Through 25 years on-orbit, the Space Telescope has repeatedly changed our understanding of the Universe. Astronaut John M. Grunsfeld, now NASA's Associate Administrator Science Mission Directorate, illuminates why we love this instrument.
The supermassive black hole is 40 million times as massive as the sun and powers a quasar that existed 700 million years after the Big Bang.
The asteroid zoomed by Earth at a perfectly safe distance of around 1.8 million miles (2.9 kilometers).
Images show surprise changes to the spacecraft as it interacted with the atmosphere.
