Hydrogen engine

[sleek chasm]

Middle-game generator, analog of a fusion reactor.

• Requires liquid oxygen and hydrogen to operate.
• Requires many times more fuel than a fusion reactor to travel between planets.
• Fusion reactor will become even more expensive and rare.

[wild shadow]

There is no 'Middle-game' here, you can luck into a reactor on day one, but I agree that more types of engines would be nice, for both main propulsion and RCS. And as we are in a derelict field, would make sense to meet some 'dated' propulsion methods. Plus thrusters shouldn't be 'one size fits all'.

[sleek chasm]

Good point

[wild shadow]

Requires many times more fuel than a fusion reactor to travel between planets.
As a non-radioactive method it should be immune to 'no ignition zone', so player is going to abuse it 'locally'. Probably better to make it as 'local' delivery and for local patrol vessels from the start, plus dated vessels instead of 'between planets'.

[minor nymph]

Well I would not go so far as to say chemical rocket engines have no wake. It might not be as bad as a fusion engine but insignificant it ain't 😉 :
https://www.youtube.com/watch?v=JbFdOYgQs9I

[wild shadow]

Neither sound nor heat travel in vacuum. Besides that rocket exhaust in space is more like a narrow beam thanks to nozzle shape. As long as engine points not directly at a station you are fine.

[minor nymph]

If heat doesn't travel in space why are we not freezing our asses of as the heat from the sun can't reach us? 😉 A fusion and a chemical engine are not fundamentally different in their operating principle: shoot hot gas in one direction to go the opposite way. The main difference is how that jet of hot gas is created and how fast and hot it is.
Though I admit I am no expert so I don't really know how close either needs to be to a structure to cause damage. But one thing I am certain gasses in a vacuum will expand so neither will stay a narrow beam for very long.

[wild shadow]

I think the problem of a fusion engine is not exhaust, but neutron radiation and overall danger level.
Neutron radiation is far more penetrating and damaging than proton or electron radiation. It has no charge and ignores magnetic coils, so it doesn't get directed as precisely as the rest of the exhaust does. This type of radiation doesn't last long, but due to initial speed it's going to travel far.

Besides that if an O2+H2 rocket blows up 1km away, in space the worst that happens - you get hit by small debris (the fuel isn't stored mixed so crew might survive). If a fusion rocket containment fails surroundings get bombarded by neutrons, those neutrons will interact with surrounding materials thus creating isotopes and those isotopes are going to be radioactive. Despite not producing nuclear waste (or not producing as much), fusion engine is still no joke (the fuel isn't stored mixed either, but fallout is stronger).

[bright mauve]

In this game, it's explicitly the exhaust.

-which has enough kinetic energy to push our very heavy ships at multiple G's, even disregarding thermal energy!

[gaunt venture]

...I hate to um ackshually but helium-3 fusion is aneutronic. I think the 'no-wake zone' is referring entirely to the thruster plume, as JPR said.

[distant gate]

chemical rocket engines are a common ask, whilst they are a nice real world device they're kinda inefficient and outdated as a tech in a world with torch drives and hyper effective RCS (remember our RCS is about 10x stronger than it should be IRL)
Reactors themselves allow for different levels of setup already, there's no 1 true reactor setup, there's several working configurations with more or less power, and the weight of your ship itself has a big impact on the amount of speed you will get too.

Generally I'd say its not worth it for us to add this feature