[Spaceships]If Hyperspace is a fluid medium

[Adina]

I have been thinking about building spaceships for a TL10 setting. I have decided that hyperspace and reactionless thrusters exist and was thinking about appropriate techno-babble.

Both stardrives and reactionless thrusters require a vehicle minimum mass greater than 300 tons, i.e. SM+8 or larger. They are also gravity limited, they can get you in and out of orbit but surface/orbit transfers need fusion torches or other reaction drives.

So it occurred to me that if hyperspace is filled with some type of fluid medium (ether?) it could explain a couple of things.

1) Drag from this medium explains why FTL drives have a top speed rather than an acceleration.

2) "Reactionless" actually use this hyperspace fluid as reaction mass.

Some questions for speculation:

Would reactionless drives be pseudovelocity?

Would their acceleration be felt by the occupants?

If hyperspace + normal-space are a closed system could the various conservation laws remain valid? Would this require a transfer of energy/momentum between hyper and normal space?

What other effects fall out of this setup?

Jeff