April 23, 2014
Two instruments that played critical roles in discoveries made by NASA's Hubble Space Telescope now are on display in an exhibit at the Smithsonian National Air and Space Museum in Washington.
"Repairing Hubble" recognizes the 24th anniversary of Hubble's launch into space aboard space shuttle Discovery on April 24, 1990. The exhibit features Hubble's Corrective Optics Space Telescope Axial Replacement (COSTAR) instrument and the Wide Field and Planetary Camera 2 (WFPC2).
Soon after Hubble began sending back images in 1990, scientists discovered that the telescope's primary mirror had a flaw called spherical aberration. The 7.9-foot (2.4-meter) primary mirror was ground too flat by a depth of 4 microns at its outer edge, which is roughly equal to one-fiftieth the thickness of a human hair. The flaw prevented images of objects being studied from coming into proper focus. After the amount of aberration was understood, scientists and engineers developed the Wide Field and Planetary Camera 2 (WFPC2) and the Corrective Optics Space Telescope Axial Replacement (COSTAR) to correct the optical error. They were both installed into Hubble by astronauts working from the space shuttle Endeavour during the telescope's first servicing mission in December 1993.
WFPC2, a new imaging camera about the size of a baby grand piano, contained a set of internal corrective optics to compensate for the error in the Hubble telescope's primary mirror. This allowed the camera to record razor-sharp images of celestial objects -- from nearby planets to remote galaxies. Serving as the primary visible-light camera for more than ten-and-a-half years, and taking more than 135,000 observations of the universe, it was the longest serving and most prolific instrument to have served aboard Hubble.
WFPC2 images would go on to adorn posters, album covers, screen savers and science textbooks throughout the world. A landmark observation was the Hubble Deep Field taken in 1995. This long exposure captured the light of 4,000 galaxies stretching 12 billion years back in time. WFPC2 replaced the original Wide Field and Planetary Camera (WFPC), the main science instrument that launched with Hubble in 1990. Both WFPC and WFPC2 were built by NASA's Jet Propulsion Laboratory in Pasadena, California.
During their fourth spacewalk, astronauts installed COSTAR, a device which replaced the High Speed Photometer instrument, and which deployed mirrors to intercept and correct the light headed to the three remaining science instruments: the European Faint Object Camera, the Goddard High Resolution Spectrograph, and the Faint Object Spectrograph. COSTAR was built by Ball Aerospace & Technologies Corp. in Boulder, Colorado.
Both WFPC2 and COSTAR were removed from Hubble in May 2009, during the fifth and final servicing mission, and returned to Earth. WFPC2 was replaced by the more modern Wide Field Camera 3, and COSTAR's removal made way for the Cosmic Origins Spectrograph.
Development of the National Air and Space Museum exhibit was supported by NASA, including the agency's Goddard Space Flight Center in Greenbelt, Md., and the Space Telescope Science Institute in Baltimore. The exhibit was designed and constructed by museum staff.
A reception at the National Air and Space Museum in April 2014 featured presentations by NASA Administrator Charles Bolden, who was the pilot for Discovery during the Hubble deployment mission in 1990; Gen. J.R. "Jack" Dailey, museum director; John Grunsfeld, NASA's Science Mission Directorate associate administrator and astronaut on several shuttle Hubble servicing missions; and John Trauger, former WFPC2 principal investigator at JPL. The presentations aired on NASA Television. For NASA TV streaming video, downlink and scheduling information, visit:
For more information about the new Hubble exhibit and the Smithsonian National Air and Space Museum, visit:
For more information about the WFPC2, visit:
For more information about NASA's Hubble Space Telescope, visit these sites:
Jet Propulsion Laboratory, Pasadena, Calif.
NASA Headquarters, Washington
Smithsonian's National Air and Space Museum