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  • Writer's pictureChris Baker


April 24th, 2020 was the 30th anniversary of the launch of the Hubble Telescope into space.

Over the decades much has been written about this remarkable space observatory. Countless stunning images have been published by NASA – inspiring generations to take an interest in the cosmos.

On this special anniversary I wanted to take a different tack to the normal discussions: Answer some basic questions: What exactly is the Hubble telescope?

Apart from taking amazing images, what does it actually do up there?

What is it?

Hubble is a space based telescope comprising a range of cameras to peer deep into space. It was the first space based observatory and has been serviced and upgraded along the way.

Hubble’s mission was to spend at least 15 years probing the farthest and faintest reaches of the cosmos. Hubble has exceeded this goal, operating and observing the universe for almost 30 years.

Hubble’s primary mirror is 2.45 metres in diameter and collects an immense amount of light. Hubble can detect objects that are 10 billion times fainter than the unaided eye can see. High above the blurring effects of Earth’s atmosphere, Hubble also gets a much clearer view of the cosmos than do telescopes located on the ground.

Here is an image of the Hubble Space Telescope

Hubble is 43.5 feet long (13.2 m) and 14 feet wide (4.2 m) at the back, where the scientific instruments are housed. Weighing about 27,000 pounds (12,246 kg), the telescope is approximately the same size and weight as a bus. The observatory is powered by two solar arrays that convert sunlight into electrical energy that is stored in six large batteries. The batteries allow the observatory to operate during the shadowed portions of Hubble’s orbit when Earth blocks the satellite’s view of the Sun.


The telescope has a range of cameras that are used to capture images or data, for scientific purposes. Each camera probes a different part of the spectrum. Sometimes they are used in combination.

Hubble has two main camera systems to capture images. Called the Advanced Camera for Surveys (ACS) and the Wide Field Camera 3 (WFC3), these two systems work together to provide superb wide-field imaging over a broad range of wavelengths.

Hubble has two spectrographs: the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS). COS and STIS are complementary instruments that provide scientists with detailed spectral data for a variety of celestial objects.

What does it do?

During its time in orbit, the telescope has made more than 1.4 million observations, and astronomers have used that data to publish more than 16,000 peer-reviewed scientific publications. So it does a lot of science!

Examples of the science and discoveries

1) Age of the universe One of Hubble’s main tasks was to figure out the age and size of the universe. Researchers now know that the universe is about 13.7 billion-years-old thanks to research performed using Hubble’s data.

2) Understanding the early universe

A series of images- probing deep into space has allowed astronomers to probe the star formation history of the universe over 95% of its lifetime.

3) Moons of Pluto

Hubble was responsible for discovering four of the five moons that are currently known to orbit the dwarf planet Pluto.

4) Understanding the weather on other solar system planets

Hubble has been able to track seasonal changes on planets within our solar system. Hubble tracked Jupiter’s weather, for example, allowing researchers to see colour changes in bands of clouds in the huge gas giant’s atmosphere.

5) Discovering new worlds

About 20 years ago the first planet was discovered orbiting a star other than the sun- in other words the discovery of a new planetary system. These planets are called exo-planets and since that first one there have been many thousands identified. Hubble has made its own contribution to the search, discovering new exo planets and taking the first image of a planet around another star. It has also probed the atmosphere of some of these fascinating objects.

There is much more – these are just a few examples.

And what’s next? Sadly there are no more Shuttles so there will be no more service missions. Eventually all the instruments on Hubble will fail.

The replacement is the James Webb Telescope- which is planned to be in space within a few years. This will make a giant leap in discoveries – not least in searching for and learning more about those exo planets…and maybe if they have life…..

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