astronomy

Thaicom 4

Thaicom 4 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 Thaicom 4 rather than just read about it. In short: THAICOM 4, also known as IPSTAR 1, is a high throughput satellite built by Space Systems/Loral (SS/L) for Thaicom Public Company Limited. It was launched on August 11, 2005, from the European Space Agency's spaceport in French Guiana on board the Ariane rocket.

Key takeaways

Thaicom 4 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Thaicom 4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Thaicom 4 from memory before moving on to harder problems.

Reference excerpt

THAICOM 4, also known as IPSTAR 1, is a high throughput satellite built by Space Systems/Loral (SS/L) for Thaicom Public Company Limited. It was launched on August 11, 2005, from the European Space Agency's spaceport in French Guiana on board the Ariane rocket. The satellite had a launch mass of 6486 kilograms and is from SS/L's LS-1300 series of spacecraft. IPSTAR 1 is the world's first High Throughput Satellite capable of providing service to up to two million broadband users or nearly 30 million mobile phone subscribers in the Asia Pacific region. Compared to the one or two gigabit per second (Gbit/s) capacity of a typical satellite designed for Fixed Satellite Services (FSS), IPSTAR was designed to provide broadband Internet service. Its 45 Gbit/s of capacity had never been achieved on a satellite before, enabling IPSTAR to provide up to 6 Mbit/s user download and up to 4 Mbit/s upload speeds for a variety of applications and services.

Technology The satellite's 45 Gbit/s bandwidth capacity, in combination with its platform's ability to provide an immediately available, high-capacity ground network with affordable bandwidth, allows for rapid deployment and flexible service locations within its footprint. The IPSTAR broadband satellite system is composed of a gateway earth station communicating over the satellite to provide broadband packet-switched communications to a large number of small terminals with network star configuration. A wide-band data link from the gateway to the user terminal employs an Orthogonal Frequency Division Multiplexing (OFDM) with a Time Division Multiplex (TDM) overlay. These forward channels employ highly efficient transmission methods, including Turbo Product Code (TPC) and higher order modulation (L-codes) for increased system performance. In the terminal-to-gateway direction (or return link), the narrow-band channels employ the same efficient transmission methods. These narrow-band channels operate in different multiple-access modes based on bandwidth-usage behavior, including ALOHA and TDMA for STAR return link waveform. Traditional satellite technology utilizes a broad single beam to cover entire continents and regions. With the introduction of multiple narrowly focused spot beams and frequency reuse, IPSTAR is capable of maximizing the available frequency for transmissions. Increasing bandwidth by a factor of twenty compared to traditional Ku-band satellites translates into better efficiencies. Despite the higher costs associated with spot beam technology, the overall cost per circuit is considerably lower as compared to shaped beam technology. IPSTAR's Dynamic Power Allocation optimizes the use of power among beams and allocates a power reserve of 20 percent to be allocated to beams that may be affected by rain fade, thus maintaining the link.

Worked examples

Example 1 — a first encounter with Thaicom 4

Start with the simplest possible case. Write down what Thaicom 4 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 Thaicom 4 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 Thaicom 4 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 Thaicom 4

In research: Thaicom 4 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 Thaicom 4 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: Thaicom 4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2005 in Thailand, Communications satellites in geostationary orbit, High throughput satellites, so understanding it makes those chapters shorter.
In everyday life: Look for Thaicom 4 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 Thaicom 4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Thaicom 4 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 Thaicom 4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Thaicom 4 in simple terms?

Why does Thaicom 4 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 Thaicom 4?

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 Thaicom 4.