science

USA-235

USA-235 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 USA-235 rather than just read about it. In short: USA-235, also known as Advanced Extremely High Frequency 2 or AEHF-2, is a military communications satellite operated by the United States Air Force. It is the second of six satellite to be launched as part of the Advanced Extremely High Frequency program, which replaced the earlier Milstar system.

Key takeaways

USA-235 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect USA-235 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of USA-235 from memory before moving on to harder problems.

Reference excerpt

USA-235, also known as Advanced Extremely High Frequency 2 or AEHF-2, is a military communications satellite operated by the United States Air Force. It is the second of six satellite to be launched as part of the Advanced Extremely High Frequency program, which replaced the earlier Milstar system.

Satellite description The USA-235 satellite was constructed by Lockheed Martin Space, and is based on the A2100 satellite bus. The satellite has a mass of 6,168 kg (13,598 lb) and a design life of 14 years. It will be used to provide super high frequency (SHF) and extremely high frequency (EHF) communications for the United States Armed Forces, as well as those of the United Kingdom, the Netherlands, and Canada.

Launch USA-235 was launched by United Launch Alliance, aboard an Atlas V 531 flying from Space Launch Complex 41 (SLC-41) at the Cape Canaveral Air Force Station (CCAFS). The launch occurred at 18:24 UTC on 4 May 2012, first placing the satellite in a parking orbit of 185 kilometers by 905 kilometers. A second burn placed the satellite into a geostationary transfer orbit (GTO) with a perigee of 225 km (140 mi), an apogee of 50,031 km (31,088 mi), and 20.6° inclination. The satellite was successfully deployed in this orbit 51 minutes after launch.

Illustrations

Worked examples

Example 1 — a first encounter with USA-235

Start with the simplest possible case. Write down what USA-235 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 USA-235 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 USA-235 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 USA-235

In research: USA-235 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 USA-235 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: USA-235 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Communications satellites of the United States, Military communications, so understanding it makes those chapters shorter.
In everyday life: Look for USA-235 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 USA-235 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what USA-235 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 USA-235 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is USA-235 in simple terms?

Why does USA-235 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 USA-235?

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 USA-235.