Simplified/Rough results:

  Terrestrial Fibre:                20.6ms IPv4 / 21.5ms IPv6
  Geo-Stationary Satellite Service: 660ms IPv4
  LEO Satellite Service:            60.6ms IPv4

Standard UNIX utility to measure round trip delay, using standard method - send ICMP packet and receive response and measure delay.

https://linux.die.net/man/8/ping

Sure, it is not 100% reliable and in some cases it could show values not corresponding to real delay.

Fibre ~21 ms

GSS ~650 ms

LEO ~60 ms

I think it's how long a response to a request takes.