On April 24, 1990, the Space Shuttle Discovery launched the Hubble Space Telescope into orbit. This was a thrilling moment for space exploration because Hubble promised to deliver amazing images that would give us a better look at our universe. Over the past 30 years, Hubble has lived up to that promise, becoming the most famous telescope in the world. However, it almost didn’t happen due to a major problem.
Shortly after Hubble was launched, scientists discovered a problem with its mirror, which caused the images it captured to be extremely blurry. The mirror, which is 2.5 meters wide, is the heart of the telescope. It needs to be perfectly shaped to produce clear images. The main mirror captures light and reflects it onto a smaller mirror, which then sends the light to Hubble’s cameras and other instruments. If the mirror’s shape is perfect, all the light focuses on the same spot. Unfortunately, because of a tiny flaw, light hitting the inner parts of the mirror was focused incorrectly. The mirror’s shape was off by just 2,000 nanometers, which is about 1/50th the thickness of a human hair, but this small error made Hubble almost useless.
The mirror was built 10 years before Hubble’s launch and went through a lot of testing. Interestingly, a backup mirror was also made in case the main one had problems. So, why did the flawed mirror end up in space, and why wasn’t the backup used?
In 1977, NASA got the funding to start building the Hubble telescope, expecting it to cost around $300 million. They hired a company called Perkin-Elmer to design and build the main mirror using high-tech machines for precise shaping. This technology was very advanced at the time because the mirror needed to be polished to an accuracy of just 10 nanometers. To avoid problems, NASA also asked Kodak to make a backup mirror. Kodak suggested that both companies check each other’s mirrors for mistakes, but this didn’t happen.
Perkin-Elmer started building the mirror in 1979, using a special type of glass and polishing it for two years. After adding a reflective coating, the mirror was finished. It was tested to make sure it could handle the vibrations of a rocket launch and the harsh conditions of space. However, when checking the mirror’s shape, engineers used a device called a null corrector. Unfortunately, one of the mirrors in this device was set up wrong, hiding the flaw in Hubble’s mirror and giving false results that said the mirror was perfect.
Meanwhile, Kodak was almost done with their mirror, but since NASA chose Perkin-Elmer’s mirror, Kodak’s mirror was left unfinished and stored away. This mistake wasn’t caught during testing, and in 1990, Hubble was launched. When the first images came back blurry, it was clear something was wrong. This was a huge disappointment after so much work and money had been spent, and Hubble was at risk of being seen as a big failure.
Tests on the Kodak mirror showed it was polished correctly. If Perkin-Elmer and Kodak had checked each other’s work, the mistake might have been found before Hubble was launched. Even though Kodak’s mirror was perfect, it couldn’t be used because replacing the mirror in space wasn’t possible. However, Hubble was designed to be fixable. It had five instrument bays at the back, each holding a scientific tool that could be swapped out for newer versions over time.
NASA came up with a clever solution to fix Hubble’s mirror problem. Although the polishing machine made a mistake, it was a consistent mistake, so NASA could figure out exactly how the mirror was flawed. They created a small set of mirrors and lenses to refocus the light correctly. This new tool, called COSTAR, had two small mirrors: one flat and one curved, designed to fix the flaw in Hubble’s main mirror.
After spending $50 million and two years developing COSTAR, it was ready to launch. On December 2, 1993, the Space Shuttle Endeavour took off with seven astronauts and COSTAR on a mission to save Hubble. During a seven-hour spacewalk, astronauts carefully replaced one of Hubble’s instruments with COSTAR. It took a few weeks for COSTAR to fully work, but when Hubble sent back new images, they were crystal clear, proving the repair mission was a success. The scientists who worked so hard on this project were thrilled that Hubble could finally do what it was meant to do.
Over the next few decades, Hubble made incredible discoveries, capturing breathtaking images and helping us understand the universe like never before. The telescope was regularly serviced by the Space Shuttle, and in 2009, COSTAR was removed because other instruments had been upgraded with built-in optics. The Kodak mirror stayed in storage until 2000, when it was moved to the National Air and Space Museum in Washington, D.C. Even though it was never used, this mirror was perfect and could have saved NASA a lot of money and effort.
The amazing engineering needed to fix Hubble shows how clever and capable humans can be. As time goes on, Hubble’s systems are becoming less reliable, and its end is near. New telescopes with advanced technology will take its place, but Hubble will always be remembered for its huge contributions to our understanding of the universe.
Explore the concept of light reflection and how mirrors work by conducting a simple experiment. Use a flashlight and a small mirror to reflect light onto different surfaces. Try adjusting the angle of the mirror to see how it changes the direction of the light. Discuss how this relates to the Hubble’s mirror and its importance in capturing clear images.
Create a timeline of the key events in the Hubble Space Telescope’s history. Include its launch, the discovery of the mirror flaw, the COSTAR mission, and its major discoveries. Use online tools or poster boards to make your timeline visually appealing. This will help you understand the sequence of events and the efforts made to fix the telescope.
Imagine you are part of a team tasked with designing a new space mission to repair or upgrade a telescope like Hubble. Consider the challenges faced by astronauts during the COSTAR mission. Write a brief plan outlining the objectives, tools needed, and potential obstacles. Present your plan to the class.
Research one of Hubble’s significant discoveries or images and prepare a short presentation. Explain the scientific importance of the discovery and how it has contributed to our understanding of the universe. Use visuals to enhance your presentation and engage your classmates.
Participate in a class debate about the costs and benefits of space exploration projects like the Hubble Space Telescope. Divide into two groups, with one arguing for the importance of investing in space exploration and the other questioning the high costs. Use facts from the article and additional research to support your arguments.
On April 24, 1990, Space Shuttle Discovery launched the Hubble Space Telescope into orbit. This marked an exciting era for space exploration, as Hubble promised to deliver groundbreaking images, offering us an early glimpse into our universe. After 30 years of service, Hubble has indeed fulfilled that promise. However, despite becoming the most renowned telescope globally, it’s easy to overlook that it nearly faced failure.
Shortly after its launch, scientists discovered a defect in Hubble’s mirror that caused it to produce extremely blurry images. This 2.5-meter-wide mirror is the core of the telescope and must be perfectly shaped to generate high-quality images. The main mirror captures light and reflects it onto a smaller mirror, which then directs the light to Hubble’s various imaging instruments. If the mirror’s curvature were perfect, light hitting any part of it would focus on the same spot. Unfortunately, due to the defect, light hitting the inner sections of the mirror was focused elsewhere. The mirror’s shape was only off by 2,000 nanometers (1/50th the thickness of a human hair), but this minor flaw rendered Hubble ineffective.
The mirror was constructed 10 years before Hubble’s launch and underwent extensive testing. Interestingly, an identical backup mirror was also created in case the main mirror encountered issues. So, how did this flawed mirror end up in space, and why wasn’t the backup mirror utilized?
In 1977, NASA secured funding to begin constructing the Hubble telescope, anticipating a cost of around $300 million. They contracted the optics company Perkin-Elmer to design and build the main mirror, as they planned to use custom-built computer-controlled polishing machines for precision shaping. This technology was cutting-edge at the time, as the mirror needed to be polished to an accuracy of just 10 nanometers. To mitigate potential problems, NASA asked Perkin-Elmer to subcontract Kodak to create a backup mirror. Kodak, known for its camera equipment and optical lenses, suggested that both companies cross-examine their mirrors for any issues, but this did not occur.
With NASA’s budget in place, Perkin-Elmer began building the mirror in 1979, starting with a blank sheet of ultra-low expansion glass and meticulously polishing it for two years. After washing and applying a reflective aluminum coating, the mirror was completed. Over the following years, it underwent tests to ensure it could withstand the intense vibrations of a rocket launch and the harsh conditions of space. However, to verify the mirror’s shape, engineers used a device called a null corrector, which employed a special lens and mirrors to ensure the light was focused correctly. Unfortunately, during setup, one of the mirrors was misaligned, which inadvertently masked Hubble’s flaw, leading to incorrect results indicating that the mirror was perfect.
Meanwhile, Kodak was nearing completion of their mirror, but since NASA had opted for Perkin-Elmer, Kodak’s mirror was left uncoated and stored. This oversight went undetected through testing, and in 1990, Hubble launched. It quickly became evident that something was amiss when the first images received were blurry, indicating that the telescope was not functioning correctly. This was a significant disappointment for engineers after decades of work and billions of dollars invested, as Hubble risked being remembered as a major failure.
To compound the situation, tests on the Kodak mirror revealed it had been polished correctly. If Perkin-Elmer had agreed to cross-examine both mirrors, the mistake might have been identified before Hubble’s launch. Despite the Kodak mirror being perfect, it was essentially useless since replacing the mirror in space was not feasible. However, Hubble was designed to be repairable. Located at the back of the telescope were five instrument bays, each housing a scientific instrument that allowed Hubble to take various measurements. This modular design enabled the replacement of instruments with more advanced versions over Hubble’s lifetime.
NASA devised an innovative solution to fit into one of the instrument bays and repair Hubble’s faulty mirror. Although the polishing machine had made an error, it was a precise error, allowing NASA to determine exactly how the mirror was flawed. They developed a compact set of mirrors and lenses to refocus the light onto Hubble’s instruments. This new instrument, called COSTAR, featured two small mirrors: one flat mirror reflecting light onto a second curved mirror, which was shaped to counteract Hubble’s main mirror’s flaw.
After $50 million and two years of development, COSTAR was ready for launch. On December 2, 1993, the Space Shuttle Endeavour launched with seven astronauts and COSTAR on a mission to save Hubble. During a seven-hour spacewalk, astronauts carefully removed one of Hubble’s instruments and replaced it with COSTAR. It took several weeks for COSTAR to fully deploy, but when Hubble sent back new images, they were incredibly clear, confirming that the repair mission had been successful. The scientists who worked tirelessly on this telescope were overjoyed that Hubble could finally perform as intended.
Over the next few decades, Hubble made remarkable discoveries, capturing stunning images and revealing the universe in unprecedented ways. The telescope was regularly serviced by the Space Shuttle, and in 2009, COSTAR was removed as other instruments had been upgraded with built-in optics. The Kodak mirror remained in storage at Perkin-Elmer’s facility until 2000, when it was transferred to the National Air and Space Museum in Washington, D.C. Despite never being used, this mirror was perfect and could have saved NASA millions of dollars and countless hours of effort.
The incredible engineering required to fix Hubble demonstrates human ingenuity and capability. Over the years, Hubble’s systems have become less reliable, and its end is approaching. New telescopes with advanced imaging systems will emerge, but Hubble will always be remembered for its significant contributions to our understanding of the universe.
Hubble – A space telescope launched by NASA to observe distant stars and galaxies. – The Hubble Space Telescope has provided us with stunning images of the universe.
Telescope – An instrument designed to make distant objects appear closer and more detailed. – Astronomers use telescopes to study planets and stars that are far away.
Mirror – A reflective surface used in telescopes to gather and focus light. – The large mirror in the telescope helps capture faint light from distant galaxies.
Light – Electromagnetic radiation that is visible to the human eye and is used in astronomy to observe celestial objects. – Light from the sun takes about eight minutes to reach Earth.
Images – Pictures or representations of objects, often captured by telescopes in astronomy. – The images from the Hubble Telescope have revealed new details about the universe.
NASA – The National Aeronautics and Space Administration, responsible for the United States’ space exploration efforts. – NASA’s missions have greatly expanded our understanding of space.
Space – The vast, seemingly infinite expanse that exists beyond Earth’s atmosphere. – Space is filled with stars, planets, and galaxies waiting to be explored.
Discovery – The act of finding or learning something for the first time, often used in the context of new astronomical findings. – The discovery of a new planet excited astronomers around the world.
Universe – The totality of all space, time, matter, and energy that exists. – Scientists study the universe to understand its origins and structure.
Engineering – The application of scientific principles to design and build machines, structures, and other items, including spacecraft. – Engineering is crucial in developing the technology needed for space exploration.
