Dr Chris Castelli, UK Space Agency
Ben - The UK Space Agency has recently announced a pilot program, inviting companies and academics to device innovative ideas for payloads to be launched in a tiny cube shaped satellite called a CubeSat. To find out more, I spoke to Dr. Chris Castelli, Head of Space Science Projects for the UK Space Agency.
Chris - A CubeSat is, as the name implies, a very small satellite. The basic CubeSat is cube shaped, so it has dimensions, 10x10x10 centimetres and it’s a fully functional satellite. The sort of CubeSats you can buy are made out of standardised parts. So, this is perhaps one of the most important things to understand - the standardisation allows lots of suppliers worldwide to make the various components for the satellites. And you could source these and build these into a standard structure which is the CubeSat. So the basic building block, the 10x10x10 cube satellite is called a 1U. You can make bigger CubeSats. You can go to a 2U and I think probably, the largest size is a 3U, and as the name suggests, it’s a sort of oblong shape satellite which is three units long.
Ben - They're really tiny. When reading about these, I was picturing something perhaps the size of a desktop computer or something around that size.
Chris - Right.
Ben - But these are really very small, aren’t they?
Chris - They are extremely small. Basic one unit CubeSats could only weigh just a few kilograms. And a lot of people have said, “Well what could you do with something so small?” and I think this is where innovation comes in to the equation. If you look at the power, the computing power that is available in your average mobile phone these days, it gives you an idea of the sort of sophistication that you can pack into a small unit now. What is happening worldwide is, people are realising that with very small satellites and advances that are made in microelectronics, putting those together forces people to think about clever ways of doing things, where you're limited in terms of mass and power and volume that you have. But nevertheless, you can actually do some exciting sorts of things with them. So, what we envisage is using a CubeSat as a vehicle, a platform for rapidly testing new technologies in space, for example, where you wouldn’t have to go through the more classical route, which takes a very long time of ground base qualification, and testing, and more testing, before you get to really prove a technology is ready to go on a very expensive multi-million dollar satellite. You can use a CubeSat as a way of getting an in-orbit demonstration very quickly, very cheaply, and very effectively.
Ben - What sorts of technology can you demonstrate with a CubeSat?
Chris - If we take the area of space science for example, future missions that are going to the planets, to Jupiter for example or other planets, want to use more sophisticated plasma and magnetospheric instrumentation, they're very sophisticated, they use new technologies. A CubeSat, even though it’s got small dimensions, could be used to test a new generation of plasma sensor, and get some in-orbit verification of how it survives the extremes of the space environment. So, just putting a new technology into orbit would be one way of using a CubeSat platform. It gets it into orbit in the environment of space, in the radiation, the cold, and the harshness of space, the vacuum of space, and you can get some real in-orbit understanding of how it has performed. The other application of CubeSats is that you can fly many of these. So what people are thinking about doing is, flying hundreds, or certainly 10s of CubeSats in a constellation of small satellites going around the Earth. And you can actually, with the advances that are made in imaging sensors, you can get very powerful sensitive imaging sensors with optics, into say, a 3U CubeSat. With constellation of these satellites whizzing around the Earth, you can pretty much get global coverage of any points from the Earth within 20 minutes, in a very cheap, and cost-effective way, which you can't do with any other system. So people are talking about launching maybe 60 or 70 of these things in orbits that swing around the poles of the Earth, and with multiple CubeSats as a constellation, you can get live images – almost live images, every say, 15 to 20 minutes of anywhere on the globe.
Ben - How does launching a CubeSat or a constellation of CubeSats compare with launching a more traditional, larger payload?
Chris - Again, it goes back to this idea of standardization. One way I look at it is, if you remember the early PCs - as soon as PCs developed in a way that you could slot cards from various suppliers, so you could get a disk drive from different manufacturers, you can get mother boards, and memory cards. You could assemble them altogether from standardisation, the cost really came down. So obviously, the cost through standardisation is a key driver. The fact that they are of this known mechanical interface means that low cost launchers provided by say, the Indian PSL rocket, they actually have standard attachments which are designed specifically for CubeSats to go on. So, you have a big science or telecommunications satellite that is being launched and around it are attachments on the launcher interface for CubeSats to go up at the same time. So essentially, the CubeSat is being piggy backed on the main payload which is paying for the launcher. What you have to pay for of course is the necessary licensing and certification, to make sure that these things are safe, are worthy, or have a mechanical integrity to go on to the launcher, and they don't sort of fall apart during launch, and damage the main spacecrafts, which may cost hundreds and millions of dollars.
Ben - The UK Space Agency is still, really, in its infancy...
Chris - Yes.
Ben - Why are CubeSats a priority for them?
Chris - We’re looking at this longer term. What we hope to have is a longer term program, a rolling program of CubeSat developments built on the experience of this pilot program. So the pilot program really is just a really cheap way of getting something off the ground, so to speak. What we want to do is have a long term program of maybe one or two CubeSats every year to 18 months, then, therefore have a rolling call of ideas. We could even have, for example, specific CubeSats which are just targeted at education – at schools, colleges and universities where students and teachers get together with help maybe from the industry, and from the CubeSat providers, to put little experiments onboard. So they act as a vehicle for inspiring and also training young engineers of the future. We want to sort of have a rolling program which then leverages opportunities for the UK in the future.
Ben - That was Chris Castelli from UK Space Agency, explaining how CubeSats devices, barely bigger than a Rubik’s cube, can help us to test out new technology in orbit.