Thread by @Etienne_Marcuz

🚀 The Worst-Case Scenario - How Russian engineers envisioned last week SARMAT failure 🇷🇺

Thanks to a document found by the talented @La_souris_DA, we have concrete data on what would happen if a SARMAT heavy ICBM exploded during launch.

Let's dig into it 🧶

The source is an environmental study published in 2023 in order to assess the potential dangers of testing SARMAT at Plesetsk test ground. Many different aspects are studied, from stages drop zones to propellant leaks, including impact on Earth's ozone layer.

This is the same document that allowed us to find out Russia plans to test SARMAT as far as the Southern Pacific Ocean.

The most interesting part for today thread is of course:
"6.10 Assessment of the impact on the environment in the event of possible emergency situations during flight tests of the "128" complex product"

Complex 128 being SARMAT.

First, it confirms SARMAT's propellant: UDMH+NTO

Both are very dangerous chemical products, easily recognizable during launch due to the orange smoke coming out of the engines.

To give an idea on how dangerous it is, 2 graphs show the danger zones in case of spills at launch site.

Total propellant mass (UDMH+NTO) is 190 tons.

Now, what would happen if a catastrophic event during launch 🔥

🇷🇺 engineers assessed that the probability of failure during launch was below 0,01 and the probability of an explosion "much lower".

However, they had to work on this scenario and estimated that such an...

...explosion would be equivalent of the explosion of 21 tons of TNT.

Strangely, this seems inconsistent with a graph later in the document, displaying the dependence of TNT equivalent on time of occurrence of the failure, showing a max. value of ~82 tons of TNT at t=0sec.

Other graphs show what would be the concrete effect of such a failure. For example, the shock wave would destruct windows up to 12 km away (!) or a brick wall nearly 500 m away.

Another chart says that 25 cm thick concrete wall would be destroyed 25 m away.

Maybe the most interesting figure is a map of launch area, showing the zones of complete destruction of reinforced concrete structures and of people fatalities.

When compared to the aftermath of last week launch, it seems the engineers slightly underestimated the destruction...

...radius of the explosion. But this is still fairly consistent with what we can see on the satellite images.

Voilà ! Those are the most interesting and digestible info I could extract from this document. It helps understanding what happened last week, while giving credits to the explosion during launch, the worst-case scenario 🇷🇺 engineer could envisioned.

Disclaimer: the translations are made using Google Translate but they seem fairly accurate.

Moreover, I am not a demolition/safety expert.

Let me know if you think I made a mistake or if you want to know more. Unfortunately I don't have the link to the doc anymore.

cc @russianforces @krakek1 @MeNMyRC1 @Strike_Flanker @The_Lookout_N @HFayet @nukestrat @Observateurs

PS: I did some bad copy/paste on the graphs 🇬🇧/🇷🇺, sorry for that !