I, Voyager

About

What is I, Voyager?

I, Voyager is

  1. an open-source software Planetarium
  2. a development platform for creating games and astronomy/educational apps in a realistic space simulation (or unrealistic if you want).

I, Voyager is free, open-source software built on the free, open-source Godot Engine. It is designed to be improved, modified and extended by the community. Our projects and editor plugins mainly use Godot’s GDScript (similar to Python) and shading language. Godot supports project development in GDScript, C# and C++.

What does I, Voyager cost?

I, Voyager is free to use and distribute under the permissive Apache License 2.0. Projects built with I, Voyager are owned by their creators. You can sell what you make. There are no royalties or fees.

How can I support this effort?

Help us grow the community by following us on Facebook, X, and Bluesky.

Please consider supporting us at our Sponsors Page. Become a Mercury Patron for $1 per month! Small contributions provide a morale boost and help us pay our web hosting bills. If you are a company, consider sponsoring us as a Saturn or Jupiter Patron. Our long-term goal is to become a non-profit entity. This would allow us to apply for grants and secure our existence into the future.

Can I become an I, Voyager developer?

Absolutely! To get started, introduce yourself at our Forum where you can exchange ideas and receive help. Report bugs or astronomical inaccuracies at our issue tracker. To see where we are going and how you might help, visit our official Roadmap. Code developers should visit our Developers page.

Developers will be added as “Contributors” to our AUTHORS list after 10 code commits or some similar contribution. We have leeway in “similar contribution,” but it might include contributing original assets (permissively licensed) or creating a major feature or capability regardless of commit number. For example, it would certainly count to implement a mobile version of our Planetarium with an appropriate mobile GUI.

Where did I, Voyager come from?

Its creator (Charlie Whitfield) stumbled onto the Godot Engine in November, 2017, not aware of what a “game engine” was at the time. Maybe a week later there was a TestCube orbited by smaller TestCubes orbited by even smaller TestCubes. The name “I, Voyager” is a play on Voyager 1, the spacecraft that captured an image of Earth from 6.4 billion kilometers away. I, Voyager became an open-source project on Carl Sagan’s birthday, November 9, 2019.

Authors, credits and legal

I, Voyager is possible due to public interest in space exploration and funding of government agencies like NASA and ESA. It’s also possible due to open-source software developers, and especially Godot Engine’s creators and contributors. Copyright © 2019-2026 Charlie Whitfield. I, Voyager® is a registered trademark of Charlie Whitfield in the U.S. For up-to-date authors, credits, license, and 3rd-party information, follow these links:

  • AUTHORS – Direct contributors to code and assets.
  • CREDITS – Individuals and organizations whose efforts made this possible.
  • LICENSE – Our license.
  • IVOYAGER_WORKS.md – Original I, Voyager works (models, maps, etc.) with attribution of source material.
  • 3RD_PARTY – Files distributed under third-party copyright and license.

Screen captures!

I, Voyager screen capture of Jupiter and Io viewed from Europa.
Jupiter and Io viewed from Europa. (Also featured in our website header.)
Saturn and its rings. New! Just in time for our beta release, we have shadows! Semi-transparent shadows from Saturn’s rings are visible here. After considerable effort, we have shadows working at both planetary and spacecraft distance scales (see ISS below).
The International Space Station. This is one of only three spacecraft at this time. We would like to add more with historical flight paths or representative orbits. We need more 3D models to do that…
Our Planetarium’s user interface provides easy navigation and tons of information. Links in the panels open Wikepedia.org pages for more than a hundred solar system bodies and dozens of astronomy concepts.
Positions of ~70,000 asteroids. Here, the Main Belt asteroids are cyan, with the Hilda subset in yellow. The Trojans at Jupiter’s L4 and L5 are magenta. (For programmers: Each point is a GPU vertex shader that knows its own orbital elements and calculates its own position.)
Asteroid orbits. Or is it an abstract painting? The “wheel” at the center are the Trojans (yellow) encompassing the Main Belt (reddish). The outer orbit lines are the sparse Centaurs (cyan) and Trans-Neptune Objects (orangish).
I, Voyager screen capture of Uranus' moons from the "north". Uranus' 98° axial tilt puts the solar system almost directly to the south.
Uranus’ moons are an interesting cast of characters (literally). The planet’s 98° axial tilt puts the inner solar system almost due south in this image.
I, Voyager screen capture of the solar system showing outer planets and Pluto on July 14, 2015, the day of New Horizon's Pluto flyby.
Here’s the solar system on July 14, 2015, the day New Horizons flew by the dwarf planet Pluto (♇). Not coincidentally, Pluto was near the plane of the ecliptic at this time.
I, Voyager screen capture of Pluto and Charon.
Pluto and its moon Charon. Both are tidally locked so their facing sides never change.
For developers, you can quickly build GUI from a large set of widgets. These widgets communicate with simulator internals and in some cases build themselves from simulator data (e.g., the planet/moon navigator widget above/left). See also the Planetarium GUI above, which is composed entirely of existing widgets in the Core plugin.