astronomy

T12 (satellite)

T12 (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 T12 (satellite) rather than just read about it. In short: T12, formerly known as D12, is a Boeing model 702 satellite built by the Boeing Satellite Development Center. It was launched on December 29, 2009 and became operational on May 19, 2010.

Key takeaways

T12 (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 T12 (satellite) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of T12 (satellite) from memory before moving on to harder problems.

Reference excerpt

T12, formerly known as D12, is a Boeing model 702 satellite built by the Boeing Satellite Development Center. It was launched on December 29, 2009 and became operational on May 19, 2010. It is used by DirecTV to provide additional high definition channels and Video on demand content, as well as 3DTV channels and content. The satellite adopted its current name in 2017.

Technology This satellite is similar to T10 and T11, but features a 17/24 GHz BSS payload carrying the moniker RB-2A. It is co-located with T10 very near 103.0°W.

Launch data On November 27, the satellite was shipped to the Baikonur Cosmodrome in the Kazakhstan desert from the Boeing facility in El Segundo, California. T12 was launched successfully by International Launch Services on December 29, 2009 at 6:22 AM Kazakhstan time (00:22 UTC) from the Baikonur Cosmodrome in Kazakhstan aboard an Enhanced Proton Breeze-M rocket. The launch was televised publicly live on DirecTV channel 577, on C-Band satellite, and online at ILS's website.

Testing stage T12 reached 76° W on February 11, 2010 and began testing 2 days later. After 3 weeks of scheduled testing, RB-2A began being tested. On April 23, T12 was granted a Special Temporary Authority to continue testing at 76° W for 30 more days. Testing was completed in late April.

Drift to final position On March 31, 2010 DirecTV filed a Special Temporary Authority for permission to drift to its final position at 103° W. It was granted on April 23. It reached its final position on May 11 and began operations on May 13. Boeing handed the satellite over to DirecTV on May 17.

Broadcasting to customers T12 increased DirecTV's national HD channel capacity to over 200 channels and expanded its availability of local channels in HD. DirecTV has used the new satellite to add more HD channels, expand its pay-per-view movie service "DirecTV Cinema" and on demand titles. It also carried 3DTV channels. DirecTV began adding new HD channels on May 19 and continued June 23 and later in the summer. DirecTV added the first 3D channel to T12, ESPN 3D, on June 11, and new channels n3D and a pay-per-view 3D movie channel on July 1. A few more HD channels were added onto it in the fall of 2010, the winter of 2010-11, and the spring and summer of 2011; and more in 2012. The 3DTV channels were removed by 2014 due to consumer disinterest in the format.

Worked examples

Example 1 — a first encounter with T12 (satellite)

Start with the simplest possible case. Write down what T12 (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 T12 (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 T12 (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 T12 (satellite)

In research: T12 (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 T12 (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: T12 (satellite) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Communications satellites in geostationary orbit, DirecTV, Satellite television, so understanding it makes those chapters shorter.
In everyday life: Look for T12 (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 T12 (satellite) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what T12 (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 T12 (satellite) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is T12 (satellite) in simple terms?

T12, formerly known as D12, is a Boeing model 702 satellite built by the Boeing Satellite Development Center. It was launched on December 29, 2009 and became operational on May 19, 2010.

Why does T12 (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 T12 (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 T12 (satellite).