Are you looking at the video John posted with the school bus in the image? It's a little more than 1 and less than 2 seconds from the time of the flash to the sound.
The main observation is that they're off the FAR property in order to be at a safe distance as an observer.
I'm pleading the fifth across the board on this topic.
Conclusion: even at 1000 ft, a person becomes an observer and not a part of the debris field of a P cato.
If high-density, non-ductile (fragmenting) materials were allowed, there's a probability a piece could reach 1000ft ballistically. For TRA-allowed materials, it's rather impossible. The piece would need a high ballistic coeffient (mass/area) or it needs to be a propulsive object.
That is the video I was referring to.
Around 1000 ft is what I suspect the distance is as well.
No. For a P motor the TUSC safe distance is already set at 2000 feet.
And we're confident that no debris made it past 2000ft in any direction from this incident? Has anyone walked the site to look? This would be a good opportunity to check that safe distances are safe, through monitoring of a RUD to look for evidence that we are safe.
Your question is posed as a "what-if" scenario. "What if grasshoppers carried pistols?... Then birds wouldn’t mess with them!”
There WAS a P cato. There's no "what if", the question is "what has occurred?" We have the opportunity to learn from it. Checking the debris field is one of those things that needs to be done to validate the safe distances we use.
Thanks for sharing this! If I understand this correctly, the standards use a cube root for distance. Table 5-10 has 84 feet for 100 pounds of propellant? That seems way too close. Am I missing something?
Table 5-10 is for intraline distances:
I am very curious to see what the NASA standards says regarding standoff distances. I will try to read it in detail when I get a chance.
Do you have a reference which is applicable? I looked for one awhile ago and never found something exact.
I mean something developed by professionals who either did some rigorous analysis or empirical testing to create solid models. Amateurs might have something rigorous as well but I am hoping for something similar to what Tony posted. The Tripoli distances, based off the NFPA distances were just "looks about right" and no real analysis was done. This is my understanding from talking to NFPA committee members who were around in the original NFPA 1127 write up.
Not true. The safe distances for model rockets has its foundation in an analysis done at MIT. There are plenty of other models out there for blast field prediction based on energy, action time, material size and density. There have also been tests to verify the models (NM Tech in Socorro has done this work). I'm not going to point to them on the open web. Make whatever conclusion you want, but educate yourself first.
There are plenty of studies on High Explosives. Storing them in a bunker and how far the earth would fly if it went woops.
