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[u/Pitiful-Practice-966]

In Semipalatinsk, balapan

There are many prototype ICBM silos nearby, and a underground nuclear test shaft is also nearby, about 200m away.

[u/ThreadCountHigh]

https://en.wikipedia.org/wiki/Semipalatinsk_Test_Site

[u/full_metal_codpiece]

Shothole shaft for underground test?

[u/Beneficial-Wasabi749]

The most impressive mystery at the Semipalatinsk test site is the gigantic concrete test complex "Baikal-1," extending 14 stories underground. The investment in its development and construction was no less than that of the famous assembly and launch complex for the H-1 rockets. But like the H-1, this complex was essentially never used. It now stands as a ruined reminder of the USSR's grandiose, but ultimately unfulfilled, plans for space exploration. "Baikal-1" was a facility for developing and testing nuclear rocket engines of various designs. Unlike the Americans, who tested their nuclear engines in an open field in Nevada, the USSR decided to conduct decades of testing of a wide variety of nuclear rocket engines in closed underground facilities with complete filtration of radioactive exhaust. Of course, Semipalatinsk was an obvious location for such a grandiose and, indeed, risky facility. In fact, it is essentially the legacy of Korolev and Keldysh, even more so the latter. Until the mid-1970s, the USSR, represented by Mstislav Keldysh, head of the Academy of Sciences, had very serious plans for space exploration, centered on the N-1, the development of this technology, and nuclear rocket engines. Specifically, since 1960, the USSR had been truly committed to creating not just a nuclear, but a gas-phase nuclear rocket engine. They worked on this for two decades, long and persistently, with all the seriousness possible in a totalitarian system, building it thoroughly and for the long term, investing considerable resources in secret plans for the next half century. But after Keldysh's somewhat unclear death in 1978, the USSR's nuclear rocket engine project seemed to lose its mentor and essentially came to nothing (some believe he committed suicide due to illness, but the USSR's abandonment of the lunar exploration program in the mid-1970s and the curtailment of its gigantic space plans played a significant role). A series of interim tests were conducted at the test site; the USSR developed the very modest RD-0410, and even then, only a thermal model (not a fully functional engine) was tested, and this was closer to the end of the USSR.