Calculations
All calculators use SI units internally and constants from CODATA 2018, the IAU and JPL. Each is covered by automated tests that compare results with independently published reference values — for example the 86,164-second geostationary period, the 2,953 m Schwarzschild radius of the Sun and the textbook 3.89 km/s LEO-to-GEO Hohmann transfer.
Models and their limits
Our models are deliberately simplified so they can be understood: two-body orbits, impulsive burns, ideal rocket equations, uniform-disk transits with linear limb darkening, and exponential atmospheres. Assumptions are listed next to every tool. Results are suitable for learning and first-order estimates only.
Do not use SpaceWonder for spacecraft navigation, mission planning, flight operations, safety-critical engineering or any decision where an error could cause harm or loss.
Visual scale
The Cosmic Atlas offers an educational view in which planet sizes and distances are compressed and enlarged for readability, and a scientific view with linear distances and stated size magnification. The active convention is always shown on screen. Spacecraft models in AstroCraft Lab are schematic.
Simulations versus real data
Every value in Mission Control carries a data-mode badge. Battery, power, temperature and link status are not published in real time by agencies, so they are shown only as a labelled educational simulation.
Corrections
If you find an error, please contact us with a source. Pages show the date their reference content was last reviewed.
Last updated 2026-10-23.