Hubble Space Telescope

The Hubble Space Telescope (HST) was launched into orbit around Earth on 25 April 1990. HST is an observatory first originally conceived in the 1940s and finally operational in the 1990s. The observatory was designed to have a long life span of 15 years. The HST is a co-operative programme of the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA). The aim of the observatory is to operate a long-lived space-based observatory for the benefit of the international astronomical community.

HST is a 2.4m reflecting telescope which was launched into a low-Earth orbit (600km) by the crew of the space shuttle Discovery (STS-31) in 1990. The science operations and control of the telescope lies in the hands of the Space Telescope Science Institute (STScI) on the Johns Hopkins University Homewood Campus in Baltimore, Maryland. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc. (AURA).

TRACKING AND DATA RELAY SYSTEM (TDRS)

HST works much like a robot or computer in space, performing tasks only in response to detailed instructions from people on the ground. The telescope has communications antennae so that astronomers and technicians can transmit instructions. Four antennae send and receive information between the telescope and the Space Telescope Operations Control Centre at NASA's Goddard Space Flight Centre, using the Tracking and Data Relay Satellite (TDRS) system. There are currently five TDRS satellites located at various locations in the sky.
HST incorporates three cameras, two spectrographs, and fine guidance sensors (primarily used for astrometric observations). Due to its location above the hazy atmosphere of Earth, these science instruments can produce high resolution images of astronomical objects. Ground-based telescopes seldom provide resolution better than 1.0 arc-seconds, HST's resolution is about ten times better, or 0.1 arc-seconds.

WIDE FIELD/PLANETARY CAMERA

Originally the telescope functioned on a Wide Field/Planetary Camera 1 (WF/PC1). However, an early malfunction on one of its mirrors meant the images received were blurry. In 1993 the STS-61 shuttle mission, which was the first servicing mission for the telescope, saw the implementation of WF/PC2, a spare instrument developed in 1985 by the Jet Propulsion Laboratory in Pasadena, California. From this moment on HST sent back images of the highest quality. WF/PC2 is actually four cameras, consisting of an L-shaped trio of wide-field sensors and a smaller, high resolution ('planetary') camera tucked in the square's remaining corner.

CHARGE-COUPLED DEVICES (CCDs)

Four postage stamp-sized pieces of high-tech circuitry called Charge-Coupled Devices (CCDs) collect information from stars and galaxies to make photographs. CCDs are electronic circuits composed of light-sensitive picture elements (pixels). Each pixel is given a number and then transmitted to ground computers on Earth to form an image.

HUBBLE'S SPACE TELESCOPE IMAGING SPECTROGRAPH (STIS)

Hubble's Space Telescope Imaging Spectrograph (STIS), enables the telescope to separate the light entering the camera in order to analyse properties such as temperature, radial velocity, rotational velocity and magnetic fields, across a spectral range from the UV (115nm) through the visible red and the near-IR (1000nm). It is capable of performing two-dimensional rather than one-dimensional spectroscopy, thus allowing analysis of many locations in the galaxy simultaneously and can also record a broader span of wavelengths in the spectrum of a star at one time.

NEAR INFRARED CAMERA AND MULTI-OBJECT SPECTROMETRE (NICMOS)

The Near Infrared Camera and Multi-Object Spectrometre (NICMOS) is an HST instrument providing the capability for infrared imaging and spectroscopic observations of astronomical targets. Nicmos works only at very cold temperatures, thus uses cryogenic technology to keep the detectors cold.

FAINT OBJECT CAMERA (FOC)

The Faint Object Camera (FOC), built by the European Space Agency, uses image intensifiers to produce images, which are 100,000 times brighter than the light received. These images are then scanned by an electron-bombarded silicon (EBS) television camera. The FOC provides an ultra sensitive means of analysis.

MULTILAYERED INSULATION

The designers of the Hubble Space Telescope were careful to take into account operating conditions. Hubble would be subject to the rigors of zero gravity and temperature extremes, which includes fluctuations of more than 100°F during each orbit as the Earth blocks out the Sun's light. To accommodate for this, a 'skin', or blanket, of multilayered insulation (MLI), which protects the telescope from temperature extremes was installed. Beneath this lies a lightweight aluminium shell, which houses its optical system and science instruments. The telescope's optical system is held together by a truss (skeleton). This was specifically made of graphite epoxy (used for tennis racquets/golf clubs), due to the material being stiff, strong and lightweight and, resists expanding and contracting in extremes of temperature.

SPESIFICATION :

Order year

1940

Project type

Space Craft

Base country

USA

Estimated investment

Unknown

Completion

1990

Key Players:

Sponsor

NASA and European Space Agency (ESA)

Lead contractor

NASA Jet Propulsion Laboratory

Financing

NASA and European Space Agency (ESA)

Others

Space Telescope Science Institute (STScI), Association of Universities for Research in Astronomy

Output:

Number

1