• After 31 years in space, the Hubble Space Telescope has developed a fault.
  • Scientists hope it can be fixed soon – but nothing can detract from its achievements.
  • Hubble discovered the age of the universe and found new stars and galaxies.

There’s trouble in space… Hubble trouble. The Hubble Space Telescope, which has helped scientists determine the age of the universe and map dark matter, has developed a computer fault.

It’s hardly surprising, given that the telescope was launched in 1990 and its computers were built in the eighties. How many of us have a PC that’s lasted anywhere near that long?

But this glitch won’t detract from Hubble’s amazing achievements in the time it has been in space.

a picture of the hubble telescope
Into orbit: the Hubble Space Telescope is released from the Space Shuttle.
Image: NASA

What is the Hubble Space Telescope?

The Hubble Space Telescope is a large, space-based observatory. It has revolutionized astronomy since it was launched in 1990, according to NASA, which developed the telescope with the European Space Agency.

It is named after pioneering US astronomer Edwin Hubble, who was the first to find evidence of the accelerating expansion of the universe, the foundation of the Big Bang theory about how the universe and stars were created.

Before its computer issues surfaced in June 2021, Hubble had made more than 1.3 million observations resulting in more than 18,000 scientific papers. It’s been credited with transforming our understanding of the universe.

Orbiting 547 kilometres above the Earth’s surface, Hubble gets a clear view of space without the distorting effects of our atmosphere, capturing some stunning imagery and solving some long-standing mysteries of the universe.

The size of a school bus, Hubble has travelled more than 6 billion kilometres in this low Earth orbit, at a speed of 27,000kph.

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a picture of jupiter
Jupiter’s great red spot seen by Hubble.
Image: NASA

What can Hubble see?

On its travels, the Hubble Space Telescope has helped show that black holes lie at the centre of all galaxies, including our own.

It also mapped the presence of dark matter in the universe for the first time and has tracked colliding asteroids. It’s been able to see the formation and destruction of stars, planets and whole galaxies.

The interaction of two doomed stars has created this spectacular ring adorned with bright clumps of gas — a diamond necklace of cosmic proportions. Fittingly known as the Necklace Nebula, this planetary nebula is located 15 000 light-years away from Earth in the small, dim constellation of Sagitta (The Arrow). The Necklace Nebula — which also goes by the less glamorous name of PN G054.2-03.4 — was produced by a pair of tightly orbiting Sun-like stars. Roughly 10 000 years ago, one of the aging stars expanded and engulfed its smaller companion, creating something astronomers call a “common envelope”. The smaller star continued to orbit inside its larger companion, increasing the bloated giant’s rotation rate until large parts of it spun outwards into space. This escaping ring of debris formed the Necklace Nebula, with particularly dense clumps of gas forming the bright “diamonds” around the ring. The pair of stars which created the Necklace Nebula remain so close together — separated by only a few million kilometres — that they appear as a single bright dot in the centre of this image. Despite their close encounter the stars are still furiously whirling around each other, completing an orbit in just over a day.  The Necklace Nebula was featured in a previously released Hubble image, but now this new image has been created by applying advanced processing techniques, making for a new and improved view of this intriguing object. The composite image includes several exposures from Hubble’s Wide Field Camera 3.
The interaction of two doomed stars, seen by Hubble, caused this ring of light and gas.
Image: ESA/Hubble & NASA, K. Noll

To take its laser-sharp images, Hubble must hold a steady position. It has no thrusters but instead uses Newton’s third law of motion – the one about every action having an equal and opposite reaction – by spinning its three gyroscope reaction wheels in opposing directions.

With no atmosphere to interfere with the light reaching it, Hubble could spot a night light on the surface of the Moon from Earth. And using its gyroscopes to steady its flight means that Hubble can remain focused on distant objects, limiting its potential movement to 0.000002 of a degree.

The oldest objects it has seen so far are more than 13.4 billion light-years from Earth, meaning that it is looking at space objects that were formed very soon after the universe itself came into existence 13.8 billion years ago. We have Hubble to thank for pinpointing that date.

a picture of a nebular
Quasar – Hubble’s successor the James Webb space telescope will study their origins.
Image: NASA

What’s wrong with the telescope – and how will it be fixed?

Hubble's payload computer stopped working on 13 June 2021. The telescope itself and its instruments are not affected.

Since it was placed into orbit by the Space Shuttle, Hubble has been upgraded several times by spacewalking astronauts. And the current glitch is not the first. In 2018, the telescope went into “safe mode” after problems with its gyroscopes. And in early 2019, a hardware problem caused its camera to fail.

In the past, problems with the telescope could be fixed by sending up astronauts in the Space Shuttle to work on it in orbit. So far, five servicing missions have upgraded the onboard technology.

But since the end of the Shuttle programme in 2011, that’s no longer an option. NASA says it hopes to restart the failed computers from Earth. Scientists think a fault on a component elsewhere in the telescope may be the cause of the trouble.

Hubble is due to be replaced by a new orbiting observatory, the James Webb Telescope, which has a planned launch date at the end of 2021. Among the objects scientists plan to focus it on are quasars – supermassive black holes that are millions to billions of times the mass of the Sun.

Until the new telescope arrives in orbit, the global astronomical community are hoping that the team at NASA can get Hubble up and running again to continue its work of revealing the secrets of the stars and the universe.