Internet of things standard LoRa could become relevant for future lunar communications
A European team of scientists have bounced, for the first time ever, a LoRa® (long range) message off the Moon. The feat set a new record of 730,360 km for the furthest distance a LoRa message has ever travelled. It was also the first time a data message was bounced using an off-the-shelf small RF (radio-frequency) chip. For a brief moment in time the entire message “PI9CAM” (the call sign of the telescope) was in space on its way from Earth to the Moon and back.
It also proved that LoRa technology, used for many IoT (Internet of things) applications, can cover such great distances, and that it is possible to send and receive low-powered messages from the Moon. This could become relevant for future lunar communications.
The team, some of them licensed radio amateurs, consisted of Jan van Muijlwijk (CAMRAS), Tammo Jan Dijkema (CAMRAS), Thomas Telkamp (Lacuna Space) and Frank Zeppenfeldt (ESA). To achieve the transmission, the team used the Dwingeloo radio telescope, operated by the CAMRAS foundation in the Netherlands. The radio telescope has a history of being used in amateur radio experiments and is now often used for moon bounces.
Nicolas Sornin, co-inventor of LoRa, said: “This is a fantastic experiment. I had never dreamed that one day a LoRa message would travel all the way to the moon and back. I am impressed by the quality of the data captured.
This dataset is going to become a classic for radio communications and signal processing students. A big thumbs up to the team and CAMRAS foundation for making this possible.”
Thomas Telkamp, CTO of Lacuna Space, a global connectivity provider for the Internet of Things, said: “Seeing the message coming back from the Moon was exhilarating. From the round-trip time we were able to calculate the distance to the moon, matching very well the predicted values of NASA’s JPL Horizons ephemeris system. We even used the echo to see the shape of the moon, which we didn’t imagine we could.”
LoRa is one of the low-power wide-area network communication technologies, and it is Semtech’s proprietary ultra-long-distance wireless transmission technology. On 5 October 2021, the team transmitted the signal with a Semtech LR1110 RF transceiver chip (in the 430-440 Mhz amateur band), amplified to 350 Watt, using the 25-meter dish of the telescope. 2.44 seconds later, it was received by the same chip.
Using the LR1110 RF chip the team also measured the frequency offset due to the Doppler effect caused by the relative motion of the Earth and the Moon.
One of the messages contained a full LoRaWAN® frame consisting of a header (information such as device address and message counter), payload (the data actually sent) and payload CRC (integrity check of payload).
In addition to the LoRa chips, the team used an SDR (software defined radio) to capture both the transmitted and received signal for further analysis. These measurements together with analysis notebooks will be published as open data. An in-depth overview of the entire experiment and results will be presented at The Things Conference next year.
Anglo-Dutch company Lacuna Space provides ultra-low power tracking and connectivity service for short data messaging to sensors and mobile equipment via its LoRaWAN-based IoT gateways in space. Based on open source LPWAN protocols it enables companies to gather data from remote sensors or tracking the status of moving assets.
https://lacuna.space/lora-moon-bounce
The Things Conference on 27 – 28 January, 2022: https://www.thethingsnetwork.org/conference
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Harry Pirrwitz
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