NASA’s Hubble Space Telescope celebrates 25th anniversary

On 24 April 1990, the Hubble Space Telescope was launched into orbit aboard the Space Shuttle Discovery, but straight away it was obvious that something was wrong. The images being sent back were disappointingly blurry, and it was soon discovered that a tiny flaw in the primary mirror was to blame. In December 1993, NASA sent up a crew to fix the problem, and after five days of spacewalks, the were done. On 13 January 1994, Hubble began sending the beautiful, high resolution images that were first promised, and it has been capturing these stunning views of deep space ever since. To celebrate the 25th anniversary of this incredible science instrument, BAFTA nominated filmmaker Christopher Riley has directed a documentary about its incredible journey. We spoke to him about why Hubble is so important, what’s in store for its future, and why the engineers that built it were reluctant to be in his film…

What made you decide to create this documentary?

My history with the Hubble Space Telescope goes back to when I was doing my PHD in the early 90s when it was launched. At that time I was working on data from the space shuttle so I had an interest in that field and I was aware of how long it had taken to build. I have followed the story for most of the last 25 years, including the subsequent success that it’s had which coincided with the rise of the world-wide-web. I think that’s what’s behind its huge popularity. It is without doubt the most celebrated and famous science instrument in history and that’s largely because its launch coincided with the invention of the JPEG file format. It was a sort of birth of a time for society where we could share things more visually, more independently, and that coincided with this extraordinary avalanche of amazing imagery that it was producing. So I lived through all of that and I’d always wanted to make a film about it, so when the opportunity came up last year I just jumped at it.

Hubble in orbit
Hubble in orbit

What did you learn from talking to the Hubble team?

I think the thing that surprised me the most was that all these decades on, the engineering team, particularly those who made the mirror that had the flaw in it, still had this terrible burden of blame that had been poured on them. It took me quite some time to persuade them to take part in the film at all. These were the characters that directly made this extraordinary mirror, which was the largest, smoothest mirror ever created in human history at the time, and what’s ultimately responsible for the telescope still being at the cutting edge of science a quarter of a century later. They were so ahead of their time engineering-wise that the digital camera technology on the telescope, which was refitted every few years during space shutter missions, only caught up in 2009 and they made this mirror back in the 70s. Yet despite that they were still thought to be the problem rather than something to be celebrated because of the initial problems with the mirror. I had to persuade them that the objective of the film wasn’t to vilify them further but to recognise that what they had done was incredible.

What excites you the most about Hubble?

There are so many extraordinary images that have illustrated covers of books and magazines over the years that just look aesthetically beautiful, but for me the most powerful images are these deep field images that started to be taken in the mid 1990s. They are visually less aesthetically stunning because they are usually just full of tiny specks of light, but they’re more profound in that they capture some of the deepest most ancient light that human beings have ever seen.

The team basically open the iris of the telescope and point it at a tiny speck of seemingly empty sky and they do this repeatedly for hundreds of hours over the course of years. The great thing about Hubble is that they can point it at exactly the same bit of sky. It’s the equivalent of it being on top of the Washington Monument and pointing a laser at a coin on top of the Empire State Building that’s 250 miles away, and holding the laser steady not just on the coin but on the face of whoever it is on the coin. That’s how precisely they can point it. So when they point it at these tiny bits of space, they can essentially repeat the same experiment again and again and collect more and more light, and then they build this up digitally until they’ve got these fabulous exposures of deep parts of the cosmos that reveal our universe as it was over 13 billion years ago.

Extreme deep field image captured by Hubble
Extreme deep field image captured by Hubble

What questions do you hope Hubble we help us answer in the future?

I think there’s a good five years of life left in Hubble before it needs to be retired. The thing about its first 25 years was that it tackled some of the really big profound questions about the future fate of the universe, its expansion rate and that kind of thing. That work is sort of done now, but what it still strives to do are these deep surveys of the sky that are very much ongoing. When I was filming at mission control, or the dock as it’s called, it was tracking down new target objects for NASA’s New Horizons mission which is on its way to Pluto. It will pass Pluto this summer and then head out to one of the other icy objects beyond in what’s called the Kuiper belt. Hubble was trying to track down an object for this mission to divert to. These objects are fairly faint, only tens of miles wide, very dark in colour and over 4 billion miles away, so they are pretty difficult to spot. But thanks to Hubble’s power, even 25 years after it was launched, it can still contribute to modern day missions. There is much still to come.

Will you be sad when Hubble is decommissioned?

I think we will all be sad and I think we take it for granted somewhat at the moment that it’s up there. The fact is, it is well beyond its design life. They’ve got various mitigation measures in place to keep it working even when certain components fail, but even then that’s not going to be enough to keep it going indefinitely. I think we will all mourn its loss. The objective is to keep it in orbit until the next generation of space telescope, the James Webb Space Telescope, is in operation but at the moment that is quite a few years behind schedule. There could be a gap in our ability to perceive the deep universe and that will have a big impact on science.

Hubble’s Cosmic Journey will air on Saturday 18 April at 8pm on National Geographic Channel. 

Plus, take a look at:

How Hubble’s colour images are made

NASA photographs oldest galaxies ever seen 

Amazing barred spiral galaxy video