Craft for Retrieving Satellites : TRW Gets Contract for Shuttle’s ‘Space Tug’

A “space tug” that could fly from the space shuttle and retrieve nearby satellites will be built by TRW Inc. of Redondo Beach, the National Aeronautics and Space Administration has announced.

Officially described as an “orbital maneuvering vehicle,” the remote-controlled tug will be able to zip around in low Earth orbit to perform a wide range of chores and is to become a component of the United States’ planned permanent orbiting space station.

The tug will extend the reach of the shuttle from its normal orbit altitude of about 300 miles to about 1,400 miles above the Earth, and it will be designed to be either carried aboard the shuttle or left in space and refueled when necessary. It will be remotely controlled from the ground, thus giving the agency the ability to do some things--like pushing satellites from one orbit altitude to another--when the shuttle isn’t around.

The contract is for design, production and testing of one tug, with an option for a second. The cost will be negotiated, but both NASA and TRW estimated it at about $200 million. TRW’s design was selected over two other bidders, LTV Aerospace & Defense Co. of Dallas, and Martin Marietta Corp. of Denver.

Hopes for Fleet of Tugs

Eventually, NASA hopes to have a fleet of space tugs that could venture as far as 23,000 miles from the Earth to pick up communications satellites in stationary orbits, but this early version will be restricted to lower operations. However, many satellites, including most Earth observation satellites, are on orbits that are within the operational range of the tug.

As satellites travel around the Earth their orbits degrade, allowing them to slip closer to the ground. The tug, according to NASA, could simply push the satellites back up to their correct orbits.

According to Allan M. Frew, TRW program manager, the tug will be of modular construction, and “propulsion modules of varying sizes” can be attached to meet different needs.

Greater range could be achieved, he said, “by simply adding larger fuel tanks.”

The propulsion modules can be fueled on the ground and carried to the tug by the shuttle and “simply plugged in,” Frew said.

Space tugs are viewed by NASA as essential components of the proposed space station, which would be in permanent orbit and could not retrieve even nearby objects. That would be the task of tugs that could be sent out to capture satellites and bring them back for servicing.