I know I know, I hate posting “random” youtube links and expect everyone to go and watch them. But this one is quick/short and to the point, I promise.

But in case you don’t want to watch the youtube video, I’ll highlight the key points:
– Liquid Nitrogen has the most power/energy but is a serious PITA to work with because
— Small molecules, can slip through even the tiniest of cracks
— Requires it to be super, stupidly, cold, when stored. Which means every pipe/tube/bend/connector it passes through as it moves throughout the ships system has to be super reinforced for that extreme cold and have to deal with things like shrinkage, we all know things “shrink” when they get cold. So when this liquid nitrogen causes tubes and materials it comes into contact with to shrink, and then they expand again when they warm up, they create these fun little “cracks” that these tiny little liquid nitrogen molecules can pass through.
– SpaceX and Blue Origin have both said “to he!! with this, so many NASA missions in the 80’s and 90’s were scrubbed due to dealing with Liquid Nitrogen leaks, so we’re going to use the next most powerful substance, Liquid Methane”
— Liquid Methane isn’t as powerful as Nitrogen, but it’s a much larger molecule and does not require to be as cold as Nitrogen. So the trade off is you get a lot more stability and less chances of a leak and having to abort a mission and look silly in front of many thousands of people. But you do have to carry more of the fuel, ie weight, to compensate. But both private companies felt the trade off was well worth it.
– NASA is only using Liquid Nitrogen in the 2020’s now, for Artemis, because of politics. In an effort to try and save some money (HA! That didn’t work out very well did it, Artemis 1 is way over budget and was way behind schedule) NASA was mandated to reuse old technology and propulsion systems. Not the actual parts, good lord those are sitting in museums rotting, but I guess all their expertise and design specs for tubes/pipes/connectors and machining and such were designed for Liquid Nitrogen.
— But still, Liquid Nitrogen was a PITA to deal with then, causing many a scrubbed mission, and surprise surprise, it’s a PITA to deal with now causing Artemis 1 to have been postponed not once, but twice. And it almost caused the 3rd attempt to fail but they luckily (Red Team ftw!) managed to get it patched/sealed up and no more leaks. For now.

Don’t you love when politics plays a role in space technology? That’s why SpaceX and Blue Origin avoids it, poor poor NASA.

Filed under: Personal - @ 2022-11-16 5:26 pm