astronomy

US-K

US-K 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 US-K rather than just read about it. In short: Upravlyaemy Sputnik Kontinentalny (US-K; Russian: Управляемый Спутник Континентальный meaning Continental Controllable Satellite; Russian: УС-К) is a series of Russian, previously Soviet, satellites used to detect missile launches as part of the Oko system. It consists of a constellation of satellites, usually in molniya orbits, designated under the Kosmos system.

Key takeaways

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

Reference excerpt

Upravlyaemy Sputnik Kontinentalny (US-K; Russian: Управляемый Спутник Континентальный meaning Continental Controllable Satellite; Russian: УС-К) is a series of Russian, previously Soviet, satellites used to detect missile launches as part of the Oko system. It consists of a constellation of satellites, usually in molniya orbits, designated under the Kosmos system. The satellites are built by the company NPO Lavochkin and are launched on Molniya-M rockets. Oko can be directly translated as the Russian word for eye. As of June 2014, only two of the eight satellites in orbit were still functional, rendering the system inoperable.

History US-K are the first generation of Oko satellites, the first of which was launched in 1972. The vast majority of the satellites launched (86 out of 100 as of March 2012 ) have been US-K satellites in molniya orbits. Seven first generation satellites were launched into geosynchronous orbits, called US-KS, starting in 1975. A decree of 3 September 1979 led to the creation of the second generation satellites US-KMO which had their first launch in 1991. In total, 101 satellites have been launched. After the dissolution of the Soviet Union, the rate of launches decreased, but Russia remained committed to the programme. A fully functioning constellation with 5 satellites was restored in 2001, but a fire in May 2001 in the Oko control facility at Serpukhov-15 near Kurilovo outside Moscow reduced the number of operational satellites to 2. A further satellite was launched in the same year. Between 2002 and 2006, there were no Oko launches, until another Oko satellite, designated Kosmos 2422, was launched in July 2006. In 2006, Russia had one operational US-KMO (Kosmos 2379) satellite and four US-K satellites (Kosmos 2422, Kosmos 2393, Kosmos 2351, Kosmos 2368). In June 2011, Kosmos 2422, Kosmos 2430, Kosmos 2446 and Kosmos 2469 were reported to be the only operational satellites.

Satellites The Oko satellites are drum-shaped, 2 metres long and with a diameter of 1.7 m. They weigh 1,250 kilograms without fuel and 2,400 kilograms when fully loaded. They have a 350 kg infrared telescope pointing toward Earth, with a 4 m conical sunshield and an instrument bus. The telescope, which is the satellites' main instrument, is able to detect radiation from ascending missiles. Two solar panels provide a total of 2.8 kW of power. There are also several smaller, wider-angle telescopes to supplement the main instrument. The satellites have 16 liquid fuel engines for attitude control and 4 for maneuvering. The system requires at least 4 satellites to be fully functional. The danger of false alarms increases when there are fewer than 4 satellites in orbit, due to the inability to double-check a detection. However, this risk is reduced by the presence of the US-KMO geosynchronous satellites. The satellites are built by NPO Lavochkin and launched with Molniya-M rockets. The advantages of Oko include that the system is reliable and well-established, and that it uses the relatively inexpensive (but now discontinued) Molniya launcher. The last US-K satellite (Kosmos 2469) was launched on 30 September 2010. As of December 2015, the entire Oko programme is being replaced by the new EKS system.

References

Worked examples

Example 1 — a first encounter with US-K

Start with the simplest possible case. Write down what US-K 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 US-K 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 US-K 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 US-K

In research: US-K 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 US-K 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: US-K is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1973 in spaceflight, Military satellites, Military satellites of Russia, so understanding it makes those chapters shorter.
In everyday life: Look for US-K 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 US-K in 20 minutes

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

Frequently asked questions

What is US-K in simple terms?

Why does US-K 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 US-K?

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 US-K.