PSAT (NO-84) works exactly the same way as the ISS, and you can even use ARISS as the path. Unfortunately its digipeater has been off lately. NO-103 should also work the same way, whenever it eventually will be turned on. For those who can reach it, IO-86 works the same way, but the path is YBSAT. All are on 145.825 MHz.
Falconsat-3 is V/U mode and 9600 baud. Some Falconsat-3 instructions are here: https://www.amsat.org/wordpress/wp-content/uploads/2018/03/FalconSAT-Stoddar...
https://andrewbnortham.com/ke8fzt/falconsat/
Aisat looks to have stopped working, as has the APRS portion of NO-104.
One issue I notice when using my TH-D72 is that some people send packet messages that are not in the full APRS format, so they aren't decoded properly. This shouldn't be an issue when using software like Xastir or UISS.
Also, the longer the message, the more likely it will pick up errors and not be digipeated or decoded. So shorter is better.
-Stephen, N8URE