# What's the geometry of Ignition Overpressure Protection system protecting rocket launches?

During a rocket launch, both the rocket as well as the launch pad have to be protected. This is usually done by shooting enormous amounts of water somewhere 'at' the rocket engines.
The then evaporating water is often popularly mistaken for the evaporated rocket fuel.

After reading a recent article and seeing a modern Ignition Overpressure Protection system in test, I was thinking the following:

• Seeing the interesting arrangements of towers, channels and blocks at the launch pad made me assume that there is some optimization process behind the structures
• If the flows of water have had to be somehow optimized, then the answer to 'where is the energy absorbed?' is not simply 'well, below the rocket, duh'

So my question is

• Where exactly on the launch pad is the water during launch, and where is most of the heat and acoustic energy absorbed?

It would be nice if someone knowledgable could point to sketches of the situation during launch, as me looking for it would take hours probably...

Not sure about more modern systems, but there is a lot of information available about the STS system.

This page (in French) has a lot of good information including pictures. It shows the "rainbird" sprayers for the deck area of the launch pad

And the system around the Solid Rocket Booster holes, including the water bags that were added after the STS-1 overpressure event.

If you have an interest in the Shuttle water suppression system, this page is really good with lots of great pictures, take a look at it.

I found a picture of the differences between the STS-1 and STS-2 configurations.

(This picture is from the Bo Bejmuk presentation "Space Shuttle Integration Lessons Learned" which has various versions around; there is a version on Scribd but I'm not looking at it since I hate Scribd.)

As far as optimizing the system, there are a number of technical papers available publicly. They usually analyze a simplified geometry but may be of interest.

(image from 2nd linked paper)

Paper 1

Paper 2

• Thank you! That should already give me a number of important hints in order to understand this part of rocket launching. I'll wait a few days and if no other answer comes I'll accept. – AtmosphericPrisonEscape Oct 28 '18 at 22:21
• And I guess I could answer my own question, for people who are not fluent in french... – AtmosphericPrisonEscape Oct 28 '18 at 22:23