Do Kerbals have mass? If not, why this?

[Kelderek]

My space plane naturally wants to pivot on the rear wheels because they are close to the CoM, but on most landings it stays stable on the ground on all wheels. I've noticed this on the KSC runway with full fuel tanks and also with reduced fuel landed on Laythe (pointed slightly downhill even). The plane is stable, but when I have a Kerbal go on an EVA, the nose lifts up in the air - as if that was a small enough difference in mass to cause the pivot. Do Kerbals actually have noticeable mass or is there some other explanation for what I'm seeing here?

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[GoSlash27]

Kerbals do not have mass when they are inside a cockpit, but they do have mass when on EVA or in an external command seat.

Likewise, ships that you are not controlling at the moment exhibit weird physics.

When you go EVA, your kerbal can kick around a multi-ton spaceplane pretty effortlessly. That's probably what you're seeing.

Best,

-Slashy

[UmbralRaptor]

0.0937 tonnes outside of craft, 0 inside or on ladders. That said, what happens when the kerbal gets off the ladder? (Ladders allow for interesting phantom forces)

[Kelderek]

Well the funny thing is if he descends to the bottom of the ladder then the plane drops back to the ground and he can just step off and get back on the ladder easily. When he climbs back up the ladder the nose lifts up into the air again until he boards the cockpit and then the nose drops back down again. This isn't really any sort of problem, but it's bizarre behavior that I just want to understand.

EDIT: Oh and BTW, this was my first ever landing on Laythe with a space plane, yay me!

[Vectura]

If he's going up the ladder there is a chance he is somehow pushing the spaceplane up, similar and stranger things have happened

[Sirrobert]

Probably phantom forces caused by the ladder

[Kelderek]

Opening and closing the ladder does not do anything to the plane. The nose only lifts up whenever there is a kerbal on top of the hatch or near the top of the ladder. Maybe I should try doing an EVA with the ladder closed and see if it still tips up.

[RocketPilot573]

Other than phantom forces, it could be that the Kerbal is a pilot, and when it gets out the SAS turns off and the ship falls back.

[Axelord FTW]

By the by, I think someone made a mod to add the weight of kerbals to the total mass of the command module they are in.

[thadisjones]

If he's going up the ladder there is a chance he is somehow pushing the spaceplane up

This, there is a phantom force acting on the ladder. That is the basis for the ladderkerbal > infinitethrust bug exploit that lets a kerbal, a ladder, and a bunch of massless parts go to Eve and back.