science

LOFTI-1

LOFTI-1 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 LOFTI-1 rather than just read about it. In short: LOFTI-1 was an American satellite which was launched in 1961 and operated by the United States Navy and Naval Research Laboratory. It was used to conduct research into the propagation of very low frequency radio signals in the ionosphere, and to investigate if these signals could be received by submarines.

Key takeaways

LOFTI-1 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect LOFTI-1 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of LOFTI-1 from memory before moving on to harder problems.

Reference excerpt

LOFTI-1 was an American satellite which was launched in 1961 and operated by the United States Navy and Naval Research Laboratory. It was used to conduct research into the propagation of very low frequency radio signals in the ionosphere, and to investigate if these signals could be received by submarines. A 136.17 MHz transmitter was used for this investigation. The launch of LOFTI-1 was conducted at 03:45 UTC on 22 February 1961, using a Thor DM-21 Ablestar rocket flying from Launch Complex 17B at the Cape Canaveral Air Force Station. It was a secondary payload aboard the rocket, with the primary payload being the Transit 3B prototype navigation satellite. The rocket and upper stage used had the serial numbers Thor 313 and Ablestar 007 respectively. The launch resulted in a partial failure, with the spacecraft being placed in a more eccentric orbit than planned, and failing to separate from the upper stage.

LOFTI-1 was a 26-kilogram (57 lb) spacecraft, which was powered by six groups of solar cells charging a nickel-cadmium battery. It ended up in a low Earth orbit with a perigee of 167 kilometres (104 mi), an apogee of 1,002 kilometres (623 mi), and 28.3 degrees of inclination. It had an orbital period of 96.4 minutes. Due to the low perigee of its orbit, LOFTI-1 decayed quickly, and reentered the atmosphere on 30 March 1961, less than 37 days after launch. Despite being in the wrong orbit and operating for less time than had been planned, some useful data was returned from the mission. Together with data returned by later satellites, the data returned by LOFTI-1 proved that very low frequency signals were not suitable for satellite communications with submarines.

Illustrations

Worked examples

Example 1 — a first encounter with LOFTI-1

Start with the simplest possible case. Write down what LOFTI-1 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 LOFTI-1 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 LOFTI-1 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 LOFTI-1

In research: LOFTI-1 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 LOFTI-1 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: LOFTI-1 is common in secondary-school and first-year university syllabi. It links to neighbouring topics American spacecraft stubs, Satellite launch anomalies, Spacecraft launched in 1961, so understanding it makes those chapters shorter.
In everyday life: Look for LOFTI-1 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 LOFTI-1 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what LOFTI-1 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 LOFTI-1 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is LOFTI-1 in simple terms?

Why does LOFTI-1 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 LOFTI-1?

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 LOFTI-1.