The Orion Nebula

Someone here may know about this, so I thought I'd ask as I can't seem to find information on this anywhere.

Does anyone have the exact mechanics/formula for boarding combat, especially with regards to High-G?

A simple test I performed strongly suggests that High-G confers a significant hidden bonus to boarding actions. For a test I created two races equal in all technologies and race attributes except one had High Gravity and the other didn't, and tasked both of them to capture an opponent's Battleship with their own Battleship. For this test, both the attacking and defending vessels were fully manned (no deaths caused by Neutron Blasters or other weaponry), and no vessels had any specials equipped which would effect boarding, such as Security Stations or Troop Pods. Chosen boarding action was 'Capture.' All ships have Green Crews.

High-G vs Normal
Attacker Bonus: 10, 10 Marines, 8 Killed, 2 Survive
Defender Bonus: 10, 20 Marines, 20 Killed
Ship Captured

Normal vs High-G
Attacker Bonus: 10, 10 Marines, 10 Killed
Defender Bonus: 10, 20 Marines, 2 Killed, 18 Survive
All Attackers Eliminated

+20 Ground Combat vs Normal
Attacker Bonus: 30, 10 Marines, 9 Killed, 1 Survive
Defender Bonus: 10, 20 Marines, 20 Killed
Ship Captured

Normal vs +20 Combat
Attacker Bonus: 10, 10 Marines, 10 Killed
Defender Bonus: 30, 20 Marines, 3 Killed, 17 Survive
All Attackers Eliminated

HG race got both +10 GC bonus and 1 extra HP included. They are roughly like a Tanks.

So, does that mean ship boarding combat is calculated the exact same way as ground combat invasions, even if the information displayed for attack/defense bonuses is quite different? High-G doesn't add a +10 combat bonus in the ship boarding summary.

Yes, sorry, wrong info, there is no +10 for them, only additional HP.
Ship capture is calculated pretty the same way as invasions, ship raiding is a totally different story, and unaffected by HG.