American theoretical astrophysicist Lyman Spitzer proposed placing a telescope in space during 1946. His document titled Astronomical Advantages of an Extra-terrestrial Observatory argued that Earth's atmosphere hindered observation.
The Hubble Space Telescope finally launched on the 24th of April 1990 aboard the Space Shuttle Discovery. Nancy Grace Roman later championed this vision as the first Chief of Astronomy at NASA to convince Congress and agency leaders that the project was worth the cost.
Earth's atmosphere filters electromagnetic radiation through scattering and absorption processes which blur images captured by ground telescopes. Twinkling stars result from atmospheric refraction while the atmosphere blocks X-rays and largely obstructs infrared and ultraviolet radiation.
The American Orbiting Astronomical Observatory OAO-2 became operational in 1968. This mission marked one of the earliest successful deployments of a space-based observatory before Soviet astronomers followed with the Orion 1 ultraviolet telescope aboard the Salyut 1 station in 1971.
Most instruments cannot be serviced once they leave Earth's surface but the Hubble Space Telescope remained an exception because it was designed for servicing by the Space Shuttle. Engineers faced prohibitive financial expenses trying to repair equipment located in orbit due to logistical difficulties arising from the need to launch astronauts or robotic arms into space.