3
$\begingroup$

Whilst cobbling together an answer for this question, I found myself thinking about the effects of hot rocket exhaust on a rocket launching from a confined space. I assumed it would be generally considered to be a Bad Thing.

So I found myself watching this video of a Minuteman launch, and it looks to me like hot exhaust is shooting straight up the silo and the rocket is launching through it... there seems to be a good couple of seconds where it would be toasted, and I see no indication of exhaust being vented anywhere else. I check another video (which starts with a Titan II launch with obvious venting away from the rocket, which I had assumed to be essential and standard on silos) and I can see a moment where a Minuteman, clear of the silo, is apparently wreathed in flames.

Minuteman silo launchAnother minuteman launch

Am I interpreting this correctly? Was the Minuteman made specially flame retardant, or am I a) overestimating the hazards of rocket exhaust and b) underestimating the toughness of a solid-fuelled ICBM?

Improve this question
$\endgroup$

1 Answer 1

Reset to default
4
$\begingroup$

Am I interpreting this correctly?

Yes

Was the Minuteman made specially flame retardant?

No. 1) The hottest part of the exhaust is below the rocket. 2) Metal (Probably Al or an Al alloy) is fairly flame resistant. The flame may be hot enough to burn through eventually, but the metal is only subjected to the flame for a few seconds.

ICBMs have been repurposed as satellite launch vehicles, and they look basically the same.

https://en.wikipedia.org/wiki/LGM-30_Minuteman#Satellite_launching_role

Note that the Russians have used a different launch method; compressed air ejects the rocket from the ground before the rocket ignites. An added complication, but has the advantage of being able to quickly reload.

Improve this answer
$\endgroup$
2
  • 1
    $\begingroup$ Submarines use a steam canon to get the missile out of the water before the missile engines fire. $\endgroup$
    – Fred
    Commented Feb 22, 2021 at 10:15
  • $\begingroup$ @Mattman944 Regarding Aluminium, if used as you describe, I'd suggest the emphasis being on the short duration as Aluminium has a comparatively low melting point (660degC). $\endgroup$
    – Puffin
    Commented Feb 22, 2021 at 15:03

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.