Explorer
For everyone, no maths needed
Our place in space, the true scale of the solar system, days and years, seasons, phases and eclipses, and the night sky.
6 lessons
Magenta Initiative
Free space learning for everyone
Courses, interactive tools and a knowledge base about the solar system, orbits, space travel and the space economy. Free forever, no account needed.
NASA, ESA, CSA, and STScI, J. DePasquale (STScI) (CC BY 4.0)
Learning paths
Five paths from first steps to mission design and the space economy.
Navigator
For everyone ready for a little maths
Gravity, Kepler's laws, orbital elements, speeds, escape, the rocket equation and how spacecraft travel between worlds.
15 lessons
Builder
For anyone who likes to build and calculate
Mission design end to end: propulsion, life support, communications, radiation, landing and using resources found in space.
7 modules planned
Venture
For anyone curious about the space economy
The space economy today and tomorrow, launch costs, space resources, space law, and the Planetary Business Idea Lab.
10 modules planned
Earth from Space
For everyone
Oceans, air quality, ice and sea level, energy and resources, seen from orbit.
4 modules planned
Interactive tools
Orrery
The solar system in real time. Travel through time, change the speed, switch to true scale and compare any two worlds.
Orbit Sandbox
Change an orbit's shape and watch its speed change. See Kepler's second and third laws in action.
Scale Walk
Scroll from the Sun to Neptune at true scale, with light-travel time markers along the way.
Delta-v Map
How much change in speed it takes to move between Earth, orbit, the Moon, Mars and the asteroids.
Newton's Cannon
Fire a cannonball faster and faster from a mountain top until it orbits, then escapes.
Seasons Explorer
Earth's tilt, the Sun's height and the length of the day for any place and date.
Moon Phases and Eclipses
Move the Moon around the Earth and see its phase from Earth, and when eclipses can happen.
Night Sky and Light Pollution
A real star catalogue. Drag the light pollution slider and watch the stars disappear.
Knowledge base
The Sun, the planets, their major moons, the dwarf planets and some famous small bodies. Every number comes from one shared, sourced dataset.
Glossary
Short definitions, with formula cards for the key equations.
How it works
- Free forever, no account. Your progress stays in this browser.
- Every idea starts with something you can play with, before any formula.
- Three depths per lesson: Look, Understand, Master.
- Open licence (CC BY-SA 4.0): copy it, translate it, teach with it.
- Numbers come from NASA and JPL data, checked against JPL Horizons.
Tools and lessons use simplified models for learning only. They must not be used for navigation, mission planning or any operational decision. Certificates are free and non-accredited. Read the educational content disclaimer