astronomy

Sakigake

Sakigake 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 Sakigake rather than just read about it. In short: Sakigake (さきがけ; lit. 'pioneer', 'pathfinder'), known before launch as MS-T5, was Japan's first interplanetary spacecraft and the first deep space probe to be launched by any country other than the US or the Soviet Union. It aimed to demonstrate the performance of the new launch vehicle, test its ability to escape from Earth gravity, and observe the interplanetary medium and magnetic field.

Key takeaways

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

Reference excerpt

Sakigake (さきがけ; lit. 'pioneer', 'pathfinder'), known before launch as MS-T5, was Japan's first interplanetary spacecraft and the first deep space probe to be launched by any country other than the US or the Soviet Union. It aimed to demonstrate the performance of the new launch vehicle, test its ability to escape from Earth gravity, and observe the interplanetary medium and magnetic field. Sakigake also served as a reference probe for Halley's Comet. Early measurements would be used to improve the mission of the Suisei probe launched several months later. Sakigake was developed by the Institute of Space and Astronautical Science for the National Space Development Agency (both of which are now part of the Japanese Aerospace Exploration Agency, or JAXA). It became a part of the Halley Armada together with Suisei, the Soviet Vega probes, the ESA Giotto and the NASA International Cometary Explorer, to explore Halley's Comet during its 1986 sojourn through the inner Solar System.

Design Unlike its twin Suisei, it carried no imaging instruments in its instrument payload.

Launch Sakigake was launched January 7, 1985, from Kagoshima Space Center by M-3SII launch vehicle on M-3SII-1 mission.

Halley encounter It carried out a flyby of Halley's Comet on March 11, 1986, at a distance of 6.99 million km.

Giacobini-Zinner encounter There were plans for the spacecraft to go on to an encounter with 21P/Giacobini-Zinner in 1998, but the flyby had to be abandoned because of a lack of propellant.

End of mission Telemetry contact was lost on November 15, 1995, though a beacon signal continued to be received until January 7, 1999.

References

External links

Sakigake Sakigake Mission Profile by NASA's Solar System Exploration Halley's Comet Flyby Sakigake Mission Comet Halley Data Archive at the NASA Planetary Data System, Small Bodies Node

Illustrations

Worked examples

Example 1 — a first encounter with Sakigake

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

In research: Sakigake 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 Sakigake 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: Sakigake is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1985 in spaceflight, Derelict space probes, Earth flybys, so understanding it makes those chapters shorter.
In everyday life: Look for Sakigake 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 Sakigake in 20 minutes

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

Frequently asked questions

What is Sakigake in simple terms?

Why does Sakigake 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 Sakigake?

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 Sakigake.