The Hubble Space Telescope Celebrates 30 Years
Is your desktop, by chance, a celestial image? If so, it is very likely that it was captured by the Hubble Space Telescope (HST). As the 30th anniversary of it’s launch approaches, let’s take a look back on Hubble’s history and see how far it has come.
From 1923 where the prospect of an earth orbiting telescope was theorized, to the HST’s specific design concepts introduced in 1962, to its launch in 1990, and its final service mission in 2009, the HST has persevered to become a scientific marvel.
Hubble has been orbiting Earth for 30 years, and it has certainly accomplished more than beautiful pictures. (click image for timelapse of Hubble orbit) It helped us understand the relationship between black holes and galaxies. Specifically, that the mass of a black hole governs many of the characteristics of its galaxy. The HST helped us learn more about the universe as a whole too. Its age and expansion were unrefined metrics at the time. Without such fundamental knowledge, strange theories like the idea that old stars existed before the universe began were allowed to proliferate. Thank goodness for the Hubble Space Telescope.
While there is indeed a lot of matter in the universe, there is a lot more empty space. Dark energy is a uniform and dilute form of energy that can be found throughout, making up 68% of all the universe's energy. Dark energy is a means of explaining the acceleration of the universe. Data collected from the HST is what led to this concept.
Hubble is a reflecting telescope. This type of telescope uses mirrors to develop the image the eye sees instead of lenses, a characteristic of refracting telescopes. Reflecting telescopes are often preferred over refracting telescopes. Part of that has to do with the difficulty of creating large, high quality lenses as opposed to large high quality mirrors. A mirror only needs a single sided thin film coating of excellent quality whereas a lens needs to be flawless throughout its entire thickness.
The HST project overcame many challenges. At one point its funding was entirely cut. The combined effort of numerous astronomers speaking with government officials allowed the project to get back on its feet. It faced challenges after launch as well. The primary mirror suffered from severe spherical aberration on its launch, causing its images to appear blurry and essentially rendering the telescope useless. This was only fixed three years later in 1993, which would be the first of five service missions.
The final service mission in 2009 achieved a level of future proofing, a significant feat in our fast growing technological world. While the telescope had been in active service for nineteen years at the time, it still lacked full functionality until the completion of the mission. Furthermore, it installed a powerful new instrument called the Wide Field Camera 3, which showed off its value to the world by unveiling updated photos of the already famous celestial spectacle: The Pillars of Creation.
Exoplanets, planets that orbit stars other than our own, are objects that the Hubble Space Telescope spends time searching for. When an exoplanet passes in front of a star, it is called a transit. Light travelling through an atmosphere can either be absorbed by it or not. Since certain elements absorb certain wavelengths of light, we can determine which elements make up the atmosphere by expanding the target’s spectra and seeing which bands have darkened, indicating they were absorbed. Our own atmosphere reminds us that certain substances are red flags for life such as: carbon dioxide, carbon monoxide, ammonia, and water.
What the HST has done for us is not just collect data, and further our scientific endeavours. It has not just provided us with cosmic art, and celestial inspiration, but it has also turned the vastness of space into something tangible. No longer is the cosmos completely unfathomable, shrouded in mystery in the mind’s eye. It turned nameless stars into titled works of art and “space” into “the known universe”. Although the passing of the torch to the James Webb Space Telescope is imminent, it was the HST that first turned the formless unknown of space into something comprehensible for the masses beyond mathematical models, a feat that no other telescope can lay claim to.
Photo source: NASA Gif source: Wikipedia
Cool Hubble Facts
|The Hubble Space Telescope has been cited over 800,000 times in scientific papers. It's own data has been used to publish over 17,000 papers directly.
|Hubble had 5 service missions. The first of which was to fix a major flaw in the mirror. The last of which was to future proof it, improving its longevity.
|The HST was not a one and done project. It grew in functionality over the years, and was not considered fully functional until its final service mission in 2009.
|Different institutions handled different aspects of the construction. Perkin-Elmer designed and manufactured the optical components and sensors. Marshall Space Flight Centre helmed the telescope itself. Goddard Space Flight Centre was granted control of the instrumentation and ground support systems. Lockheed designed the spacecraft.
|Hubble physically rotates to point at celestial targets by spinning wheels attached to its frame. Via Newton's Third Law, as the wheels turn in one direction, the telescope will turn in the other. This design decision was mainly chosen to maintain image quality, as the alternative use of propellants could contaminate the atmosphere around the telescope's field of view.
|The James Webb Space Telescope (JWST) is the successor to the HST. Its current planned launch date is March 30, 2021.
|For more Hubble facts, visit the NASA website.