The leading rover Perseverance and the robotic reconnaissance drone Ingenuity (many call it a helicopter because of its external similarity), which are currently engaged in research missions on Mars, communicate with each other via the ZigBee protocol at 900 MHz. The same protocol is used in smart kettles, smart bulbs, and many other absolutely standard smart home gadgets of most manufacturers. The Verge reported this.
The reason why NASA scientists chose ZigBee (and not Wi-Fi, GSM, or something completely new) was the same advantages that consumer gadget manufacturers on Earth use it thanks to – the protocol is very economical and at the same time reliable in terms of signal loss. And failures in the delivery of data packets. In addition, ZigBee has a long-range – it is about 45 meters, and this is in the conditions of a standard home on Earth. On Mars, where there is practically no physical interference, and many other signals of a similar frequency, the range of ZigBee is significantly greater.
According to NASA, the Ingenuity drone can communicate with the Perseverance rover base station at a distance of about 825 meters – the length of approximately nine football fields.