Why your smartphone takes better photographs than the Hubble space telescope

For those who keep up with the latest developments in space exploration, the last couple of years have offered a rich feast of images: from close-up pictures of water-worn pebbles on the surface of Mars to the views of galaxies at the edge of the visible universe, by way of the cratered surface of comet 67P/Churyumov-Gerasimenko. We are becoming almost blase with the seemingly daily occurrence of a fresh view of a star or planet.

Back on Earth, we are also no longer amazed by the instant communication of social media or the ability to watch films in high definition on our smartphones. Rather, we tend to complain if our mobile signal drops out when going through a tunnel on a train journey or the internet speed slows because it can’t cope with the 10GB film you are streaming at the same time your kids are playing an online fantasy game ported through a server some thousand miles away. The latest developments in hi-tech communications incorporate 64bit architecture, 1GB RAM, 1.4 GHz speed, 20 megapixel cameras and so on. How does all this relate to the wonderful images produced by space instruments?

Looking at the technical specifications for the camera on the Hubble space telescope (HST), you are immediately in a different world. One of 16bit architecture. One of 48k memory and a speed of 1.25MHz. How antiquated! How ancient! How slow! How does the HST manage to produce anything at all? How come it isn’t using the latest technology?

What we forget is how long the space missions that deliver these images have taken to plan. The HST was launched in 1990, but planning started in 1975 and instrument build began around 1978. Mission architecture requires reliable components and the standard “space-qualified” computer was a monster, weighing in at around 50kg. Imagine having to lug a portable computer around that weighed 50kg. Laptops these days are 2kg or less.

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The reason that the HST is still operational is mostly thanks to five space shuttle missions that repaired and upgraded ageing instruments. The third servicing mission was in 1999 and that was when the processor was last upgraded, from 1.25MHz to 25MHz, still way below the specifications we are familiar with today.

Over its lifetime, the HST has gradually been equipped with more advanced technologies, but that is only because it is in low Earth orbit and could be reached by astronauts in the shuttle. The same does not apply to spacecraft that have left Earth’s orbit. For example, the Rosetta mission, which kept us on tenterhooks from last November until last month about the health of its Philae lander, was launched in 2004, but design specifications were first sketched out in the mid-1990s. Rosetta is now more than 270m kilometres (170m miles) from Earth, so there is no chance of any hardware upgrades at all. The best that can be done is in the form of system upgrades, which take even longer than when your PC takes it into its mind to upgrade without your permission; how often have you switched on to the dread words “new updates are available” or “Windows is installing upgrade 1 of 579”?

Rosetta has had to undergo other indignities. For two and a half of the 10 years it took Rosetta to reach comet 67P, all the spacecraft systems were switched off – a deep-space hibernation. Imagine taking the PC you used 15 years ago and putting it in a freezer for two years. How surprised would you be if, when it came back out of the freezer, it worked perfectly when you switched it on? That is the type of performance spaceflight engineers expect and almost take for granted. Rosetta was aroused from hibernation in January 2014, in front of a waiting world. There was no hiding if the spacecraft needed to be switched on and off again a few times before communication was re-established.

Because we take the wonderful images produced by space missions somewhat for granted, and forget the (often) aged technology behind them, there is perhaps an even greater sense of disappointment when a space mission doesn’t deliver as spectacular an image as anticipated. In 10 days or so time, the New Horizons mission will race past Pluto and produce the first close-up images of this distant object. They will be black-and-white pictures of something still a bit blurry. But they will be the clearest images of this remote body and worthy of as much celebration as the most colourful panorama of a Martian landscape or a galaxy.