engineering

Space blanket

Space blanket 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 Space blanket rather than just read about it. In short: A space blanket is an especially low-weight, low-bulk blanket made of heat-reflective thin plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people.

Key takeaways

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

Reference excerpt

A space blanket is an especially low-weight, low-bulk blanket made of heat-reflective thin plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur quickly due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in first aid kits and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised distress beacon for searchers and as a method of signalling over long distances to other people.

Name Space blankets are also known by the names of Mylar blanket, emergency blanket, first aid blanket, safety blanket, thermal blanket, weather blanket, heat sheet, foil blanket, or shock blanket.

Manufacturing

First developed by NASA's Marshall Space Flight Center in 1964 for the US space program, the material comprises a thin sheet of plastic (often PET film) that is coated with a metallic, reflecting agent, making it metallized polyethylene terephthalate (MPET) that is usually gold or silver in color, which reflects up to 97% of radiated heat. For use in space, polyimide (e.g. Kapton, UPILEX) substrate is usually chosen due to its resistance to the hostile space environment, large temperature range (cryogenic to −260 °C and for short excursions over 480 °C), low outgassing (making it suitable for vacuum use), and resistance to ultraviolet radiation. Aluminized Kapton, with foil thickness of 50 and 125 μm, was used on the Apollo Lunar Module. The polyimide gives the foils their distinctive amber-gold color. Space blankets are made by vacuum-depositing a very precise amount of pure aluminum vapor onto a very thin, durable film substrate.

Usage In their principal usage, space blankets are included in many emergency, first aid, and survival kits because they are usually waterproof and windproof. That, along with their low weight and ability to pack into a small space, has made them popular among outdoor enthusiasts and emergency workers. Space blankets are often given to marathoners and other endurance athletes at the end of races, or while waiting before races if the weather is chilly. The material may be used in conjunction with conductive insulation material and may be formed into a bag for use as a bivouac sack (survival bag). In first aid, the blankets are used to prevent or counter hypothermia. A threefold action facilitates this:

The airtight foil reduces convection Heat loss caused by evaporation of perspiration is reduced The reflective surface inhibits losses caused by thermal radiation In a hot environment, they can be used to provide shade or protection against radiated heat, but using them to wrap a person would be counterproductive, because body heat would get trapped by the airtight foil. This effect would exceed any benefit gained from heat reflection to the outside. Wearing a space blanket produces an insignificantly slower cooling rate after running in hot, humid conditions. Space blankets are used to reduce heat loss from a person's body, but as they are constructed of PET film, they can be used for other applications for which this material is useful, such as insulating containers (e.g. DIY solar concentrators) and other applications. In addition to the space blanket, the United States military also uses a similar blanket called the "casualty blanket". It uses a thermal reflective layer similar to the space blanket, backed by an olive drab-colored, reinforcing, outer layer. It provides greater durability and warmth than a basic space blanket at the cost of greater bulk and weight. It is also used as a partial liner inside the layers of bivouac sacks in very cold weather climates. Space blankets were also used by the Taliban to hide their heat signature from NATO forces.

See also Emergency shelter Emissivity R-value (insulation) Radiant barrier Reflectivity Thermal insulation Thermoregulation Thin-film deposition

References

External links Media related to Space blankets at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Space blanket

Start with the simplest possible case. Write down what Space blanket 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 Space blanket 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 Space blanket 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 Space blanket

In research: Space blanket 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 Space blanket 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: Space blanket is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1964 introductions, American inventions, Blankets, so understanding it makes those chapters shorter.
In everyday life: Look for Space blanket 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 Space blanket in 20 minutes

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

Frequently asked questions

What is Space blanket in simple terms?

Why does Space blanket 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 Space blanket?

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 Space blanket.