Perhaps you should have looked at the various iterations (MWM Jumpspace article, MT SOM, TNE FF&S, T4 FF&S, T5)
post 22 of this very thread:
At some point someone wrote that the masses of hydrogen in fuel were used to fill the area of the jump bubble. I'm assuming this is an attempt to reconcile that era with the other explanations of jump tech. But I never liked that hydrogen bubble theory. Of course, I don't like the "power plant...
forum.mongoosepublishing.com
I'll stick with MWM and the majority of Traveller iterations - you have adopted the T4 fanon made canon, one from five sources, it is the outlier.
We did, multiple times. But the long and short of it is this: this book is a Mongoose Traveller book, and Mongoose Traveller has chosen to use the hydrogen-inside-the-bubble paradigm from T4. Irrespective of its merits, it is one of the hanging threads we had the obligation to weave together.
For is worth, however;
Could it be handwaved that at higher TL, the hydrogen bubble is no longer necessary as refinements in jump drives mean the jump field has enough stability? The Vilani dimmed the lights to save every last bit of power to ensure jump, but then with time and advancement this was no longer necessary and persisted purely out of a sense of tradition.
That is my reasoning as well, especially considering that in Mg2nd you can already have a Jump Drive use only 8.5% of the ship's volume per parsec jumped by using three
Decreased Fuel advantages (High Guard 2022, Pg.71) on any given jump drive, once at 3 TLs above its introduction.
The existence of Collectors and that they both power
and create/expand the jump field
without requiring literal tons of hydrogen is already in-universe evidence that, not only is it possible, it is viable
and done. From there it is not a stretch to assume a sophont species that has figured out how to miniaturise M/AM Annihilation Plants down to a starship-portable size
and create the infrastructure to supply it with its fuel would have figured out how to do that as well.
Why carry water and liquid hydrogen? Just carry water there is a greater density of hydrogen per displacement ton then in liquid hydrogen.
Yes, that's precisely what I was saying, and why despite a good idea, I think a pure "hydrogen-as-coolant" hypothesis presents some problems.
Since you have brought up heat and coolant - where does all the waste heat produced on the ship go?
It flows very efficiently into the good-will of the Traveller players who kindly accept it as part of the suspension of disbelief for the setting*.
*I'm being tongue-in-cheek
At some point any work of fiction, when sufficiently scrutinised, breaks. We paid lip-service to the realities of thermodynamics, but either we'd have retconned huge thermal management systems into Traveller ships, or we accepted that we'd have to dust it under the carpet of disbelief suspension, and that's what we chose.
For what it's worth, I actually think that your idea of gravity waves carrying away the waste heat as part of M-Drive operations is excellent, and I've already readily accepted it into my headcanon.
