It’s the barn-find bit I like… Supposedly were all supposed to be destroyed but someone decided to warehouse them instead, where they sat for about 30 years, til someone from Aerojet decided to follow up a longstanding industry legend and found 150 of the most powerful rocket engines ever built just waiting. You can imagine them throwing off the dustsheet…
It’s probably a much drier story in reality but frankly if it is, I don’t care to hear it 😉 It’s like buried spitfires.
But then, the reason the russians cancelled their moon program was partly because they had a high fail rate- supposedly it’s a great way to make a very light, very powerful, fairly unreliable rocket motor.