217 terms defined — from orbit types and orbital elements to satellite tracking, space debris, and manoeuvres. Each term explained in plain language with diagrams, key data, and links to live trackers.
The major orbital regimes used by satellites — from low Earth orbit to geostationary and beyond. Each orbit type serves different mission requirements for communications, navigation, imaging, and scientific research.
The six classical Keplerian elements that fully describe a satellite's orbit — defining its size, shape, orientation, and the position of the satellite within it.
How satellites and debris are detected, catalogued, and monitored. From radar systems and tracking formats to the identification standards that underpin global space situational awareness.
The physics and operations of changing orbits — from collision avoidance and orbit raising to interplanetary transfers. Every manoeuvre costs delta-v, the fundamental currency of spaceflight.
The growing challenge of orbital debris — how collisions are predicted, how satellites dodge threats, and the rules and technologies being developed to keep space sustainable.
The subsystems that make up a satellite — from the bus and payload to attitude control, power, thermal management, and communications.
Key concepts in getting to orbit — launch windows, staging, orbital insertion, and the variables that determine what a rocket can carry and where.
The space environment that satellites must survive — radiation belts, solar storms, atmospheric drag, and the geomagnetic phenomena that affect spacecraft and ground systems.
The international treaties, national regulations, and coordination bodies that govern who can launch what, where, and how — from spectrum allocation to debris mitigation rules.
The sensors, techniques, and orbital parameters used to image and monitor Earth from space — from synthetic aperture radar and multispectral imaging to revisit time and ground resolution.
The amateur radio systems aboard satellites — frequencies, modulation modes, Doppler correction, and the coordinate systems used by operators worldwide to make contacts through space.
Concepts in deep-space exploration and astrophysics — exoplanets, biosignatures, space telescopes, and the Lagrange points that enable observation from beyond Earth orbit.
The systems, operations, and milestones of crewed space missions — from life support and EVAs to docking, crew vehicles, space stations, and the boundary of space itself.
The technology behind broadband from space — mega-constellations, laser inter-satellite links, ground terminals, latency, and the race to connect the unconnected.
The study of planets, moons, and small bodies — from rovers and sample return to asteroid deflection, near-Earth objects, and the search for habitable worlds beyond Earth.
The words behind solar and lunar eclipses: the shadows that make them, the moments that time them, the cycle that repeats them and the sights that only totality reveals.