astronomy

ProtoStar

ProtoStar 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 ProtoStar rather than just read about it. In short: ProtoStar Ltd was a private company incorporated in Bermuda, with U.S. operations based in San Francisco, California and Asian operations based in Singapore. ProtoStar intended to operate an initial fleet of three geostationary satellites.

Key takeaways

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

Reference excerpt

ProtoStar Ltd was a private company incorporated in Bermuda, with U.S. operations based in San Francisco, California and Asian operations based in Singapore. ProtoStar intended to operate an initial fleet of three geostationary satellites. Two satellites were acquired and launched. ProtoStar's anchor customer, Dish TV India Limited, is the largest direct-to-home television operator in India.

Bankruptcy and auction ProtoStar Ltd filed for Chapter 11 bankruptcy protection in the United States District Court for the District of Delaware on June 29, 2009. ProtoStar sought and was made by the bankruptcy court to auction its two satellites to pay its outstanding liabilities. The auction for ProtoStar I was set by the bankruptcy court for October 14, 2009, however the auction was delayed until October 31, 2009, based on interest from 11 different satellite operating companies. The auction was won by Intelsat Corp with a bid of $210M, beating out European rival Eutelsat.

ProtoStar I The ProtoStar I satellite was built by Space Systems/Loral (SS/L) based on the SS/L 1300 spacecraft design. It was originally built by SS/L as the ChinaSat 8 satellite and scheduled for launch in April 1999 on a Long March 3B rocket. However, the U.S. Department of State blocked its export to China under ITAR regulations. The satellite was placed in storage and sold to ProtoStar in 2006. On January 5, 2007, SS/L announced that the satellite would be modified to meet ProtoStar's requirements. The fueled satellite weighed 4,100 kilograms (9,000 lb) and will operate in both the Ku band and the C band. On January 8, 2007 Arianespace announced that ProtoStar had contracted with Arianespace for the launch of ProtoStar I. It was launched aboard an Ariane 5 ECA rocket on July 7, 2008. Post-launch maneuvering of the satellite was performed successfully July 8, 2008., and ProtoStar I was placed into its geostationary orbital location of 98.5 degrees East Longitude. Following the sale of ProtoStar I in the ProtoStar bankruptcy auction, October 29, 2009, and the completion of the sale with Intelsat, Intelsat renamed the satellite Intelsat 25. Intelsat 25 will serve for African market at 31.5 West orbital location.

ProtoStar II

On January 14, 2008, Boeing announced that the Boeing Satellite Development Center in El Segundo, California would provide a spacecraft based on the Boeing 601HP spacecraft design for use as ProtoStar II. The spacecraft was originally built for PanAmSat (now Intelsat) to be used as Galaxy-8iR, but that contract was terminated November 15, 2002. On May 16, 2009, ProtoStar II was carried to orbit on a Proton rocket provided by International Launch Services. On June 16, 2009, Boeing announced the successful in-orbit handover of the satellite to ProtoStar Ltd. following successful in-orbit tests. In December 2009 SES purchased Protostar II at auction for its SES World Skies unit. The purchase price was $185 million.

Ground control segment The ProtoStar I ground control system is in Singapore and will be operated by SingTel. For ProtoStar II the primary control system will be installed in Indonesia and operated by Indovision, with a backup system integrated into the control system for ProtoStar I. Hardware and software for these systems are being provided by Integral Systems.

References

Worked examples

Example 1 — a first encounter with ProtoStar

Start with the simplest possible case. Write down what ProtoStar 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 ProtoStar 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 ProtoStar 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 ProtoStar

In research: ProtoStar 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 ProtoStar 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: ProtoStar is common in secondary-school and first-year university syllabi. It links to neighbouring topics Communications satellites, Satellite operators, so understanding it makes those chapters shorter.
In everyday life: Look for ProtoStar 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 ProtoStar in 20 minutes

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

Frequently asked questions

What is ProtoStar in simple terms?

Why does ProtoStar 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 ProtoStar?

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 ProtoStar.