Ares VII

dicktice · 2007-01-19 12:16:26

We really must wean ourselves from SRB's. They've had their day, as quick and dirty boosters adopted for the sake of expediency, but to base the future of space travel on "skyrocketry" is a sad tribute to the liquid-fuel rocket pioneers--who devoted their lives to find a way out of the solid-fuel blind alley, eh?

RedStreak · 2007-01-19 18:54:30

Those same pioneers never dealt with the headaches of liquid hydrogen and the wonderful world of cryogenics that prevails.

Solid rockets are more reliable than liquids for better or worse. Liquids can give better performance but it comes at an annoying cost: cryogenics that limit storage time (which has HUGE implications both within and certainly beyond CisLunar space) and demand thick insulation (which in the case of STS shed and lead to deaths) and complex engines (that are heavy and impractical like the SSME or have to be imported from Russia like Lockheed has done with many engines). You fill a solid rocket up like you fill a tube of cauking, slap it together, and then light up.

The SRBs never once caused a flight delay nor failed in performance whereas your precious liquid SSME are often the contrairy; hell even the ET was PECKED into a launch abort by a woodpecker because of the insulation! Liquid rocketry...defeated by a bird!!

Michael Bloxham · 2007-01-19 20:40:15

These are problems with the Shuttle system only. I doubt whether anyone will care when woody woodpecker takes a bite out of Ares V's delicious foam.

In the environmentally conscious world of 2020, SRB's just won't work.

GCNRevenger · 2007-01-19 21:30:51

You guys are nuts...

First of all Michael, giving any credibility to gaetano is a mistake: he is a gibbering fool, and listening to him greatly reduces your credibility.

Whether the transporter can move the mass of a fully assembled "Paris" type rocket is irrelevant, because no such vehicle can be built in the VAB nor fit on Pad 39. Already Ares-V is within meters of the maximum height of the bays: remember, you must have room for the crane and some space between stages/payload for mating the interstages. Also, I really don't think that the VAB's four bays have anywhere near >30m of clearance for the width of the monster.

You have entered the realm of rockets known as the "NOVA class," which will require all new facilities for manufacture, assembly, and launch. Anyway, I think its impossible that the combined cost of these new facilities, development for the monster rocket, and actual flight costs ($840M of RS-68s per Paris-III, not including upper stage) will never match a few Ares-V's. Also, interstage fuel lines will greatly enhance complexity, cost, and weight.

And you are all forgetting the elephant in the room, that the Shuttle stack uses massive solid rockets for some reasons: why does Shuttle need them? The SSMEs are the most efficient large engine available, close to the edge of what is possible with H2/O2 engines. It needs the SRBs because the thrust-to-weight ratio of just the SSMEs is awful.

Thats a problem with huge cryogenic rockets, that Hydrogen engines have wonderful efficiency in/near vacuum, but suffer from three major drawbacks:

-Fuel tank volume/mass penalty
-Poor low altitude efficiency (with vacuum nozzles)
-Poor thrust (low propellant mass)

These problems will severely limit the payload of your rocket, at least versus what it could achieve if you added engines better suited for liftoff and the early phases of flight.

SRBs have the reverse of all three of these drawbacks, plus are cheap and reliable. They compliment cryogenic engines well and should be used. NASA seems to think so, and are keeping them for the Ares rockets, which they are more than up to the task according to M. Griffin, who is a sight more credible than the "hot dog suicide bomber motif" gaetano.

The nonsense about them being an environmental hazard is silly, the "pollution" is perchlorate salts, which are part of the famous class of chemicals known as "endocrine disruptors" that the environmental zealots have latched onto, which supposedly "hurt children" at ridiculously small doses. They still can't prove it, but that doesn't matter, since it can't be "disproven" without testing toxic chemicals on children. That doesn't stop the neo-luddites or the EPA of course from setting extremely low exposure limits to an imagined, rumored, unsubstantiated risk. SRBs are safe for the environment.

RedStreak · 2007-01-19 21:58:26

For a second thought you were nuts GNC but I'm glad you're supporting the actually working components of the STS & Ares.

Looks like the SRBs aren't so bad after all. I am definetely not suprised about the height issue with Ares-V as is; it'll probably be the only rocket to near Saturn-V's height for another century I'm betting...at least assuming space agency budgets and politics as they are now. SSME were, alas, an experiment that proves reuseability has limits and, worse still, limits that can hamper performance.

We can cut alot out of the old STS hardware but the SRBs won't be among them...and that's going out to you little SRB-hating-so-and-sos

Michael Bloxham · 2007-01-19 22:57:05

As for the SRB's, from a rocketeers perspective they are damn fine machines. However, with anything more than 2 of them the crawler transporter starts to sink into the ground. It may be seen that even the 5-segs are not powerful enough for 'The Stick', and they're hella-environmentally unfriendly.

I never really looked at gaetanomarano's arguments in detail. I'm just saying that our conclusion is the same: Developing the 5-seg SRB is not worth it.

Michael Bloxham · 2007-01-19 23:40:56

From Wikipedia articles:

The propellant mixture in each SRB motor consists of ammonium perchlorate (oxidizer, 69.6% by weight), aluminum (fuel, 16%), iron oxide (a catalyst, 0.4%), a polymer (such as PBAN or HTPB, a binder that holds the mixture together, also acting as secondary fuel, 12.04%), and an epoxy curing agent (1.96%).

---------------

Ammonium perchlorate is a chemical compound with the formula NH4ClO4. It is the salt of ammonia and perchloric acid. Like other perchlorates, it is a powerful oxidizer.

This salt generates toxic gas and extremely high temperature elevation following its decomposition.

Like all ammonium salts, it decomposes before fusion. Mild heating results in chlorine, nitrogen, oxygen and water, while strong heating may lead to explosions.

It is an important oxidizer used in solid rocket propellants, such as the Space Shuttle Solid Rocket Boosters, as well as many other solid rockets including some fireworks, amateur and hobby high powered rockets, and larger rockets used for space launch and military purposes.

The PEPCON disaster happened at an ammonium perchlorate manufacturing plant. The resulting explosions measured 3.5 on the Richter scale

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Aluminium is a neurotoxin that alters the function of the blood-brain barrier.[11] It is one of the few abundant elements that appears to have no beneficial function to living cells. A small percent of people are allergic to it — they experience contact dermatitis from any form of it: an itchy rash from using styptic or antiperspirant products, digestive disorders and inability to absorb nutrients from eating food cooked in aluminium pans, and vomiting and other symptoms of poisoning from ingesting such products as Rolaids, Amphojel, and Maalox (antacids). In other people, aluminium is not considered as toxic as heavy metals, but there is evidence of some toxicity if it is consumed in excessive amounts. The use of aluminium cookware, popular because of its corrosion resistance and good heat conduction, has not been shown to lead to aluminium toxicity in general. Excessive consumption of antacids containing aluminium compounds and excessive use of aluminium-containing antiperspirants are more likely causes of toxicity. In research published in the Journal of Applied Toxicology, Dr. Philippa D. Darby of the University of Reading has shown that aluminium salts increase estrogen-related gene expression in human breast cancer cells grown in the laboratory. These salts' estrogen-like effects have lead to their classification as a metalloestrogen.

It has been suggested that aluminium is a cause of Alzheimer's disease, as some brain plaques have been found to contain the metal. Research in this area has been inconclusive; aluminium accumulation may be a consequence of the Alzheimer's damage, not the cause. In any event, if there is any toxicity of aluminium it must be via a very specific mechanism, since total human exposure to the element in the form of naturally occurring clay in soil and dust is enormously large over a lifetime.[12],[13]

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PBAN - Polybutadiene Acrylonitrile copolymer. Also noted as Polybutadiene — Acrylic acid — Acrylonitrile terpolymer.

This was the binder formulation widely used on the 1960-70's big boosters (e.g., Titan III and Space Shuttle SRBs). It is also sometimes used by amateurs due to simplicity, very low cost, and lower toxicity than the more common HTPB. HTPB uses isocyanates for curing, which are generally toxic.

PBAN is normally cured with the addition of an epoxy resin, taking several days at elevated temperatures to cure.

---------------------------------

The reactivity of isocyanates makes them harmful to living tissue. They are toxic and are known to cause asthma in humans, both through inhalation exposure and dermal contact. Exposure to isocyanates and their vapors should be avoided.

Michael Bloxham · 2007-01-19 23:50:32

The propellant mixture in each SRB weighs 499,000 kg.

Therefore, each shuttle flight consumes about 696 tonnes of ammonium perchlorate, 160 tonnes of aluminum, 4 tonnes of iron oxide, 120 tonnes of binder, and 20 tonnes of epoxy curing agent.

However, this is the stuff thats sits benignly on the pad; I'm not sure exactly what it is that leaves the nozzle. We need to look at this further.

Michael Bloxham · 2007-01-20 00:01:00

"The chemistry of the solid rocket booster propellant can be summed up in this reaction:"

Michael Bloxham · 2007-01-20 00:04:47

This salt generates toxic gas

What exactly is this toxic gas that GCNRevenger seems to be aware of?

Michael Bloxham · 2007-01-20 00:21:32

Now let it be clear: I don't care much myself about the environmental effects of a shuttle launch. I don't recycle, I drive a gas-guzzling sports car, and well, generally I don't care much for the environment. However, that is not to say that the environmental effects of a shuttle launch won't play a negative part in the future. In other words, I'm afraid that the greenies will give NASA bad PR, whether they deserve it or not.

Whether you like greenies or not doesn't matter.

GCNRevenger · 2007-01-20 14:03:09

I am saying that you and you "co-conclusion" with that boob gaetano about the five-segment SRBs is nonsense: why are they not powerful enough? Because gaetano says they are not? Because "unnamed sources" say that they are not on news sites? NASA believes that they are powerful enough, plus consider the situation of Ares-V, that even with four of the monster boosters, it only increases payload by ~13%. Compare this to the Delta-IV Medium rockets, that with addition of extra boosters from the 52 model (two boosters) versus the 54 (four boosters) increases payload by ~30%. Thus, NASA's Ares-V has plenty of booster power.

As far as the pollution problem goes, its entirely overblown. Aluminum oxide is one of the most inert stuff in the inorganic chemical world, chlorine reacts with water to form nontoxic hydrochloric acid, aluminum chloride isn't especially toxic either. We let the freshmen here at the University handle the stuff even. The only chemical involved with the SRBs that is presently "scary" is unburned perchlorate, which is a favorite radical environmentalist "evil pollutant" that as previously mentioned is a red herring. Note that Perchlorate is used extensively in military weapons, which is probably why the left-leaning green nuts have painted it as a "but the chiiildren!!!" poison. Perchlorate is bad for you, but nowhere near the tiny, minuscule, hard-to-detect dose they claim it is. Isocyanates are almost completely combusted during firing, and likewise the small amounts remaining aren't an issue. Its hard enough to separate them from the polymer without destroying them.

Michael Bloxham · 2007-01-20 14:51:58

I haven't really done much research (as you can probably tell), but I'm learning fast. I think I briefly skimmed over some chat in the nasaspaceflight forums which mentioned that 'The Stick' won't be good enough to lift the Orion. That's the only source I remember. Frankly, I'm surprised at my current 'hit score' considering the next-to-nothing research I have actually done.

Nevertheless, at the very least, I hope to promote discussion and thought, just in case there is some room for improvement somewhere...

With that said, I'll continue: What is this toxic vapor related to the ammonium perchlorate that the wikipedia article mentions? I wasn't able to find any more info on it. Edit: Is it just unburned perchlorate?

BTW, while you may be a bit biased, I appreciate your vast and detailed knowledge. I guess we need realists like you to bring dreamers like me back to earth. However, dreamers have been right in the past. Perhaps the idea is to be able to seperate the potentially viable dreams from the pure fantasies...

gaetanomarano · 2007-01-20 23:36:28

...says they are not? Because "unnamed sources" say that they are not...

the only REAL test made in 2003 shows that a 5-seg.SRB has ONLY a +9% thrust vs. a 4-seg.SRB, then, SO FAR, I'm right
of course (someday) when (and IF) the SRB's upgrade twill give the (expected) +25% increase of thrust, you can say that I was wrong

...it only increases payload by ~13%...

SRBs are not so efficient like a LH2/LOX engine, but they are a cheap way to add "power"

.

GCNRevenger · 2007-01-21 15:37:01

You don't know anything gaetano,

The uprated "five segment test booster" you speak of was a four-segment booster with an additional segment.

The VSE "five segment booster" is not such a modification

The five segment booster will have a new nozzle, new propellant, and a new fuel grain shape all of which will change the performance characteristics.

You are wrong

gaetanomarano · 2007-01-21 22:36:24

...don't know anything...

I know everything I need

...The uprated "five segment test booster" you speak of was a four-segment booster with an additional segment...

probably you've found that info following the NASA link published in my Aug 12, 2006 SRB-article's update here: www.gaetanomarano.it/articles/011srb5.html

The five segment booster will have a new nozzle, new propellant, and a new fuel grain shape all of which will change the performance characteristics.

...and its REAL performances are unknown now (since, to-day, it doesn't exist)

.

Michael Bloxham · 2007-01-22 00:06:18

He is probably right based on his assumptions.

Criticize his assumptions, not his intelligence.

I'm probably in the same boat, btw.

gaetanomarano · 2007-01-22 00:22:15

He is probably right.

"he" GCNR or "he" me?

Michael Bloxham · 2007-01-22 00:37:57

Was directed to GCNR about you.

He (gaetanomarano) is...

GCNRevenger · 2007-01-22 19:11:18

You have actually looked at his website and such, right Michael?

Okay then say for a moment that he's not crazy etc etc:

Why did he say the five-segment booster isn't powerful enough and admits that we don't know the actual performance of said booster?

Back to reality where gaetano is nuts, he has made the same argument about other things over and and over and over again: that he is right about his statements (most often about NASA being wrong and he being right), but when challenged - this has happened again and again - "oh but we don't know I'm not right(!!!)" And then demands we assume he be right until we know with total certainty that he isn't as well as demanding we prove a negative.

He's not here to debate and discuss

gaetanomarano · 2007-01-22 19:57:47

Why did he say the five-segment booster isn't powerful enough and admits that we don't know the actual performance of said booster?

also a 10-years old student is able to say that, if a car has +22% of weight and (only) +9% of power vs. another car, the first car has LESS performances than the latter... only IF the 5-seg.SRB can add a +25% of extra-thrust may give the power to lift the (planned) Ares-I payload (but we don't know, now, if it can do that, or not) while (if it CAN'T) the newSRB will have (only) too much "extra dry mass" to lift ...don't forget that latest weeks' rumors about an "underpowered Ares-I", don't come from my (five months ago) article...

.

Michael Bloxham · 2007-01-22 20:31:35

No I haven't really looked at gaetanomarano's website (frankly it is a little hard to read). However, I think you both make the mistake of being overly-fanatic, albeit in opposite extemes.

You should know well what you don't know. And show clearly where you make assumptions.

GCNRevenger · 2007-01-23 20:28:24

Apparently gaetano doesn't understand the concept of irony: "its obvious that NASA is full of lies" with "oh but we don't know" in the very same breath. Its self-contradictory. Claiming that he's just parroting the Ares-I rumor mongers but "oh THEY said it" is just weaseling. Either the booster is not powerful enough (assertion) or else it is too dissimilar from any previous version such that comparisons are irrelevant ("we don't know"). One or the other.

Thrust thrust thrust all thrust... gaetano doesn't seem to understand much about rocketry either, that thrust influences but does not determine payload. A slower burning rocket conserves its fuel and can burn longer, especially nice for Ares-I since it probably has too much thrust actually (5G acceleration estimated vs 3G for Shuttle). And if the new fuel is more efficient, then less thrust can still provide the same payload or better. Furthermore, the five-segment booster adds more fuel but doesn't add much to the heavy metal end-caps or nozzle necks, making it more efficient pound-per-pound.

gaetanomarano · 2007-01-24 07:50:52

One or the other.

since the new SRB doesn't exit now, the "underpowered" rumors may come from recent ATK tests and/or Ares-I design calculations and/or computer simulations

...slower burning rocket conserves its fuel and can burn longer...

that is true for a liquid stage or for a longer-burn SRB, but, all NASA and ATK claim, specs and tests talk of ONLY five second more burning time on the new SRB (vs. the old) then, NO "burn longer" and the new SRB absolutely NEEDS the expected extra-thrust (to avoid penalization from the extra dry mass)
.

GCNRevenger · 2007-01-24 13:35:42

the "underpowered" rumors may come from recent ATK tests and/or Ares-I design calculations and/or computer simulations

Oh yes! ATK would go out of its way to spread rumors questioning the viability of their product! Makes perfect sense!

But you also ignore the change in propellant, which affects the characteristics. Also since a significant portion of the boosters' dry mass is the end cap and nozzle throat, which won't be much heavier, then it doesn't need as much thrust.

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