A solar flare is localized eruption of electromagnetic radiation in the Sun's atmosphere. They are thought to occur when magnetic energy stored in the Sun's atmosphere accelerates charged particles in the surrounding plasma. This results in the emission of electromagnetic radiation across the electromagnetic spectrum, and may be accompanied by coronal mass ejections, solar particle events, and other solar phenomena. Electromagnetic radiation from solar flares is absorbed by the daylight side of Earth's upper atmosphere, in particular the ionosphere, and does not reach the surface.

Solar flares were first observed by Richard Carrington and Richard Hodgson (independently) on 1 September 1859. Although accurate measurements were not taken at the time, it is suspected that this was the most powerful flare ever observed.

Skylab 3 was the second crewed mission to the first American space station, Skylab. The mission began on July 28, 1973, with the launch of NASA astronauts Alan Bean, Owen Garriott, and Jack Lousma in the Apollo command and service module on the Saturn IB rocket, and lasted 59 days, 11 hours and 9 minutes. The mission carried out various medical experiments to investigate the effects of space travel on the human body - these tasks were recognised on the circular crew patch worn by the astronauts representing Leonardo da Vinci's c. 1490 Vitruvian Man (albeit retouched to remove the genitalia!), personifying the mission's medical experiments.

The Skylab 3 command module returned to Earth on September 25, 1973, and, in 1977, was transferred to the Smithsonian Institution by NASA. It was subsequently moved to the Great Lakes Science Center in June 2010.