What’s the size of a school bus, orbits the Earth, and can see farther than anything else? The answer is the Hubble Telescope. Hubble is an orbiting telescope. It can help us find water on other planets and might eventually lead us to colonizing those planets.

Hubble Basics

Why Was Hubble Created?

Hubble was designed to collect better data about the universe than can be collected from Earth. One way Hubble can get better information is by taking better pictures. From Earth, we are looking through the atmosphere. Dust, air currents, water vapor, and clouds in the atmosphere can make pictures blurry and less detailed. Because Hubble orbits 370 miles above Earth, it doesn't have to look through the atmosphere, so, it can take clearer and more accurate pictures.

What is Hubble?

Hubble is a reflecting telescope that orbits the Earth every 97 minutes. A reflecting telescope works by reflecting light using mirrors. First, light comes into the telescope. Then, light is reflected off a mirror in the back of the telescope called the primary mirror. The light then hits another mirror and is reflected to where it needs to go. These mirrors are very important because they are needed to focus the light.

When Was Hubble Launched?

The Hubble telescope was launched in 1990 by the shuttle Discovery. Hubble was supposed to be launched in 1986, but it was delayed because of the destruction the shuttle Challenger.

Repairing and Refitting

An Expensive Mistake

Two months after Hubble was launched, a problem was discovered. The primary mirror in the telescope was too flat on the edge. Because the telescope needed the mirror in perfect condition to take clear pictures, a shuttle mission was sent to fix it.

First Maintenance Mission

In December 1993, the shuttle Endeavor left for a five-day mission. It installed several things to fix the flaw in the mirror. One of them was a group of mirrors that redirected light to where it was supposed to go. The other one was an advanced camera to help make up for the flaw. Also installed were more efficient solar panels and a gyroscope. The gyroscope helps to keep the telescope aimed in the right direction. This mission cost 8 million dollars!

Second Maintenance Mission

In February 1997, the shuttle Discovery installed several more devices. In order for Hubble to see far away, it needed to be able to see in infrared. (Infrared is a type of light that humans can’t see.) So a device was installed to make Hubble able to see infrared light. Infrared light is basically heat. The infrared camera allows Hubble to see objects in space by looking for the heat he objects produce. Also installed was a stronger data recorder, allowing Hubble to store more information, and better aiming devices.

Third Maintenance Mission

In 1999, three of the six gyroscopes had stopped working. Hubble needed at least three to function properly. Without three gyroscopes, the telescope wouldn't be able to aim correctly. A mission was sent to replace the gyroscopes, and all six gyroscopes were replaced. Other replaced items were the transmitter that sends the pictures to Earth, a stabilizing device, an advanced computer, and more layers of heat protection.

Fourth Maintenance Mission

On February 28, 2002 another maintenance mission will be sent. The space shuttle Columbia will install many more devices. The most important one is an advanced camera. This camera can take pictures of objects that are twice as far away as we can take right now. It will also help by collecting data ten times faster. Another improvement to be installed are stronger solar panels. These panels will produce 30% more power than the ones currently on Hubble. Also to be replaced is a device that will distribute power from the solar panels and batteries to other parts of the telescope and a new cooling device for the infrared camera. This mission is the most risky one yet. This is because, of the installation of the power control unit. The telescope had to be shut down while this installation was taking place. They crew of the Columbia had to hours to replace the power unit before it would freeze. If it froze the telescope wouldn’t be able to work again. To help prevent against this layers of thermal covering were put on Hubble. These layers would help to keep it from freezing. Also, there was a chance that the telescope would never turn back on. Luckily, this mission was successful.

Hubble’s Discoveries

Jupiter

Hubble has made several interesting discoveries. One of them was seeing Comet Shoemaker crash into Jupiter in 1994. Hubble also helped to map Jupiter.

Mars

Hubble also observed Mars. Some of the pictures from Hubble helped to find a place for the Mars Pathfinder to land. It has seen giant dust storms and several other weather conditions.

Black Holes

Hubble discovered the first black hole in 1994. It saw a disk of gas swirling around a point in space. This area was a black hole. It looked like a whirlpool in space. Scientists found out that this gas was moving at over a million miles per hour. From the speed that the gas was moving, they were able to find out the mass of the black hole. It had the mass of two billion of our suns! Also, scientists found out that this black hole was the size of our solar system!

The Universe’s Age

Hubble has helped scientists begin to discover how old the universe is. By taking pictures of far away supernovas, it can be determined how long ago the universe was formed. The estimated time is 15 billion years ago.

A Galaxy's Life

Hubble has looked far away at other galaxies. It has discovered how they evolve. Since light can take a long time to travel from far away galaxies, it’s possible to look back in time. This lets us see the different stages of a galaxy. The pictures have led scientists to believe that after the Big Bang, there was a time when stars were formed rapidly. The leftover materials created planets. Hubble continues to observe many things.

NGST

Hubble’s End

The Hubble telescope was only meant to be orbiting for fifteen years. Since it was launched in 1990, it was scheduled to come down in 2005. However, it has been decided that Hubble will not come down until 2010.

New Telescope

When Hubble comes down, a new telescope will be needed. The NGST (Next Generation Space Telescope) is being designed right now. The NGST is expected to be 10 times more powerful than Hubble. This means we will be able to see 10 times farther into the universe. If all goes according to plan, the NGST will be launched in 2009. Some questions that scientists want answered by NGST are:

Interesting Facts

The Hubble Telescope has given us most of the detailed pictures of outer space we have today. It has looked at black holes, supernovas, planets, comets, stars, nebulas, and more. It has proven and disproved many things such as the existence of black holes. Someday its mission will end, and a new more powerful telescope will teach us even more about the Universe.

Links to a Great Site on Hubble

Barnbaum, Cecila. "Hubble Space Telescope" World Book Encyclopedia, 2001.

Space Today, Tomorrow, and Always. </J0112188 > Last Visited: February 2002.

Space Telescope Science Institute. <http://www.stsci.edu/resources/> Last Visited: February 2002.

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All pictures courtesy of NASA unless otherwise noted