Hubble Space Telescope

The Hubble Space Telescope (HST) is the most famous astronomical instrument of its time and one of the best-known robotic vehicles ever put into space. Its launch and deployment into low-Earth orbit from the Space Shuttle Discovery in April 1990 appeared to fulfill the plans and dreams of astronomers since the beginnings of space exploration to place a telescope beyond the distorting effects of Earth’s atmosphere.

The first images from Hubble contained a stunning surprise: the space telescope’s main mirror had been precisely ground to the wrong shape. With the future of NASA on the line, scientists and engineers devised fixes for the spherical aberration afflicting Hubble, and astronauts flying on the first of five shuttle servicing missions to HST installed new instruments that restored the space telescope’s capabilities. Within weeks HST produced the breathtaking images and other data that astronomers and the public had long anticipated, and Hubble went on to become a symbol of American technological and scientific prowess.

Not Yet Imagined: A Study of Hubble Space Telescope Operations was published by the NASA History Division in 2021, and its e-book versions are available for free download. Free hard copies of this book are available from the NASA Information Center,, 202-358-0000, Suite 1U72, NASA Headquarters, Washington, DC 20546. One per customer please.

This book documents the history of HST from its launch through its first 30 years of operation in space. It focuses on the interactions among the general public, astronomers, engineers, government officials, and members of Congress during that time. The decision-making behind the changes in Hubble’s instrument packages on servicing missions that made HST a model of supranational cooperation amongst scientists is chronicled, along with HST’s contributions to our knowledge about our solar system, our galaxy, and our universe. Not Yet Imagined also covers the impact of HST and the images it produces on the public’s appreciation for the universe, and how HST has changed the ways astronomy is done.