From One Unit Tech Demo to Three Unit Class D Constellation: Ops Lessons from RainCube to INCUS DAR

INvestigation of Convective UpdraftS (INCUS) is a NASA Earth Venture Mission (EV-M) managed by JPL for the Colorado State University (CSU) PI. The INCUS mission will be comprised of a constellation of three observatories, each consisting of the spacecraft bus, and the Dynamic Atmospheric Radar (DAR). One observatory will also host the Dynamic Microwave Radiometer (DMR), based on the TEMPEST-D technology demonstrator. DAR is an evolution of RainCube (Radar In a Cubesat), with 7-beam cross-track scanning capability. The three observatories will fly in low-Earth-orbit (LEO) in a train formation to make measurements of tropical convective storms at three different times (0, 30 and 120 seconds). The temporal sampling of the DAR reflectivity profiles is used to measure reflectivity changes with time, allowing the detection of convective updrafts and the estimation of their transport of air and water between the surface and upper troposphere, known as Convective Mass Flux (CMF), and elucidates how this transport varies with storm type and throughout the storms' lifecycles. The INCUS measurements will increase our understanding of how, when, where, and why storms form, and will allow us to better model and predict the role of convective storms in current and future climates. This paper focuses on how the lessons learned from on-orbit flight operations as well as the design heritage and implementation and test experience of RainCube technology demonstration were leveraged in developing the concept, system requirements and implementation approach for the INCUS mission's DAR instrument. We also present the programmatic considerations associated with translating a technology demonstration mission to a higher class (class C or D) mission and the trade-offs considered during such development. RainCube was a 35.75 GHz Ka-Band radar with 0.5 m deployable antenna in a 17 kg 6U CubeSat form factor. RainCube was successfully launched to ISS on May 21, 2018, deployed to an orbit of 350 km in August, 20218 and completed a 2-year extended mission in LEO on Dec 24, 2020. INCUS is a 35.75 GHz Ka-Band radar with a 1.6 m deployable antenna in a 130 kg Small Satellite and has a target orbit of 575 km. INCUS is scheduled to launch in 2026.