Space News
space history and artifacts articles

Messages
space history discussion forums

Sightings
worldwide astronaut appearances

Resources
selected space history documents

Websites
related space history websites

  collectSPACE: Messages
  Stamps & Covers
  Space Cover 18: Hubble Space Telescope

Post New Topic  Post A Reply
profile | register | preferences | faq | search

next newest topic | next oldest topic
Author Topic:   Space Cover 18: Hubble Space Telescope
Apollo-Soyuz
Member

Posts: 868
From: Shady Side, Md
Registered: Sep 2004

posted 08-16-2009 11:06 AM     Click Here to See the Profile for Apollo-Soyuz   Click Here to Email Apollo-Soyuz     Edit/Delete Message   Reply w/Quote
Space Cover of the Week, Week 18 (August 17, 2009)

Space Cover #18, Hubble Space Telescope

Launched on April 24, 1990 aboard Space Shuttle Discovery, the Hubble Space Telescope (HST) was designed to be the most powerful astronomical observatory ever built. HST far surpasses the capabilities of ground based optival telescopes. In addition, HST was the forst observatory designed for extensive on-orbit maintenance and refurbishment.

Two months after launch, Hubble produced a discovery not about space but about itself. Hubble was out of focus by 1/50th the width of a human hair due to the curvature of the mirror being too flat near the edge. The result was a focusing defect of spherical aberration. To compensate for the out of focus mirror, corrective optics had to be installed much the same as glasses of contact lenses correct human sight.

The first HST Servicing Mission (SM-1) launched December 2, 1993 aboard Space Shuttle Endeavour was an unqualified success restoring the optical capabilities of HST to its original specifications.

The above cover was cancelled on the launch dates of STS-31 and STS-61. I chose this cover to demonstrate what extra can be done to make a cover more interesting with, in this case, an appropiate cancel added for a subsequent and relevant mission.

------------------
John Macco
Space Unit#1457

All times are CT (US)

next newest topic | next oldest topic

Administrative Options: Close Topic | Archive/Move | Delete Topic
Post New Topic  Post A Reply
Hop to:

Contact Us | The Source for Space History & Artifacts

Copyright 1999-2012 collectSPACE.com All rights reserved.


Ultimate Bulletin Board 5.47a





advertisement