>>14389585>Though the ISP is pretty underwhelming for ORSC kerolox and the thrust is a joke. Too small.The small thrust is no big deal, a cluster of them can still do babby's first smallsat launcher, and if they were ambitious they could do a 9 engine upper stage with a 30 engine first stage and get something that's fully reusable, lands propulsively, and is approximately half the mass of Falcon 9.
What worries me is the Isp, actually. For atmospheric kerolox operation 325 Isp is actually quite good, (Raptor gets 330 Isp), but that vacuum optimized Isp of only 350 seconds is shockingly low. Merlin 1D Vac gets 345 Isp, and sea level Raptor operating in vacuum gets ~355 Isp. For this ORSC kerolox engine to only get 350 Isp when the sea level version gets 325 on the ground, tells me either their optimization is fucked or they just aren't planning on putting a big nozzle on their upper stage, which seems unwise to me.
Anyway. Heating issues are always worse with smaller rocket engines, because more surface area in contact with hot gas in proportion to propellant flow rates than in bigger engines, so if they can pull off that 100 kN ORSC engine, they will likely be able to scale up to 1000 kN without huge issues (still small enough that combustion is stable but also 10x the flow rate with <10x the total heating to deal with, so overall thermodynamically easier, plus the corrosion-proof alloys can be identical. Still kinda dumb that they chose kerosene fuel instead of the chad propalox (one day someone will wise up to its superiority) but w/e.
