astronomy

PAS-4

PAS-4 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 PAS-4 rather than just read about it. In short: PAS 4, was an American geostationary satellite that was launched by an Ariane 4. Satellite description PAS-4 was constructed by Hughes Aircraft Corporation, based on the HS-601 satellite bus.

Key takeaways

PAS-4 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect PAS-4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PAS-4 from memory before moving on to harder problems.

Reference excerpt

PAS 4, was an American geostationary satellite that was launched by an Ariane 4.

Satellite description PAS-4 was constructed by Hughes Aircraft Corporation, based on the HS-601 satellite bus. It had a mass at launch of 2,920 kg (6,440 lb), which decreased to around 1,727 kg (3,807 lb) by the time it was operational. Designed for an operational life of 15 years, the spacecraft was equipped with 20 C-band and 30 Ku-band transponders. Its two solar panels, which had a span of 26 m (85 ft) generated 4.7 kW of power when the spacecraft first entered service, which was expected to drop to around 4.3 kW by the end of the vehicle's operational life.

Launch Arianespace launched PAS-4, using an Ariane 4 launch vehicle, flight number V76, in the Ariane 42L H10-3 configuration. The launch took place from ELA-2 at the Centre Spatial Guyanais, at Kourou in French Guiana, on 3 August 1995, at 22:58:00 UTC.

References

Worked examples

Example 1 — a first encounter with PAS-4

Start with the simplest possible case. Write down what PAS-4 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 PAS-4 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 PAS-4 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 PAS-4

In research: PAS-4 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 PAS-4 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: PAS-4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1995 in spaceflight, American spacecraft stubs, Communications satellites in geostationary orbit, so understanding it makes those chapters shorter.
In everyday life: Look for PAS-4 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 PAS-4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PAS-4 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 PAS-4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PAS-4 in simple terms?

PAS 4, was an American geostationary satellite that was launched by an Ariane 4. Satellite description PAS-4 was constructed by Hughes Aircraft Corporation, based on the HS-601 satellite bus.

Why does PAS-4 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 PAS-4?

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 PAS-4.