astronomy

Orbital Test Satellite

Orbital Test Satellite is a astronomy 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 Orbital Test Satellite rather than just read about it. In short: The Orbital Test Satellite (OTS) programme was an experimental satellite system inherited by the European Space Agency (ESA) in 1975 from its predecessor, the European Space Research Organisation (ESRO). OTS was the first three-axis-stabilised Ku-band satellite, and its design has inspired the conception of almost 30 other satellites in Europe.

Key takeaways

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

Reference excerpt

The Orbital Test Satellite (OTS) programme was an experimental satellite system inherited by the European Space Agency (ESA) in 1975 from its predecessor, the European Space Research Organisation (ESRO). OTS was the first three-axis-stabilised Ku-band satellite, and its design has inspired the conception of almost 30 other satellites in Europe. Its successors, the Maritime European Communications Satellite (MARECS) and European Communications Satellite (ECS) series of satellites, consolidated Europe's position in communications satellite technology and manufacturing.

OTS 1 The first of the pair of OTS satellites, OTS 1, was launched on 13 September 1977 at 11:31 pm UTC at the Cape Canaveral Space Launch Complex 17. However, it was destroyed 54 seconds later due to its United States Delta launcher exploding. The failure was caused by a horizontal crack in the solid propellent core of one of the strap-on boosters, which caused the core gases to burn through the casing and ignite the fuel in the main tank of the launcher. The debris of the satellite landed in the Atlantic Ocean.

OTS 2 OTS 2 was successfully launched on 11 May 1978 at 10:59 pm UTC at the same launch complex as OTS 1, using the same Delta launch vehicle. It became one of the first geostationary communications satellites to carry six Ku-band transponders and was capable of handling 7,200 telephone circuits. With a mass of approximately 865 kg (1,907 lb), the OTS satellite bus was hexagonal with overall dimensions of 2.4 by 2.1 x 1.7 m. Two solar panels with a span of 9.3 m provided 600 watts of electrical power. British Aerospace was the prime contractor from the European MESH consortium which developed the satellite. It completed its primary mission in 1984 after which the spacecraft was involved in a 6-year program of experiments, including the testing of a new attitude control technique taking advantage of solar radiation pressure forces. In January 1991, OTS 2 was moved out of the geostationary ring and into a graveyard orbit.

References

Illustrations

Worked examples

Example 1 — a first encounter with Orbital Test Satellite

Start with the simplest possible case. Write down what Orbital Test Satellite claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, 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 Orbital Test Satellite 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 Orbital Test Satellite 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 Orbital Test Satellite

In research: Orbital Test Satellite appears in astronomy 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 Orbital Test Satellite 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: Orbital Test Satellite is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1977 in Florida, 1978 in Florida, Communications satellites of the European Space Agency, so understanding it makes those chapters shorter.
In everyday life: Look for Orbital Test Satellite 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 Orbital Test Satellite in 20 minutes

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

Frequently asked questions

What is Orbital Test Satellite in simple terms?

Why does Orbital Test Satellite matter?

Because it connects several astronomy 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 Orbital Test Satellite?

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 Orbital Test Satellite.