atmospheric distortions. As rocket launchings became more frequent, the idea became feasible, and in 1969, official approval was
given for the launch of a large space telescope. However, its development took longer than preparing for a trip to the moon.
A few years later, in 1975, the European Space Agency (ESA)
collaborated with NASA on a plan that would eventually become
Hubble. Funding was approved by Congress approved in 1977,
and with the development of the Space Shuttle, NASA now had a
means to deliver the telescope to orbit.
Originally dubbed the Large Space Telescope, it was later renamed the Hubble Space Telescope (HST) in honor of Edwin Hubble, the American astronomer who determined that the universe
was expanding. On April 24, 1990, world’s first space telescope was
then launched aboard the Space Shuttle Discovery. The development and construction of Hubble originally cost $1.5 billion, but
there would be ongoing costs – both expected and unexpected.
With the very first observation, researchers noticed an issue – the
telescope’s images were fuzzy. Hubble’s main mirror had a major
defect: a spherical aberration, a fraction of the diameter of a single
human hair, caused by a manufacturing error. Hubble was effectively near sighted. Researchers worked quickly to develop a fix.
However, it would be three years before NASA could undertake a
repair mission. On Dec. 2, 1993, the Space Shuttle Endeavor ferried
a crew of seven astronauts to fix Hubble across five days of spacewalks. During the missions two new cameras, including the WideField Planetary Camera 2 (WFPC-2) were installed. When the first
new images from Hubble reached Earth, they were breathtaking.
Images of the spiral galaxy Messier 100 demonstrate the improvement in Hubble images after
corrective optics were installed during Servicing Mission 1 in 1993. Credit: NASA
Hubble has been serviced a total of five times. Among the repairs, astronauts had to replace batteries and directional gyroscopes. The final servicing mission took place in 2009, and the telescope is expected to continue to function for years to come. NASA
is currently developing Hubble’s replacement, the James Webb
Space Telescope (JWST), which is scheduled to launch in 2018.
The Hubble Space Telescope’s elevated perspective and advanced optics allow it to peer farther away than ground-based optics can dream of. Because light takes time to travel long distances,
the range of the HST makes it function like a time machine. Looking
through the orbiting telescope is like peering back in time; the light
collected from remote objects shows the object as it appeared
when the light left, not how it would appear today. Take our closest
neighbor, the Andromeda galaxy -- at a distance of 2.5 million lightyears from Earth we see it as it was 2.5 million years ago.