Pathfinding Low Frequency Radio Astronomy with the DORA Radio Background Experiment

The DORA mission is a 3U cubesat multi-experiment testbed for advancing technology relevant to infrared laser communications and radio astronomy. The primary experiment is an environmental test of a solid state infrared silicon photo-multiplier detector element for the Deployable Optical Receiver Aperture, a widefield laser receiver concept. Here we report on the design and laboratory characterization of the secondary payload on the cubesat. The DORA Radio Background Experiment is a low frequency radio spectrometer to measure the intensity in LEO of terrestrial radio transmitters in the 20–200 MHz band used in 21 cm cosmology. The radio re-ceiver includes a coarse-band spectrometer with eight channels and a narrow-band spectrometer implemented using a software defined radio yielding 300 kHz channels. The radio experiment will be used to map integrated transmitter power over low-population regions, focusing on FM and other high-power broadcast stations. As a TRL-raising measure, the design uses proposed high precision RF switches and other elements that are being investigated for future 21 cm cosmology missions. The spacecraft was built as an educational activity by undergraduate and graduate students at Arizona State University. It was launched as part of ELaNa 52 on the NG-21 resupply services mission to the International Space Station. Deployment and on-orbit operations are expected in October 2024.