March 18

In August 1898, astronomer William Henry Pickering captured photographic plates that revealed Phoebe, a previously unknown moon of Saturn. On March 18, 1899, Pickering announced the discovery, marking the first time a natural satellite was identified through photography. Phoebe's irregular, retrograde orbit puzzled scientists and hinted at a capture origin from beyond Saturn's system. This pioneering use of astrophotography revolutionized observational astronomy, demonstrating the power of photographic techniques. The find opened the door for future discoveries of faint celestial bodies and expanded our understanding of the Solar System.

Cosmonaut Alexei Leonov exited the airlock of Voskhod 2 on March 18, 1965, becoming the first human to conduct an extravehicular activity (EVA). His 12-minute spacewalk represented a major milestone in space exploration during the Cold War. Leonov's suit inflated unexpectedly, making re-entry into the spacecraft challenging. He ingeniously vented suit pressure to complete the EVA safely. This pioneering achievement paved the way for future human activities in space, including moonwalks and long-duration stays on space stations. It showcased the technological capabilities of the Soviet space program and intensified the space race with the United States.