Hubble Space Telescope | Can’t Sleep? Explore the Universe

The Hubble Space Telescope nearly failed before it ever launched. Its main mirror, ground over years at enormous expense, turned out to be the wrong shape—a flaw so subtle that it compromised the telescope's ability to focus, yet so fundamental that it threatened to turn a $1.5 billion observatory into a high-orbit joke. The story of how that happened, and how it got fixed, is woven into a longer arc: a decades-long fight to get a telescope above the atmosphere, a fight that involved budget tricks, political lobbying, and a scientist named Nancy Grace Roman who spent years explaining to Congress why the project mattered.

The Case for Leaving the Ground

The idea of putting a telescope in space dates to 1946, when astronomer Lyman Spitzer published a paper called "Astronomical Advantages of an Extraterrestrial Observatory." He identified two main problems with ground-based telescopes. First, the atmosphere blurs images—stars twinkle because turbulent air bends their light, limiting resolution to about 0.5 to 1.0 arcseconds. A telescope above the atmosphere could reach a theoretical diffraction-limited resolution of 0.05 arcseconds, a tenfold improvement. Second, Earth's atmosphere absorbs most ultraviolet and infrared light. A space telescope could see the universe in wavelengths that never reach the ground.