Prototech additional content suggestion

Prototech has managed to augment the ion thruster significantly and make it only barely worse than the large grid H2 thruster. However, the humble hydrogen rocket has seen no advancement in over a century since it was concieved! everyone is plagued by attempting to make builds that don't crumple in on themselves that also can fly on planets, only to come to this simple slap in the face we know as the square-cube law, summed up in one image (kgs / kg output of 1 LG-L-h2)

this specific breed of agony is known as encountering the laws of physics in a way that is offensive to someone in the final turn of the 21st century, where electricity alone can produce more thrust than the estimated force acting on the manhole lid at the Plumbob nuclear testing facility on August 15th, 1957 at 5PM on a crisp afternoon.

In today's time, the small grid H2 thruster is outperformed by its closest real-world counterparts at SpaceX by half an order of magnitude; the Raptor engine, ran on Methane, outputs 2.8MN depending on the weather

In 1969, NASA, fuelled by John Frederick Kennedy's endless pockets and undiagnosed autism, managed to make the F-1 Kerosene engine output 8MN before the advent of computation that didn't rely on punchcards and with prior attempts using WD-40 as fuel instead of kerosene.

Therefore, Surely, in 2077, when purely-electric engines can outperform the raw power of burning hydrogen, a fuel almost unrivalled in its energy release, they could find a way to make H2 engines many times more powerful, even at the cost of no longer being as good in space...

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the concept is simple. invert the prototech thruster's functionality as a space thruster:

1. 3x8 thruster
2. max output, space: 2.8MN
3. max output, atmosphere: 30MN
   (thrust falloff is barely enough that momentum is needed to carry craft into range for ions/proto-ion to carry it to space)
4. requires: electricity, H2, O2
5. thrust-responsiveness: 10 seconds to reach full power, 10 seconds to wind down
6. components: hydrogen thruster components along with prototech thruster components.
   PROS
   planetary logistics are easier
   an end-game option for a complete spectrum of heavy lifting
   builds can be larger planet-side without compromising too much on armor
   factorum update feels slightly more complete
   More uses for O2
   Cons
   Explodes with the force of a large warhead on destruction, even more powerfully than H2 tanks due to high amount of oxidiser
   slow response time requires more piloting skill
   higher fuel consumption, also needs O2 to work
   

If lore is an issue, you can frame it as the factorum or even an internal division of them testing chemical rockets to build truly huge planetary warships, with the things being so huge because they're only experienced in electric engines (thereby explaining why the really huge H2 proto is so inefficient) you don't even need a small-grid version, if you really want a break.

for aesthetics, it may be tricky to make the sleekness of the factorum look experimentally un-neat, however for that you can try to look at aerospikes and the sheer bulk of plumbing behind them, then try to compartmentalise all of that into a cylinder of greebling with an aerospike nozzle spitting raw fury when in air.

From an effects standpoint you can just make the plume welder-bright, opaque, smoking (?) and also very, very loud at max power. in atmos, it's long and thin. at space, the plume effect is compressed to look more like an orb than a flame, like how the ion thruster works. below is an example aerospike engine running on liquefied H2. this is the RDRE by AFR labs as a sample.

but PLEASE I AM BEGGING YOU... THIS IS THE ONLY THING MISSING AN ACTUAL UPGRADE TO THE MOST USED THRUSTER I BEG OF YOU!!!