Hubble Space Telescope

From the dawn of humankind to a mere 400 years ago, all that we knew about our universe came through observations with the naked eye. Then Galileo turned his telescope toward the heavens in 1610. The world was in for an awakening.

Saturn, we learned, had rings. Jupiter had moons. That nebulous patch across the center of the sky called the Milky Way was not a cloud but a collection of countless stars. Within but a few years, our notion of the natural world would be forever changed. A scientific and societal revolution quickly ensued.

In the centuries that followed, telescopes grew in size and complexity and, of course, power. They were placed far from city lights and as far above the haze of the atmosphere as possible. Edwin Hubble, for whom the Hubble Telescope is named, used the largest telescope of his day in the 1920s at the Mt. Wilson Observatory near Pasadena, Calif., to discover galaxies beyond our own.

Hubble, the observatory, is the first major optical telescope to be placed in space, the ultimate mountaintop. Above the distortion of the atmosphere, far far above rain clouds and light pollution, Hubble has an unobstructed view of the universe. Scientists have used Hubble to observe the most distant stars and galaxies as well as the planets in our solar system.

Hubble's launch and deployment in April 1990 marked the most significant advance in astronomy since Galileo's telescope. Thanks to four servicing missions and more than 25 years of operation, our view of the universe and our place within it has never been the same.

Hubble Facts

NASA's Hubble Space Telescope was launched April 24, 1990, on the space shuttle Discovery from Kennedy Space Center in Florida. 

• Hubble has made more than 1.2 million observations since its mission began in 1990.
• Astronomers using Hubble data have published more than 14,000 scientific papers, making it one of the most productive scientific instruments ever built.
• Hubble does not travel to stars, planets or galaxies. It takes pictures of them as it whirls around Earth at about 17,000 mph.
• Hubble has traveled more than 3 billion miles along a circular low Earth orbit currently about 340 miles in altitude.
• Hubble has no thrusters. To change pointing angles, it uses Newton’s third law by spinning its wheels in the opposite direction. It turns at about the speed of a minute hand on a clock, taking 15 minutes to turn 90 degrees.
• Hubble has the pointing accuracy of .007 arc seconds, which is like being able to shine a laser beam on a dime 200 miles away.
• Outside the haze of our atmosphere, Hubble can see astronomical objects with an angular size of 0.05 arc seconds, which is like seeing a pair of fireflies in Tokyo from your home in Maryland.
• Hubble has peered back into the very distant past, to locations more than 13.4 billion light years from Earth.
• The Hubble archive contains more than 120 terabytes, and Hubble science data processing generates about 10 Terabytes of new archive data per year. 
• Hubble weighed about 24,000 pounds at launch and currently weighs about 27,000 pounds following the final servicing mission in 2009 – on the order of two full-grown African elephants.
• Hubble's primary mirror is 2.4 meters (7 feet, 10.5 inches) across.
• Hubble is 13.3 meters (43.5 feet) long -- the length of a large school bus.