science

NEXTAR

NEXTAR is a science 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 NEXTAR rather than just read about it. In short: NEXTAR (from NEC Next Generation Star) is a Low Earth orbit Earth observation satellite bus designed and manufactured by NEC Space Systems of Japan. This three axis stabilized platform has a bus dry mass of 250 kg (550 lb), it can carry payloads up to 250 kg (550 lb) and 600 W.

Key takeaways

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

Reference excerpt

NEXTAR (from NEC Next　Generation　Star) is a Low Earth orbit Earth observation satellite bus designed and manufactured by NEC Space Systems of Japan. This three axis stabilized platform has a bus dry mass of 250 kg (550 lb), it can carry payloads up to 250 kg (550 lb) and 600 W. It uses tri-junction GaAs has an expected life between 3 and 5 years. Its telemetry and control subsystem includes S band and X band channels.

Platform models As of 2014, there are three different models of the NEXTAR standardized platform. All feature a common core of features like using the SpaceWire communications protocol, the SpaceCube2 on-board computer and autonomous control functions. The different models are:

NX-300L: Low Earth orbit platform for small observation satellites in the 300 to 500 kg (660 to 1,100 lb) range. It was born out of the ASNARO 1 work and is used mainly for Earth observation applications. NX-1500L: Low Earth orbit platform for medium observation satellites in the 1,000 to 1,500 kg (2,200 to 3,300 lb) range. It began with the work on GCOM-W and is used mainly for Earth observation applications. NX-G: Geosynchronous orbit platform for small communication satellites in the 1.5 to 3 t (1.7 to 3.3 tons) range. Based on the work of the WINDS satellite, it will be used mainly for communications applications.

List of satellites Satellites using the NEXTAR platform.

See also DS2000 - Mitsubishi Electric's standard satellite bus Star Bus – Another comparable satellite bus made by Orbital ATK.

References

External links NEC's NEXTAR page

Worked examples

Example 1 — a first encounter with NEXTAR

Start with the simplest possible case. Write down what NEXTAR claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 NEXTAR 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 NEXTAR 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 NEXTAR

In research: NEXTAR appears in science 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 NEXTAR 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: NEXTAR is common in secondary-school and first-year university syllabi. It links to neighbouring topics Asian spacecraft stubs, Communications satellite stubs, Satellite buses, so understanding it makes those chapters shorter.
In everyday life: Look for NEXTAR 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 NEXTAR in 20 minutes

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

Frequently asked questions

What is NEXTAR in simple terms?

Why does NEXTAR matter?

Because it connects several science 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 NEXTAR?

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 NEXTAR.