[Spaceships] Homebrew: Alternate Chemical Rocket Fuel

[Anthony]

Originally Posted by Brett

Isp (specific impulse) is not measured in seconds in the SI, only in US customary units.

If it's labeled Isp, it's commonly measured in Seconds even under SI. If instead it's labeled as Ve, it's not measured in Seconds, despite the fact that these two names are measuring exactly the same thing.