A near-Earth object (NEO) is an asteroid or comet whose trajectory brings it to within 1.3 astronomical units of the Sun and hence within 0.3 astronomical units, or approximately 45 million kilometres, of the Earth’s orbit (UN OOSA, no date).

An airburst is defined as an explosion in the air, especially of a nuclear bomb or large meteorite (Lexico Dictionary, no date).

A geomagnetic storm is a worldwide disturbance of the Earth’s magnetic field induced by a solar storm (Cannon et al., 2013).

UV radiation is the portion of the electromagnetic (EM) spectrum between X-rays and visible light. Depending on its wavelength, UV radiation can penetrate the ozone layer and affect human health in different ways (Government of Canada, 2019).

A meteorite is an object that survives a trip through Earth’s atmosphere and hits the ground (adapted from NASA, no date).

Radio blackout is a prolonged period of fading or faded radio communications, primarily in the high frequency range from ionospheric changes because of increased solar activity, in particular solar flares of C-class level or higher on the sunlit side of Earth (AMS, 2018).

Solar radiation storms occur when large quantities of charged particles, primarily protons, accelerated by eruptive processes at or near the Sun reach the near-Earth environment (NOAA, 2019).

A space accident is any accident involving space objects that causes damage (adapted from UNGA, 1971).