Westar

Key takeaways

Westar belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Westar to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Westar from memory before moving on to harder problems.

Reference excerpt

Westar was a fleet of geosynchronous communications satellites operating in the C band which were launched by Western Union from 1974 to 1984. There were seven Westar satellites in all, with five of them launched and operating under the Westar name.

Background Westar 1 (launched on April 13, 1974) has the distinction of being the USA's first commercially launched geosynchronous communications satellite, following North America's first geosynchronous communications satellite, Canada's Anik A1 in 1972. Westar 1 was put into orbit at 99° W in the Clarke belt (99° W now being the home of Galaxy 16). Westar 2 was launched shortly afterward on October 10, 1974. Westar 3, the first satellite to use TDMA switched data, was launched on August 10, 1979. Westars 1, 2 and 3 were built by Hughes using the HS 333 platform of spin-scan stabilized satellites. They only had 12 transponders on board, as opposed to later C-band communications satellites having 24, and even contemporary satellites of the same era, such as RCA's Satcom 1.

The later Westar 4 (launched on February 26, 1982) and Westar 5 (launched on June 9, 1982) satellites, were based on the Hughes HS-376 platform, and had 24 transponders available, as opposed to the 12 on Westars 1, 2, and 3. Westar 6, also an HS-376 based satellite, was launched from STS-41-B on February 3, 1984, to be put into service afterward, but the perigee kick motor (also known as the Payload Assist Module, or PAM) on the satellite failed during its approach to geosynchronous orbit, placing it at an improper and inoperable low Earth orbit. It was retrieved on November 16, 1984, by the STS-51-A mission of NASA's Space Shuttle, where it was brought back to earth. It was then resold to AsiaSat in Hong Kong, who refurbished it and relaunched it on April 7, 1990 as AsiaSat 1 aboard a Long March 3 rocket. The Space Shuttle mission to retrieve Westar 6, as well as the Palapa B2 satellite which shared the launch payload with Westar 6, was partially funded by the insurance companies led by Lloyd's of London who insured the launch of those two satellites. An on-ground spare satellite to Westar 6, Westar 6S, was in development by Western Union and Hughes when Western Union decided to divest themselves of their telecommunications-based assets starting in the early 1980s after suffering heavy financial losses. This resulted in Western Union selling the Westar satellite fleet and operations to Hughes in 1988. Hughes then finished development of Westar 6S, and renamed it Galaxy 6. Modifications were made to it, and Galaxy 6 was launched on October 12, 1990. Hughes later launched the Galaxy 4 satellite in 1992 and Galaxy 5 in 1993 to replace Westar 4 and 5 respectively, after the latter satellites reached the end of their useful life.

Satellite fleet

Uplink sites for Westar During the life of the Westar fleet, Western Union operated these dedicated uplink sites (now defunct, unless noted) for Westar:

The Yacolt earth station at Yacolt, Washington 45°51′47″N 122°23′44″W (45.8633,-122.3956). (now a satellite uplink site for Verizon Communications) The Sky Valley earth station, located near Cordelia, California 38°09′39″N 122°11′18″W (north of San Francisco) The Steele Valley earth station, near Perris, California 33°45′29″N 117°18′54″W (southeast of Los Angeles, now the location of Lumen Vyvx Teleport Los Angeles) The Kipapa earth station, near Waipio Acres, Hawaii 21°28′13″N 157°58′21″W The Cedar Hill earth station, at Cedar Hill, Texas (near Dallas) (now a satellite teleport station once again, as the headquarters of All Mobile Video's Westar Satellite Services division [1]) The Estill Fork earth station, at Estill Fork, Alabama 34°54′30″N 86°09′46″W The Lake Geneva earth station, at Lake Geneva, Wisconsin 42°37′18″N 88°25′55″W (northwest of Chicago) and the Glenwood earth station at Glenwood, New Jersey 41°12′43″N 74°29′38″W. Glenwood was the head earth station for the Westar fleet, providing TT&C (telemetry, tracking & control) & uplink services. (now the primary uplink site for the SiriusXM satellite radio service)

References

External links Description of the Westar satellites at Boeing Satellite System's (formerly Hughes) web site Gunter's Space Page - information on Westars 1, 2 & 3 Gunter's Space Page information on 4, 5, & 6 Photos of the Westar Sky Valley earth station Map of terrestrial microwave relay sites of Western Union, including satellite uplink sites for Westar at the time

Worked examples

Example 1 — a first encounter with Westar

Start with the simplest possible case. Write down what Westar claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Westar before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Westar ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Westar

In research: Westar appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Westar in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Westar is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1974 establishments in the United States, 1974 in science, 1988 mergers and acquisitions, so understanding it makes those chapters shorter.
In everyday life: Look for Westar outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Westar in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Westar means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Westar out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Westar in simple terms?

Westar was a fleet of geosynchronous communications satellites operating in the C band which were launched by Western Union from 1974 to 1984. There were seven Westar satellites in all, with five of them launched and operating under the Westar name.

Why does Westar matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Westar?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Westar.