Hubble and its fellow observatories give us an unprecedented, crystal-clear look at the far reaches of the cosmos. Explore these orbiting pioneers and learn what they've discovered. 3 min read The ...

Hubble was built to be tuned up in orbit. But it wasn't designed for the major overhaul NASA astronauts undertook during its fourth servicing mission, 3B, in March 2002. They delved into the ...