science

RAISE-4

RAISE-4 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 RAISE-4 rather than just read about it. In short: RAISE-4 (RApid Innovative payload demonstration SatellitE-4) is a smallsat for technology demonstration developed by Mitsubishi Heavy Industries (MHI). Part of the Japanese space agency JAXA's Innovative Satellite Technology Demonstration Program, RAISE-4 carries multiple technologies that were selected for in-orbit demonstration.

Key takeaways

RAISE-4 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RAISE-4 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RAISE-4 from memory before moving on to harder problems.

Reference excerpt

RAISE-4 (RApid Innovative payload demonstration SatellitE-4) is a smallsat for technology demonstration developed by Mitsubishi Heavy Industries (MHI). Part of the Japanese space agency JAXA's Innovative Satellite Technology Demonstration Program, RAISE-4 carries multiple technologies that were selected for in-orbit demonstration. RAISE-4 was launched on a dedicated Electron rocket flight, 'Raise And Shine' in December 2025.

Overview RAISE-4 is a reflight of the RAISE-3 satellite which was launched by an Epsilon rocket on 12 October 2022 but failed to reach orbit. As with RAISE-3, RAISE-4 was developed by MHI, the prime contractor of Japan's H-IIA and H3 rockets. MHI also previously developed Z-Sat, a satellite launched in 2021 as part of the Innovative Satellite Technology Demonstration-2 mission. RAISE-4 is operated from MHI's Nagoya Guidance & Propulsion Systems Works plant in Komaki, Aichi. The satellite carries eight of the 16 themes that will be tested in Innovative Satellite Technology Demonstration-4. Among them, five are reflights from RAISE-3, one (KIR-X) has its design modified from RAISE-3, and two (CF-CAM and AIRIS) were newly selected to be flown on RAISE-4.

Spacecraft As RAISE-4 was deployed into a different orbit than RAISE-3, the thermal design of the satellite was modified.

Technologies Eight technologies are being tested on board RAISE-4.

Low Earth orbit satellite MIMO for 920 MHz band IoT platform (LEOMI) COTS GPU-based edge-computing for mission systems utilizing model-based systems engineering (GEMINI) KIR-X Takahashi Denki Seisakusho Pulsed-Plasma Thruster (TDS-PPT) Membrane deployment deorbit mechanism (D-SAIL) HELIOS-R CF-CAM Artificial Intelligence Retraining In Space (AIRIS)

GEMINI GEMINI, developed by Mitsubishi Electric (MELCO) is a device that includes a commercial off-the-shelf graphics processing unit (COTS GPU). GEMINI has SAR images preinstalled to replicate a typical Earth observation satellite, and the GPU will format and process the image in orbit before sending it to a ground station. The main goal of GEMINI is to test how a consumer-grade GPU performs in space. During development, recently recruited engineers at MELCO were charged with the designing and testing of the device.

D-SAIL D-SAIL is a deployable sail that uses its large surface area to generate friction with the atmosphere and decrease the orbital speed of the satellite, which allows it to lower altitude, ultimately leading to the satellite's deorbiting and entering Earth's atmosphere. D-SAIL was developed by Axelspace Corporation.

Worked examples

Example 1 — a first encounter with RAISE-4

Start with the simplest possible case. Write down what RAISE-4 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 RAISE-4 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 RAISE-4 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 RAISE-4

In research: RAISE-4 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 RAISE-4 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: RAISE-4 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2025 in spaceflight, JAXA, Satellites of Japan, so understanding it makes those chapters shorter.
In everyday life: Look for RAISE-4 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 RAISE-4 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RAISE-4 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 RAISE-4 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RAISE-4 in simple terms?

Why does RAISE-4 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 RAISE-4?

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 RAISE-4.