Increasing Hubble's Power
This is Steve Ember. And this is Bob Doughty with the VOA Special English program EXPLORATIONS. Today we tell about plans to make the Hubble Space Telescope a much more powerful scientific instrument.
Later this month, NASA astronauts plan to replace much of the equipment that makes the Hubble Space Telescope one of the most valuable science tools ever invented. The new equipment will help Hubble do ten times more work than it can today.
The Hubble Space Telescope is an eye in space that permits humans to look far into the universe. The Hubble telescope orbits six-hundred kilometers above the Earth. It works twenty-four hours a day, seven days a week helping scientists understand the secrets of the universe. It provides information and images of the universe that cannot be seen from Earth because of clouds or atmospheric conditions.
NASA launched the Hubble Space Telescope in Nineteen-Ninety. Since then, the telescope has made more than three-hundred-thirty-thousand scientific observations of distant objects in space. It has observed more than twenty-five thousand different objects. And it has provided the scientific information that helped researchers produce more than two-thousand six-hundred scientific papers.
The Hubble Space Telescope produces enough good science information to fill about thirty large books each day. It has provided information that has helped us understand the structure of our universe. Scientists say the telescope has expanded our knowledge of how stars and planet systems form together.
Hubble has provided detailed pictures and images that help us in understanding the history of our solar system. It has also helped us understand what makes Earth similar to or different from other planets.
NASA's plans call for the Space Shuttle Colombia to be launched from the Kennedy Space Center in Florida on February twenty-eighth. It will carry seven astronauts on an eleven-day flight to work on the space telescope.
The Hubble telescope is the first scientific instrument ever designed to be repaired and rebuilt by astronauts who work in space. The telescope was built so astronauts can take it apart and replace old or broken equipment with newer technology. More than ninety percent of its parts can be replaced by space shuttle astronauts.
As new technology is developed, the telescope is provided with more modern devices. Each instrument that is replaced is much more powerful than the older one.
In February, Colombia's astronauts will complete a number of tasks during their flight. They will replace Hubble's camera with new, advanced technology that will permit the telescope to do ten times the amount of work.
The new camera is called the Advanced Camera for Surveys or A-C-S. NASA says the new A-C-S camera will permit researchers to study huge galaxies.
The A-C-S is really three different cameras. Each deals with different kinds of light. Each one can see and record light that is far beyond what the human eye can see.
The A-C-S also carries equipment that can control light that enters the camera. It does this by placing different pieces of glass in front of the camera's eye.
NASA says the information provided by Hubble's new A-C-S camera will lead to a better understanding of how our universe changed over time.
The Hubble Space telescope also will receive new equipment that permits it to make electric power from sunlight. The old power equipment has been in use for eight years. Radiation and small space objects have damaged it.
The power equipment looks like large wings. These wings are called solar arrays. The new solar arrays are smaller than those being replaced, but can produce thirty percent more power. They can also operate better in the extreme temperature changes found in space.
The astronauts also will replace the electric power control device on the space telescope. It has been controlling Hubble's power for the eleven years it has been in space.
To replace the device, all power on Hubble will have to be turned off for the first time since it was launched in Nineteen-Ninety. The new power control device will permit the space telescope to use all of the increased power provided by the new solar arrays.
Astronauts also will repair an instrument called the Near Infrared Camera and Multi-Object Spectrometer. They will replace the cooling system for the camera. This special camera was put in the space telescope in Nineteen-Ninety-Seven. It stopped working two years later after its cooling device failed.
NASA hopes the new device will be able to provide the extremely cold temperatures needed by this special camera. They also hope to extend the camera's working life by several years.
The shuttle crew has learned how to replace or repair each of the many systems that are part of the space telescope. Some of these include the spacecraft's communications system, its computers, and the instrument that points the telescope at distant objects.
Hubble's pointing system is extremely powerful. It is a good example of the kind of device the astronauts must learn to repair. It finds and then keeps the Hubble telescope pointing at objects so they can be studied. Imagine pointing a small light at a very small object two-hundred kilometers away. Then imagine holding the light for hours or days with little or no movement. The pointing device on Hubble has a small computer that watches for any movement or mistakes forty times a second. If movement occurs, other instruments change speeds to bring the telescope back into the correct position.
When all the work is completed on the space telescope, the astronauts may use the shuttle's small rockets to place Hubble in a higher orbit. This has been done two times before.
Very little atmosphere surrounds the Earth six-hundred kilometers in space. Yet enough atmosphere exists to cause the Hubble to slow down over a long period of time. When this happens, the Earth's gravity pulls the orbit of the telescope lower. If the space telescope were left alone it would continue to fall lower and faster towards Earth until it burned up in the atmosphere.
Repairing the Hubble Space Telescope in space is a very difficult task. The crewmembers of the Space Shuttle Colombia have been training for their flight for many months. They have done each task many times here on Earth. The new equipment they will place in the telescope has been tested again and again for many thousands of hours.
The astronauts will have to use more than one-hundred-fifty special tools and aids to work on the telescope in space. They have worked with these tools until they are experts in the use of each one.
The astronauts also prepare for this difficult flight by asking the question, "What if?" This is the method they use to prepare for surprises.
It is similar to you asking yourself, "What if it there is a heavy rain tomorrow morning." Or "What if I turn here instead of there." You would think of an answer for each of these questions and a solution to each problem. By working out the answers to these "what if" questions, the Hubble team tries to be prepared for any problem that might develop.
Experts have spent many days providing the astronauts with different "what if" surprise problems. The astronauts then spent hundreds of hours working on the correct solutions.
Hubble has provided many thousands of pictures of distant objects in the universe. Many of them are thousands of light years away from Earth.
The Hubble Space Telescope has seen the birth of stars and their deaths. You do not need to be a scientist or a researcher to enjoy the beautiful pictures the telescope provides. If you have a computer that can link with the Internet, you can see hundreds of them. Have your computer search for the word Hubble. That is H-U-B-B-L-E. Once again, H-U-B-B-L-E.
Your computer will answer with several web sites that will permit you to see millions of kilometers into our universe.
This Special English program was written and produced by Paul Thompson. It was produced by George Grow. Our studio engineer was John Ellison This is Steve Ember. And this is Bob Doughty. Join us again next week for another EXPLORATIONS program on the Voice of America.