Hubble and James Webb Search for the Edge

By: James William Smith

Its price tag was 500 million dollars in 1990. It certainly was a lot of money to pay for a telescope that circled the Earth and could not focus. A faulty mirror on the Hubble was the reason the expensive space telescope could not see. The Hubble would quickly become an object of ridicule and the subject of numerous jokes on late night television.

In 1993, astronauts?repaired that faulty mirror on the Hubble. Fifteen years later, it is very safe to say that nobody is laughing now. In fact, even though the cost of the telescope has eclipsed 5 billion dollars, it has become a very inexpensive investment in astronomy and our understanding of outer space through time.

For more than a decade, the Hubble telescope has captured many of the most spectacular images of outer space. In addition, it has enabled direct observation of the Universe as it was billions of years ago, discovered black holes at the center of galaxies, provided measurements that helped establish the size and age of the Universe, and offered evidence that the expansion of the Universe is actually accelerating.

However, even though the final planned servicing mission for the telescope is scheduled for October of this year, the Hubble's best pictures of the Universe may be yet to come. The Hubble is about to receive a powerful upgrade in capability during an eleven day shuttle mission that will feature five space walks. The space walks will be necessary for astronauts to install new scientific instruments to enhance the telescope. NASA intends for the Hubble Telescope to get a wider, more distant, and sharper view of objects.

During the mission, the Hubble will receive a new set of the gyroscopes that will stabilize the telescope, and batteries and thermal blankets to extend Hubble's operational life until at least the year 2013. In addition, a degrading Fine Guidance Sensor unit, one of three aboard Hubble, will be replaced with a refurbished unit to help maintain the telescope's ability to point and focus on astronomical objects throughout the Universe.

The Hubble Telescope is responsible for dating the age of the Universe at 12-14 billion years. However, it cannot see back that far in time. It cannot see the period after the big bang when the Universe began an expansion that continues to accelerate to this day. It is important for our increased understanding of the Universe that scientists now see that time in distant space. The years after the Big Bang are known for the formation of the first stars and the creation of the first galaxies. In effect, to see this happen is a scientific search for the edge of the Universe. It is a search that will be undertaken by Hubble's successor, the James Webb Space Telescope (JWST).

The successor to Hubble, scheduled for launch in 2013, will be designed to see objects even farther in distance, and therefore time, than the Hubble now can. However, in order for the James Webb Space Telescope to see objects at the edge of the Universe after the Big Bang, it will need to be a much different telescope than the Hubble.

Therefore, in 2013, an unmanned spacecraft will release the James Webb Space Telescope (JWST) into an orbit 930,000 miles away from Earth. This distance puts the telescope well beyond the reach of space shuttle servicing missions, and therefore the telescope is expected to have a much shorter life than the Hubble.

After entering its orbit, a light shield the size of a tennis court will unfold to hide the JWST from the light of the sun. Finally, powerful cooling systems will help to dramatically lower the spacecraft's temperature to a -447 degrees Fahrenheit in order to be cold enough to complete its mission.

The James Webb telescope will carry three different types of cameras, all tuned to detect infrared light, which is invisible to the human eye. In contrast, the Hubble was equipped to capture mostly visible light and ultraviolet parts of the spectrum. This difference in light spectrum is due to the fact that the further astronomers look back in time, the redder the light from objects appears to be. Scientist call this phenomenon red shift, and it means that light from the most distant (and therefore oldest) object is deep in the infrared part of the light spectrum, a part of the light ectrum which the Hubble is currently unable to see.

The James Webb Telescope's primary goal will be to see what happened when the Universe created its first light when it was about one billion years old. It is hoped that the telescope will allow astronomers to observe the birth of galaxies, the physics of star and planet formation, and the entire early development of the Universe. The information might also provide answers about how other solar systems form and evolve.

Hubble was the trailblazer in the search of outer space through time. James Webb is designed to look further back to the point of first light. It is a scientific search to see the edge of the Universe, a view from the distant past that will increase our understanding of space, for?the world of tomorrow.

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