How Cameras on Satellites Manage To Shoot High-Def Images
As satellite camera technology continues to evolve, more compact and innovative models are entering the market. Choosing the right optical payload for your Earth observation mission requires a keen consideration of several factors. Learn more about this below.
With the ever-increasing number of Earth observation and space exploration missions, the demand for high-quality satellite cameras is also rising. Today, several models are designed for various applications, from climate change monitoring to managing natural resources.
So, how do cameras on satellites work, and why use satellite cameras? We've answered these questions and more in the sections below.
What is a Satellite Camera?
A satellite camera is an optical payload on a satellite designed to take images in space before sending them back to Earth. These camera sets feature a unique design that allows them to operate optimally in adverse environmental conditions. That said, the cameras on satellites do not work like ordinary smartphone cameras; rather, they use multiple instruments such as infrared sensors, heat detectors, and visible light filters.
Satellites launched into space for Earth observation missions carry different satellite camera sets and communication systems with them. There are three orbits that artificial satellites operate in: the low Earth, medium Earth, and geostationary orbits. The low Earth orbit is closer to the Earth's surface, while the geostationary orbit is further away. The type and design of the camera on these satellites vary.
Here are some of the common uses of a satellite camera:
- Natural resources monitoring – keeps track of agricultural farms, freshwater bodies, and energy sources such as coal mines. They also report on and respond to natural disasters such as floods, earthquakes, and tsunamis.
- Weather forecasting – helps with predicting and mitigating climate change.
- Monitoring wildlife trends and biodiversity – migration of birds and wild animals and tracking of endangered animal and plant species.
- Measuring land-use change – high-resolution images from space can help monitor events such as deforestation, drought, etc.
How Does Satellite Camera Work?
Cameras on satellites work just like aerospace cameras. They are designed to capture images of theEarth and space objects using electromagnetic (EM) waves. So instead of taking digital images, they use sensor detectors to scan the Earth's surface for EM radiation emitted or reflected.
These sensors then send radio, infrared or thermal signals in digital format where specialized software then filters the signals and draws a corresponding image. There are three types of satellite imagery: panchromatic, multispectral, and hyperspectral.
A black and white camera takes panchromatic images on a spacecraft. Multispectral images have at least three visible colors, red, blue, and green (RBG), while hyperspectral images record several narrow bands covering a continuous light spectrum. Multi and hyperspectral imagery is used for advanced imaging applications, e.g., tracking subtle changes in vegetation growth.
How to Choose the Right Satellite Camera
With several satellite camera modules in the market, choosing the best satellite camera can be a daunting experience. Even so, there are certain factors that you can look out for to choose the right satellite camera module for your unique Earth observation or space exploration missions. These factors include:
- Satellite camera resolution – Depending on the unique application of your satellite camera, you should choose one with the right resolution. A camera designed for imaging and mapping applications comes with a high-end resolution.
- Physical size and mass – The physical size and mass of the camera should be compatible with that of the satellite. In other words, the satellite should be bigger and powerful enough to accommodate the satellite camera.
- GSD and Swath – the smaller the GSD (ground sampling distance), the bigger the spatial resolution of the image and the more detailed the images. Swath is the area that's imaged on the surface of the Earth. The bigger the Swath, the larger the size of the area captured, but the less detailed the images. Most satellite camera modules come with a Swath ranging from 10km to 100 km.
Besides the factors above, you also want to pay attention to both the satellite's and camera's lifespan. The ruggedness of the design, as well as the quality of lenses, are also worth considering.
Lastly, ensure the product manufacturer has a proven track record in the industry. Always check the customer reviews, the years of experience, industry certifications, number of successful launches, and the presence of detailed instructions on how to use the satellite camera.
In today's space exploration industry, smaller and more compact satellites enter the market. This has seen rapid innovation of satellite cameras to meet the changing market dynamics. So, when choosing an optical payload for your unique applications, pay attention to the factors we've highlighted above.
If you have any questions or suggestions about Earth observation and satellite camera modules, leave us a note in the comments section below.