WEEKLY WHINE

HST through the years

The Hubble Space Telescope is now rapidly approaching its second decade, which means that it's been in orbit for ten years.

But more importantly than this, it means that it's produced ten years worth of images for the scientific community and for the general public. This is an important thing to remember about the Hubble Space Telescope: normal people benefit from its images as well as astronomers and physicists. Every once in a while, an HST image is released and immediately makes its way to the front page, where it sparks people's imaginations.

For example, Release 95-44 from the Space Telescope Science Institute [STScI] showed expanding gas globules in portions of the Eagle Nebula [M16], where stars are in the process of forming. This image instantly became popular across the world. People saw shapes in the gaseous pillars, and tabloids proclaimed that UFOs and other random objects were to be found somewhere in the Eagle Nebula.

The Hubble Space Telescope, deployed by the crew of STS-31 on WED 25 APR 1990, produced interesting data its first several years, but it was hampered by a spherical aberration in its primary mirror, making images of all objects, especially dimmer objects, blurry.

The problem was resolved on WED 08 DEC 1993, when Astronauts Kathryn Thornton and Tom Akers installed the Corrective Optics Space Telescope Axial Replacement, a set of corrective optics, during STS-61. Since then, HST has produced images of preposterous clarity, including excellent views of Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Meanwhile, Astronauts Thornton and Akers have retired from NASA.

The second servicing mission was STS-82, which lifted off on TUE 11 FEB 1997. The crew of six included Astronaut Steve Hawley, also a veteran of STS-31. This year, he helped deploy another space observatory, the Chandra X Ray Observatory, as a crew member of STS-93.

NASA is now preparing for STS-103. This mission will be Servicing Mission 3A, due to launch on THU 02 DEC 1999. The crew will install such objects as a new computer and extra handrails. The most important part, though, is the reason that Servicing Mission 3 was divided into A and B components. Three of HST's six gyroscopes have failed, and the other three are the bare minimum that it needs. The SM3A crew will replace the three failed gyroscopes. One member of the crew is John Grunsfeld, a two mission veteran who came to Caltech as a postdoc. He served as a faculty advisor for the GAMCIT project by Caltech SEDS.

After this mission, there is Servicing Mission 3B, which will include what 3A didn't get to. This is planned for 2001. Servicing Mission 4 is slotted for 2003, to be highlighted by the insertion of the Wide Field Camera 3, a replacement for HST's current Wide Field/Planetary Camera 2. Finally, Servicing Mission 5 will occur in 2010, after the telescope's 20 year mission ends. This is not really a servicing mission. Instead, HST will be retrieved and brought back to Earth. This option was selected over a Skylab-style reentry because HST is of size comparable to Skylab, making reentry unsafe.

Throughout these nearly ten years, HST has collected an impressive assortment of objects of all sorts. Here's a partial list, compiled from this STScI index. Numbers after the objects tell you how many HST images of that object have been released since 1994.

• Solar System [62]
• Venus [1]
• Luna [1]
• Mars [10]
• Jupiter and friends [16]
• Saturn and friends [9]
• Uranus and friends [6]
• Neptune and friends [5]
• Pluto and Charon [2]
• Comet Hyakutake [2]
• Comet Hale-Bopp [2]
• Comet Shoemaker-Levy 9 crash [3]
• Other comets [1]
• Asteroids [4]
• Stars, Multiple Star Systems, Other [33]
• Nebulas [31]
• Clusters [10]
• Novas, Supernovas [13]
• Stellar Evolution [19]
• Galaxies [53]
• Quasars [7]
• Cosmology [25]

And remember, for the most bestest information about the Hubble Space Telescope and its activities, you may zoom to http://oposite.stsci.edu/. If, on the other hand, you'd like to apply for observing time or want other astronomically oriented information, you should head for http://www.stsci.edu/.

Happy hunting, and remember: You can see several of these objects yourself, just not with the same detail of HST.