Less than the size of a suitcase and floating around 500km above earth, micro satellites are already proving themselves to be an efficient way to have an eye on the world. Unlike their deep-space counterparts, these ‘small explorers’ stay closer to earth, but today’s advances in miniaturisation mean they can still carry some seriously powerful tech.
Having been around for over sixty years, we’re all familiar with the concept of a traditional satellite and rely heavily on their technology for all sorts of day to day services, such as GPS, weather forecasting, TV and radio. Traditionally the business of satellite research, development and launching was limited to government agencies and very specialist companies, but in the last few years organisations, such as Canon and various universities around the world, have been working to ‘shrink’ the traditional satellite, packing power into small, light structures that can be launched cost-effectively into space. But besides a lower cost, what is the purpose of sending satellites smaller siblings into space?
Nature is unpredictable and natural disasters can have devastating consequences. Some countries have already seen some real success in deploying ‘constellations’ of small satellites, which allow the swift assessment of these events as they happen. This means that the disaster response programme can be implemented in the right place and at the right level, while other vicinities can be evacuated. The data collected from each occurrence can also build a picture for analysis – helping in the prediction and response for future incidents.
Covering a specific area, low earth orbit satellites connected with on-ground sensors can combine this information with images from the on-board camera to create an overall data set that can be used to analyse the effects of climate change over a period of time. More sophisticated satellites are in development, which will also be able to gather CO2 emissions data.
Commercially available, high resolution images of earth? “Yes please!” said anyone who has ever been lost in a city. The new accessibility of small satellites to commercial businesses means that accurate, scrollable and zoomable online maps are a readily available to anyone with an Internet connection.
Small satellite, big challenges
However, even sending a micro satellite to a low-earth orbit is a big deal and most are launched into space by a rocket. Canon Electronics Inc. sent the CE-SAT-I (Canon Electronics Satellite 1) orbit in 2017 from a space centre in Southern India and this tiny satellite (just 500mm x 500mm x 850mm) has been returning images of the earth from a 500km orbit above the earth ever since.
In the small chassis of the CE-SAT-I sits a DSLR camera with a catadioptric optical system, a compact camera for wide-angle image capture, and other features. Its tiny body is powerful enough to identify individual cars on a road and capture wide-angle shots within a 740km x 560km frame.
The build of the CE-SAT-I wasn’t easy, but Canon Electronics rose to the challenges presented by space. “We had real difficulties in three technical areas,” says Nobutada Sako, Group Executive, Satellite Systems Laboratory, Canon Electronics Inc. “One was the absence of gravity; two was the vacuum environment; and three was the unrelenting radiation in space.” The vacuum and radiation challenges were particularly difficult to overcome. Since there is no air in a vacuum, a fan will not create convection even if it turns. Therefore, any heat generated by a CPU or other unit cannot be dissipated and if it overheats, the system will shut down. The team counteracted this through a clever radiative cooling method that uses metal to conduct heat away from where it was generated. Radiation also presents the danger of a system stoppage or malfunction. Radiation in the CPU can alter the data being written, causing an error. The development team tested a large number of semiconductor chips, and eventually found one that was radiation resistant.
The development doesn’t stop here, and work continues at Canon Electronics lab in Japan to create smaller and more powerful satellites. The CE-SAT-III is already smaller enough to fit in your hand, measuring just 100mm x 100mm x 300mm.
Equipped with the most sophisticated imaging technology available, the future accuracy and efficacy in the areas already mentioned above is vast, but in potential new markets, such as agriculture and tracking of commercial shipping, there is so much more to come.
Discover more about the CE-SAT-I on the Canon Global Website.