Thread by @ArmsControlWonk

So, we're now trying to understand precisely what the Russians were working on at Nenoksa and what went wrong. We can, at least, confirm the outlines of the Russian account -- after an engine test, there was an explosion and fire on a barge that killed five nuclear scientists.

We can confirm the major aspects of the Russian version. Yes, there was an explosion -- the @ctbto_alerts detected it around 6:00 UTC or 9:00 am local time. It would be great if a seismologist worked out the precise event time.

https://twitter.com/ctbto_alerts/status/1160130156922642433

We can also see the damaged barge in satellite images. @planetlabs got a 70 cm image on August 11; @Maxar (via @ckoettl) got a 30 cm image on August 12.

There are two reasons for thinking the explosion was related to a nuclear-powered cruise missile. The first is that some of the structures on the land suggest that Russia has moved testing of the SSC-X-9 to Nenoksa.

Second, AIS and satellite images demonstrate that Russia had the Serebryanka, a nuclear fuel carrier, sitting inside the exclusion zone PRIOR to the accident. In other words, it was waiting to carry away a highly radioactive cargoe like an SSC-X-9 propulsion unit.

Now, Russian officials have stated the five scientists killed were working on a small nuclear reactor, comparing it to @NASA's Kilopower reactor. That points to something like Skyfall, but the Russians don't seem to want to explain their design approach.

https://twitter.com/sbidgood/status/1160632621673545729

How does the nuclear reactor power the missile engine? The obvious reference is the direct-cycle US effort, Project Pluto. But there are also indirect-cycle concepts, including concepts that are closer to Kilopower.
fas.org/nuke/space/anp…

A nuclear reactor to power a missile could be Skyfall (the program we know about) or a follow-on effort assuming that Skyfall, uh, fell short of its design goals. We really don't know. Boy, it would be great to still have some lab-to-lab contacts.

https://twitter.com/CherylRofer/status/1162107767915601920

What went wrong? It's hard to guess unless we can understand how the nuclear reactor relates to the missile engine. But if we can tie together the backgrounds of the scientists and possible failure modes, we may be able to guess what the Russians don't want to tell us.