The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. Although not the first space telescope, Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. read more
Hubble is nearly the size of a large school bus — but it can fit inside a space shuttle cargo bay. Enlarge image Hubble's two mirrors were ground so that they do not deviate from a perfect curve by more than 1/800,000th of an inch. read more