A signal awaits astronomical interpretation

Tereshkova’s launch showed a woman could perform an orbital spaceflight despite earlier exclusion.

The spacecraft put Tereshkova in Earth orbit for a mission lasting nearly three days.

The satellites recorded the first known cosmic gamma-ray burst; its extraterrestrial source was recognized later.

The gamma-ray signal was initially detected by instruments built to monitor nuclear explosions.

The detection later helped establish the study of transient cosmic gamma-ray sources.

Armstrong and Aldrin landed in the Sea of Tranquility while Collins remained in lunar orbit.

The landing prepared for direct observations and sample collection by human explorers on the Moon.

Michael Collins piloted the command module while the lunar module descended to the surface.

The landing was a milestone in human exploration of the solar system; the first steps took place later in UTC on 21 July.

The spacecraft became the first human-made object to orbit another planet.