engineering

PrOP-M

PrOP-M is a engineering 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 PrOP-M rather than just read about it. In short: PrOP-M (Russian: Прибор оценки проходимости — Марс (ПрОП-М), Passability Estimating Vehicle for Mars or Device Evaluation Terrain—Mars) were two Soviet Mars rovers that were launched on the unsuccessful Mars 2 and Mars 3 missions in 1971. PrOP-M were the first rovers to be launched to Mars, 26 years before the first successful rover mission of NASA's Sojourner in 1997.

Key takeaways

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

Reference excerpt

PrOP-M (Russian: Прибор оценки проходимости — Марс (ПрОП-М), Passability Estimating Vehicle for Mars or Device Evaluation Terrain—Mars) were two Soviet Mars rovers that were launched on the unsuccessful Mars 2 and Mars 3 missions in 1971. PrOP-M were the first rovers to be launched to Mars, 26 years before the first successful rover mission of NASA's Sojourner in 1997. Because the Mars 2 and Mars 3 missions failed, the existence of the rovers was kept secret for nearly 20 years. The rovers, built by a team led by Alexander Kemurdzhian, were small, rectangular devices that were tethered to the lander and used skis for movement.

History

The PrOP-M rover was designed and manufactured at the Mobile Vehicle Engineering Institute (VNIITransmash) by a team of approximately 150 engineers led by Alexander Kemurdzhian, who also developed the Lunokhod rover. The Mars 2 and Mars 3 landers each carried a PrOP-M rover, designed to move across the Martian surface on skis while connected to the lander with a 15-meter (49 ft)-long power cable. Two small metal rods were used for autonomous obstacle avoidance because radio signals from Earth would have taken too long to drive the rovers using remote control. Each rover carried a dynamic penetrometer (made by Transmash) and a gamma-ray densitometer (made by the Institute of Geochemistry of the Soviet Academy of Sciences). After landing, the rovers were planned to be placed on the Martian surface by a 6-joint manipulator arm and to move in the field of view of the lander's cameras. They would have stopped to make measurements every 1.5 m (4.9 ft), with maximum range of 15 m (49 ft)—the length of the tether. The rovers' tracks in the Martian soil would have been used to determine the soil's material properties. The rovers' main chassis was a 4.5-kilogram (9.9 lb) square box with a small protrusion at the center. Sources differ on the dimensions of the rover. The frame was supported on two wide, flat skis, one extending from each side, elevating the frame slightly above the surface. At the front of the box were obstacle detection bars. Rover's maximum speed was up to 1 meter per hour. PrOP-M was the only rover that used skis for locomotion, all other rovers used wheels. The rover had an algorithm to overcome obstacles: when it approached one, it was programmed to reverse and "use the skids on alternate sides to walk around the obstacle". The first rover was destroyed in the November 27, 1971 crash landing of Mars 2, launched May 19, 1971. The second one was launched on May 28, 1971 on Mars 3 and was lost when the lander stopped communicating 110 seconds after landing on December 2, 1971. The loss of communication may have been due to the extremely powerful Martian dust storm taking place at the time or a problem with the Mars 3 orbiter's ability to relay communications. The second rover was never deployed. The rover missions were secret and were not mentioned in official news reports about the landings; their existence was revealed almost 20 years later in 1990. The PrOP-M rovers preceded NASA's 1997 Sojourner by 26 years. Authors of the Planetary Landers and Entry Probes wrote that Mars 6 and Mars 7 also carried PrOP-M rovers. A model of the rover can now be seen in the Memorial Museum of Cosmonautics in Moscow, another is in the Museum of Space and Missile Technology in Saint Petersburg.

Notes

References

External links Soviet films about Mars exploration, featuring PrOP-M rover Mars 2 and Mars 3 From Moonrover to Marsrover Found 42 years later: How Leningrad scientists created the world's first rover. (Russian: Нашли спустя 42 года: Как ленинградские ученые первый в мире марсоход создавали.)

Illustrations

PrOP-M: Rover moving during a field testing — Rover moving during a field testing

Worked examples

Example 1 — a first encounter with PrOP-M

Start with the simplest possible case. Write down what PrOP-M claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, 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 PrOP-M 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 PrOP-M 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 PrOP-M

In research: PrOP-M appears in engineering 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 PrOP-M 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: PrOP-M is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1971 on Mars, Mars rovers, Robots of the Soviet Union, so understanding it makes those chapters shorter.
In everyday life: Look for PrOP-M 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 PrOP-M in 20 minutes

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

Frequently asked questions

What is PrOP-M in simple terms?

Why does PrOP-M matter?

Because it connects several engineering 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 PrOP-M?

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 PrOP-M.