science

Luna 20

Luna 20 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 Luna 20 rather than just read about it. In short: Luna 20 was the second of three successful Soviet lunar sample return missions. It was flown as part of the Luna program as a robotic competitor to the six successful Apollo lunar sample return missions.

Key takeaways

Luna 20 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Luna 20 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Luna 20 from memory before moving on to harder problems.

Reference excerpt

Luna 20 was the second of three successful Soviet lunar sample return missions. It was flown as part of the Luna program as a robotic competitor to the six successful Apollo lunar sample return missions. Luna 20 was placed in an intermediate Earth parking orbit and from this orbit was sent towards the Moon. It entered lunar orbit on 18 February 1972. On 21 February 1972, Luna 20 soft landed on the Moon in a mountainous area known as the Terra Apollonius (or Apollonius highlands) near Mare Fecunditatis (Sea of Fertility), 120 km from where Luna 16 had landed. While on the lunar surface, the panoramic television system was operated. Lunar samples were obtained by means of an extendable drilling apparatus. The ascent stage of Luna 20 was launched from the lunar surface on 22 February 1972 carrying 1.9 ounces (55 grams) of collected lunar samples in a sealed capsule. It landed in the Soviet Union on 25 February 1972. The lunar samples were recovered the following day.

Overview

This was the eighth Soviet spacecraft launched with the intent of returning lunar soil to Earth. It was evidently sent to complete the mission that Luna 18 had failed to accomplish. After a 4.5-day flight to the Moon, which included a single midcourse correction on 15 February, Luna 20 entered orbit around the Moon on 18 February. Initial orbital parameters were 100 x 100 kilometers at 65° inclination. Three days later, at 19:13 UT, the spacecraft fired its main engine for 267 seconds to begin descent to the lunar surface. A second firing further reduced velocity before Luna 20 set down safely on the Moon at 19:19 UT on 21 February 1972 at coordinates 3.7863 North and 56.6242 East, only 1.8 kilometers from the crash site of Luna 18. After collecting a small sample of lunar soil, the spacecraft's ascent stage lifted off at 22:58 UT on 22 February and quickly accelerated to 2.7 kilometers per second velocity—sufficient to return to Earth. The small spherical capsule eventually parachuted down safely on an island in the Karkingir River, 40 kilometers north of the town of Jezkazgan in Kazakhstan, at 19:19 UT on 25 February 1972. The 30-gram soil sample differed from that collected by Luna 16 in that the majority (50 to 60%) of the rock particles in the newer sample were ancient lunar highlands anorthosite (which consists largely of feldspar) rather than the basalt of the earlier one (which contained about 1 to 2% of anorthosite). The American Apollo 16 mission returned similar highlands material two months later. Like the Luna 16 soil, samples of the Luna 20 collection were shared with American and French scientists. A 0.4983g sample of material from a depth of 27 and 32 cm was sent to Britain.

In March 2010, NASA reported that its Lunar Reconnaissance Orbiter satellite had spotted Luna 20 on the lunar surface.

Illustrations

Worked examples

Example 1 — a first encounter with Luna 20

Start with the simplest possible case. Write down what Luna 20 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 Luna 20 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 Luna 20 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 Luna 20

In research: Luna 20 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 Luna 20 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: Luna 20 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1972 in the Soviet Union, 1972 on the Moon, Luna programme, so understanding it makes those chapters shorter.
In everyday life: Look for Luna 20 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 Luna 20 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Luna 20 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 Luna 20 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Luna 20 in simple terms?

Why does Luna 20 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 Luna 20?

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 Luna 20.