Video of Today's Solid Rocket Motor Test

It not just that "They're expensive. Nobody else needs them.".

It is also that they are tremendously destructive of the environment, generating huge amounts of toxic pollution both in use and in manufacturing.

Spidey!!!

Who in the hell is James Muncy and why should anyone listen to him?

Editor's note: First: Jim uses his real name you don't. Second: Jim has decades of space policy experience in and around Capitol Hill and has had a personal hand in drafting a number of important pieces of legislation and organizing countless congressional hearings, meetings, and other activities vital to the creation of space policy and legislation. Third: you are just plain lazy. A simple Google of Jim would reveal his long and distinguished background. Fourth "who the hell are you", eh "jski"?

Big ugly yellow flame == low ISP.

Studies done by both NASA and private research firms have shown that SRBs from NASA and military launches only contribute 725,000 kilograms of toxic chlorine to the atmosphere annually assuming 9 shuttle launches and six Titan launches every year. Private industry, however, places 300 million kilograms into the stratosphere annually. And even nature itself, through volcanic eruptions, places 75 million kilograms of chlorine into the atmosphere annually on average.

So even if there were hundreds of HLV launches annually with SRBs strapped to them, they would still contribute only an insignificant amount of chlorine to atmosphere relative to nature and especially relative private industry chlorine pollution.

Marcel F. Williams

Great, now we have the environmental loons out to police space technology. While you're at it, why don't we also ban every material/chemical in the space program that's hazardous to humans. Oh wait, that's nearly all of them. Are we going to worry about all the animals at KSC that are disturbed from their everyday routine when a shuttle goes off? I mean, poor poor Astrobat. How about we make it easy for you and cancel all spaceflight. Would that satisfy your environmental goals?

The company building the product decides how to do it.

It shows you how screwed up this whole situation is when you see regular people debating whether a rocket part is good or not. Uh, aren't the rocket scientists supposed to decide?

Rocket design by committee! Sign on the dotted line!

Insignificant test. Yet another demonstration of 3,000 year old technology from our good friends in Utah. Yawnnnn.....

To heck with politics, those puppies put out some thrust with minimal moving parts!
I don't get the whole pro-ATK, anti-ATK polarity that exists within the aerospace community. Solids are a pain for the Explosive Safety requirements that must be addressed through the entire ground processing flow, but the simplicity of how they work during ascent is certainly intriguing.

This has nothing to do with Pro or Anti ATK. The engine needs to fit the mission requirements.

Solid boosters come from a military background. They need to have infinite shelf life and launch in minimal notice. No time to cool, pump, pressurize, etc. They are great for that.

Their down side: No control of the burn, low ISP, high dead weight, rough ride. And - they are always fueled and dangerous.

For a manned or cargo mission, they are not a good fit. I see them as a "cop out" when you can't build a "proper" bi-propellant engine that's powerful enough, so you use an SRB as a first stage.

Sails are simple. Should all ships use sails?
Jet engines are complicated. Should airplanes stop using them?

Hear, hear!

Maybe so, but ISP doesn't matter a lot in a first stage, because fuel is cheap. There are more important reasons to hate big solid boosters: low reliability because they cannot be fully tested, dangerous because they cannot be shut down, etc. On the whole it would have been better if this sucker had blown up.

"Big ugly yellow flame == low ISP."

I'm not sure I would call it low, but it's in the same ballpark as LO2/Kerosene engines. LO2/LH2 are higher, but they have their own problems.

"The engine needs to fit the mission requirements. ... For a manned or cargo mission, they are not a good fit."

I can see the manned part of that, but why aren't they good for cargo either (especially for first stages, where the low ISP and rough ride - which the mass of the upper stages will damp - aren't such a problem)? So what if they can't be turned off - a problem is going to lose you the payload anyway.

The 'always fueled and dangerous' is a canard, IMO - how many instances are there of a solid going off when it was not specifically ignited?

Noel

Noel, I can see why you separate manned from cargo in this context, but I can't agree. If the payload
was millions of dollars worth of satellite (or whatever) that belonged to me, I'd want it launched on
something that could be controlled.

As we all know, SRBs can not be either turned off or throttled back, so I don't consider them to be
controllable. A non-human payload can have abort recovery mechanisms added, just like HSF launches;
in fact, I'm willing to bet that it's just a matter of time before the insurance companies and the
government regulators insist on it.

Steve

" Low Reliability because they can't be tested" Hardly. DOD routinely test launches Trident missiles to verify performance and reliability. If solids were so unreliable I doubt we would rely on them for our strategic deterrence mission.

It would be interesting to know how expensive this test was as compared with the $900 million Ares 1X launch.

"A non-human payload can have abort recovery mechanisms added, just like HSF launches; in fact, I'm willing to bet that it's just a matter of time before the insurance companies and the government regulators insist on it."

I dunno - abort technology has been around for fifty years (Mercury had it), but I've seen no sign so far of cargo launches going with abort recovery.

Noel

A $2B and counting development project...and why is it that NASA is paying for this test? A monumental waste of taxpayers dollars! Yes, we know the technology works - so why does one need 760 instruments? Alas, another enormous jobfair program for prime contractors.

"why is it that NASA is paying for this test? A monumental waste of taxpayers dollars! Yes, we know the technology works - so why does one need 760 instruments?"

Well, I don't know for sure why they felt they needed this particular test, but one guess as to why is that critics were saying that the SRB's (especially the 5-segment one) might have too much longitudinal vibration for use in a manned launcher. So one would want to do due diligence and test that to see it was OK....

Noel

ISP is not the #1 consideration for first stage, but it is a consideration nonetheless.

High dead weight is a big consideration for a first stage, and they flunk here too.

Reliability/Controllability for a $2B DOD satellite is every bit as important (in the eye of the customer) as a human life.

Reliability for the nuclear deterrence? hardly. This the the one mission where reliability doesn't count. It's part of MAD, it only has to work 90% or even less to be effective. Who cares is some of the missiles explode on launch? However, I was thinking more about AA missiles when I made the analogy. Boosters are reliable but not controllable.

If it wasn't for the high dead weight, then I agree the rest of the arguments are not conclusive... But when all these things point in the same direction, I don't really see the point in using them.