Printer Friendly

Discovery; TDRS and other plans.

Discovery: TDRS and other plans

The major mission activity in the upcoming flight of Discovery, representing the shuttle program's return to life 32 months after the Challenger disaster, continues a satellite project that never did get off on the right foot.

It was in the early 1970s that NASA first began planning the use of a network of satellites to replace the ground stations with which it tracks spacecraft and relays their data. "The hope was to greatly increase the amount of time for which satellites -- including the then-untried shuttle itself -- could communicate with the ground. The first Tracking and Data-Relay Satellite (TDRS-1) was launched on April 4, 1983 (Challenger's maiden flight). But trouble with its booster rocket left it in too low an orbit, which required nearly three months of gradual nudges to correct. The second TDRS was destroyed in 1986 with Challenger itself.

The latest TDRS is the heaviest item in Discovery's payload, weighing more than 2 tons, plus 16 tons for its booster. TDRS-1 is now relaying data for the Solar Maximum Mission satellite, the Solar Mesosphere Explorer, the Earth Radiation Budget Satellite and Landsats 4 and 5. NASA plans to phase out many of its ground stations, but the TDRS system must first consist of two operational satellites plus a third in orbit as a spare. The third is tentatively scheduled for launch early next year, to be followed later by one to replace the now-aging TDRS-1.

Besides deploying the new TDRS, Discovery's astronauts are to conduct microgravity experiments in materials processing and life sciences, as well as observing lightning and other phenomena below. They also plan to test a system of secure on-board communications using infrared devices like television remote-control units, which produce no radio transmissions that can be picked up outside the shuttle.
COPYRIGHT 1988 Science Service, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1988, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Tracking and Data-Relay Satellite
Author:Eberhart, Jonathan
Publication:Science News
Date:Sep 24, 1988
Words:299
Previous Article:The complexity of computer security.
Next Article:Opening delayed for nuclear waste site.
Topics:


Related Articles
The shuttle and the satellite: the great flyswatter caper.
Shuttle loss sets back space program.
NASA sets shuttle launch date, schedule.
Radio interferometry steps off the earth.
NASA plans other baskets for its eggs.
Whale tracking is all up in the air.
Spacebound again: the mixing of the fleet; NASA's launch plans for 1988 and beyond represent more than just the shuttles' return.
An act of Discovery: on the road again.
Space telescope: a saga of setbacks.

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters