Hubble Space Telescope

The Hubble Space Telescope, launched in 1990, overcame a famously flawed mirror—fixed during one of the most dramatic spacewalks ever—to capture over 1.5 million observations, fundamentally altering astronomy. It proved the universe's expansion is accelerating, earning a Nobel Prize, and revealed galaxies forming just 500 million years after the Big Bang. Hubble's images became cultural icons, making the public care about the cosmos more than any other mission, surpassing even Voyager 1 in public engagement.