble has undergone four servicing missions in the past, and was at one point revived after being declared defunct. “Hubble has a habit of coming back from adversity - the whole team works miracles. We’ll find a way to get this fixed,” Mr Burch said.

The telescope is one of Nasa’s most successful and enduring projects, peering deeper into space than any other instrument and taking highly detailed snap-shots of distant objects to give mankind an unprecedented window on the universe. Since its launch in 1990 it has helped to unlock numerous space mysteries, such as determining the age of the universe at 13 to 14 billion years, identifying the existence of dark energy and documenting the birth process of new planets and galaxies.

The astronauts will be led by the US Navy fighter pilot Scott Altman, 49, who flew many of the aerial stunts for Tom Cruise in the 1986 film Top Gun.

If Atlantis develops any problems while in orbit she will be flying too high for her crew to seek safety at the International Space Station. Instead, her sister ship, Endeavour, will stand ready on the launchpad at Cape Canaveral, Florida, in case a rescue mission is required.

“This is one of those things that goes with spaceflight,” John Shannon, Nasa’s shuttle programme manager, said. “The astronauts are very stoic. They will be ready.”

Nasa’s Phoenix spacecraft, which landed on Mars in May, has discovered evidence of water in the past at its landing site - and spotted falling snow for the first time. A laser on board the craft recently detected the snow falling from clouds more than two miles above the northern arctic plains, but it disappeared before hitting the ground. “Is this a habitable zone on Mars? I think we're approaching that hypothesis,” said Peter Smith, of the University of Arizona. Nasa has extended the craft’s three-month mission to the end of the year - if Phoenix can survive that long.

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