astronomy

Syncom

Syncom is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Syncom rather than just read about it. In short: Syncom (for "synchronous communication satellite") started as a 1961 NASA program for active geosynchronous communication satellites, all of which were developed and manufactured by the Space and Communications division of Hughes Aircraft Company (now the Boeing Satellite Development Center). Syncom 2, launched in 1963, was the world's first geosynchronous communications satellite.

Key takeaways

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

Reference excerpt

Syncom (for "synchronous communication satellite") started as a 1961 NASA program for active geosynchronous communication satellites, all of which were developed and manufactured by the Space and Communications division of Hughes Aircraft Company (now the Boeing Satellite Development Center). Syncom 2, launched in 1963, was the world's first geosynchronous communications satellite. Syncom 3, launched in 1964, was the world's first geostationary satellite. In the 1980s, the series was continued as Syncom IV with some much larger satellites, also manufactured by Hughes. They were leased to the United States military under the Leasat program.

Syncom 1, 2 and 3

Common features The three early Syncom satellites were experimental spacecraft built by Hughes Aircraft Company's facility in Culver City, California, by a team led by Harold Rosen, Don Williams, and Thomas Hudspeth. All three satellites were cylindrical in shape, with a diameter of about 71 centimetres (28 in) and a height of about 39 centimetres (15 in). Pre-launch fueled masses were 68 kilograms (150 lb), and orbital masses were 39 kilograms (86 lb) with a 25-kilogram (55 lb) payload. They were capable of emitting signals on two transponders at just 2 W. Thus, Syncom satellites were only capable of carrying a single two-way telephone conversation, or 16 Teletype connections. As of 25 June 2009, all three satellites are still in orbit, although no longer functioning.

Syncom 1

Syncom 1 was intended to be the first geosynchronous communications satellite. It was launched on February 14, 1963, with the Delta B #16 launch vehicle from Cape Canaveral, but was lost on the way to geosynchronous orbit due to an electronics failure. Seconds after the apogee kick motor for circularizing the orbit was fired, the spacecraft fell silent. Later telescopic observations verified the satellite was in an orbit with a period of almost 24 hours at a 33° inclination.

Syncom 2 Syncom 2 was launched by NASA on July 26, 1963 with the Delta B #20 launch vehicle from Cape Canaveral. The satellite successfully kept station at the altitude calculated by Herman Potočnik Noordung in the 1920s.

During the first year of Syncom 2 operations, NASA conducted voice, teletype, and facsimile tests, as well as 110 public demonstrations to show the capabilities of this satellite and invite feedback. In August 1963, President John F. Kennedy in Washington, D.C., telephoned Nigerian Prime Minister Abubakar Tafawa Balewa aboard USNS Kingsport (the first satellite communication ship) docked in Lagos Harbor—the first live two-way call between heads of government by satellite. The Kingsport acted as a control station and uplink station. Syncom 2 also relayed a number of test television transmissions from Fort Dix, New Jersey to a ground station in Andover, Maine, beginning on September 29, 1963. Although it was low-quality video with no audio, it was the first successful television transmission through a geosynchronous satellite.

Syncom 3

Syncom 3 was the first geostationary communication satellite, launched on August 19, 1964, with the Delta D #25 launch vehicle from Cape Canaveral. The satellite, in orbit near the International Date Line, had the addition of a wideband channel for television and was used to telecast the 1964 Summer Olympics in Tokyo to the United States. Although Syncom 3 is sometimes credited with the first television program to cross the Pacific Ocean, the Relay 1 satellite first broadcast television from the United States to Japan on November 22, 1963.

Transfer to Department of Defense control By the end of 1964, Syncoms 2 and 3 had completed NASA's R&D experiments. On January 1, 1965, NASA transferred operation of the satellites to the United States Department of Defense (DOD) along with telemetry, command stations, and range and rangefinding equipment. DOD had, in fact, provided the communications ground stations used to relay transmissions via the two Syncoms since their launch. DOD agreed to provide telemetry and ranging data of continuing scientific and engineering interest. In 1965, Syncom 3 was implemented to support the DOD's communications in Vietnam. Turned off in 1969, Syncom 3 remains in geosynchronous orbit as of 2024. In 50 years it has drifted east, to longitude 123 W.

Syncom IV (Leasat)

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Syncom

Start with the simplest possible case. Write down what Syncom 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 Syncom 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 Syncom 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 Syncom

In research: Syncom 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 Syncom 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: Syncom is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1961 establishments in the United States, 1963 in spaceflight, Communications satellites, so understanding it makes those chapters shorter.
In everyday life: Look for Syncom 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.

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How to study Syncom in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Syncom 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 Syncom out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Syncom in simple terms?

Why does Syncom 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 Syncom?

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 Syncom.