In 1868 Pierre Janssen watched the moon pass in front of the Sun. Using a special prism, he became obsessed with a line of yellow light that everyone assumed was sodium so he kept studying that mysterious line. Joseph Lockyer worked on the same problem and both are credited for helium
Beads of Lunar Glass Boost Hopes for Using the Moon’s Water
NASA to name Artemis 2 crew next week, the first moon astronauts in 50 years