Hoshi no Isan 星の遺産

Children of the JAXA Legacy — a ship built from Japan's space history

Future

Hoshi no Isan
星の遺産

Pre-production. Design, lore, and ship documentation exist — but this is not in active daily development. Planned after the Physical ROC program is established. This page is the concept archive.

A first-person exploration game set aboard the Yamabiko — a JAXA Heritage Ship and living museum of Japan's most extraordinary space missions. Walk every corridor. Know your crew. Carry the legacy forward. Set more than a century from now.

Game Design Document Explore the Ship

"The ship is not just where the story happens. The ship is the story. Every compartment is a shrine. Every crew member is a descendant."

Japan's space program produced some of the most remarkable engineering stories ever told. Spacecraft that refused to fail. Missions that waited years for a second chance. Almost none of these stories have been told in gaming.

Hoshi no Isan puts you aboard the Yamabiko — a ship that, more than a century from now, keeps the memory of Japan's greatest space missions alive. Walk its decks, read its plaques, find its artifacts. Its crew descend from the teams who built that legacy: know them, and earn their trust.

Visual Direction

Interior Look & Feel

Inspiration only — not final assets. These images suggest the mood, lighting, and walkable compartment style for the Yamabiko. Production interiors will be built in Blender and UE5 as the project enters active development.

Heritage corridor

Compartment atmosphere

Lived-in ship space

Core Experience

Three Ways to Inhabit the Ship

🚶

Walk Every Corridor

Explore the Yamabiko in first person. Mission-named compartments, interactive plaques, artifacts, and ancestor shrines. The ship reveals its stories to those who look carefully.

Explore the Ship
💬

Know Your Crew

Six crew members — each descended from the teams behind a real JAXA mission. Visual novel conversations in specific rooms. Trust unlocks ancestor biographies, story arcs, and new spaces.

Meet the Crew
✨

Collect the Legacy

A gacha system where every crew member carries real historical lineage. Recruiting means inheriting a person — their skills, their story, their ancestor's unfinished mission.

Crew System (GDD)
Where This Stands

Road to Production

Hoshi no Isan is built in the open, one proven step at a time. The order below is the plan, not a deadline.

1

Physical ROC

The trailer-mounted, two-crew spaceship simulator comes first. It funds and proves the craft behind everything else.

See the ROC
2

Yamabiko MVP

Three walkable rooms in Unreal Engine 5: Kaguya Observation Lounge, Hayabusa Engine Bay and SLIM Navigation Bridge, with readable plaques and a first playable demo.

The Yamabiko
3

Crew & Conversations

The visual novel layer arrives with the first crew member, then trust, recruitment and the wider roster.

Meet the Crew
Real JAXA History

The Missions That Built the Yamabiko

Every compartment aboard the ship is dedicated to a real JAXA mission — not inspired-by stories, but the actual missions and their perseverance.

🛸
JAXA · 2003
Hayabusa — The One That Refused to Die
Seven years. Two billion kilometers. A single functioning engine. It came home.
Hayabusa Engine Bay
🌑
JAXA · 2014 – ongoing
Hayabusa 2 — The Perfectionist
Deployed rovers, fired a bullet into an asteroid, returned samples — then kept going. In July 2026 it flew within about 400 m of asteroid Torifune, a flyby record.
Science Laboratory
🌕
JAXA · 2007
Kaguya — The Poet
First HD footage of Earth rising over the lunar surface. Named after the moon princess.
Observation Lounge
☁️
JAXA · 2010 / 2015
Akatsuki — The Patient One
Failed engine. Five years. Tiny thrusters. One second chance at Venus. Taken.
Meditation Room
🌙
JAXA · 2024
SLIM — The Precise One
100-meter lunar landing accuracy. Engine failed. Landed inverted. Mission completed.
Navigation Bridge
🌍
JAXA / ISS · Ongoing
Japanese ISS Legacy — The Bridge Builders
Wakata, Hoshide, Noguchi, Mukai, Mohri. Five pioneers. Centuries of orbit between them.
Heritage Gallery
🔴
JAXA · Launching Oct. 20, 2026 (JST)
MMX — The Next Echo
Land on Mars's moon Phobos, take a sample, bring it home in 2031. The next compartment waiting to be named.
Future Wing
Full Mission Archive
Crew Gacha System

Children of the Pioneers

Each crew member descends from the people behind a real JAXA mission, more than a century on. Recruit them. Earn their trust. Unlock their ancestors' story.

Fictional crew. The crew are invented characters set more than a century in the future. They descend from mission teams and fictional pioneers; real astronauts are honored only through factual mission history. This project is independent and is not affiliated with or endorsed by JAXA.

★★★★★

Hana Minase

Medical Officer
Lineage: ISS Kibo Operations Team
★★★★★

Kenji Sakurai

Science Officer
Lineage: Hayabusa 2 Science Team
★★★★

Yuki Aoyama

Navigation
Lineage: SLIM Landing Team
★★★★

Ren Takanashi

EVA Specialist
Lineage: ISS Assembly EVA Teams
★★★

Sora Mizuhara

Historian
Lineage: Kaguya Imaging Team
★★★

Hayato Itokawa

Ship Engineer
Lineage: Hayabusa Team
Meet the Full Crew
From the Source

JAXA Latest News

Recent press releases from Japan Aerospace Exploration Agency — the real missions that inspire the Yamabiko. Links open on the official JAXA website.

All press releases at JAXA
Design Archive

Concept Documentation

Written when Hoshi was the primary site focus — still valid as design reference for a future production phase.

The Yamabiko: JAXA Heritage Ship

Mission-named decks and environmental storytelling for the heritage ship concept.

  Read Article

Introducing Hoshi no Isan

The original direction announcement — universe framing and design intent.

  Read Article

Ship Interior Design

Multi-deck layout and modular interior philosophy for the Yamabiko.

  Read Article

Explore the Concept

Full game overview, ship pages, and the complete design document — preserved for when this project enters production.

Game Design Document   The Yamabiko
Active work: Physical ROC     All Projects