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How Do CubeSat Cameras Take and Transmit Satellite Images?
CubeSat cameras are a hot commodity in the space industry! They can take incredible satellite images and aid in food production, climate control, logistics, urban planning, and more! But how exactly does a CubeSat camera take and transmit images? Let’s find out!
What Is a CubeSat Camera?
A CubeSat camera is a special camera mounted on a type of minisatellite known as a CubeSat. CubeSats were invented by researchers from Cal Poly and Stanford in 1999. They have a classic box shape, measure 10cm by 10cm, and weigh up to 1.33kg. As CubeSats are very small, many of them can be packed into rockets which radically reduces launch costs. CubeSat cameras can make much more frequent observations than traditional large satellites and have played a pivotal role in shifting the space industry to the private sector and broadening the use of CubeSat imagery. CubeSat cameras are produced by private startups and used by many businesses, from farms and shipping companies to urban planners.
How Are Satellite Images Taken?
A CubeSat camera system works just like a typical satellite camera. A CubeSat camera can take pictures in space by collecting reflected electromagnetic radiation from the Earth. A CubeSat relies on passive sensors which do not require energy and rely on radiation from the Sun. A CubeSat camera scans the Earth back and forth and builds up long chunks of images. These chunks need to be edited and turned into a digestible picture.
CubeSat cameras can take high-resolution satellite images, including panchromatic and hyperspectral images. A panchromatic image uses a single band which allows for very detailed images with high spatial resolution. A hyperspectral image uses many bands, far more than the 3 visible wavelengths humans can detect. Hyperspectral pictures are mostly used for studying vegetation, agriculture, geology, and soil because the narrow bands allow for accurate classification.
CubeSat cameras can take a variety of images along the EM spectrum ranging from visible to infrared images. Visible satellite images are similar to standard photos and require the sun to be shining. These CubeSat images are great for identifying cloud cover, clear weather, and snowy areas. In contrast, infrared measures heat where dark areas are hotter and light areas are cooler. Infrared pictures are very helpful for identifying thunderstorm intensity and monitoring crops or vegetation.
How Are Satellite Pictures Transmitted?
CubeSat pictures are a little different from what a normal camera takes. CubeSat cameras scan the globe back and forth and take pictures in long strips. These strips are also made up of a variety of different colors and look very different from the edited CubeSat camera image we later see and can also capture invisible colors such as infrared. They can either be transmitted in true color, which combines red, blue, and green to create an image as it would appear to the human eye, or in the false spectrum, which uses colors one wavelength outside the visible range.
Scientists feed the raw pictures into a supercomputer which lines up all of the strips, matches all of the colors, and compares it to previous satellite images. These supercomputers can line up different landscape features and find matches like one big jigsaw puzzle! Once the supercomputer has done its thing, the picture needs to be color corrected as every image is slightly blue due to the blue sky creating a barrier between the satellite and Earth. When correcting a night picture taken using infrared, scientists have to add color to clouds based on infrared glow.
How Often Are Satellite Images Updated?
There are over 2000 CubeSats and over 4000 total satellites in orbit. These CubeSat cameras are constantly taking different pictures. How often satellite camera images are updated depends on the specific satellite and provider. For example, Google updates its satellite camera pictures every 1 year for major cities, every 2 years for medium-sized cities, and 3 years for small towns. Google chooses these timeframes to ensure its pictures are accurate but still cost-effective. There are now services that track a range of Earth-imaging satellites and allow you to access brand new satellite images every day. There are even companies that provide free access to their satellites so you can view pictures live!
A CubeSat is a type of minisatellite that has a distinctive box shape and weighs a maximum of 1.33kg. The CubeSat camera is revolutionizing the space industry thanks to its cheap parts and low launch costs, which have allowed private companies to manufacture them. CubeSats are equipped with incredible cameras that can take panchromatic and hyperspectral pictures along the EM spectrum. These pictures are being used to improve agriculture, protect water supplies, predict the weather, monitor deforestation, and more! The next time you view a satellite image may well have been taken by a CubeSat camera!