ArticleslgStudy

science

USA-239

USA-239 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-239 rather than just read about it. In short: USA-239, also known as GPS IIF-3, GPS SVN-65, and Navstar-67 is an American navigation satellite which forms part of the Global Positioning System. It was the third of twelve Block IIF satellites to be launched.

USA-239 — main illustration
USA-239 — illustration

Key takeaways

  • USA-239 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-239 to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of USA-239 from memory before moving on to harder problems.

Reference excerpt

USA-239, also known as GPS IIF-3, GPS SVN-65, and Navstar-67 is an American navigation satellite which forms part of the Global Positioning System. It was the third of twelve Block IIF satellites to be launched. Built by Boeing and launched by United Launch Alliance, USA-239 was launched at 12:10 UTC on 4 October 2012, atop a Delta IV carrier rocket, flight number D361, flying in the Medium+(4,2) configuration. The launch took place from Space Launch Complex 37B at the Cape Canaveral Air Force Station, and placed USA-239 directly into medium Earth orbit. The rocket's second stage failed to provide the expected full thrust in all of its three burns due to a leak above the narrow throat portion of the thrust chamber, however the stage had enough propellant margins to put the satellite in the correct orbit. As of 15 April 2026, USA-239 was in an orbit with a perigee of 19,717.2 kilometers (12,251.70 mi), an apogee of 20,661.0 kilometers (12,838.15 mi.) a period of 718 minutes, and 53.6 degrees of inclination to the equator. It is used to broadcast the PRN 24 signal, and operates in slot 1 of plane A of the GPS constellation. The satellite has a design life of 15 years and a mass of 1,630 kilograms (3,590 lb). As of 2026 it remains in service.

References

Illustrations

USA-239 illustration

Worked examples

Example 1 — a first encounter with USA-239

Start with the simplest possible case. Write down what USA-239 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-239 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-239 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-239

In research
USA-239 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-239 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-239 is common in secondary-school and first-year university syllabi. It links to neighbouring topics American spacecraft stubs, GPS satellites, Spacecraft launched by Delta IV rockets, so understanding it makes those chapters shorter.
In everyday life
Look for USA-239 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.
Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “USA-239” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study USA-239 in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what USA-239 means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain USA-239 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is USA-239 in simple terms?

USA-239, also known as GPS IIF-3, GPS SVN-65, and Navstar-67 is an American navigation satellite which forms part of the Global Positioning System. It was the third of twelve Block IIF satellites to be launched.

Why does USA-239 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-239?

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-239.

Tags

  • American spacecraft stubs
  • GPS satellites
  • Spacecraft launched by Delta IV rockets
  • Spacecraft launched in 2012
  • USA satellites

Keep exploring