A Compact Five-Channel VLF Wave Receiver for CubeSat Missions

Very low frequency (VLF) waves play an important role in controlling the evolution of energetic electron distributions in near-Earth space. This paper describes the design of a VLF receiver for the Climatology of Anthropogenic and Natural VLF Wave Activity in Space (CANVAS) CubeSat mission, designed to make continuous observations of VLF waves in low-Earth orbit originating from lightning and ground-based transmitters. The CANVAS VLF receiver will observe five components of VLF waves in the 0.3–40 kHz frequency range, using three orthogonal magnetic search coils deployed on the end of a 1-meter carbon fiber boom and four deployable electric field antennas operated as two orthogonal dipoles. Together, these five wave components will be used to calculate real and imaginary spectral matrix components using real-time fast Fourier transforms calculated in an onboard FPGA. Spectral matrix components will be averaged to obtain 1 second time resolution and frequency resolution better than 10%. The averaged spectral matrix will be used to determine the complete set of wave parameters, including Poynting flux, polarization, planarity, and k-vector direction. CANVAS is currently in the manufacturing and assembly phase and is planned to launch at the end of 2022.