The Mammoth Book of Space Exploration and Disasters

Hubble’s troubles

In 1962 the US National Academy of Sciences proposed building a large telescope that would allow astronomers to study the universe. The new telescope would be placed in orbit which would enable it to make observations free from atmospheric interference. The Hubble Space Telescope (HST) was named after Edwin Hubble, in 1929 who had observed that distant galaxies were moving away from us therefore the universe was expanding.

In 1977 the US Congress approved funding for the HST and construction of the telescope began.

In 1981 the Baltimore, Maryland-based Space Telescope Science Institute (STScI) became operational and the precision-ground mirror of the telescope was completed.

In 1985, construction of the entire HST was completed and the ground control facility for the telescope was established at the Space Telescope Operations Control Center in Goddard.

The Hubble Space Telescope should have resolving power ten times better than any ground-based telescope. It should be able to see objects which are fifty times fainter. In addition it would be able to observe wavelengths which are not detectable from the ground, particularly ultraviolet.

The launch of the HST was delayed due to the Challenger disaster in 1986, but in October 1989 the telescope was moved from Lockheed, California to its launch site at the Kennedy Space Center in Florida and on 24 April 1990 the HST was launched aboard the STS-31 mission of the Discovery space shuttle.

As soon as the Hubble Space Telescope was deployed in space, it became apparent that the primary mirror was the wrong shape. The 2.4 m concave mirror was too shallow by 2 mm at the edge and this caused light from the outer part of the mirror to converge to an F/24 focal point some 38 mm behind the light from the central region. As a result star images were surrounded by haloes, several being seconds in diameter instead of being pin sharp and only a fraction of a second in diameter. The primary mirror was clearly suffering from a severe case of spherical aberration, and it was later found that this was the result of faulty testing in the optical works, because one test component was 1.3 mm out of position. Five 6-hour space walks were required to repair the Hubble Space Telescope.