Designing optics for micro and nanosatellites

The nanosatellite and microsatellite market has seen significant growth in the past few years driven by a desire to reduce satellite costs and the increasing availability of miniaturised technologies. A recent published report has forecast that the global market for nanosatellites and microsatellites is expected to grow from US$2.8 billion in 2022 at an annual rate of nearly 20% over the next 5 years.

A nanosatellite is any satellite weighing between 1kg and 10kg, whereas microsatellites weigh between 10kg and 100kg. These satellites are used for a growing range of applications including remote sensing, earth observation, data communications, scientific analysis, and security / surveillance.

As satellites decrease in size there is the necessity for the optics that lie at the heart of nano and microsatellites to reduce in size and weight. This is not always a straightforward task as quite often the satellite sensor has already been chosen and is 2/3-inch format or larger. A rule of thumb for optical design is the larger the sensor format, the larger the lens. That is unless you are willing to reduce the aperture of the lens. Consequently, if you are developing a camera system for a nanosatellite or microsatellite-based space mission, keep your sensor compact and then it will be possible to keep the lens compact as well. 

As the available space for optics in nano- and microsatellites is often a challenge this also has an impact on designing a lens with an appropriate focal length. For instance, if you require your lens to have a focal length of 300mm, then you should expect the lens to be approximately 250mm in length. An alternative optical strategy would be to use a catadioptric or mirror lens. Such lenses are diffraction limited, so offer good resolution, but they typically start at f/3.5 depending on the central obstruction. The overall length of a catadioptric or mirror lens will be shorter, but the diameter will be larger than a conventional lens design.

Being able to keep the size of the lens compact also helps with them withstanding vibration and shock during launch into space as the mass is small. To ensure your nano- or microsatellite optics are sufficiently robust, all elements in our space-ready optics are secured and unable to break loose when subjected to the rigours of launch and other environmental factors.

Currently miniature optical systems for nanosatellites and microsatellites have lower resolution capability compared to dedicated optics installed on large Earth remote sensing systems. However, the considerably lower cost of nanosatellites and microsatellites incorporating compact, low weight optics allows them to form the basis for large-scale orbital constellations made of hundreds of such devices. The development of nano and microsatellite constellations enable Earth monitoring in near real-time mode allowing you to quickly obtain images of your target part of the Earth surface without waiting for a large remote sensing satellite to reach the desired location. This immediate monitoring capability will be valuable in applications including military surveillance in a changing scenario, monitoring spreading disasters (wildfires and flooding) as well as for observation of maturing agricultural crops.

To discuss development of space ready miniature optics optimised for your micro- or nanosatellite application please click here.