Hubble's orbit above the Earth's distorting atmosphere allows astronomers to make the very high resolution observations that are essential to open new windows onto planets, stars and galaxies. Hubble was designed as a high standard flagship mission and has paved the way for other space-based observatories. Notably it can access the otherwise invisible ultraviolet part of the spectrum, and also has access to areas of the infrared not visible from the ground.
The Hubble Space Telescope is named after Edwin Powell Hubble (1889-1953) who was one of the great pioneers of modern astronomy.
Design: At the heart of Hubble are a 2.4 m primary mirror and a collection of five science instruments that work across the entire optical spectrum - from infrared, through the visible, to ultraviolet light. There is one camera, three combined camera/spectrographs and a set of fine guidance sensors onboard Hubble. Hubble was designed to be serviced in space, allowing outdated instruments to be replaced. The telescope was placed into a low-Earth orbit by the Space Shuttle and uses modular components so that it can be recovered on subsequent Shuttle Servicing missions and faulty or outdated parts more easily replaced before being re-released into orbit.
Power: Power for the computers and scientific instruments onboard is provided by two 2.6 × 7.1 m solar panels. The power generated by the panels is also used to charge six nickel-hydrogen batteries that provide power to the spacecraft for about 25 minutes per orbit while Hubble flies through the Earth's shadow.
Manoeuvring: The telescope uses an elaborate system of attitude controls to improve its stability during observations. A system of reaction wheels manoeuvres the telescope into place and its position in space is monitored by gyroscopes. Fine Guidance Sensors (FGS) are used to lock onto guide stars to ensure the extremely high pointing accuracy needed to make very accurate observations.
Dimensions: Length: 13.2 m, diameter: 4.2 m. In addition two solar panels each measuring 2.6 × 7.1 m.
Mass: 11 110 kg (at the time of launch).
Hubble was deployed by the Space Shuttle Discovery (STS-31) into a circular orbit 600 km above the ground, inclined at 28.5 degrees to the Equator. The time for one orbit is between 96 and 97 minutes.
The science operations are co-ordinated and conducted by the Space Telescope Science Institute (STScI) in Baltimore and at NASA's Goddard Space Flight Center (GSFC) in Greenbelt.