RC telescope (Ritchey Chrétien) in ScanSAT satellite.
High-resolution remote observations of the situation in other countries, monitoring of mines, crops or the process of population concentration – these and other applications require an appropriate optical system.
Which kind of telescope to choose? What parameters will allow for multispectrali imaging in a broad spectrum band? How do we design a telescope – space optics – for the ScanSAT satellite?
Reflector telescopes as a optical device working on the principle of light reflection provide high image resolution with small size of the whole system. They also allow the observation of a wide spectrum of light, which is impossible to achieve in refractor (lens) telescopes.
The result is the use of a proprietary RC telescope, with a design that allows stable operation at huge temperature gradients, under the influence of higher radiation, in a space vacuum conditions and after being launched to the Earth orbit in a rocket. This system allows to gather images from 500 km height with very high accuracy and resolution. At the same focal length, thanks to the construction based on two hyperbolic mirrors, the instrument can be twice smaller, without loosing any performance. The use of mirrors instead of lenses makes the system free from many optical distortions/aberrations and what is the most important – allows it to be used for multispectral applications in a very wide electromagnetic spectrum. Telescope must be integrated with a mechanical structure, which is athermal – resistant to temperature changes during orbital flight; those changes are negatively influencing optical parameters of the telescope.
Do you want more details?
More about Scanway work on ScanSAT satellite can be found here (link).
More about the RC telescope can be found here (link).
Designing and implementation of the RC telescopic system is quite a challenge. When developing our own telescope we used components of the shelf in the first phases of the project. Their use allowed to check and solve some of the difficulties encountered in the system, as well as to verify initial assumptions and technical parameters.
The next step was to design a layout that matched the dimensions of the 6U CubeSat satellite. At this stage of the telescope creation, the cooperation of two teams was very important: optics and mechanics. Each square millimetre of the mirror must fit in the tolerance field measured in nanometers.
The key step in the design of the telescope for the ScanSAT satellite was the selection of the optical parameters of the mirros. As it is known, the RC system in the wider field of view is not a non-aberration system. Because of that a lot of focus was put on creating a proper concealer. All calculations and analyses were performed in a numerical environment and a program for creating advanced optics – in Zemax software.
As a results, the first version of the ScanSAT satellite telescope will be tested soon. Our product will be one of the best options for Earth observation micro- and nanosatellite missions.
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