Ellen Glad, Millennium Space Systems, A Boeing Company
Keywords: Optics, Sensing, SSA, COTS, Market Survey, Sensor Trades
Abstract:
The use of commercial off the shelf (COTS) optical systems for space applications is important for reducing system cost and schedule. While often preferable, the design, build, and testing required for a homegrown optical system may take several years which may not meet program schedule needs. We present a comprehensive market survey on which cameras and optics are available to be pursued for space applications and where gaps exist. First, we examine how many components are candidates for surviving the space environment, and then we show through sensor calculations which mission applications these candidates apply to.
The market survey is conducted for several wavelength bands of optical systems: visible (VIS), shortwave infrared (SWIR), mid-wave infrared (MWIR), longwave infrared (LWIR), X-ray, and ultraviolet (UV). Our research is conducted using publicly available, open-source material, and we take advantage of the knowledge we have gained from interacting with COTS sensor vendors for years.
Especially in the visible (VIS) band, the market is saturated with sensors and lenses. There’s even a considerable amount of large aperture VIS lenses/telescopes appealing to the astronomy and photography markets. However, the criteria for a space-rated optical system are much more stringent compared to something designed for use on the ground, and this limits options. Both the camera head and the optics likely need to be “ruggedized,” which for an optic may mean that the lens elements must be cemented together with a material that can withstand harsh shock, vibration, and thermal environmental conditions of space. On the sensor side, the materials required for the focal plane and the read-out electronics must be analyzed for items such as tolerance to outgassing and failure due to radiation effects. Most COTS sensors are not designed to all these tolerances, presenting the need to show which options are most viable for surviving the space environment.
Next, we include in our survey a discussion on which space mission applications the COTS optical sensor market appeals to and where gaps exist. For example, an earth-staring optical system likely looks different than a system designed for space situational awareness (SSA)/resident space object (RSO) tracking applications. Specific optical bands will be more useful for certain applications than others, e.g., a VIS lens being chosen for general SSA applications because a small aperture will result in longer maximum detection distance when compared to an IR lens. In this discussion, we use sensor modeling calculations to show effectiveness of COTS sensors for example mission scenarios.
We expect the VIS band to offer the widest range of potential options regarding space survivability, followed by the IR. Furthermore, our previous surveys have shown ruggedized COTS cameras are more common than ruggedized COTS lenses. Regarding mission applicability, longer focal length lenses with smaller instantaneous field of views (IFOV) are expected to be more appealing towards an earth staring system, while shorter focal length/ “fast” aperture optical systems are expected to be the better selection for SSA applications for their light gathering capabilities. Understanding the COTS sensor market and its limitations is important as the space industry rapidly grows and as solutions are required on a short timeline.
Date of Conference: September 19-22, 2023
Track: Space-Based Assets