US satellite repair robot faces orbital field test

CAPE CANAVERAL, Fla, Mar 9 (Reuters) A prototype satellite repair robot that can refuel, upgrade and repair satellites is slated to begin a three-month orbital field test after its launch from Florida.

The two-satellite system, called Orbital Express, was developed by the U.S. military in cooperation with NASA to extend the lives of spy satellites and lay the groundwork for servicing and repair of government-owned spacecraft and telescopes after the space shuttle fleet is retired.

Launch is scheduled between 9:37 and 11:42 pm EST (0807 IST and 1012 IST) from the Cape Canaveral Air Force Station.

''What we're really trying to do with Orbital Express is to change the paradigm of how we operate in space,'' said programme manager Fred Kennedy, with the Defense Advanced Research Projects Agency, or DARPA.

With few exceptions, such as the Hubble Space Telescope, which was designed for in-flight servicing by space shuttle crews, spacecraft need to have everything aboard at the time they are launched. Once a key component breaks down, or when maneuvering fuel runs out, the satellites are dead.

Officials hope the repair robot will be able to refuel a satellite, replace faulty components and install equipment upgrades.

The two satellites which comprise Orbital Express are among six experimental spacecraft being carried into orbit aboard an unmanned Atlas 5 rocket.

The US Air Force bought the launch service from Atlas manufacturer Lockheed Martin Corp., which in December began sales of its boosters along with Boeing Co.'s Delta rockets through a Denver-based joint-venture called United Launch Alliance.

FIELD TESTS IN SPACE Once in space, Orbital Express will go through a week-long systems test period ahead of demonstrations expected to last at least three months.

The servicing craft, called ASTRO -- an acronym for Autonomous Space Transport Robotic Operations -- is filled with about 300 pounds of hydrazine propellant and includes a small robotic arm to latch onto or pass equipment to its partner spacecraft, known as NextSat.

The first tests involve fuel transfers and will take place while the two vehicles are attached to each other. After that, ASTRO will sep rate from NextSat.

Among the tasks the Orbital Express will attempt during the mission are transferring and hooking up a 53-pound battery, switching between a primary and backup computer and testing rendezvous and capture techniques.

''We're trying out brand new technology,'' said Carol Welsch, a U.S. Air Force officer who helped put together the Orbital Express.

''Quite honestly, some of these are very challenging technologies and they may not work.'' Boeing is the prime contractor for the mission, which cost about 300 million dollar. Partners include Ball Corp, Northrop Grumman Corp., Draper Laboratory of Cambridge, Massachusetts and Canada-based MacDonald, Dettwiler and Associates.

REUTERS DKS PM0430