Category: Hubble Telescope

Introduction

The development of space-borne telescopes has heavily influenced our astronomical research and broadened our fundamental understanding of the universe. They have paved the way for astronomers to view and understand the cosmological evolution of galaxies that ground-based telescopes could not fully uncover. In recent years, advancements in space telescopes with the achievements of the Hubble Space Telescope and the upcoming James Webb Space Telescope have revolutionized the data we have in the field of astrophysics. [1] As a result, current and future space exploration operations now rely heavily on space telescopes.

The Need for Telescopes in Space

Initially, the opportunity for space-based research had been restricted by hazy, unclear images produced by ground-based telescopes until the availability of more precise data obtained by space telescopes. [2] Because space telescopes are placed outside of Earth, their observations will not be interfered with by getting absorbed or suffering from scintillation as a result of the Earth’s atmosphere, unlike ground-based telescopes. Their ability to bypass Earth’s atmosphere allows space-based telescopes to make extremely accurate photometric observations at wavelengths unattainable from the ground. The many forms of radiation such as gamma rays, X-rays, and certain parts of ultraviolet cannot be observed from Earth because they are completely blocked out by its atmosphere. Even certain broad bands in the near-infrared would not be able to evade it as they are immediately absorbed by water molecules within Earth’s atmosphere. As a result, with the limited ability to see the entire electromagnetic spectrum our studies will be severely inadequate unless information is to be gathered by space telescopes. [3]

Moreover, the reduced resolution ground-based telescopes experience when subject to atmospheric distortion is another restraint only space-borne telescopes can fully overcome. This distortion is a result of the constantly fluctuating atmospheric conditions and densities above the ground which reduces the practical resolution of the telescope despite its higher theoretical resolution. Although the application of ground-based adaptive optics imaging has been able to improve the clarity of celestial bodies such as stars, such performing enhancements are not powerful enough to surpass the efficiency of space telescope technology such as the images of the Hubble Space Telescope (HST) can capture. For these reasons, taking telescopes into space beyond the limits of the Earth’s atmosphere is the only method to view how the universe appears at various wavelengths and could not otherwise be studied using conventional ground-based telescopes. Hence, HST has been one of the most successfully employed instruments for exoplanet atmosphere studies, which often require precise, near-infrared spectroscopy. [3]

Hubble Space Telescope

Crucial to the pioneering success of space-based technologies, are the accomplishments of the Hubble Space Telescope (HST). Ever since its first space launch in 1990 by NASA, the HST has enabled the detection of some of the most distant galaxies, with its suite of instruments such as the Space Telescope Imaging Spectrograph (STIS), the Near Infrared Camera and MultiObject Spectrometer (NICMOS), the Advanced Camera for Surveys (ACS) and the Cosmic Origins Spectrograph (COS). [5][6] In fact, the technology and discoveries of the large telescope have powerfully evolved our study of the universe and its origins which has arguably been unprecedented since the time of Galileo. [7]

With its advanced picture resolution, Hubble’s countless contribution of images in space include the Orion clusters which are sharply derived from infrared imaging interpretations as well as the sharpest image ever taken of the ‘grand design’ spiral galaxy M81 which is tilted at an oblique angle directly parallel to our line of sight. Hubble has also provided observations of exoplanets in transit with their host stars only made possible because of its impressive imagery stability. In addition, HST has confirmed the existence of black holes and their common positioning within the center of all galaxies, revealed the age of the universe to a close percent as well, and revealed the existence of ‘dark matter’ and ‘dark energy’ taking over approximately 96 percent of the universe. Moreover, the HST has been able to extrapolate data from the Hubble Deep Field and Ultra Deep Field to discern an abundance of a wide range of galaxies of various ages of all which have formed less than a billion years after the Big Bang. [7] [8]

Alongside HST’s astronomical achievements, the space telescope is also serviceable which enables it to maintain durability as well as establish necessary methods to effectively execute future deployment and service missions. Developing such methods provides instrumental experience and assured proficiency in such operational techniques needed to accomplish launches for future space telescopes, especially for the forthcoming James Webb Space Telescope (JWST). With the remarkable tasks Hubble has performed, it would be unfortunate if all its existing observations were to only be seen once. Ultimately, an archive of all of the data HST has accumulated is open to the general public. The readily available information has exponentially facilitated larger use of such information for projects and research other than for the endeavors which it was originally taken for. The use of advanced computing operators has been able to expose previously unknown material in existing observations. Evidently, the legacy of the HST will never be lost and will continue to expand for decades even when it is no longer orbiting space. [6][7][8]

Looking into the Future: James Webb Space Telescope (JWST)

Consequently, the technology and discoveries of Hubble have been able to lay down the groundwork for all future space telescope missions and their potential cosmic breakthroughs. Newly developed by NASA following the Hubble Telescope, a notable mission that is reaching beyond the parameters of image-based wavefront sensing is the James Webb Space Telescope (JWST). While the length of the mission for HST has been 24 to 30 years, the JWST will be shortened to approximately 5 to 10 years. Set to launch in 2021, the JWST is a 6.5-metre diameter space telescope that will act as a successor to the Hubble Space Telescope. As opposed to Hubble’s measurements which sit only at a 2.4 metre diameter, the JWST has a larger optimised mirror with more light-gathering power. As well as that, the JWST will have a longer wavelength coverage of 0.6 – 28.5 μm and a higher range of sensitivity as it is situated further away from Earth. In contrast to Hubble’s tube-enclosed mirrors and instruments, JWST’s mirrors and instruments are open to allow the telescope to cool. Additionally, JWST’s arrangement of 18 Beryllium mirrors will be 2 and a half times more magnified in size than Hubble’s main mirror while also being twice as light. The larger mirror diameter will give JWST a sensitivity 3× greater than HST, which, coupled with its 10× higher spectral resolution, means it will become the unparalleled instrument for exoplanet atmosphere studies. [7][9]

The JWST is primarily an infrared space telescope and its suite of four instruments (NIRCam, NIR Spec, MIRI, and NIRISS) is said to provide a great range of imaging and spectroscopic capabilities. As a result, the telescope should be expected to conduct extended surveys of galaxies in the near-infrared over the redshift range 1 < z < 6 with the use of its powerful 4 instruments. The JWST is also expected to obtain hierarchical merging observations in which dark matter, gas, stars, metals, morphological structures, and active nuclei are built up to form the galaxies we see today. [6] [7]

However, with the JWST situated further away than the Hubble service mission, secure phase retrieval methods are heavily significant throughout its remote orbit within space. The development of new algorithmic data has been currently designed to process a wide spectrum of wavefront aberrations, source characteristics, and vibrational environments in case extreme environmental conditions arise so the JWST’s consistency in performance can be maintained. Because of its versatility, JWST will be used to answer a diverse set of questions from many branches of astronomy, including one of NASA’s broader institutional questions of how the first galaxies in the universe formed, and what the atmospheres of exoplanets are made of. We can therefore expect JWST to revolutionize our understanding of exoplanet atmospheres, and allow us to observe smaller and cooler celestial bodies than has previously been possible. [10]

Conclusion

The productivity and impact of space telescopes have continued to grow ever since the launch of the Hubble Space Telescope. With the continual growth of the next generation of extremely powerful space telescopes, one has been prioritized by the National Research Council to be launched as the complementary and surpassing candidate of the HST. The forthcoming James Webb Space Telescope is expected to serve as the next key program that will yield scientific results for future years to come. Nevertheless, as was the case with the HST, the most exciting discoveries that are likely to be made by JWST cannot be scripted in advance.

References

1. (2019). Eso.org. Retrieved 27 October 2019, from https://www.eso.org/public/archives/books/pdfsm/book_0045.pdf
2. Space versus Ground Telescopes. (2019). UA Research. Retrieved 27 October 2019, from https://research.arizona.edu/stories/space-versus-ground-telescopes
3. Melina, R. (2010). Why Are Space Telescopes Better Than Earth-Based Telescopes? Space.com. Retrieved 27 October 2019, from https://www.space.com/8286-space-telescopes-earth-based- telescopes.html
4. What Is the Hubble Space Telescope? (2019). NASA. Retrieved 27 October 2019, from https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-the-hubble-space-telecope- 58.html
5. About the Hubble Space Telescope. (2019). NASA. Retrieved 27 October 2019, from https://www.nasa.gov/mission_pages/hubble/story/index.html
6. Spake, J. (2019). The cold, the hot, and the puffy: atmospheric lessons from three transiting exoplanets. University Of Exeter. Retrieved from https://ore.exeter.ac.uk/repository/handle/10871/38528
7. PQDT Open. (2019). Pqdtopen.proquest.com. Retrieved 27 October 2019, from https://pqdtopen.proquest.com/doc/902628387.html?FMT=AI
8. FAQ for Scientists Webb Telescope/NASA. (2019). Jwst.nasa.gov. Retrieved 27 October 2019, from https://www.jwst.nasa.gov/content/forScientists/faqScientists.html
9. Database Access – UNSW Library electronic resource. (2019). Link-springer- com.wwwproxy1.library.unsw.edu.au. Retrieved 27 October 2019, from https://link-springer- com.wwwproxy1.library.unsw.edu.au/content/pdf/10.1007%2F978-1-4020-9457-6.pdf
10. THE NEXT GREAT OBSERVATORY: ASSESSING THE JAMES WEBB SPACE TELESCOPE. (2019). Govinfo.gov. Retrieved 27 October 2019, from https://www.govinfo.gov/content/pkg/CHRG- 112hhrg72165/html/CHRG-112hhrg72165.html

Ever since the invention of telescopes, there has been more demand for research and observations of the universe. With a growing number of diverse telescopes, each new one that came out improved, advanced, and changed our perspective on how we see the cosmos and gave us sharper and brighter resolution. With the combination of engineering and astronomy, it has marked the birth of Space telescopes. Space telescopes are essential observation instruments and are used as a technique providing researchers and astronomers the capability to automatically monitor space. They are telescopes that are launched into space serving the purpose of what a ground-based telescope can’t do and issues that are faced with using a ground telescope.

Unlike ground-based telescopes space telescopes are not affected by the earth’s atmosphere such as weather, light, and pollution, making them more expensive to invest in, Although cost and damage are a consequence, the results and observations made from space telescopes are significantly much better and clearer compared to ground-based telescopes (O, Jeffery., O, Megan., Donahue., Schneider. N., Voit.M. 2016. p178). Due to constant changes within the earth’s atmosphere, the resolution from ground-based telescopes is not as sharp causing blurriness, hence the only solution was to build space telescopes to collect much sharper observations of the universe (O, Jeffery., et al. 2016. p175).

Because radiation poses a threat to us besides visible light and radio waves, there is an invisible layer of protection preventing us from being exposed to infrared radiation, ultraviolet rays, X-rays, and gamma rays (English N, 2017 p10). However, because of this reason space telescopes are designed to image these radiations as using the whole light spectrum can determine and find new and fascinating observations.

Hubble space telescope

The Hubble Space Telescope still remains the most iconic space telescope today 28 years after it was built(1985), launched (1990) and functioned (1993). With the collaboration of engineers, astronomers, and scientists, started the launch of the Hubble, the images provided by Hubble showed the complexity and dynamic nature of the cosmos and this changed the way the universe is seen. Figure 1.0. On the left is an image produced of a galaxy from a ground-based telescope similar in size to Hubble. The right is the same galaxy produced by Hubble, ‘Adaptive Optics’ is used in Hubble to sharpen the resolution. (Hubble 15 years of discovery, 2006)

Made with glass and coated with aluminum combined with a compound that reflected ultraviolet lights, Hubble was a reflecting telescope and was built with a 2.4m diameter primary mirror which was smaller than expected however it was powerful enough to capture what was needed (Christensen, L.L & Fosbury, R. A. 2006. p24-25). With the wide field of vision, it provided the power to monitor the whole electromagnetic spectrum within the universe.

Just like the primary mirror, the secondary mirror was also made from glass and coated with aluminum, however as both primary and secondary mirrors are “hyperbolic” in shape it was hard to assemble and test (Chen, James, L., & Chen, Adam. 2015. p2). The result of Hubble’s sharp and deep captures is a result of its solar panels converting sunlight into electricity. By emitting enough power from these panels it allows all the other parts of Hubble to operate at the same time and with stable and strong panels it produces sharper and clearer images. With built-in communication antennas, Hubble sends its data to a satellite first in the “Tracking and Data Relay Satellite System” which then transfers it to White Sands, New Mexico, USA (Christensen, L.L & Fosbury, R. A. 2006. p26).

Hubble was involved in 4 missions in 1993,1997,1999 and 2002 (Christensen, L.L & Fosbury, R. A. 2006. p19) Its first mission was a huge success, with the success of the first Hubble Space Telescope mission NASA managed to revive themselves from the failure of the Space Shuttle Challenger which caused several damages (Chen, James, L., & Chen, Adam. 2015. p4). With 2 teams of astronauts completing spacewalks in 35 hours and 28 minutes, it had marked the end of the first mission with results showing high-resolution photos captured from the Hubble space telescope.

It was in July 1994, several months after its first mission which marked one of Hubble’s greatest findings, when it captured pieces of a comet tearing apart Jupiter’s gravitational field and colliding with its atmosphere. Through this opportunity, it showed its capability of being able to capture planets that flew by in a high-quality resolution (English N, 2017 p52). In addition, the observation made of a planet orbiting another star and the atmosphere of other exoplanets was considered one of Hubble’s major achievements.

November 2008 marked the discovery of visible light of a planet orbiting the star Fomalhaut, considering the fact that it was able to capture a planet 1 billion times lighter than its parent star was an achievement (English N, 2017 p283). With advancements in technology, the Hubble telescope was also upgraded, As years have passed by, it has managed to capture the most amazing and fascinating images of the cosmos, Its most famous image is the “Pillars of Creation” which is part of “Messier 16” allowing researchers to gain a deeper understanding of the universe.

James Webb Space telescope

As the Hubble space telescope has soon come to an end it has successfully served its purpose and job to provide amazing high-resolution captures of the cosmos. Its ancestor James Webb space telescope also known as ‘The Next Generation Telescope’ is in the process of being designed, built, and later released in the future. With the universe changing and developing it is built with upgrades and advancements from Hubble for future observations. It is expected to showcase the development of telescopes holding the power to capture next-level images of the universe. Because of this it is said to be extremely complex and advanced holding the capability to make discoveries that weren’t within Hubble’s ability. In order to do so, it is designed with an 18-segmented 6.5m primary mirror which will be facing and directed near the earth’s sun point (Kalirai, 2018). Designed to transit and move around the sun, moon, and earth once every year, it will be directly facing radiation with temperatures at least 358K and for this reason, a 21 by 14m sun shield is constructed and serves as a layer of protection preventing its instruments from heating up too much ensuring it stays below -220 degree Celsius (Kalirai, 2018).

A combination of infrared imaging instruments such as spectroscopy and coronagraphy is used and built into it to discover and show the redshifted light of the electromagnetic spectrum of most galaxies in space (Kalirai, 2018). The composition of stars, the atmosphere of planets, the motion of objects, and the physical environment in an astronomical object can be gathered and measured through the use of a method called Spectroscopy. While coronagraphy is a method where there is an attachment used on a telescope to block the sunlight allowing the faintest and lightest stars and astronomical objects to be seen, doing so can assist researchers and astronomers in monitoring and capturing objects near the sun without the sunlight acting as a barrier.

Its size is a barrier that may be preventing it from being launched sooner. As the rocket is smaller in shape with dimensions of 4.6m and 16.2m (Kalirai, 2018), there are modifications that must be made before it is launched. In saying so, Webb is at least 10m in 2 dimensions and 20 in the third, hence engineers, scientists, and more have designed Webb in a way where it is able to fold and compress together decreasing its size (Kalirai, 2018), however, there are still a lot of tests that need to be completed, ensuring it is designed accurately to serve and perform its job. Once it has been launched into space it will soon be able to unfold itself as seen in the figure above Figure 1.3. James Webb Space Telescope unfolding, (Kalirai. J, 2017)

Webb has been designed on a very technical and complex scale, with an 18 beryllium segment telescope, 4 science instruments, a fine guide sensor, and a spacecraft acting as a path of communication, direction guide, and orbit maintenance (Kalirai, 2018) it is expected to have the capability to make major new revolutionary discoveries following its main goals which are divided into 4 main categories.

The end of the Dark Ages: First Light and Reionization aiming to find the first formed luminous and ionization history (Stiavelli, M., Thronson, H.A., & Tielens, A. G. G. M. 2009 p.13) The Assembly of Galaxies which involves monitoring astronomical objects in a very far distant such as the very first stars and how galaxies and dark matter, gas, stars and metal evolved from the epoch of reionization (Stiavelli, M et al. 2009 p.14). Webb will serve its purpose by capturing molecular clouds, planetary systems and migration, star clusters and more allowing researchers to comprehend the start and development of stars and planets which is involved in The Birth of Stars and Protoplanetary systems (English N, 2017 p283). To find the origins and history of living organisms Webb also aims to discover the physical and chemical properties of planetary systems tied with The Planetary System Origins Life (Gardener, Jonathan, Mather, John, Clampin, Mark, Doyone, Reyne, Greenhouse, Matthew, Hammel, Heidi, Hutchings, Jakobsen, Peter, Lilly, Simon.2006). Through monitoring infrared light within the electromagnetic spectrum, these missions can be achieved more effectively and efficiently (English N, 2017 p287). Unlike Hubble, it focuses its capability to perform infrared astronomy which allows researchers to identify further galaxies. Figure 1.4. James Webb Space Telescope creation (NASA, 2019)

However, the discovery of exoplanets is also another objective of the James Webb Telescope. With the use of Spectroscopy utilized by Webb to determine the planet’s atmosphere, ground-based telescopes combined with the transit method will identify faint lights of a star as its planets transit between us and the star. Through this researchers will be able to measure the mass of astronomical objects providing the ability to search for other planets’ atmospheres (English N, 2017 p293)

Conclusion

In conclusion, both The Hubble and James Webb Space Telescope have served their purpose and job allowing researchers to gain a greater and deeper understanding of the universe which is changing many perspectives on how the cosmos is seen now. From the launch of The Hubble Space Telescope, it captured high-resolution images and successfully completed four of its missions as the catalyst for revolutionary space advancements. Its ancestor The James Webb Telescope is soon to be launched and with its aim to discover further, lighter, and fainter astronomical objects no doubt it will enhance and determine the future of the study of astronomy. Thus, it is safe to say that with evolving and advancing technology, the future of identifying astronomical objects will be enhanced with soon-to-come telescopes with stronger capability and power than Hubble and James Webb.

References

1. Chen, James, L., & Chen, Adam. (2015). A Guide to Hubble Space Telescope Objects: Their Selection, Location and Significance. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F978-3-319-18872-0
2. Christensen, L.L & Fosbury, R. A. (2006). Hubble 15 Years of Discovery. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F0-387-36082-4
3. English, N. (2017). Space Telescopes: Capturing the Rays of the Electromagnetic Spectrum. [ProQuest eBooks Collection]. Retrieved from https://ebookcentral.proquest.com/lib/unsw/reader.action?docID=4737165
4. Gardener, Jonathan, Mather, John, Clampin, Mark, Doyone, Reyne, Greenhouse, Matthew, Hammel, Heidi, Hutchings, Jakobsen, Peter, Lilly, Simon, Long, Knox, Luinne, Mccaughrean, Mountain, Matt, Nella, Rieke, George, Marcia, Rix, Hans-Walter, Smith, Eric, Sonneborn, George, Stiavelli, Massimo, Stockman, H., Windhorst, Rogier, Wright, Gillian. (2006). The James Webb Space Telescope. Space Science Reviews, 123(4), 485-606. doi: 10.1007/s11214-006-8315-7
5. Kalirai, J. (2018). Scientific Discovery With the James Webb Space Telescope. Contemporary Physics, 59(3), 251-290. doi:10.1080/00107514.2018.1467648
6. Miller, G. , Rosenthal, D., Cohen, W., & Johnson, M. (1987). Expert Systems Tools for Hubble Space Telescope Observation Scheduling. Telematics and Informatics, 4(4), 301-311. doi: 10.1016/S0736-5853(87)80016-3
7. NASA. (2019). James Webb Space Telescope [image]. Retrieved from https://www.nasa.gov/feature/goddard/2019/nasa-s-james-webb-space-telescope-has-been-assembled-for-the-first-time
8. NASA. (2018). The Pillars of Creation [image]. Retrieved from https://www.nasa.gov/image-feature/the-pillars-of-creation
9. O, Jeffery., O, Megan., Donahue., Schneider, N., Voit.M. (2016). The Cosmic Perspective,8th edition. USA, Boston: Pearson
10. Stiavelli,M.,Thronson,H,A., & A. G. G. M. Tielens. (2009). Astrophysics in the Next Decade: The James Webb Space Telescope and Concurrent Facilities. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F978-1-4020-9457-6

Introduction

The development of space-borne telescopes has heavily influenced our astronomical research and broadened our fundamental understanding of the universe. They have paved the way for astronomers to view and understand the cosmological evolution of galaxies that ground-based telescopes could not fully uncover. In recent years, advancements in space telescopes with the achievements of the Hubble Space Telescope and the upcoming James Webb Space Telescope have revolutionized the data we have in the field of astrophysics. [1] As a result, current and future space exploration operations now rely heavily on space telescopes.

The Need for Telescopes in Space

Initially, the opportunity for space-based research had been restricted by hazy, unclear images produced by ground-based telescopes until the availability of more precise data obtained by space telescopes. [2] Because space telescopes are placed outside of Earth, their observations will not be interfered with by getting absorbed or suffering from scintillation as a result of the Earth’s atmosphere, unlike ground-based telescopes. Their ability to bypass Earth’s atmosphere allows space-based telescopes to make extremely accurate photometric observations at wavelengths unattainable from the ground. The many forms of radiation such as gamma rays, X-rays, and certain parts of ultraviolet cannot be observed from Earth because they are completely blocked out by its atmosphere. Even certain broad bands in the near-infrared would not be able to evade it as they are immediately absorbed by water molecules within Earth’s atmosphere. As a result, with the limited ability to see the entire electromagnetic spectrum our studies will be severely inadequate unless information is to be gathered by space telescopes. [3]

Moreover, the reduced resolution ground-based telescopes experience when subject to atmospheric distortion is another restraint only space-borne telescopes can fully overcome. This distortion is a result of the constantly fluctuating atmospheric conditions and densities above the ground which reduces the practical resolution of the telescope despite its higher theoretical resolution. Although the application of ground-based adaptive optics imaging has been able to improve the clarity of celestial bodies such as stars, such performing enhancements are not powerful enough to surpass the efficiency of space telescope technology such as the images of the Hubble Space Telescope (HST) can capture. For these reasons, taking telescopes into space beyond the limits of the Earth’s atmosphere is the only method to view how the universe appears at various wavelengths and could not otherwise be studied using conventional ground-based telescopes. Hence, HST has been one of the most successfully employed instruments for exoplanet atmosphere studies, which often require precise, near-infrared spectroscopy. [3]

Hubble Space Telescope

Crucial to the pioneering success of space-based technologies, are the accomplishments of the Hubble Space Telescope (HST). Ever since its first space launch in 1990 by NASA, the HST has enabled the detection of some of the most distant galaxies, with its suite of instruments such as the Space Telescope Imaging Spectrograph (STIS), the Near Infrared Camera and MultiObject Spectrometer (NICMOS), the Advanced Camera for Surveys (ACS) and the Cosmic Origins Spectrograph (COS). [5][6] In fact, the technology and discoveries of the large telescope have powerfully evolved our study of the universe and its origins which has arguably been unprecedented since the time of Galileo. [7]

With its advanced picture resolution, Hubble’s countless contribution of images in space include the Orion clusters which are sharply derived from infrared imaging interpretations as well as the sharpest image ever taken of the ‘grand design’ spiral galaxy M81 which is tilted at an oblique angle directly parallel to our line of sight. Hubble has also provided observations of exoplanets in transit with their host stars only made possible because of its impressive imagery stability. In addition, HST has confirmed the existence of black holes and their common positioning within the center of all galaxies, revealed the age of the universe to a close percent as well, and revealed the existence of ‘dark matter’ and ‘dark energy’ taking over approximately 96 percent of the universe. Moreover, the HST has been able to extrapolate data from the Hubble Deep Field and Ultra Deep Field to discern an abundance of a wide range of galaxies of various ages of all which have formed less than a billion years after the Big Bang. [7] [8]

Alongside HST’s astronomical achievements, the space telescope is also serviceable which enables it to maintain durability as well as establish necessary methods to effectively execute future deployment and service missions. Developing such methods provides instrumental experience and assured proficiency in such operational techniques needed to accomplish launches for future space telescopes, especially for the forthcoming James Webb Space Telescope (JWST). With the remarkable tasks Hubble has performed, it would be unfortunate if all its existing observations were to only be seen once. Ultimately, an archive of all of the data HST has accumulated is open to the general public. The readily available information has exponentially facilitated larger use of such information for projects and research other than for the endeavors which it was originally taken for. The use of advanced computing operators has been able to expose previously unknown material in existing observations. Evidently, the legacy of the HST will never be lost and will continue to expand for decades even when it is no longer orbiting space. [6][7][8]

Looking into the Future: James Webb Space Telescope (JWST)

Consequently, the technology and discoveries of Hubble have been able to lay down the groundwork for all future space telescope missions and their potential cosmic breakthroughs. Newly developed by NASA following the Hubble Telescope, a notable mission that is reaching beyond the parameters of image-based wavefront sensing is the James Webb Space Telescope (JWST). While the length of the mission for HST has been 24 to 30 years, the JWST will be shortened to approximately 5 to 10 years. Set to launch in 2021, the JWST is a 6.5-metre diameter space telescope that will act as a successor to the Hubble Space Telescope. As opposed to Hubble’s measurements which sit only at a 2.4 metre diameter, the JWST has a larger optimised mirror with more light-gathering power. As well as that, the JWST will have a longer wavelength coverage of 0.6 – 28.5 μm and a higher range of sensitivity as it is situated further away from Earth. In contrast to Hubble’s tube-enclosed mirrors and instruments, JWST’s mirrors and instruments are open to allow the telescope to cool. Additionally, JWST’s arrangement of 18 Beryllium mirrors will be 2 and a half times more magnified in size than Hubble’s main mirror while also being twice as light. The larger mirror diameter will give JWST a sensitivity 3× greater than HST, which, coupled with its 10× higher spectral resolution, means it will become the unparalleled instrument for exoplanet atmosphere studies. [7][9]

The JWST is primarily an infrared space telescope and its suite of four instruments (NIRCam, NIR Spec, MIRI, and NIRISS) is said to provide a great range of imaging and spectroscopic capabilities. As a result, the telescope should be expected to conduct extended surveys of galaxies in the near-infrared over the redshift range 1 < z < 6 with the use of its powerful 4 instruments. The JWST is also expected to obtain hierarchical merging observations in which dark matter, gas, stars, metals, morphological structures, and active nuclei are built up to form the galaxies we see today. [6] [7]

However, with the JWST situated further away than the Hubble service mission, secure phase retrieval methods are heavily significant throughout its remote orbit within space. The development of new algorithmic data has been currently designed to process a wide spectrum of wavefront aberrations, source characteristics, and vibrational environments in case extreme environmental conditions arise so the JWST’s consistency in performance can be maintained. Because of its versatility, JWST will be used to answer a diverse set of questions from many branches of astronomy, including one of NASA’s broader institutional questions of how the first galaxies in the universe formed, and what the atmospheres of exoplanets are made of. We can therefore expect JWST to revolutionize our understanding of exoplanet atmospheres, and allow us to observe smaller and cooler celestial bodies than has previously been possible. [10]

Conclusion

The productivity and impact of space telescopes have continued to grow ever since the launch of the Hubble Space Telescope. With the continual growth of the next generation of extremely powerful space telescopes, one has been prioritized by the National Research Council to be launched as the complementary and surpassing candidate of the HST. The forthcoming James Webb Space Telescope is expected to serve as the next key program that will yield scientific results for future years to come. Nevertheless, as was the case with the HST, the most exciting discoveries that are likely to be made by JWST cannot be scripted in advance.

References

1. (2019). Eso.org. Retrieved 27 October 2019, from https://www.eso.org/public/archives/books/pdfsm/book_0045.pdf
2. Space versus Ground Telescopes. (2019). UA Research. Retrieved 27 October 2019, from https://research.arizona.edu/stories/space-versus-ground-telescopes
3. Melina, R. (2010). Why Are Space Telescopes Better Than Earth-Based Telescopes? Space.com. Retrieved 27 October 2019, from https://www.space.com/8286-space-telescopes-earth-based- telescopes.html
4. What Is the Hubble Space Telescope? (2019). NASA. Retrieved 27 October 2019, from https://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-the-hubble-space-telecope- 58.html
5. About the Hubble Space Telescope. (2019). NASA. Retrieved 27 October 2019, from https://www.nasa.gov/mission_pages/hubble/story/index.html
6. Spake, J. (2019). The cold, the hot, and the puffy: atmospheric lessons from three transiting exoplanets. University Of Exeter. Retrieved from https://ore.exeter.ac.uk/repository/handle/10871/38528
7. PQDT Open. (2019). Pqdtopen.proquest.com. Retrieved 27 October 2019, from https://pqdtopen.proquest.com/doc/902628387.html?FMT=AI
8. FAQ for Scientists Webb Telescope/NASA. (2019). Jwst.nasa.gov. Retrieved 27 October 2019, from https://www.jwst.nasa.gov/content/forScientists/faqScientists.html
9. Database Access – UNSW Library electronic resource. (2019). Link-springer- com.wwwproxy1.library.unsw.edu.au. Retrieved 27 October 2019, from https://link-springer- com.wwwproxy1.library.unsw.edu.au/content/pdf/10.1007%2F978-1-4020-9457-6.pdf
10. THE NEXT GREAT OBSERVATORY: ASSESSING THE JAMES WEBB SPACE TELESCOPE. (2019). Govinfo.gov. Retrieved 27 October 2019, from https://www.govinfo.gov/content/pkg/CHRG- 112hhrg72165/html/CHRG-112hhrg72165.html

Ever since the invention of telescopes, there has been more demand for research and observations of the universe. With a growing number of diverse telescopes, each new one that came out improved, advanced, and changed our perspective on how we see the cosmos and gave us sharper and brighter resolution. With the combination of engineering and astronomy, it has marked the birth of Space telescopes. Space telescopes are essential observation instruments and are used as a technique providing researchers and astronomers the capability to automatically monitor space. They are telescopes that are launched into space serving the purpose of what a ground-based telescope can’t do and issues that are faced with using a ground telescope.

Unlike ground-based telescopes space telescopes are not affected by the earth’s atmosphere such as weather, light, and pollution, making them more expensive to invest in, Although cost and damage are a consequence, the results and observations made from space telescopes are significantly much better and clearer compared to ground-based telescopes (O, Jeffery., O, Megan., Donahue., Schneider. N., Voit.M. 2016. p178). Due to constant changes within the earth’s atmosphere, the resolution from ground-based telescopes is not as sharp causing blurriness, hence the only solution was to build space telescopes to collect much sharper observations of the universe (O, Jeffery., et al. 2016. p175).

Because radiation poses a threat to us besides visible light and radio waves, there is an invisible layer of protection preventing us from being exposed to infrared radiation, ultraviolet rays, X-rays, and gamma rays (English N, 2017 p10). However, because of this reason space telescopes are designed to image these radiations as using the whole light spectrum can determine and find new and fascinating observations.

Hubble space telescope

The Hubble Space Telescope still remains the most iconic space telescope today 28 years after it was built(1985), launched (1990) and functioned (1993). With the collaboration of engineers, astronomers, and scientists, started the launch of the Hubble, the images provided by Hubble showed the complexity and dynamic nature of the cosmos and this changed the way the universe is seen. Figure 1.0. On the left is an image produced of a galaxy from a ground-based telescope similar in size to Hubble. The right is the same galaxy produced by Hubble, ‘Adaptive Optics’ is used in Hubble to sharpen the resolution. (Hubble 15 years of discovery, 2006)

Made with glass and coated with aluminum combined with a compound that reflected ultraviolet lights, Hubble was a reflecting telescope and was built with a 2.4m diameter primary mirror which was smaller than expected however it was powerful enough to capture what was needed (Christensen, L.L & Fosbury, R. A. 2006. p24-25). With the wide field of vision, it provided the power to monitor the whole electromagnetic spectrum within the universe.

Just like the primary mirror, the secondary mirror was also made from glass and coated with aluminum, however as both primary and secondary mirrors are “hyperbolic” in shape it was hard to assemble and test (Chen, James, L., & Chen, Adam. 2015. p2). The result of Hubble’s sharp and deep captures is a result of its solar panels converting sunlight into electricity. By emitting enough power from these panels it allows all the other parts of Hubble to operate at the same time and with stable and strong panels it produces sharper and clearer images. With built-in communication antennas, Hubble sends its data to a satellite first in the “Tracking and Data Relay Satellite System” which then transfers it to White Sands, New Mexico, USA (Christensen, L.L & Fosbury, R. A. 2006. p26).

Hubble was involved in 4 missions in 1993,1997,1999 and 2002 (Christensen, L.L & Fosbury, R. A. 2006. p19) Its first mission was a huge success, with the success of the first Hubble Space Telescope mission NASA managed to revive themselves from the failure of the Space Shuttle Challenger which caused several damages (Chen, James, L., & Chen, Adam. 2015. p4). With 2 teams of astronauts completing spacewalks in 35 hours and 28 minutes, it had marked the end of the first mission with results showing high-resolution photos captured from the Hubble space telescope.

It was in July 1994, several months after its first mission which marked one of Hubble’s greatest findings, when it captured pieces of a comet tearing apart Jupiter’s gravitational field and colliding with its atmosphere. Through this opportunity, it showed its capability of being able to capture planets that flew by in a high-quality resolution (English N, 2017 p52). In addition, the observation made of a planet orbiting another star and the atmosphere of other exoplanets was considered one of Hubble’s major achievements.

November 2008 marked the discovery of visible light of a planet orbiting the star Fomalhaut, considering the fact that it was able to capture a planet 1 billion times lighter than its parent star was an achievement (English N, 2017 p283). With advancements in technology, the Hubble telescope was also upgraded, As years have passed by, it has managed to capture the most amazing and fascinating images of the cosmos, Its most famous image is the “Pillars of Creation” which is part of “Messier 16” allowing researchers to gain a deeper understanding of the universe.

James Webb Space telescope

As the Hubble space telescope has soon come to an end it has successfully served its purpose and job to provide amazing high-resolution captures of the cosmos. Its ancestor James Webb space telescope also known as ‘The Next Generation Telescope’ is in the process of being designed, built, and later released in the future. With the universe changing and developing it is built with upgrades and advancements from Hubble for future observations. It is expected to showcase the development of telescopes holding the power to capture next-level images of the universe. Because of this it is said to be extremely complex and advanced holding the capability to make discoveries that weren’t within Hubble’s ability. In order to do so, it is designed with an 18-segmented 6.5m primary mirror which will be facing and directed near the earth’s sun point (Kalirai, 2018). Designed to transit and move around the sun, moon, and earth once every year, it will be directly facing radiation with temperatures at least 358K and for this reason, a 21 by 14m sun shield is constructed and serves as a layer of protection preventing its instruments from heating up too much ensuring it stays below -220 degree Celsius (Kalirai, 2018).

A combination of infrared imaging instruments such as spectroscopy and coronagraphy is used and built into it to discover and show the redshifted light of the electromagnetic spectrum of most galaxies in space (Kalirai, 2018). The composition of stars, the atmosphere of planets, the motion of objects, and the physical environment in an astronomical object can be gathered and measured through the use of a method called Spectroscopy. While coronagraphy is a method where there is an attachment used on a telescope to block the sunlight allowing the faintest and lightest stars and astronomical objects to be seen, doing so can assist researchers and astronomers in monitoring and capturing objects near the sun without the sunlight acting as a barrier.

Its size is a barrier that may be preventing it from being launched sooner. As the rocket is smaller in shape with dimensions of 4.6m and 16.2m (Kalirai, 2018), there are modifications that must be made before it is launched. In saying so, Webb is at least 10m in 2 dimensions and 20 in the third, hence engineers, scientists, and more have designed Webb in a way where it is able to fold and compress together decreasing its size (Kalirai, 2018), however, there are still a lot of tests that need to be completed, ensuring it is designed accurately to serve and perform its job. Once it has been launched into space it will soon be able to unfold itself as seen in the figure above Figure 1.3. James Webb Space Telescope unfolding, (Kalirai. J, 2017)

Webb has been designed on a very technical and complex scale, with an 18 beryllium segment telescope, 4 science instruments, a fine guide sensor, and a spacecraft acting as a path of communication, direction guide, and orbit maintenance (Kalirai, 2018) it is expected to have the capability to make major new revolutionary discoveries following its main goals which are divided into 4 main categories.

The end of the Dark Ages: First Light and Reionization aiming to find the first formed luminous and ionization history (Stiavelli, M., Thronson, H.A., & Tielens, A. G. G. M. 2009 p.13) The Assembly of Galaxies which involves monitoring astronomical objects in a very far distant such as the very first stars and how galaxies and dark matter, gas, stars and metal evolved from the epoch of reionization (Stiavelli, M et al. 2009 p.14). Webb will serve its purpose by capturing molecular clouds, planetary systems and migration, star clusters and more allowing researchers to comprehend the start and development of stars and planets which is involved in The Birth of Stars and Protoplanetary systems (English N, 2017 p283). To find the origins and history of living organisms Webb also aims to discover the physical and chemical properties of planetary systems tied with The Planetary System Origins Life (Gardener, Jonathan, Mather, John, Clampin, Mark, Doyone, Reyne, Greenhouse, Matthew, Hammel, Heidi, Hutchings, Jakobsen, Peter, Lilly, Simon.2006). Through monitoring infrared light within the electromagnetic spectrum, these missions can be achieved more effectively and efficiently (English N, 2017 p287). Unlike Hubble, it focuses its capability to perform infrared astronomy which allows researchers to identify further galaxies. Figure 1.4. James Webb Space Telescope creation (NASA, 2019)

However, the discovery of exoplanets is also another objective of the James Webb Telescope. With the use of Spectroscopy utilized by Webb to determine the planet’s atmosphere, ground-based telescopes combined with the transit method will identify faint lights of a star as its planets transit between us and the star. Through this researchers will be able to measure the mass of astronomical objects providing the ability to search for other planets’ atmospheres (English N, 2017 p293)

Conclusion

In conclusion, both The Hubble and James Webb Space Telescope have served their purpose and job allowing researchers to gain a greater and deeper understanding of the universe which is changing many perspectives on how the cosmos is seen now. From the launch of The Hubble Space Telescope, it captured high-resolution images and successfully completed four of its missions as the catalyst for revolutionary space advancements. Its ancestor The James Webb Telescope is soon to be launched and with its aim to discover further, lighter, and fainter astronomical objects no doubt it will enhance and determine the future of the study of astronomy. Thus, it is safe to say that with evolving and advancing technology, the future of identifying astronomical objects will be enhanced with soon-to-come telescopes with stronger capability and power than Hubble and James Webb.

References

1. Chen, James, L., & Chen, Adam. (2015). A Guide to Hubble Space Telescope Objects: Their Selection, Location and Significance. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F978-3-319-18872-0
2. Christensen, L.L & Fosbury, R. A. (2006). Hubble 15 Years of Discovery. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F0-387-36082-4
3. English, N. (2017). Space Telescopes: Capturing the Rays of the Electromagnetic Spectrum. [ProQuest eBooks Collection]. Retrieved from https://ebookcentral.proquest.com/lib/unsw/reader.action?docID=4737165
4. Gardener, Jonathan, Mather, John, Clampin, Mark, Doyone, Reyne, Greenhouse, Matthew, Hammel, Heidi, Hutchings, Jakobsen, Peter, Lilly, Simon, Long, Knox, Luinne, Mccaughrean, Mountain, Matt, Nella, Rieke, George, Marcia, Rix, Hans-Walter, Smith, Eric, Sonneborn, George, Stiavelli, Massimo, Stockman, H., Windhorst, Rogier, Wright, Gillian. (2006). The James Webb Space Telescope. Space Science Reviews, 123(4), 485-606. doi: 10.1007/s11214-006-8315-7
5. Kalirai, J. (2018). Scientific Discovery With the James Webb Space Telescope. Contemporary Physics, 59(3), 251-290. doi:10.1080/00107514.2018.1467648
6. Miller, G. , Rosenthal, D., Cohen, W., & Johnson, M. (1987). Expert Systems Tools for Hubble Space Telescope Observation Scheduling. Telematics and Informatics, 4(4), 301-311. doi: 10.1016/S0736-5853(87)80016-3
7. NASA. (2019). James Webb Space Telescope [image]. Retrieved from https://www.nasa.gov/feature/goddard/2019/nasa-s-james-webb-space-telescope-has-been-assembled-for-the-first-time
8. NASA. (2018). The Pillars of Creation [image]. Retrieved from https://www.nasa.gov/image-feature/the-pillars-of-creation
9. O, Jeffery., O, Megan., Donahue., Schneider, N., Voit.M. (2016). The Cosmic Perspective,8th edition. USA, Boston: Pearson
10. Stiavelli,M.,Thronson,H,A., & A. G. G. M. Tielens. (2009). Astrophysics in the Next Decade: The James Webb Space Telescope and Concurrent Facilities. [SpringerLink eBooks Collection]. Retrieved from https://link-springer-com.wwwproxy1.library.unsw.edu.au/book/10.1007%2F978-1-4020-9457-6