astronomy

Thor (satellite)

Thor (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 Thor (satellite) rather than just read about it. In short: Thor (previously known as Marcopolo) is a family of satellites designed, launched and tested by Hughes Space and Communications (now part of Boeing Satellite Systems) for British Satellite Broadcasting (BSB), and were used for Britain's Direct Broadcast Service. Thor was owned by Telenor, but the division was sold to Space Norway in 2023.

Key takeaways

Thor (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 Thor (satellite) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Thor (satellite) from memory before moving on to harder problems.

Reference excerpt

Thor (previously known as Marcopolo) is a family of satellites designed, launched and tested by Hughes Space and Communications (now part of Boeing Satellite Systems) for British Satellite Broadcasting (BSB), and were used for Britain's Direct Broadcast Service. Thor was owned by Telenor, but the division was sold to Space Norway in 2023. Marcopolo 1 launched on 27 August 1989 on the 187th launch of a Delta rocket, and Marcopolo 2 launched on 17 August 1990, on a Delta II rocket. Both satellites were based on the HS-376 satellite bus. Although the satellites performed as designed, BSB merged with Sky Television to form British Sky Broadcasting and the BSB satellites were sold off and renamed. This also resulted in the obsoletion of the Squarial satellite-reception antenna, which was designed to operate with Thor 1 only.

Marcopolo 1 (Sirius 1/Sirius W) Sirius W, previously known as Sirius 1, was launched on 27 August 1989. It was Hughes Space and Communications's first satellite. Marcopolo 1 was sold in December 1993 to Nordic Satellite AB of Sweden and operated until 2000 as Sirius 1 at 5°E. It was then moved to 13°W, and renamed Sirius W. It had five Ku band transponders.

Marcopolo 2 (Thor 1) Marcopolo 2 was launched on 18 August 1990. It had five Ku band transponders. It was sold in July 1992 to Telenor of Norway and renamed Thor 1. It was located at 0.8°W. It was switched off in January 2002, and in November of that year it was moved to 7.4°W and reactivated with digital test signals broadcasting toward Scandinavia. Marcopolo 2 was sent up to the junk orbit in early January 2003.

Thor 2 Thor 2 was launched on 21 May 1997, and retired in 2008 although it remained in an inclined geostationary orbit until January 2013 when it de-orbited to the graveyard orbit. It weighs 1467 kg, and has 15 Ku band transponders, with three spares, powered by 40-watt traveling-wave tube amplifiers (TWTAs).

Thor 3 Thor 3 (the "3" is officially "III") was a satellite used by Canal Digital in the Nordic areas for DTH services. It launched on 9 June 1998 with an expected lifetime at 12 years, and was located at 0.8°W. It had 14 active Ku band transponders powered by 47-watt traveling-wave tube amplifiers (TWTAs). The satellite was targeted on Scandinavia, Eastern Europe, and parts of Central Europe. Thor 3 is no longer in operation and was moved to its graveyard orbit in 2019. Thor 3 was replaced by Thor 6 in June 2010.

Intelsat 10-02 (Thor 10-02) Intelsat 10-02 was launched on 16 June 2004, located at 1°W, and was beamed toward Central Europe and the Middle East.

Thor 5

Thor 5 was launched on 11 February 2008. It was first planned that the satellite would be called Thor 2R, but Telenor named it Thor 5. It has 24 active Ku band transponders.

Thor 6 Thor 6 built by Thales Alenia Space was launched from the Guiana Spaceport on 29 October 2009. Telenor Satellite Broadcasting announced on 15 December that Thor 6 had completed all necessary in-orbit and ground-related testing and would commence commercial service in late December. Thor 6 has 36 Ku band transponders. It provides direct-to-home television broadcasting services from the orbital location 0.8°W. It replaced Thor 3.

Thor 7 Thor 7 was built by SSL. It was successfully launched by Arianespace from Kourou spaceport on 26 April 2015. It will mainly serve maritime customers and have a total capacity of 9 Gbit/s. It was launched in tandem with the Italian/French Sicral 2 defense satellite.

References

External links Thor 2 presentation Thor 3 coverage map Thor 4 (Intelsat 10-02) coverage map Thor 5 coverage map Thor 6 coverage map Thor 7 coverage map

Worked examples

Example 1 — a first encounter with Thor (satellite)

Start with the simplest possible case. Write down what Thor (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 Thor (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 Thor (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 Thor (satellite)

In research: Thor (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 Thor (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: Thor (satellite) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Communications satellites, Communications satellites in geostationary orbit, Satellite television, so understanding it makes those chapters shorter.
In everyday life: Look for Thor (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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Thor (satellite)” →

Affiliate

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

How to study Thor (satellite) in 20 minutes

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

Frequently asked questions

What is Thor (satellite) in simple terms?

Why does Thor (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 Thor (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 Thor (satellite).