Artemis 1 scrubbed again
NASA scrubbed the launch of Artemis 1 again today (Saturday Sept. 3, 2022). The reason was different, a hydrogen leak.
A lot of the newer rockets have changed from liquid hydrogen fuel to liquid methane. Tradeoffs exist depending on which fuel is used. Hydrogen gives better performance but it's bulky and hard to handle. Methane's performance isn't as good but it is easier to handle (temperatures aren't quite so close to absolute zero). Methane does have one nasty property being heavier than other gases it will stay close to the ground. If ignited, watch out ! (as Spacex found out in a recent Starship test in July 2022). Hydrogen is lighter than nitrogen/oxygen so will tend to disperse up and away.
But as Eric Berger says: "hydrogen leaks":
https://arstechnica.com/science/2022/09/years-after-shuttle-nasa-rediscovers-the-perils-of-liquid-hydrogen/
In the first year of the PBS program: NOVA there was a show about hydrogen's potential for the future. But it's never come to pass, some things are just hard or expensive, hydrogen is one of them I guess.
But you have to wonder, if they don't use hydrogen (and oxygen) as the fuel, how will people make methane on the Moon ? Where would the carbon come from even if they do find water ? Is it in the rocks ?
BTW, since Artemis is initially moon focused, this article by Arthur C. Clarke from December 1961 Harper's Magazine was interesting. The article is entitled: The Uses of the Moon
https://archive.org/details/sim_harpers-magazine_1961-12_223_1339/page/56/mode/2up
or download the magazine here (52 Mb, the article is on page 56):
https://archive.org/download/sim_harpers-magazine_1961-12_223_1339/sim_harpers-magazine_1961-12_223_1339.pdf
Clarke mentions the novel: Advise and Consent which I've never read but in which a space contest with the Russians concerning the Moon is featured. I watched the movie and the Moon part of the story was cut and the story concentrated on the machinations between the Senate and the White House.
Clarke's premise is that the space race shouldn't be a one and done (as it turned out to be) - that the Moon had real benefits for humanity. He mentions water may exist on the moon as ice but that even if there is no water the building blocks of carbon/hydrogen/oxygen and so on will exit. However he supposes the existence of fusion energy:
He was wrong about fusion, it's still in the future, and his generation did have grandchildren.
The Lunar catapults mentioned were in effect: electromagnetic rail guns. They would take advantage of two of the Moons features: no atmosphere and low gravity. He also mentions some other lunar features: no atmosphere = no weather. No people and their EMI producing gadgets means perfect radio astronomy conditions on the far side of the Moon.
Considering that the article was written over 60 years ago it is still valid and worth reading in the context of the Artemis plan to explore and stay on other celestial bodies in the solar system.
Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm