The Hubble Space Telescope (HST) is celebrating its 24th birthday. The craft was launched on 24 April 1990, becoming the first major optical telescope ever launched into space.
Soon after launch, astronomers noticed images recorded by the space observatory were blurry. Investigation revealed the main (primary) mirror of the instrument was ground to the wrong shape. The error, present in the outer edge of the mirror, was off by one-fiftieth of the thickness of a human hair. That small mistake destroyed the capabilities of a wide range of observations made using the $2.5 billion dollar craft.
Four primary instruments of the Hubble Space Telescope were impaired by the error. Three of these, the Goddard High Resolution Spectrometer, Faint Object Spectrograph, and the Faint Object Camera were corrected with the addition of a single module.
"The Corrective Optics Space Telescope Axial Replacement (COSTAR) instrument, installed in 1993, fixed a major flaw in Hubble's primary mirror," NASA officials wrote in a press release about the anniversary of the Hubble mission.
COSTAR was not capable of improving the measurements of the Wide Field and Planetary Camera (WFPC) on Hubble. That instrument was designed to record deep-space images in great detail. Work had already started on an upgrade, the Wide Field and Planetary Camera 2 (WFPC2). That replacement mechanism was adapted to account for the error in the orbiting observatory.
The Pillars of Creation, an image of the Eagle Nebula photographed by the Hubble telescope in 1995 captivated viewers around the world.
Hubble travels at around 17,000 miles per hour during its orbit, which it has completed over 110,000 times since the start of its mission. During that time, the orbiting observatory has traveled 2.8 billion miles, approximately the distance between the sun and the planet Neptune.
The NASA observatory uses 2,800 watts of electricity to complete, about the same as a 20,000 BTU air conditioner.
Some of the oldest galaxies in the observable universe have been imaged by Hubble, which also determined limits of their age. Planets around other stars, including those still in the process of formation, have been viewed by astronomers using the HST.
Gamma Ray Bursts (GRB's), the most powerful explosions ever witnessed by mankind, have also been examined by Hubble, revealing information about the cataclysmic events. During the 1960's, GRB's were discovered by military satellites searching for evidence of nuclear tests.
COSTAR and the WFPC2 were returned to Earth in 2009. Both modules have recently been put on display at the Smithsonian National Air and Space Museum in Washington DC.
Happy Birthday, Hubble!
