astronomy

ViaSat-2

ViaSat-2 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 ViaSat-2 rather than just read about it. In short: ViaSat-2 is a commercial communications satellite launched June 1, 2017 and went live late February 2018. It was advertised to be the world's highest capacity communications satellite with a throughput of 300 Gbit/s, exceeding that of HughesNet EchoStar XIX, which launched in December 2016.

Key takeaways

ViaSat-2 belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect ViaSat-2 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of ViaSat-2 from memory before moving on to harder problems.

Reference excerpt

ViaSat-2 is a commercial communications satellite launched June 1, 2017 and went live late February 2018. It was advertised to be the world's highest capacity communications satellite with a throughput of 300 Gbit/s, exceeding that of HughesNet EchoStar XIX, which launched in December 2016. It is the second Ka-band satellite launched by ViaSat after ViaSat-1. The satellite provides internet service through ViaSat (Exede prior to rebranding) to North America, parts of South America, including Mexico and the Caribbean, and to air and maritime routes across the Atlantic Ocean to Europe.

History In May 2013, ViaSat gave the construction contract of the satellite to Boeing. On May 1, 2014 ViaSat sold capacity on the satellite to Xplornet Communications. In January 2015, ViaSat gave the launch contract to SpaceX in an uncontested auction. After SpaceX CRS-7 exploded after launch in June 2015, concerns arose that the investigation may affect the mission's launch window. On February 9, 2016 Arianespace announced it had won contracts to launch ViaSat-2 and ViaSat-3 in 2017 and 2019, respectively. ViaSat-2 was launched on June 1, 2017 by Arianespace from the Guiana Space Centre in French Guiana. The launch date was originally set for April 25, 2017 but was delayed due to social unrest affecting the spaceport area. ViaSat-2 successfully arrived in geostationary orbit at 69.9 degrees west longitude on December 5, 2017. The satellite employed a hybrid propulsion approach, using both traditional chemical as well as electric propulsion. The chemical propulsion subsystem was responsible for initial orbit raising and performing according to plan, setting the state for the follow-on ascent to geostationary orbit using electric propulsion, which was completed the last week of November 2017. Viasat spacecraft partner, Boeing Satellite Systems International, controlled and monitored ViaSat-2 throughout the orbit raising process, flying the satellite from its Mission Control Center in El Segundo, California.

Functionality The $600 million satellite was intended to have a 300 Gbit/s throughput, up from ViaSat-1's 140 Gbit/s in 2011. It uses Ka-band frequencies. Problems with two of the four Ka-band antennae, leading to a less optimal coverage pattern than designed have reduced throughput to 260 Gbit/s.

Illustrations

Worked examples

Example 1 — a first encounter with ViaSat-2

Start with the simplest possible case. Write down what ViaSat-2 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 ViaSat-2 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 ViaSat-2 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 ViaSat-2

In research: ViaSat-2 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 ViaSat-2 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: ViaSat-2 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ariane commercial payloads, Communications satellites in geostationary orbit, High throughput satellites, so understanding it makes those chapters shorter.
In everyday life: Look for ViaSat-2 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 ViaSat-2 in 20 minutes

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

Frequently asked questions

What is ViaSat-2 in simple terms?

Why does ViaSat-2 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 ViaSat-2?

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 ViaSat-2.