science

Soyuz T-4

Soyuz T-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 Soyuz T-4 rather than just read about it. In short: Soyuz T-4 was a Soviet space mission which launched the crew of Salyut 6 EO-6, the sixth and final long-duration crew of the Salyut 6 space station. It was launched on 12 March 1981 and docked with the station the next day.

Key takeaways

Soyuz T-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 Soyuz T-4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Soyuz T-4 from memory before moving on to harder problems.

Reference excerpt

Soyuz T-4 was a Soviet space mission which launched the crew of Salyut 6 EO-6, the sixth and final long-duration crew of the Salyut 6 space station. It was launched on 12 March 1981 and docked with the station the next day. During their stay, the EO-6 crew was visited by Soyuz 39 and Soyuz 40. Soyuz T-4 returned to Earth on 26 May 1981; its crew were the last to have inhabited Salyut 6.

Crew

Backup crew

Mission parameters Mass: 6850 kg Perigee: 201 km Apogee: 250 km Inclination: 51.6° Period: 88.7 minutes

Mission highlights The docking with Salyut 6 was delayed after the Soyuz's onboard Argon computer determined it would occur outside radio range with the TsUP. Despite this, the docking occurred successfully on 13 March 1981. The Progress 12 spacecraft was already docked to the station by the time the crew arrived, and they spent several days unloading the Progress before its undocking on 19 March. This freed the remaining docking port for the arrival of the Soyuz 39/EP-9 crew on 22 March. In mid-May, Kovalyonok and Savinykh replaced the spacecraft's probe with a Salyut drogue. This may have been an experiment to see if a Soyuz-T docked to a space station could act as a rescue vehicle in the event that an approaching Soyuz-T equipped with a probe experienced docking difficulties and could not return to Earth. The EO-6 crew undocked from Salyut 6 on 26 May, leaving behind the Soyuz's orbital module. Soyuz T-4 landed over three hours later, touching down 125 kilometres (78 mi) east of Dzhezkazgan, Kazakh SSR.

Worked examples

Example 1 — a first encounter with Soyuz T-4

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

In research: Soyuz T-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 Soyuz T-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: Soyuz T-4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1981 in the Soviet Union, Crewed Soyuz missions, Human spaceflights to Salyut space stations, so understanding it makes those chapters shorter.
In everyday life: Look for Soyuz T-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 Soyuz T-4 in 20 minutes

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

Frequently asked questions

What is Soyuz T-4 in simple terms?

Why does Soyuz T-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 Soyuz T-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 Soyuz T-4.