Question about CATOs

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Well-Known Member
Apr 7, 2004
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Hey all. What does CATO stand for and what causes them? Can the smaller A through D engine CATO? I don't want to be standing only 15 feet away when it happens (neither does my science fair partner)!
there are lots of definitions of what the letters mean. But usually it means something goes seriously wrong with the motor - catostrophically wrong - like ovverpressurizing, or a nozzle or o ring failure

BP motors can cato and do, I have been pretty close to them when they cato and you can get out of the way. Shouldnt be a problem
Originally posted by rocketsonly
don't want to be standing only 15 feet away when it happens

I wouldn't be worried about it... BP motors do CATO, but the propellant burns so fast that even if you're launching D motors from 15 feet, the fireball out the front of the rocket usually burns out within 10 feet of exiting the tube :p I've had lots of those...

Composite CATOs are fun because usually the propellant goes out (rapid drop in chamber pressure, like one big chuff), but I remember Alex McLaughlin's P motor CATO at BALLS last year while I was loading my doomed M project on the pad... when the case fell back down onto the pad leg, it knurled over the end and trapped the propellant inside, meaning it sat on the ground and flamed for a long time. Even at my "vulnerable" distance (I was at the 500 ft pads, this rocket was at the 1500 ft pads), it was no big deal. 15 feet of distance is plenty for BP motors because the propellant burns really fast outside the case.

Anybody else got CATO stories?
do we have CATO stories... :p

Is a bear Catholic? Does the Pope s...... wait, reverse that...


yea, we got Cato stories.... by the way, CATO, as far as I know, only stands for CATOstrophic failure. It isn't an acronym but many beleive that it is (kinda like SOS)...

Check out my webpage at:

BP cato's are actually quite safe. most cato's blow up/down meaning that there is little or no sideways action to the fireball (by design)

check out the site and read the captions

Sometimes smaller motors CATO because nozzles are cracked due to shipping/handling. Another way it can CATO is when a motor wont fit into the engine tube , so you take some engine casing off so it will fit. If to much is took off , BOOM!!! This has got the power to rip your centering rings & BodyTube to shreads ( the rear end of the rocket anway )!

I was just thinking about this , and would it also CATO due to the propellent being cracked (ie heavy item dropped on top) , or would it just continue to burn?
if the propellant cracked it would CATO, for two reasons, one there is more propellant burning which can cause over-pressurization. Or a piece of propellant will block the nozzle again causing over-pressurization
Originally posted by Karl
. . . would it also CATO due to the propellent being cracked (ie heavy item dropped on top) , or would it just continue to burn?

Back in the olden days of the first D-class motors by Estes, the D13 series got a reputation for having a high CATO rate. I don't think I ever knew if that was really true, because of all the stunts that we pulled on each other and then blamed on the D13's.

If you were not vigilant, someone was likely to sneak into your range box and borrow one or two of your D13's long enough to "adjust" them with a hammer and then slip them back into your stash. The additional surface area in the fractured grain made for a very rapid buildup of terminally excessive chamber pressure.

It was hilarious when you successfully pulled off one of these tricks on someone else. It was not funny at all when your rocket was the one on pads 3, 4, 5, and . . .
Doesnt it stand for Catostrophic Aborted Take-Off ??
Originally posted by WiK
Doesnt it stand for Catostrophic Aborted Take-Off ??

Yes it is , heres the complete definition of CATO :

Origin: Opinions on the meaning of the acronym range widely. Some say it's not an acronym at all, but simply a contraction of 'catastrophic' and should be pronounced 'Cat-o' (which sounds better than 'cata' over PA systems :). Others maintain that it is an acronym but disagree on the meaning, offering a broad spectrum of 'CAtastrophic Take Off,' 'Catastrophically Aborted Take Off,' 'Catastrophe At Take Off' and the self referential 'CATO At Take Off.' The acronym crowd pronounces it 'Kay-Tow', like the Green Hornet's side kick. It has been pointed out, though, that all of the above are 'post-hoc' definitions since LCO's were using the term over range PA systems long before any formal acronym was established.
Absolutely not.

it is shortened slang for "Catastrophic Failure". It can happen at any time from ignition to delay to no ejection charge.

There is no "abort". An aircraft can have an aborted take off, but it does not have anything to do with a catastophic rocket motor failure.

AND Rockets do not "Take Off". They "Launch" or they "Lift Off" or if they were from the late 1950's and early 1960's they could "Blast Off".

And we do not "Shoot" rockets either, as long as we're on the subject.

"Combo" is short for "Combination" or "Combination Plate".

Originally posted by WiK
Doesnt it stand for Catostrophic Aborted Take-Off ??


  • CatoExplanation.pdf
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I think the meaning of CATO is one of those questions that will never be answered.

Whatever it means, its a bad thing!
Heres the only ever CATO's that ive had !

This one is a Quest C6-5 , which burnt through the side of the motor rather than the nozzle.
This one is one of the Estes Missle Command set (mini motors) I dont know what happend here but the motor trashed the rocket. (A10-3T)