Optimised lenses for satellite developers

A LEO satellite operates relatively close to Earth’s surface. LEO satellites orbit at an altitude of 160 -1,000km – which is low compared to other orbits, but still very far above the Earth’s surface. Most LEO satellites are used for observation and science as being nearer the Earth’s surface allows optical instruments to take higher resolution images.

Customer support manager of Resolve Optics – Rob Watkinson said: “Optical instruments for use in space are designed to survive a specified total absorbed radiation dose (expressed in Rad) over the lifetime of a mission. Standard glass types will turn dark as they absorb radiation and although the radiation levels in LEO are relatively low, over an extended period of time a standard lens will still deteriorate until the point it is no longer useable.”

He added: “Generally, we recommend that any LEO mission lasting a year or more, should use radiation resistant optics to guarantee good transmission for the entire length of the mission. However, sometimes there may be a performance criterion that is considered more important than longevity. Recently a customer asked us to produce a custom lens able to operate over a very wide bandwidth. Using only radiation resistant optical materials in the optical design would have been limiting as there isn’t enough variety in the glass types available to provide good colour correction over the full bandwidth. In a situation like this, the customer opted for good performance over the full bandwidth for a limited time, to be more important to them than having poorer performance over an extended operating lifetime. Other optical design situations that may warrant the use of standard optical material rather than radiation resistant glasses are when the LEO application requires high resolution or a thermal performance over a very large temperature range.”

He concluded: “The key considerations when designing lenses for use in LEO satellites is how they react to the vibration and shock of launch, extremes of temperature, high vacuum and the cosmic radiation encountered in space.”

For further information please visit the online presentation ‘An introduction to space ready optics’ at https://www.resolveoptics.com/space-ready-optics/