Humans have been fascinated by the stars for thousands of years and continue to be so thanks to a burning curiosity that only grows with each new discovery. Since its launch, the Hubble Space Telescope has shaped our understanding of space in ways astronomers never thought possible. It has confirmed the age of the universe, studied planets around distant stars and has peered back in time to the start of everything. Today is its thirtieth birthday.
It had been agreed for decades that a space-based telescope would be beneficial for astronomical observations. Orbiting the Earth, it would always be free from the haze of the atmosphere and bad weather. In 1969, scientists started pushing for such a telescope—then known as the Large Space Telescope (LST).
When funding was officially approved in 1977, the project became a joint venture between NASA and the European Space Agency. The two designed, built and finalised the scientific goals of the LST. The project took longer than expected because the new technology was harder to develop than first thought and also ran over budget.
Hubble also experienced further delays to its launch due to the 1986 Challenger incident. Early into take-off, the Challenger shuttle leaked hot gases—caused by a faulty O-ring—from one of its boosters onto its fuel tank and exploded. All seven astronauts riding in the shuttle were killed and the rest of the shuttle fleet was grounded for two years while an investigation was carried out.
In 1983, the LST was renamed the Hubble Space Telescope after famous American astronomer Edwin Hubble. His discoveries included the expansion of the universe and the existence of galaxies outside of our own Milky Way. He also determined the Andromeda Galaxy was a lot further away than previously thought (2.5 million light years) and was not simply a nebula.
The Joke of NASA
The Space Shuttle Discovery finally took Hubble to orbit on April 24, 1990. On the five-day mission, the telescope was successfully deployed and tested. Everything was working perfectly until NASA tried Hubble’s optics. The images came back blurry.
Hubble’s 2.4-metre-wide mirror was the wrong size. It was only off by a fraction of the width of a human hair, but everything needed to align flawlessly for the intricate telescope to function. Hubble was useless until it could be fixed.
Thanks to this debacle and how long it took to get the telescope to space, Hubble and NASA were the punchline in many jokes. Late-night television loved making fun and the telescope was even pictured alongside disasters, such as the Hindenberg disaster, in the 1991 comedy film The Naked Gun 2 1⁄2: The Smell of Fear.
An investigation into Hubble’s error found that a contractor was at fault. There was a breakdown in communication within the company and the mirror was produced in the wrong dimensions.
In 1993, the Space Shuttle Endeavour docked with Hubble. Two pieces of equipment were installed to correct the mirror problem, as well as other technology to make Hubble more versatile. It was time for the telescope to finally get to work.
Hubble’s Golden Age
The Hubble Space Telescope is responsible for some of the biggest breakthroughs in astronomy and astrophysics in the last 30 years.
Following from its namesake’s discovery of universe expansion, Hubble revealed that the expansion of the universe is actually speeding up. It also created a 3D map of dark matter in the universe. Not much is known about dark matter, but it makes up around 84% of material in the cosmos. It interacts with gravity and scientists believe it binds large structures, such as galaxies and globular clusters, together. Hubble has witnessed supermassive black holes at the heart of every major galaxy, a discovery that scientists had not even predicted.
In 1995, for the Hubble Deep Field photo, the telescope was pointed at what looked like an empty part of space in the Ursa Major constellation. Astronomers were shocked to find the resulting image was filled with thousands of galaxies, each with around 100 thousand million stars. Hubble has taken similar photos over the years, in other regions of the universe, and has found the same thing.
The images Hubble has produced, such as the Pillars of Creation, have influenced, inspired and are staple of pop culture. They’ve been used on books and album covers as well as featured in TV shows and movies.
Hubble has been used to study exoplanets (planets around other stars). Because Hubble sees in ultraviolet and infrared wavelengths, elements in an exoplanet’s atmosphere show up at different points on the spectrums. In 2019, it discovered large amounts of water vapour in the atmosphere of K2-18b. The vapor might only be steam, but it has scientists excited. The planet is close enough to its star that the vapor could be the water of a huge ocean. This makes K2-18b a good candidate for sustaining life.
The telescope has also watched events closer to home. It’s studied the weather on Jupiter, Saturn, Uranus and Neptune—as well as their moons—and has revealed two extra moons orbiting Pluto. In 1994, Hubble caught pictures of comet Shoemaker–Levy 9 as it slammed into Jupiter. It is the first, and only time, astronomers have witnessed such an impact. It has helped them to better understand the early conditions of the solar system when such collisions were common.
Hubble orbits the Earth at a height of nearly 600 kilometres and completes a lap every 95 minutes. It only has black and white cameras onboard and takes three exposures (red, green and blue) of each astronomical target. The science team on the ground then add the information together to create the coloured photographs.
There have been five Space Shuttle servicing missions over the telescope’s lifetime. Each added new equipment to improve efficiency and replaced hardware that had failed. The last mission was in 2009 and set Hubble up to operate for decades to come.
The operations team is based at the Goddard Space Flight Center in Greenbelt, Maryland. They keep an eye on everything for Hubble, from flight control to data processing. In May 2011, Hubble operations became more automated. Previously the telescope had to be managed 24 hours a day, but now it only needs eight hours a day, five days a week. There is a robust out-of-hours text-messaging system that alerts technicians if there are any major concerns.
Any scientist can apply to use Hubble’s resources. The spots are extremely competitive and an anonymous committee overseas them. Approximately 1,000 proposals are received each year and only 200 are selected. Material produced by Hubble has been published in over 15,000 science papers.
Hubble’s Future and the James Webb Space Telescope
In time, Hubble’s orbit will begin to decay and eventually the telescope will burn up in our atmosphere. A shuttle mission was originally proposed to retrieve the telescope and bring it back to Earth. It would then have been featured in a museum, such as the Smithsonian. Such a plan is no longer possible as the shuttle fleet was retired in 2011.
The James Webb Space Telescope is the next generation of Hubble and will continue the legacy. Its technology is far more advanced and will be able to teach us more about space. Unlike Hubble, James Webb—named after one of NASA’s early directors—will orbit, like the Earth, around the Sun out beyond the Moon. Its launch is currently planned for March 2021.
The Hubble Space Telescope is one of the greatest scientific instruments of all time. We continue to learn new things from it with each passing year. NASA expect to continue to use Hubble until the late 2030s.