Future satellite technology - an interview with Sir Martin Sweeting
- our editor, Ian Poole interviews Sir Martin Sweeting, discussing how he sees future satellite technology development, in particular in the field of small satellites which includes micro-satellites, and nano-satellites.
Traditionally satellite technology has been seen as the domain of government backed organisations with almost limitless budgets or large multinational companies. However it is particularly refreshing to see a small company that started in a university laboratory making its mark on the satellite industry.
This is exactly what Sir Martin Sweeting has done with Surrey Satellite Technology, the company he founded as a technology spin off from Surrey University in the UK. It focuses its attention on a range of small satellites including micro satellites and nano satellites.
I met Sir Martin in his office at Surrey Satellite Technology in Guildford where he is the Executive Chairman. He is well known for pioneering the concept of rapid-response, low cost, yet highly capable small satellites using COTS devices. Sir Martin's work has put Britain at the leading edge of areas of future satellite technology, particularly in the field of small satellites including mini-satellites, micro-satellites and even nano-satellites.
How it started
Before looking at how he thinks future satellite technology will develop, I wanted to ask about how it all started. Having first studied for his bachelor's degree in Electronic Engineering at Surrey University in the UK, he went on to complete a PhD in Communications, researching HF antennas which is a long way from satellite communications. "How did you move from HF into satellite communications; it's something of a jump?"
Agreeing, he replied: "Being a child of the '60s with a background of the Moon landing and films such as 2001, as well as an interest in amateur radio, satellite technology has enabled me to combine both interests. I started by using home-made equipment and spent about five years tracking satellites using some of the first microcomputers which enabled me to display images on VDUs rather than using wet paper facsimile printing, the standard at the time."
Asking about the first satellite that he launched he replied: "At the time the UK satellite programme had just been axed and the only satellites being launched, both amateur and professional were from outside the UK, so I wondered why we couldn't build one ourselves and also provide something different for the amateur and educational field. We wanted to incorporate some imagery using the very first 2-D CCDs with some rudimentary on-board digital signal processing. We also wanted to have a digital voice synthesizer to 'speak' telemetry data for reception by schools."
"To keep the costs down, we used many commercial parts rather than the highly expensive space-qualified parts."
"These early satellites were all built at the University of Surrey, but we still had to raise money and support from outside. We successfully launched this first satellite piggyback on a NASA rocket and its signals were received by many schools and radio amateurs. This satellite worked for eight years until its orbit decayed and it burned up in the Earth's atmosphere - we monitored the temperature increasing until finally we lost all communication"
"We were then offered a second launch slot by NASA - but the satellite had to be designed and built within six months - it took many long nights and weekends but we did it. This satellite is still transmitting signals today, some 26 years later!"
A different attitude
In the 1980s and 1990s the main organisations putting satellite technology into space were the NASA in the USA and the Soviet Union as they were called then and they had almost limitless budgets. It must have been a challenge to 'compete' with these on a very small budget. I asked Sir Martin whether he felt it was something of a David and Goliath situation?
"Yes it was a challenge, but we have been able to be successful against such large organisations by adopting a different philosophy. Being a small company, we were able to look at smaller projects without the large overheads of these organisations, but on the other hand we are not so suited to taking on enormous projects."
"We take a different attitude to risk - it is a balance between reliability and expected life, cost, and the number of satellites you can put up. We also find that our technology refresh rate is much more rapid than the large companies - typically about two years which is very short and means we can put new technology into space very quickly to provide enhanced capabilities."
A niche in satellite technology
Competing against large competitors can often be difficult. I ask Sir Martin Sweeting how he managed to find the niche in developing the small satellites.
Sir Martin Sweeting replied: "The development of the small satellites followed on from our first satellites which were small when compared to some being launched - some direct broadcast satellites may be larger than a double-decker bus. After the first two satellites, the next half dozen focussed primarily on digital communications, providing store-&-forward communications as the Internet infrastructure was very thin at the time."
"People in remote areas could not access this early Internet and these satellites enabled people to have email - the satellite received the email, stored it and then forwarded it when it came over a ground station."
"The satellites also studied the space radiation environment to help in our selection of suitable COTS components. We were also asked by the French to supply microsatellite platforms for two experimental communications research satellites. Several of the early microsatellites carried CCD cameras looking at the Earth - the images were quite crude, but they steadily improved over the next decade and now we produce professional quality Earth images from satellites a fraction of the size and cost of conventional missions."
Working with large satellite organisations
It is recognised that SSTL is a dynamic organisation, but small when compared to the likes of NASA, and other international space agencies?
Agreeing, Sir Martin Sweeting answered: "We work with many of the large agencies including NASA and Russian space organisations, but increasingly we work with ESA, the European Space Agency."
"Sometimes the relationship can be challenging because of the different ways that large and small companies work. However, as time goes by, we are both learning how to work with each other. Despite this, it is important that we retain our identity and do not adopt large company processes where they are not needed. We pride ourselves on being dynamic and innovative and we want to retain this."
Low cost satellites
It is often difficult to reduce the cost of projects because there are certain elements for which the cost cannot be reduced. How has SSTL managed to make the reductions it has without compromising on quality?
" Well, it's mainly about a mindset - what real engineering is about. In other words, doing for a penny what anyone else can do for a pound. Let me explain a little more." He says: "While we tend to use commercial components, this is not actually the main cost driver - labour is. We have a very good team of engineers who are very innovative and are able to look at new ways of doing things and who take personal responsibility for quality and delivery within cost and schedule."
He continues: "Also we're able to use some of the latest commercial components to give us the functionality we need and we can use these quite easily as we have a launch rate of one or more satellites each year. With many large satellite projects taking ten years or more, we can introduce and gain experience with much newer technologies and thus be more innovative."
It is fine to reduce the cost of satellites, but do they perform as well - is there a compromise on quality?
In reply: "Yes they are reliable and typically have operational lifetimes of 5-7 years. For example, our second satellite UoSAT-2 is still transmitting and can be heard. However it is all about the careful choice of components. We know what can and cannot be used, and with commercial components becoming more reliable all the time, we find there is often no advantage anyway in using the expensive and long-lead time hi-rel components."
Small satellite advantages
Moving on, I ask about the advantages of small satellites?
In reply, Sir Martin Sweeting says: "Well, there are advantages and disadvantages to using small satellites. Small satellites cannot generate as much solar power as larger satellites which have much larger area to capture and convert the sunlight, so small satellites are not suitable for power-hungry applications like direct-to-home TV broadcasting. Also some applications require physically large instruments - take the Hubble telescope for instance - so these projects do not make sense with small satellite platforms."
"However small satellites have many advantages. They tend to be very rigid, they do not "flap" as they are controlled - when moved some large satellites bend, especially the solar cell panels and this sets up vibrations that can be difficult to control."
"Small satellites can be very agile, they are also much cheaper to launch as many can be launched together or they can fill a small space on a launch. Also they are much cheaper to test before launch - as smaller test facilities can be used for vibration, EMC and vacuum."
There has been much talk about small satellites, but what exactly are they and are there any definitions for them?
"Yes there are, and although they are well publicised they are by no means rigid. Typically a small satellite may be thought of as one weighing between 500 and 1000 kg, a mini-satellite as one weighing 150 to 300 kg, a micro-satellite between 50 and 100 kg, a nano-satellite as one weighing up to 10 kg."
"Often satellite weights are clustered around particular typical sizes because of the constraints of different levels of functionality or applications. Also the meanings can vary somewhat, for example an average geostationary satellite will weigh around five to eight tonnes, so one weighing one tonne will be considered 'small'."
Future satellite technology
Wondering how these satellites will develop in the future, I ask Sir Martin Sweeting where he saw the road map for these future satellites going?
"It is always difficult to see exactly where future satellite technology will go, but I imagine it will progress in a similar way to that of PC technology - basically satellites individually doing more dedicated tasks and then networking together to provide an overall greater capability. This will make individual nodes more focussed and more cost effective. We may even see clusters of satellites in the future."
Moving on, the discussion focussed on some of the major challenges facing future satellite technology.
"Future large satellites in Earth orbit may be assembled in space, so one of the major challenges for future satellite technology I can see is using robotics for small satellites to construct larger ones. Robotics is also an area of development for inter-planetary satellites."
Another idea that has been proposed is a satellite on a chip - will this happen?
"We virtually have this now, but I am not sure what such a small satellite could be used for? They may be used in a cloud, like a swarm of ants, but the main problem again is power. Such small satellites may not consume as much power, but power still needs to be generated, and there needs to be enough for them to communicate with users - either by 'shouting in unison' or, more probably, to communicate with a larger satellite that would then link to the ground."
As a final question, I asked Sir Martin Sweeting what applications he saw for satellite technology in future years?
"It is difficult to see the exact applications that future satellite technology will fulfil - if I knew this then I would be developing it quietly and I wouldn't tell you," he said smiling. "However satellite technology is rapidly becoming increasingly embedded in our everyday lives. I think there will be increasing reliance on navigation and timing through GPS and Galileo."
"Also I think we will see more about monitoring the planet for a wide range of uses and applications such as traffic monitoring, disaster management, the environment and climate, agriculture and domestic uses in buying new homes or planning holidays. We may even see a communications 'shell' around the globe providing instant communications to all areas of the world. We mustn't forget the interplanetary possibilities as well."
"But overall I think we need to see the cost of launching satellites fall to a tenth of what it is now - look at the PC revolution and how manufacturing prices there have fallen and what new applications and businesses that has enabled."
The future of satellite technology certainly sounds exciting, and it will be interesting to see what happens in the next few years. What is certain is that SSTL will be there with their innovative approach to satellite technology.
Sir Martin Sweeting is Executive Chairman of Surrey Satellite Technology Ltd based in Guildford UK. It has a turnover of ~ £50m per year and has notably achieved a number of 'firsts' in satellite technology. Focussing on small satellites, the company has very successfully lead the field in using COTS components and high levels of technology in a small satellite. Today SSTL employs nearly 300 staff at its various locations; it has launched 34 spacecraft; and there are seven more in manufacture for launch in the next 2 years. The company is also delivering missions that provide critical and valuable services to customers across the globe, including disaster monitoring, and it has provided the first of the Galileo satellites GIOVE-A, on time and within budget and has recently been awarded 14 payloads for the operational Galileo navigation constellation.