science

Progress 4

Progress 4 is a science 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 Progress 4 rather than just read about it. In short: Progress 4 (Russian: Прогресс 4), was a Progress cargo spacecraft launched by the Soviet Union in 1978 to resupply the Salyut 6 space station. It used the Progress 7K-TG configuration and was the fourth Progress mission to Salyut 6.

Key takeaways

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

Reference excerpt

Progress 4 (Russian: Прогресс 4), was a Progress cargo spacecraft launched by the Soviet Union in 1978 to resupply the Salyut 6 space station. It used the Progress 7K-TG configuration and was the fourth Progress mission to Salyut 6. It carried supplies aboard Salyut 6, as well as equipment for conducting scientific research, and fuel for adjusting the station's orbit and performing manoeuvres.

Spacecraft Progress 4 was a Progress 7K-TG spacecraft. The fourth of forty three to be launched, it had the serial number 105. The Progress 7K-TG spacecraft was the first generation Progress, derived from the Soyuz 7K-T and intended for uncrewed logistics missions to space stations in support of the Salyut programme. On some missions the spacecraft were also used to adjust the orbit of the space station. The Progress spacecraft had a dry mass of 6,520 kilograms (14,370 lb), which increased to around 7,020 kilograms (15,480 lb) when fully fuelled. It measured 7.48 metres (24.5 ft) in length, and 2.72 metres (8 ft 11 in) in diameter. Each spacecraft could accommodate up to 2,500 kilograms (5,500 lb) of payload, consisting of dry cargo and propellant. The spacecraft were powered by chemical batteries, and could operate in free flight for up to three days, remaining docked to the station for up to thirty.

Launch Progress 4 launched on 3 October 1978 at 23:09:30 UTC (4 October at 4:09 a.m. local time) from the Baikonur Cosmodrome in the Kazakh Soviet Socialist Republic. It used a Soyuz-U rocket.

Docking Progress 4 docked with Salyut 6 on 6 October 1978 at 01:00:15 UTC.

Decay It remained in orbit until 26 October 1978, when it was deorbited. The deorbit burn occurred at 16:28 UTC.

Illustrations

Worked examples

Example 1 — a first encounter with Progress 4

Start with the simplest possible case. Write down what Progress 4 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Progress 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 Progress 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 Progress 4

In research: Progress 4 appears in science 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 Progress 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: Progress 4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1978 in the Soviet Union, Progress (spacecraft) missions, Spacecraft launched by Soyuz-U rockets, so understanding it makes those chapters shorter.
In everyday life: Look for Progress 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 Progress 4 in 20 minutes

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

Frequently asked questions

What is Progress 4 in simple terms?

Why does Progress 4 matter?

Because it connects several science 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 Progress 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 Progress 4.