The Hubble Space Telescope was created by and named after astronomer Edwin P. Hubble. He was known for his creation of Hubble’s Law which is used to calculate the rate at which the universe is expanding. He is also known for his discovery of the galaxies that are outside the Milky Way. The Hubble Space Telescope is a large telescope that is placed in orbit around the earth. Scientists have figured out that by placing a telescope in space, putting it outside of earth’s atmosphere, a telescope can escape any atmospheric disturbances that hinder the quality of the pictures that taken. Since the Hubble became operational in 1990 it is well known because of the discoveries that it has contributed to astronomy. The Hubble is …show more content…
considered one of the four “Great Observatories” along with the Compton Gamma-Ray Observatory, Chandra X-Ray Observatory, and Spitzer Space Telescope. Throughout its years of service, the Hubble has been upgraded many times and is still currently being outfitted with new equipment.
2.0 Equipment on the Hubble Space telescope
2.1 Spacecraft Systems. The Hubble is not just a telescope but it is a combination of specialized equipment that work together to achieve a common purpose. Some of the spacecraft systems that help the telescope function are communications, power, computers, and housing.
The Hubble space telescope transmits it information though a series of four antennas. This provides the telescope with instructions from the ground that could be relayed at anytime. Also to help the information go to and from the telescope smoothly there are a series of relay satellites called the Tracking and Data Relay Satellite System (TDRSS).
The following are 5 steps that the telescope goes though to communicate with the science institute on earth. 1) Light from an object is captured by the Telescope. 2) The data is relayed from the Hubble Space Telescope to the TDRSS. 3) The TDRSS further relays the data from the Hubble to the ground station at White Sands, N.M. 4) the data sent to the ground station is further relayed to the Goddard Space Flight Center. 5) From the Goddard Space Flight Center the data is relayed to the Space Telescope Science Institute.
Behind all the equipment that runs on the satellite is the power that allows it to function. The Hubble generates its own power by utilizing two thin solar arrays. The power is either used directly when it is in the sun or though batteries that have been changed when it is in the earth’s shadow. The battery life on the Hubble, fully charged, would allow for up to 7.5 hours or 5 orbits of normal operation. Onboard the Hubble is two main computers which are responsible for the main operations of the telescope. One of the computers is responsible for controlling the receiving and transmitting data from the Hubble to the Space Center on earth. The other computer is responsible for positioning the Hubble using equipment like a gyroscope and a point control subsystem to help the satellite target a specified region of space while it is on the move. Each of the equipment onboard the telescope contain small computers and microprocessors that are all interconnected so that functions like temperature control, collecting data and communication can all be monitored. The equipment on the Hubble is housed by a multilayer insulation which protects the telescope from the temperature changes in space. Underneath this insulation is an aluminum shell which is essentially the backbone that holds everything from the optics to the spacecraft systems in place. The inside of the telescope is composed of a material know as graphite epoxy. This material was used because of its ability to withstand extreme temperature changes that cause other metals to expand and contract. (The Hubble Space Telescope; HUBBLESITE; European Space Agency)
2.2 Instruments. The instruments onboard the Hubble include an Advance Camera, Wide Field and Planetary Camera, and a Near Infrared Camera and multi-Object Spectrometer.
The Advance Camera is designed for surveys and is a multipurpose instrument that has become the primary imaging instrument onboard the Hubble. The camera was designed to allow the camera to view the different wavelengths of light from ultraviolet to infrared. This camera has three different settings a Wide Field Channel, a High-Resolution Channel and a Solar Blind Channel. The three different settings are used observe different events in space. The wide field channel is used to study galaxies, the high resolution channel is used to take precise pictures and the solar blind channel is used to take pictures of celestial bodies and groups of starts.
The Wide Field and Planetary Camera is the Hubble’s main camera and it is used to record images that are a great distance away. This camera has four charged-coupled devices that detect electromagnetic radiation and along with three wide field cameras they are arranged in an L formation. Also in this L formation of cameras there is a planetary camera that fits inside the L shape. When an image is taken all the cameras are used at once in order to improve the quality. The Near Infrared Camera is a combination of three sensitive cameras that can see objects in the infrared spectrum. Light is often blocked by interstellar dust and as a result the pictures taken are not really clear but that is not the case with this camera because this camera takes pictures of the infrared light or heat that can be seen. Thus the interstellar dust would not hinder the quality of the pictures being taken.
2.3 Optics.
The reason behind the Hubble’s success is that not only is it in space to escape the earth’s atmosphere but also because of a system called the Optical Telescope Assembly. This assembly of mirrors essentially redirects incoming light down a tube with baffles which are used to keep stray light out, and the light eventually hits a series of mirrors that lead to the onboard scientific instruments that piece together the picture. The mirrors used in the Hubble are made out of an ultra low expansion glass and is coated with a layer of pure aluminum and magnesium fluoride that help to give a more reflective surface all these are done to prevent the mirror from warping. One part of the telescope that has since been replaced is part of the optical telescope assembly called the Corrective Optics Space Telescope Axial Replacement (COSTAR). What the scientist first discovered was that there was a flaw in their primary mirror called spherical aberration and this caused a fuzzy image to be produced. To correct this problem the scientist created a corrective lens much like eyeglasses for a human to restore the Hubble’s vision. This was where COSTAR came into place where it was installed during servicing missions in order to fix the flaws on Hubble. However the COSTAR was removed when the new Advanced Camera was sent to replace
it.
2.4 Upgrades & maintenance. Since the Hubble’s launch in 1990 it has been upgraded and repaired many times. Hubble’s design was so that it could be easily repaired and upgraded by astronauts. In the Hubble’s early days the telescope had to be repaired with COSTAR and also its solar arrays had developed a flutter so they had to be replaced at a total repair mission cost of $700million. Since the COSTAR repair in 1993 astronauts have been back to the Hubble for another 3 times to upgrade and install new hardware. The Hubble has been in service for more then 17 years and now it will be survived by the James Webb Space Telescope which will further continue on the missions of Hubble.
3.0 Satellite vs. Observatory telescope
3.1 Similarities. The similarities between the telescopes are that both use a series of mirrors that reflect the light to a common point. The telescopes use the same concept of reflecting light until it is reduced to a small area.
3.2 Differences. The major difference between a Satellite and an observatory telescope are that one is in space and one if fixed on the earth. Other differences between the telescopes are their size, transfer of data, and housing. A satellite telescope is better then an observatory telescope because it does not have to go though atmospheric interference. The difference of having no atmosphere is what determines the size of the telescope. A telescope on earth would require larger mirrors then the one used on Hubble because the telescope would need to capture more light because the light has to go though out atmosphere and causes the images not to be as sharp. The Hubble escapes all this by being in a zero gravity environment where the only worry is constant temperature change. The transfer of data are different in both telescopes because the satellite telescope has to be relayed though a series of other satellites and ground stations while an observatory takes the picture on the spot. As said before the Hubble is housed in specially designed casing where it must last through the effects of space while an observatory telescope only needs to be housed in a dome shaped building to keep the forces of nature out.
3.3 Targeting. The Hubble requires special equipment like a gyroscope to keep it locked on its target while still moving around the earth. Although it might seem like this gives the Hubble an advantage, it does not because the telescope only passes by an area every so often so certain pictures must be taken at a certain time interval or it will be missed. The observatory is the same where the telescope needs to be used at night and also it can only aim depending on where the earth spins.
4.0 Contributions to society
4.1 Important Discoveries and observations. Throughout Hubble’s 17 years of service the Hubble has made many discoveries. Some of these discoveries include supernovas, age if the universe, quasars, nebulas and many more. The observation of supernovas have since helped astronomers discover the existence of a mysterious form of energy called dark energy that some how accelerates the expansion rate of the universe. Hubble has also helped us solve the question of how old the universe really is and it did this by observing Cepheid variable stars and by doing that astronomers have since then determined that the age of the universe is 13-14 billion years old with an accuracy of 10% which is considered small. Another interesting thing that the Hubble has helped us with is determining the chemical makeup of another planet’s atmosphere. Another observation the Hubble has helped made is the capture images of gamma ray explosions. When they were first observed it was thought that it represented the forming of a star but the truth was really the opposite where it was the result of a massive star collapsing. Images of quasars and dynamo of light and energy have helped astronomers determine that they originated at the center of galaxies. Also the Hubble has helped compare that a nebula caused by a dying star to the equivalent of a snow flake, where you can never find two snow flakes but in this case no two nebulas are the same. One of the most interesting observations made is the sight of black holes. This has lead to the theory that at the center of most galaxies there is a super massive black hole.
4.2 Historical Timeline. The Hubble was launched on space shuttle Atlantis on April 24, 1990 but because of the lens problem the first servicing mission was launched in 1993 to install the COSTAR and replace the solar arrays. In 1997 the servicing mission’s improved the telescopes capabilities and the near Infrared camera and Multi-Object Spectrometer and the Space Telescope Imaging Spectrograph were installed. In 1999 the servicing missions the gyroscopes were replaced which allowed the telescope to lock on a target more accurately. The more recent servicing mission took place in 2002 which included the installation of the Advanced Camera and a cooling system for the Near Infrared Camera and Multi-Object Spectrometer.
5.0 Conclusion
Since its launch in 1990, the Hubble Space telescope is one of the most important telescopes in the history of astronomy. Thought its years of service it has been a big factor in the study of astronomy and has helped in the understanding of our universe. With the data that the Hubble has given us we have been able to learn things from the age of our universe to the existence of dark energy. With all these facts it is clear that we should make the telescope known to the public because pretty soon the Hubble will be replaced by its successor the James Webb Space Telescope but before it is replaced it should be credited for its many years of service to mankind.