An Overview of the Smart Ice Cloud Sensing (SMICES) Instrument

The Smart Ice Cloud Sensing (SMICES) instrument is an active/passive system, enabling multi-angle and multi-resolution measurements of cloud ice particle size and tropospheric temperature and water vapor features. This will improve understanding of tropospheric events including hurricanes, tropical deep convections, tornadoes, and storms. SMICES combines an active radar with passive multi-band radiometers and sounders using a Smart AI control system. SMICES is a joint effort of Northrop Grumman Corporation (NGC) and Jet Propulsion Laboratory (JPL), sponsored by NASA Earth Science Technology Office (ESTO) under the Instrument Incubator Program 19 (IIP-19).

The passive subsystem consists of a suite of radiometer channels at 250, 310, and 670 GHz, and a sounder channel at 380 GHz. The radiometers are total power direct-detection to lower overall DC power consumption of the passive system. The system performs a continuous forward looking conical scan of the upper troposphere at a 45° incidence angle. Passive instrument calibration will be performed during each scan, allowing for near real-time detection of tropospheric features. Once the passive sensors detect a tropospheric feature, the AI controller will identify the feature, enable the active subsystem, and point-and-lock the radar to track the region of interest. This intelligent control of the radar optimizes the collection of high-resolution multi-angle data and significantly conserves DC power by toggling the radar into a low power standby mode once measurements of the event of interest have completed.

The SMICES radar operates at 239 GHz, outputting a 50 W FMCW signal from a traveling wave tube amplifier (TWTA). The TWTA is driven by a 200 mW solid-state power amplifier (SSPA) built using Northrop Grumman’s state of the art 35nm InP HEMT transistor process. The radar is designed with a low-loss quasi-optical front-end, providing +/-15° azimuth scanning capabilities, polarization transformation, and high isolation between monostatic transmit and receive paths. Calibration of the transmitted and received power is performed on board during every PRI.

The version of the instrument developed on SMICES is designed for an airborne flight campaign to validate instrument operation. After successful technology demonstration, the final goal will be to be adapt SMICES into a small satellite form factor. The Smart AI controller will significantly reduce DC power consumption of the instrument, enabling SMICES to be hosted on a low-cost small satellite platform, without compromising the quality of the data products. This work presents the latest development on the SMICES instrument.