posted 02-08-2015 10:12 AM               

The STS-31 Discovery space shuttle mission thundered into Earth orbit, April 24, 1990, at Kennedy Space Center, Florida. The Hubble Space Telescope was the shuttle's primary payload and was carried into orbit by Discovery's crew and is released the following day into a 380 mile high Earth orbit. Hubble has five times the resolution and clarity of visual and infrared objects it observes from space and exceptionally better than the best observatories images possible from Earth's surface.

The NASA photo of Hubble in orbit taken by space shuttle Discovery is graced with a first day cancellation of a United States' commemorative stamp for the namesake of the telescope, distinguished astronomer, Edwin Hubble, who championed scientific study of the cosmos and extragalactic space in astronomy.

The double cancelled first day cover above shows a vintage image of Edwin Hubble in his office at the Mount Wilson Observatory with a first day of issue stamp of him, cancelled March 6, 2008. A strip of five U.S. stamps showing incredibly rendered images of nebulae observed by his namesake the Hubble Space Telescope are cancelled April 10, 2000, at Greenbelt, Maryland, where the first day of issue of the stamps was conducted.

The Hubble Space Telescope images for these U.S. stamps were selected by the U.S. Postal Service as the best Hubble images to be displayed and showcasing Edwin Hubble's work. The nebulae from left to right on the cover are: the Eagle Nebula, Ring Nebula, Lagoon Nebula, Egg Nebula, and Galaxy NGC 1316. The stamps were released by the USPS on the 10th anniversary of the launch of the Hubble Space Telescope on space shuttle Discovery 31.

Space Cover #303: Hubble Muddle Toil and Trouble

Almost immediately after the Hubble Space Telescope went into orbit from space shuttle Discovery and became operational, something seemed very wrong. While the space telescope's pictures were better than those of Earth based telescopes, the images were not the clear crisp images anticipated. The telescope's images were blurry and were just not right. There was a major problem with the Hubble, and it was in Earth orbit.

The Hubble telescope's 2.4 meter (7.9 foot) Cassegrain reflector design consisted of two hyperbolic reflectors, and even though they were finely polished over the course of a year, the reflectors displayed a major flaw called spherical aberration distorting its images. The mirrors were slightly out of shape, causing the light reflecting off the center of the mirrors to focus in a different area than the light reflected off the outer edges of the mirrors and resulting in blurriness of the objects displayed by the Hubble telescope.

The correction of the spherical aberration was doable in an Earth environment but how could it be done in space? NASA and ESA engineers determined a series of small mirrors could be utilized to catch the light reflecting off the mirrors, correct for the flaw, and forward the light to the telescope's science instruments. The Corrective Optics Space Telescope Axial Replacement, COSTAR, could be installed in the place of one of the telescope's other instruments in order to correct the blurry images produced by remaining and future instruments.

On a subsequent shuttle mission, astronauts could replace the Wide Field Planetary Camera with a new version, the Wide Field and Planetary Camera 2 (WFPC2). The new camera would have small mirrors to correct for the telescope's aberration issue and would result in corrective vision.

Astronauts and NASA and ESA staff spent 11 months working on one of the most complex space missions ever attempted to repair Hubble and to enable the space telescope to achieve the pristine and exceptional images in space for which it was designed. More importantly, in addition to the extreme complexity of the Hubble repair mission, it would become the first important test of the Hubble space telescope to be serviced and repaired in space.

The Hubble Space Telescope was designed to have regular servicing and equipment upgrades in space. Five servicing missions (SM 1, 2, 3A, 3B, and 4) were flown by NASA space shuttle astronauts. The first servicing mission was made by STS-61 mission in space shuttle Endeavour, in December 1993, and the last one, STS-125 was made in space shuttle Atlantis and was completed in May 2009. Shuttle servicing missions were precise operations that began with a space shuttle maneuvering to close on the Hubble space telescope in orbit, and carefully retrieve it with the shuttle's Canadarm carefully pulling it into the space shuttle's payload bay.

The Hubble telescope's repair and refurbishment work was made by shuttle astronaut crew members during multiple tethered spacewalks over the shuttle's payload bay during a period of time of four to five days. After an exacting inspection of the Hubble space telescope, astronauts conducted repairs, replaced failed or degraded components, upgraded equipment, and installed new instruments on the telescope. Once the telescope work was completed and checked, the astronauts redeployed Hubble from the shuttle, boosting it into a higher orbit to correct for orbital decay caused by atmospheric drag on the Hubble as a result of the time it had spent in space.

Edwin Hubble accomplished his detailed and exacting work at the largest Earth telescopes of his time at the Wilson Observatory and Mount Palomar observatories, in California. Heralded as a great astronomer by Postmaster General William Henderson at the first day cover ceremony issuing the stamps made from images of the Hubble Space Telescope, the legacy of Edwin Hubble remains a remarkable one for astronomy. Hubble's findings fundamentally changed the scientific views of astronomy and the origin of the Universe with his proof of earlier Belgian astronomer Georges Lemaitre's Big Bang theory.

His detailed and exacting work in astronomy established major scientific astronomical findings even to today for the forming and expansion of the Universe. Astronomers who supported Hubble's expansion of the Universe theory confirmed his theory of nebulae outside our own Milky Way galaxy. Through his extragalactic astronomy work, Hubble further confirmed the Universe is expanding at a measurable rate now termed Hubble's Law and showing the way for future work in astronomy to be conducted.

Royal Mail issues four fanciful commemorative Hubble Space Telescope stamps along with Hubble Space Telescope fancy cancellations the following year as shown on this first day cover for the space telescope stamps and cancelled at Cambridge, England. Often considered a United States' space telescope because it was carried into orbit by space shuttle Discovery, the Hubble Space Telescope actually was a joint project of NASA and the European Space Agency (ESA).

If you have a favorite Hubble cover, please feel free to post a comment to this or send me your cover scan and I will post it for you.