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Syracuse (satellite)

Syracuse (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 Syracuse (satellite) rather than just read about it. In short: Syracuse (SYstème de RAdioCommunication Utilisant un SatellitE; English: Satellite-based radio communication system) is a series of French military communications satellite constellations. The Syracuse program is intended to enable safe and secure permanent communications between headquarters in mainland France and units deployed in theaters of operation around the world at all times (peace, crisis, major disaster…

Key takeaways

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

Reference excerpt

Syracuse (SYstème de RAdioCommunication Utilisant un SatellitE; English: Satellite-based radio communication system) is a series of French military communications satellite constellations. The Syracuse program is intended to enable safe and secure permanent communications between headquarters in mainland France and units deployed in theaters of operation around the world at all times (peace, crisis, major disaster...) as well as between the units themselves. It contributes to command, intelligence and logistics operations. Four generations of Syracuse constellations were deployed between 1984 and 2023.

Syracuse I and II Syracuse I and II were payloads on joint civilian-military satellite designs developed and operated by the French PTT, and were more commonly known by their civilian names Télécom 1 (3 satellites launched in 1984, 1985 and 1988) and Télécom 2 (4 satellites in 1991, 1992, 1995 and 1996). Matra Marconi Space, a development contractor on the Syracuse II, also worked on the British Skynet 4 military communications satellites.

Syracuse III This third generation of communications satellites was designed to meet the operational needs of the French Armed Forces for secure, long-distance communications that are resistant to the threat of electronic warfare. It comprises satellites, fixed ground stations, deployable terminals (land and naval) and modems to protect communications from jamming. The novelty of this program lies in the fact that its installations, both in space and on the ground, are the exclusive property of the French Joint Defense Staff, ensuring the autonomy of the French armed forces in terms of satellite communications. The constellation consists of 3 satellites:

the Syracuse-3A (launched on October 13, 2005) the Syracuse-3B (launched on August 11, 2006) the SICRAL 2 (launched on April 26, 2015), which is a third complementary satellite developed in cooperation with Italy This system is completed by Comcept (complementary needs in projection and theater elongation communications) for "non-hardened" communications, which includes the Athena-Fidus satellite. Syracuse III comprises 423 ground stations. This network is complemented on French Navy ships by the Telcomarsat commercial satellite system, which has equipped 54 ships since 2009.

Syracuse IV In 2018, the French Ministry of Defence announced the launch of the Syracruse IV program, aiming to develop of a constellation of three satellites to succeed the Syracruse III. The first two satellites, Syracuse 4A and 4B, were initially ordered, and the third, Syracuse 4C, would later follow. Surplus capacity will be sold to armed and security forces in Europe and elsewhere. Thales Alenia Space and Airbus Defence and Space were the selected contractors for the programme. The cost of the Syracuse 4 constellation is valued at €3.6 billion. Weighing in at 3850 kg, Syracuse 4A is Europe's first electrically-powered military satellite. "This innovative propulsion system based on plasma propulsion engines, is the result of French know-how and represents a major technological advance for the space industry", the DGA explained. It adds: "Its advantages are numerous: used as a replacement for chemical propulsion, electric propulsion requires less fuel on board for the same service life, and significantly increases the satellite's carrying capacity, and therefore its communications payload. In particular, this technology will enable satellites to transmit in two different frequency bands". The Syracuse 4A and 4B satellites will offer military-grade X-band and Ka-band throughput of the order of 3 to 4 Gb/s (three times higher than that offered by Syracuse 3A and 3B), as well as greater resistance to cyber threats, electromagnetic pulses and jamming. They are equipped with environmental monitoring equipment and the ability to move to counter any aggression. Syracuse 4A was launched on 24 October 2021 with an Ariane 5 ECA rocket from the Guiana Space Centre. The second one, Syracuse 4B was launched on 5 July 2023, which was the final launch of the Ariane 5 rocket, while the third one was scheduled to be launched by 2025. However in April 2023, it was announced the first two satellites would be more than sufficient and that the last, Syracuse 4C, would be cancelled in favor of financing the European Union's IRIS² satellite internet constellation. It was also announced a program to develop the next generation of communications satellite constellation (Syracuse V) would be launched in the 2024-2030 French Military Planning Law to succeed the Syracuse 4A and Syracuse 4B satellites post-2035.

See also

French space program CNES Defense Satellite Communications System Skynet (satellite)

References

Worked examples

Example 1 — a first encounter with Syracuse (satellite)

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

In research
Syracuse (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 Syracuse (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
Syracuse (satellite) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Communications satellites, Communications satellites in geostationary orbit, Communications satellites of France, so understanding it makes those chapters shorter.
In everyday life
Look for Syracuse (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 Syracuse (satellite) in 20 minutes

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

Frequently asked questions

What is Syracuse (satellite) in simple terms?

Syracuse (SYstème de RAdioCommunication Utilisant un SatellitE; English: Satellite-based radio communication system) is a series of French military communications satellite constellations. The Syracuse program is intended to enable safe and secure permanent communications between headquarters in ma…

Why does Syracuse (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 Syracuse (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 Syracuse (satellite).

Tags

  • Communications satellites
  • Communications satellites in geostationary orbit
  • Communications satellites of France
  • Military communications
  • Satellites of France
  • Thales Alenia Space spacecraft

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