On Tue, 02 Jul 2002 01:05:55 +0100, Ian Woollard <[EMAIL PROTECTED]> wrote:
>Pretty much... Kursk... then again Challenger- cryogens didn't exactly >help keep the pad warm. Kursk and Challenger are both great examples of the wrong way to do rocketry. Kursk because it was an ill-maintained, poorly operated weapons system (I give the Russian Navy enormous credit for having Kursk at sea in the first place - though how wise that was is questionable, especially in retrospect - when you can barely feed your troops, and you can't pay them at all, deploying several attack subs is quite a feat); and Challenger because they looked at safety exactly backwards. >>The downside is its cost. Paying several dollars per pound for >>peroxide is not an unusual experience. LOX costs about 1% of that, so >>any large biprop operation cries out economically for LOX >> >I think one could argue that isn't correct. If peroxide enables any >reduction in rocket costs >then you're probably looking at a net win for the forseeable future. That depends strongly on your organizational model. If your labor costs are zero, as ours are (that cost model you referred to doesn't go far enough: it has volunteers at $10.00/hr, dedicated volunteers at $2.00/hr, and fanatics at $0.50/hr. Since we pay perfectly good money to build rockets, what are we? True Believers? Blithering Idiots? Both?) and we also eat our operations costs (gas money, motel rooms, food & water), the only things we have to pay for - and account for - are commercially sourced parts, raw materials, outsourced work, and consumables. When we get into biprops, much of the simplicity peroxide affords us will go away. So the parts, materials, and outsourced work will cost about the same. Plus, with a large operation, your consumables start to become a significant part of your budget. >main downside of peroxide >that I can see is the payload- HTP and hydrocarbon only give about 2/3 >the payload to LOX and >hydrocarbon [according to Bruce Dunns pages, although I have some minor >issues with his >methodology; I understand he gave a presentation in 1996 at Space Access >with this material.] http://www.dunnspace.com/alternate_ssto_propellants.htm is derived from his SA '96 talk. He gives HTP/RP-1 payload capacity as about half that of LOX/RP-1. But he also assumes 2900 psi chamber pressure and 100:1 expansion, even at sea level. I don't think either of those is realistic. >A cost of a dollar per kg is nearer the bottom price. Enormous amounts >of 70% peroxide are used commercially. Yeah, but it's full of gunk. Stannates, phosphates, organics, who knows what else. Much of it is ruinously hard on catalyst. >I think the best you can hope for is that the 98% >approaches the 98/70 of the cost of 70% plus processing, plus profit. If we can get semiconductor grade at 70% at reasonable prices, then all we have to do is concentrate it to between 85% and 98%, depending on application, which should be easy and fairly inexpensive. If the semi- grade is only available at 30%, it may be more cost effective to buy gunk peroxide and purify it. >At that kind >of prices you are talking about maybe $50 per payload kg in fuel. Even a few >times that is probably still going to be ok. That assumes a payload mass fraction of 2%, which I think is pretty ambitious. But that's $110/lb - that's within spitting distance of the Harris Threshold. (Sydney Harris is the cartoonist who drew the "Step 2 - a miracle occurs" cartoon. At $100/lb, miracles will occur.) I also think that a group able to reliably launch small payloads into orbit for $1000/lb will not hurt for business. "Hm, should I buy a new SUV, or a buy a beat up Blazer and launch my own satellite?" -R -- "Sutton is the beginning of wisdom - but only the beginning." -- Jeff Greason _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
