Baseline Design of the Investigation of Convective Updrafts (INCUS) Mission

The Investigation of Convective Updrafts, or INCUS, mission is a NASA Earth Ventures Mission (EV-M) that will measure, for the first time ever, the convective mass flux (CMF) of convective storm systems. INCUS is led by a Colorado State University (CSU)-based principal investigator with project management and system engineering delegated to the Jet Propulsion Laboratory (JPL) in Pasadena, CA. INCUS uses Ka-band radars on three spacecraft that are separated in time to measure the change in vertical columns of water and ice in convective storms systems. Machine learning algorithms will use the change in vertical profiles of water and ice over 30, 90, and 120 seconds, ice water path and optical density measured by an on-board radiometer, and multiple program of record data points, to infer the rate at which vertical columns of water and ice are moving upwards and downwards in storm systems, also known as CMF, in different phases of a storm's life cycle.The INCUS Ka-band radar is called the Dynamic Atmospheric Radar (DAR) and the radiometer is called the Dynamic Microwave Radiometer (DMR). The DAR is built by JPL and is based on the JPL RainCube radar with increased horizontal resolution and additional feed horns to increase swath and provide context measurements. To achieve higher, 3.5 km horizontal resolution, INCUS uses a 1.6 m deployable reflector antenna built by Tendeg, a Colorado-based space deployables company. The DMR is also built by JPL and is based on the TEMPEST-D microwave radiometer. INCUS requires three radars on three separate spacecraft to obtain the unique time-varied measurement required for CMF retrieval, but only a single radiometer to provide a large 500 km swath measurement over a larger portion of the convective storm system. The instruments are integrated onto the Integrated Payload Structure (IPS), also built by Tendeg, which is integrated onto Blue Canyon Technologies (BCT) Venus-class spacecraft busses. INCUS uses heated DMR mass models on the two observatories that do not have a radiometer to keep all three spacecraft and IPS mechanically and thermally identical across all three flight systems.INCUS will fly in an inclined, low-Earth orbit to maximize the time spent over the most interesting region for convective storm systems: the tropics. INCUS science requires the three spacecraft overflights to measure the same scene, but the rotation of the Earth will cause a small angular displacement between overflights. INCUS will perform a slow roll back and forth to keep the three spacecraft pointed at the same common ground track. The INCUS mission system and ground system are distributed across mission operations and ground data systems at BCT, communications infrastructure at KSAT, payload operations at JPL, and the science data system at CSU.This paper will detail the baseline INCUS design at the start of Phase C, will highlight technical challenges and trade studies in the formulation of the mission, and will provide a status update on the implementation of the mission.