Galago-1: A Compact Day-Night Band Sensor Pathfinder

The NOAA Satellite Observing System Architecture (NSOSA) study proposed several future architecture concepts to fulfill LEO-based observing requirements currently supported in part by the Joint Polar Satellite System (JPSS) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument. These architectures include flying VIIRS as a standalone instrument, disaggregating VIIRS capability across a number of platforms, or relying on partner satellite missions (e.g. EUMETSAT) for imagery data. The disaggregated alternatives can enhance the architecture flexibility, adaptability, and resiliency. However, lower cost alternatives must be realized for these to be viable options. This paper presents a tradespace analysis for the development of a compact Day/Night Band (DNB) optical system that can be flown on a SmallSat as a standalone mission or as part of an instrument while maintaining VIIRS-DNB performance.

The JPSS Key Performance Parameter (KPP) for Near Constant Contrast Imagery, achieved by the VIIRS-DNB, requires coverage for latitudes greater than 60deg North in the Alaskan region with 87-minute data latency, and 90% global coverage refreshed every 12 hours. The imagery, used primarily in support of low-light cloud imaging, is to be delivered under all weather conditions, including any rain rate.

To ensure analogy to the VIIRS DNB mission, threshold performance requirements are baselined to those documented in the VIIRS Level 1 Requirements Document (L1RD), and objective performance requirements are aligned to achieved JPSS-VIIRS on-orbit performance metrics.

Initial analysis emphasizes the use of commercially available technologies that fit a 12U form factor while maintaining current DNB performance. In doing so, cost savings can be realized by minimizing custom, one-off design work where space-qualified technology is available. In cases where the technology is not yet qualified, the systems are used as analogy for the design custom hardware or tech maturation opportunities. While this first design is flown in the 833-km JPSS orbit, several architecture and system level trades may further reduce cost and complexity. These technologies and trades will inform future detailed design work, enabling the path forward for an operational prototype.