The Hubble Space Telescope

The Space Telescope was named after American astronomer Edwin P. Hubble.

The telescope's primary mirror is 2.4 meters in diameter, and the overall length is 13.1 meters (about 43 feet).

The telescope was initially brought into orbit via the Space Shuttle Discovery April 24th 1990. The first Service mission occurred during the first two weeks of December 1993.

A Great Observatory

HST was the first of the Great Observatories to be launched and initially covers the UV/Visible region of the spectrum. It will operate contemporaneously with the Gamma Ray Observatory (GRO), Advanced X-Ray Astronomical Facility (AXAF), and possibly Space Infrared Telescope Facility (SIRTF).

Scientific Objectives

Investigate the composition, physical characteristics, and dynamics of celestial bodies.
Examine the formation, structure, and evolution of stars and galaxies.
Study the history and evolution of the universe.
Provide long-term space-based research facility for optical astronomy.

In the first round of observing programs, three Key Projects were identified by the Space Telescope Advisory Committee:

1. Distances to galaxies and the Hubble Constant
2. Medium-deep survey of the sky
3. Quasar absorption lines.

The time dedicated to these projects in subsequent cycles has been enough to discontinue the special status of Key Project - they are listed here to help illustrate some of HST's important objectives.

Research Areas

Galaxies and Clusters
Extragalactic distances, star clusters, interacting galaxies, normal galactic nuclei, galaxy clusters, distant galaxies, cosmological tests, etc.
Interstellar Medium
Dust and extinction, supernovae remnants, planetary nebulae, star formation, circumstellar nebulosity, etc.
Quasars and Active Galactic Nuclei
Quasi-stellar objects, Seyfert galaxies, BL Lac objects, radio galaxies, galactic jets, gravitational lenses.
Stellar Astrophysics
Stellar atmospheres and chemical composition, binary and variable stars, stellar photometry and polarimetry, parallaxes and proper motions of stars, etc.
Stellar Populations
Color-magnitude and luminosity studies of star clusters, dynamics of clusters, structure of the galaxy, stellar surveys, etc.
Solar System
Planetary featuresand atmospheres, staellites and rings, asteroids and comets, extra-solar planets, tests of general relativity, etc.


The Hubble Space Telescope (HST) is distinguished from ground-based observatories by its capability to observe light in the ultraviolet and near infrared. It also has an order of magnitude better resolution than is capable from within the earth's atmosphere.

The telescope is modular in design, for on-orbit servicing via the Space Transportation System (STS). Over the course of its anticipated 15-year operational lifetime, it may be visited by several Space Shuttle crews, for installation of new instruments, repairs, and maintenance.

HST is a 2.4-meter Ritchey-Chretien reflector with a cluster of five scientific instruments at the focal plane of the telescope, and the Fine Guidance Sensors. The European Space Agency (ESA) has provided one of the science instruments (Faint Object Camera), the Solar arrays, and some operational support to the program. Data is relayed to earth via the high gain Antennae..

Orbit 611 kilometer altitude, 28.5 degree inclination circular orbit Weight 11,000 kilograms

The Space Telescope Science Institute (STScI), Baltimore, Maryland, opened in 1981. NASA selected the Association of Universities for Research in Astronomy (AURA) to manage STScI as an astronomy research center and international observatory. AURA selected the Johns Hopkins University as the site for STScI.

Instrument/PI List

Initial instruments:
Faint Object Camera (FOC) - D. Macchetto (ESA)
Faint Object Spectrograph (FOS) - D. Harms (ARC)
Goddard High Resolution Spectrometer (GHRS) - J. Brandt (University of Colorado)
High Speed Photometer (HSP) - R. Bless (University of Wisconsin)
Wide Field/Planetary Camera (WF/PC) - J. Westphal (California Institute of Technology)
Fine Guidance Sensor (FGS) Astrometry - W. Jeffreys (University of Texas)
First servicing mission:
Corrective Optics Space Telescope Axial Replacement (COSTAR) - Ball Aerospace
Wide Field/Planetary Camera-II (WF/PC-II) - J. Trauger (California Institute of Technology)
Planned replacement instruments:
Space Telescope Imaging Spectrograph (STIS) - B. Woodgate (GSFC)
Near Infrared Camera (NIC) - R. Thompson (University of Arizona)

Technology Development Requirements

Requirements for future instruments for optical astronomy:

Detectors that are UV sensitive and blind to visible radiation
Wood filters for CCDs
Tunable filters: Fabry-Perot interferometers; Cousteau optical filters for UV; birefringent filters (Lyot)
Increase the longevity of CCD detectors in high radiation environments
High dynamic range microchannel plates
Larger format detector arrays
Smaller pixels
Detectors for near IR with low noise, high uniformity
Long-life, replenishable cryogenic systems

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