In the Beginning
Since the dawn of civilization, man was limited by his vision and imagination about his understanding of the universe. The telescope enhanced his vision and tempered his pride, as observations by Copernicus, Galileo and Kepler in the 16th and 17th centuries A.D. rebuffed the millennia-old conceit that the Earth is the center of the universe, spearheading the Scientific Revolution.
By the 18th century, the telescope would become the indispensable instrument for investigations of the cosmos. Bigger and better telescopes were built all over the world. Planets, stars, and nebulae which could not be seen by the naked eye were now being routinely noted and logged. Advances in spectroscopy, photography, and photometry increased telescope versatility, sensitivity, and discovery power.
Enter Edwin Hubble
By the turn of the 20th century, most astronomers believed that the observable universe consisted of one galaxy, our Milky Way Galaxy, an oasis of stars, dust, and gas in the vastness of space. However, in 1924, American astronomer Edwin Hubble used the 100-inch Hooker Telescope (see image below) on Mount Wilson near Los Angeles, California, to observe billions of other galaxies besides our own Milky Way, almost all moving away from each other. This suggested that the universe is expanding, unleashing a Pandora's box of seminal inquiries—such as the Big Bang theory—about the possible beginning and end of the universe—issues which are still being debated to this day.
Astronomers like Edwin Hubble (before and after his time), toiled long, frigid nights inside enormous dome-shaped "observatories" pointing their telescopes skyward, yearning for the best possible snapshot of the heavens. However they faced a major obstacle that stood between them and a clear view of the universe: the Earth's atmosphere. The Earth's atmosphere is a fluid, chaotic soup of gas and dust. It blurs visible light, causing stars to twinkle and making it difficult to see faint stars. It hinders or even totally absorbs other wavelengths of light, making observations of such wavelength ranges as infrared, ultraviolet, gamma rays and X-rays difficult or virtually impossible (it is also these properties which protect us from the harmful effect of these rays).
Observatories with the largest of telescopes in various continents have been perched upon mountain tops and away from distracting city lights, from Caucasus Mountains in Europe to the Australian outback, with varying levels of success. Adaptive optics and other image processing techniques have minimized - but not totally eliminated - the effects of the atmosphere.
A Telescope in Space?
In 1923, German scientist Hermann Oberth, one of the three fathers of modern rocketry (Oberth, Robert Goddard and Konstantin Tsiolkovsky), published "Die Rakete zu den Planet engrained" ("The Rocket into Planetary Space"), which mentioned how a telescope could be propelled into Earth orbit by a rocket. In 1946, Princeton astrophysicist Lyman Spitzer wrote about the scientific benefits of a telescope in space, above Earth's turbulent atmosphere.
Following the launch of the Soviet satellite Sputnik in 1957, the fledgling National Aeronautics and Space Administration (NASA) successfully launched two Orbital Astronomical Observatories (OAOs) into orbit. They made a number of ultraviolet observations and provided learning experiences for the manufacture and launch of future space observatories.
The LST - Large Space Telescope
Meanwhile, scientific, governmental, and industrial groups planned the next step beyond the OAO program. Spitzer gathered the support of other astronomers for a "large orbital telescope" and addressed the concerns of its critics. In 1969, the National Academy of Sciences gave its approval for the Large Space Telescope (LST) project, and the hearings and feasibility studies continued.
After Armstrong's "giant leap for mankind" on the moon in 1969, funding for NASA space programs began to dwindle, putting the LST program in jeopardy. LST planners had to design the telescope under budget constraints. A number of downsizing measures were weighed and considered: decrease the size of the primary mirror, the number of scientific instruments, the diameter of the Systems Support Module and the number of spare parts created and tests performed. In 1974, the LST Science Working Group recommended the space telescope carry a large complement of interchangeable instruments. They would have specifications to resolve at least one-tenth of an arcsecond, and have a wavelength range from ultraviolet through visible to infrared light.
The Space Shuttle NASA and its industrial partners—called contractors—brought up the option of developing a vehicle that could achieve orbit and return to earth intact and be reused repeatedly; the concept of the Space Shuttle was born. The Space Shuttle could deploy the LST into space and reel it back for return to Earth.
NASA suggested that the lifetime of the space telescope be fifteen years, which implied that the instruments needed the ability to be replaced on the ground or even serviced in orbit—an ability not afforded to any satellite before or since. Scientists also had to balance the size and quantity of scientific instruments versus their cost. Too many instruments meant financial support was less likely; conversely, instruments of minimal capability would result in the loss of scientific support for the telescope. The European Space Agency (ESA) joined the project in 1975 and provided fifteen percent of the funding of the LST via contribution of the Faint Object Camera (FOC) and the solar arrays. In return, NASA guaranteed at least fifteen percent of telescope time—the amount of time astronomers use the telescope for space observations - to European astronomers. In 1977, Congress approved funding to build one of the most sophisticated satellites ever constructed.
Who Does What?
NASA chose Marshall Space Flight Center in Huntsville, Alabama, as the lead NASA field center for the design, development, and construction of the renamed Space Telescope (ST). Marshall delegated Perkin-Elmer Corporation (now, Hughes Danbury Optical Systems) the task of developing the Optical Telescope Assembly and the Fine Guidance Sensors. Lockheed Missiles and Space Company (now, Lockheed Martin) was selected by Marshall to build the cylindrical casing and the internal support systems (the Support Systems Module) and assembling the telescope together.
NASA chose Goddard Space Flight Center in Greenbelt, Maryland, to be the lead in scientific instrument design and ground control for the space observatory. Scientists were organized into "Instrument Definition Teams" which would translate scientific aims into scientific devices and incorporate them into the space telescope housing. After an announcement was made to the astronomy community, proposals were received and judged, and five devices were selected as the initial instruments that would be aboard the Space Telescope: the Faint Object Camera, the Wide Field/Planetary Camera, the Faint Object Spectrograph, the High Resolution Spectrograph, and the High Speed Photometer.
The Johnson Space Center in Houston, Texas, and the Kennedy Space Center in Florida supplied Space Shuttle support. In all, dozens of contractors, a handful of universities, and several NASA centers, spanning 21 states and 12 other countries worldwide, made the dream of a telescope above the clouds and in space a reality.
In 1983, the Space Telescope Science Institute (STScI) was established at The Johns Hopkins University in Baltimore, Maryland. The staff of STScI evaluated proposals for telescope time and managed the resulting telescope observations. A number of delays stemming from underestimating the costs and engineering requirements of the state-of-the-art telescope caused the launch date to be moved from December 1983 to the second half of 1986. NASA re-examined interfaces, instruments, and assemblies. The building of the Optical Telescope Assembly encountered engineering challenges. Scientific instruments, like the Wide Field/Planetary Camera (WF/PC), underwent redesign, removing weight and redundancy.
Hubble is Born
In regards to the maintenance and upgrading of the space telescope, plans were made to conduct servicing missions in orbit versus returning the telescope to Earth and refurbishing it on the ground. It was an innovative concept that would be even easier on a budget. In the midst of this spirit of renovation, the Space Telescope was renamed the Hubble Space Telescope (HST). By 1985, the telescope was assembled and ready for launch.
However, in 1986 disaster struck. The Challenger accident forced NASA to ground the Space Shuttle fleet for two years. However, these were years well spent by the HST Project. Solar panels were improved with new solar cell technology. The aft shroud was modified to make instrument replacement during servicing easier. Computers and communication systems were upgraded. The HST was subjected to further stress tests in the harsh environments of liftoff and space.
Finally, on April 24, 1990, the Space Shuttle Discovery lifted off from earth with the Hubble Space Telescope nestled securely in its bay. The following day, Hubble was released into space, ready to peer into the vast unknown of space, offering mankind a glimpse upon distant, exotic cosmic shores yet to be described.
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