Arduino : send data via satellite (or other solutions ? without GSM)
My two cents: A possibility might be LoRaWAN on the 2.4GHz spectrum, for which there are also satellites in orbit.
The LoRaWAN (&quot;Long Range Wide-Area-Network&quot;) protocol is based on a chirp-spread-spectrum (CSS) modulation and has a very high range.
I've used LoRaWAN before but not on 2.4GHz or with a satelitte, so I can't comment on the practical feasibility. However, there are some materials from The Things Conference (by The Things Network, a leading developer of LoRa network servers).

https://www.youtube.com/watch?v=iwocSYupdIQ
https://www.youtube.com/watch?v=jlNyBDxpKUw
https://enterpriseiotinsights.com/20190618/channels/news/lora-shoots-for-75pc-of-iot-market
https://enterpriseiotinsights.com/20200130/channels/news/lorawan-enters-2-4gh-plus-satellite-boost-network-sharing-embedded-security
https://www.semtech.com/company/press/semtech-and-swarm-deliver-satellite-communications-with-lora

Also maybe other modules that can talk to the Iridium satellites suite you better. Sparkfun has a few

https://www.sparkfun.com/products/13745
https://www.sparkfun.com/products/16394