The Hubble Space Telescope

is a joint ESA/NASA project and was launched in 1990 by the Space Shuttle mission STS-31 into a low-Earth orbit 600 km above the ground. During its lifetime Hubble has become one of the most important science projects ever.

Mission Objectives

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.

Spacecraft

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 Hubble was designed to be serviced in space, allowing outdated instruments to be replaced.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Shuttle and uses modular components so that it can be recovered on subsequent Shuttle Servicing missions and faulty or outdated parts more easily replaced before being re-released into orbit.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 for the computers and scientific instruments onboard is provided by two 2.6 x 7.1 m solar panels. The power generated by the arrays is also used to charge six nickel-hydrogen batteries which provide power to the spacecraft for about 25 minutes per orbit while Hubble flies through the Earth’s shadow.

The telescope uses an elaborate system of attitude control to improve its stability during observations. A system of reaction wheels manoeuvre 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.

Orbit

Hubble was deployed by the Space Shuttle Discovery (STS-31) into a circular orbit 589 km above the ground, inclined at 28.5 degrees to the Equator. The time for one orbit is between 96 and 97 minutes.

Did you know .. The Hubble Space Telescope whirls around Earth at a speed
of 5 miles per second. If cars moved that fast, a coast-to-coast trip across the
continental United States would take only 10 minutes.

Hubble’s Solar Panels

With an area 1/3 less than the previous ESA-built set of solar panels, Hubble’s third set of solar arrays produces 20% more power. This enables all the science instruments to be turned on at the same time thereby making the Observatory even more efficient than in the past.

The new panels are more rigid than the previous two pairs and this makes it possible to perform even more stable and pin-point sharp observations.

Gyroscopes

Hubble has six gyroscopes, or gyros, on board. Three of these are needed at all times to keep the telescope pointing in the right direction and to keep the telescope stable.

Inside a gyro a wheel is spinning more than 19,000 times per minute and there are electronics to detect the very small deflections of the wheel’s axis.

The gyros are the most accurate in the world and can keep Hubble pointing at the same target for long periods at a time.

Unfortunately some of Hubble’s gyros have been hit by problems. Normally this is not a cause for concern (there are three spare gyros), but if four out of six gyros fail, Hubble can no longer observe. This happened few weeks before Servicing Mission 3A (during which all six gyros were replaced). The source of the gyro problems is thought to be corrosion of some very thin wires inside the gyros.

Electrical Systems

Hubble’s Solar Panels are its primary source of power. Each array of solar cells
converts solar energy into electrical energy. The electricity produced by the
solar cells is used to charge Hubble’s batteries. Hubble has six batteries each
consisting of 22 cells in series (and including other components such as
additional heaters and electronics). The batteries are packaged in two groups of
three in modules weighing about 214 kg each. Each battery holds more than 75
Ampere-hours of energy. This is sufficient to keep the telescope in normal
operation for 7.5 hours.

Some interesting facts..

Did you know .. The Hubble Space Telescope whirls around Earth at a speed
of 5 miles per second. If cars moved that fast, a coast-to-coast trip across the
continental United States would take only 10 minutes.

Did you know.. In an average orbit, Hubble uses about the same amount of
energy as 28 100-watt light bulbs.

Did you know.. Hubble transmits about 120 gigabytes of science data every
week. That’s equal to about 3,600 feet (1,097 meters) of books on a shelf. The
rapidly growing collection of pictures and data is stored on magneto-optical
disks.

Did you know.. Hubble Space Telescope two mirrors were ground so that they
do not deviate from a perfect curve by more than 1/800,000ths of an inch. If
Hubble’s primary mirror were scaled up to the diameter of the Earth, the biggest
bump would be only six inches tall.

Did you know.. In order to take images of distant, faint objects, Hubble
must be extremely steady and accurate. The telescope is able to lock onto a
target without deviating more than 7/1000th of an arc second, or about the width
of a human hair seen at a distance of 1 mile. Locking onto distant celestial
targets is like holding a laser light steady on a dime that is 200 miles away.

source ESA/NASA

• Next Space Telescope Undergoes Brutal Cold Test

  The James Webb Space Telescope, set for launch around 2014, has undergone a brutal cryogenics test in preparation for work in space.

• ExHubble Astronomer Marks Telescopes 20th Birthday In Flint

  FLINT Flints Longway Planetarium is marking the 20th anniversary of the Hubble Space Telescope with a talk by a scientist who worked with it. Albert Holm recently retired as the Hubbles astronomer. Hes speaking Aug. 10.

• Starfest Celebrates Hubble

  Starfest 2010 will offer “Walks through the Solar System” and observations of the Hubble Space Telescope, marking the telescopes 20th anniversary. Presented by the Aldrich Astronomical Society, the free event runs from 6 to 10 p.m. Saturday at Founders Hall, Anna Maria College, 50 Sunset Lane, Paxton. For more information, visit www.aldrichastro.org.

• Hubble Scientist Marks Telescopes 20th Birthday

  Flints Longway Planetarium is marking the 20th anniversary of the Hubble Space Telescope with a talk by a scientist who worked with it.

• Cool Space Photos

  Here are some cool space photos. You can make any of these images into your computer desktop wallpaper. Just click on an image to enlarge it, and then choose “Set as Desktop Background”. Heres an image of a starforming region called LH 95 taken by NASAs Hubble Space Telescope. LH 95 is located in the …

• James Webb Space Telescope Completes Cryogenic Mirror Test

  by Staff Writers Huntsville AL SPX Jul 29, 2010 Recently, six James Webb Space Telescope beryllium mirror segments completed a series of cryogenic tests at the Xray and Cryogenic Facility at NASAs Marshall Space Flight Center in Huntsville, Ala.

• Cool Space Images

  Here are some cool space images. You can make any of these images into your computer desktop wallpaper. Just click on an image to enlarge it, and then choose “Set as Desktop Background”. Heres a picture of the 30 Doradus Nebula located in the nearby Large Magellanic Cloud. This view was observed by NASAs Hubble …

• Cool Space Wallpapers

  Here are some cool space wallpapers. You can make any of these images into your computer desktop wallpaper. Just click on an image to enlarge it, and then choose “Set as Desktop Background”. Here a spectacular montage of the solar system featuring the separate images captured by the Voyager spacecraft. The solar system was believed …

• Beautiful Space Pictures

  Here are some beautiful space pictures. You can make any of these images into your computer desktop wallpaper. Just click on an image to enlarge it, and then choose “Set as Desktop Background”. This is an image of the Quadrantid meteor shower and the aurora. This image was obtained from the Quadrantids MultiInstrument Aircraft Campaign …

• Earth Space Wallpaper

  Here are some cool earth space wallpapers. You can make any of these images into your computer desktop wallpaper. Just click on an image to enlarge it, and then choose “Set as Desktop Background”. Heres an image of Earth taken by NASAs Galileo spacecraft as it was speeding on its way to Jupiter. Galileo captured …