Hubble Space Telescope:

Hubble Space Telescope: “It’s like keeping a laser pointer on a dime 330km away for 24 hours”

Hubble’s science operations manager Kevin Hartnett about the future of the iconic telescope.

The Hubble Space Telescope launched 30 years ago, on 24 April 1990. Hubble’s science operations manager Kevin Hartnett joined the team in 1997, and is responsible for overseeing scientific aspects of the space telescope’s operations.


With a bachelor’s degree in physics and astronomy, his career began in the private industry before he started working at NASA.

How is the Hubble Space Telescope doing?

It’s performing at the peak of its capabilities and functioning marvellously. There aren’t as many available backups as there were some years ago. For instance, Hubble has six gyros to keep itself orientated, but only three are active and we need three to do our best science.

Our engineers are coming up with clever ways to combat ageing. Things dim, they fade, one side of the detector has a greater sensitivity than the other. But they’ve kept the observations really at the forefront of what anyone can do on the ground or in space, and that’s pretty remarkable.

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What sets Hubble apart?

It’s a one-stop-shop for very stable, high-contrast imaging and spectroscopy from the near-infrared wavelengths right through to the ultraviolet, with a 2.4m mirror above the atmosphere.

We have very fine guidance sensors too. In layman’s terms, it’s like being on top of the Washington Monument in Washington, DC and keeping a laser pointer on a dime on the top of the Empire State Building in New York City 330 kilometres away for 24 hours. So once we lock on, we really lock on target.

Kevin Hartnett working in the Space Telescope Operations Control Center during Hubble’s final servicing mission in 2009 ©
Kevin Hartnett working in the Space Telescope Operations Control Center during Hubble’s final servicing mission in 2009

What type of research does Hubble do?

Solar System astronomy, galaxies, large-scale structure of the Universe, and everything in between – Hubble has made major contributions to every astronomical field.

There are also legacy programmes. For instance, there’s a large project right now to observe every Milky Way globular cluster. Not because someone wants to write a paper on all 150 clusters, but the data is there if someone ever does.

Does the old data still get used?

Oh my, yes. There’s a lot of interesting science you can do with a 25-year baseline. If you’ve got good observations from 25 years ago, you can compare them to similar observations today.

You can see jets actually moving out of the big quasar in M87. You can calculate velocities. Scientists can get a lot out of data like that.

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How long does Hubble have left?

Hubble doesn’t have a propulsion system and it is slowly falling to Earth. A report from September 2018 predicts Hubble re-entry no earlier than 2027, and the mean date is around 2038.

We’re very in-tune with the performance of the telescope and we’re trying to pamper all of its systems, to keep it running as long as possible.

  • This article first appeared in issue 348 of BBC Science Focus Magazine