...STS is a good example of how reducing flight rate doesn't reduce cost. Heavy lift will have a humongous cost and if you reduce its flight rate by flying propellant with other vehicles, it doesn't help much at all (could make it worse).
First, it often involves financial arguments that are rational and based upon arguments that would apply to a business; but government does not play by those rules and congress is rarely rational.
For example, businesses will pay more attention to the trade-offs between up-front R&D costs and operating costs (because money not spent this year on R&D is available next year for operations) but the federal government treats every year as a unique budget with agencies unable to roll savings from one year forward into the next.
Government agencies that fail to spend all their money in a given year are often punished in following years for having proven that they did not need the extra money.
This means that it is often in the interest of DoD, NASA, and other agencies to divorce up-front costs from operating costs (oh, they'll power-point arguments to the contrary up-front, but when the chickens come home to roost later somebody else is in charge of the agency and different people are in congress writing the checks. Ultimately, the cost arguments are only ever used as political ammunition by supporters/opponents of a program as they argue for/against the program... rather than being used to actually shape plans and policies (in other words, it's ammo for arguments over the existence of the program, not actually a sincere argument about how to best implement)).
I find the argument over heavy lift to be amusing on more than one level. First, it often involves financial arguments that are rational and based upon arguments that would apply to a business; but government does not play by those rules and congress is rarely rational.(SNIP)
Your 'model' only works for projects that involve a dedicated uplift to an agency budget. I have never encountered it - we pay a lot of attention to cost, at least in my bit of the UK. You are completely wrong, at least in most contexts, about 'Ultimately, the costs are only ever used as political ammunition by supporters/opponents...'. Every working day someone is agonising about future decisions based on cost, balancing today's needs against future capability, which, in MOD terms means lives today vs. lives tomorrow.In summary, your points are only partly true at best and inapplicable to Constellation planning which is based on a fixed NASA budget.Rick
I'm fully aware of how it actually works. What I am saying is that over a ten-year development program like Ares-V, costing about $15bn (on top of Ares-I) in full-wrap terms, you will - on average - spend about $1.5bn of every year's Budget (almost 10%) on that development program alone (and yes, I know that in practice the actual value actually grows from a smaller value than that to a peak much higher than that, but mean average will do for this discussion).An average $1.5bn expenditure every year can be far better used than for building the second LV - Ares-V - *IF* you make the decision at the start to build an efficient HLLV system in the first place instead of the EELV-class Ares-I.HLLV, does not by definition limit you to only the "wastrel" Ares-V system either.
I presume until proven otherwise that you guys with Direct are not just looking for a short-term win, but want sustainability too.
Here is an article questioning EELV useThe Cost of Medium lifthttp://www.thespacereview.com/article/150/1
How much would it cost to fly the Apollo spacecraft to the moon using the Delta 4 Heavy booster?...it cannot launch the entire Apollo spacecraft in one lift and lacks an injection stage that can send the craft on a trans-lunar trajectory. It would therefore be necessary to use three to five launches
to configure the spacecraft and refuel the booster resulting in a cost of at least $510-680 million
(I have assumed the same launch costs for the Space Shuttle, Shuttle C, and Ares.)Booster 2004 Cost ($ millions) Payload to LEO (kg)Ares (Conceptual) 284 121,200Atlas 5 551 125.1 20,050Delta 4 Heavy 193.4 25,800Saturn 1B 706.9 18,600Saturn 5 2847.6 118,000Shuttle C 284 77,000Space Shuttle 284 24,400Titan 4B 491.6 21,680
Quote from: publiusr on 06/23/2008 08:04 pmHere is an article questioning EELV useThe Cost of Medium lifthttp://www.thespacereview.com/article/150/1QuoteHow much would it cost to fly the Apollo spacecraft to the moon using the Delta 4 Heavy booster?...it cannot launch the entire Apollo spacecraft in one lift and lacks an injection stage that can send the craft on a trans-lunar trajectory. It would therefore be necessary to use three to five launchesSo three or five?Quoteto configure the spacecraft and refuel the booster resulting in a cost of at least $510-680 million510/3 = 170, 680/5 = 136. Huh?? I don't understand this math of magically floating cost of one Delta IV Heavy.Quote(I have assumed the same launch costs for the Space Shuttle, Shuttle C, and Ares.)Booster 2004 Cost ($ millions) Payload to LEO (kg)Ares (Conceptual) 284 121,200Atlas 5 551 125.1 20,050Delta 4 Heavy 193.4 25,800Saturn 1B 706.9 18,600Saturn 5 2847.6 118,000Shuttle C 284 77,000Space Shuttle 284 24,400Titan 4B 491.6 21,680Ha. Ha ha ha. Shuttle flyaway cost of $284 mln. Is it Sci-Fi?
I wrote this article in response to was advocating EELVs as the solution and I was merely trying to show that EELVs are perhaps not as cost effective as the previous story indicated. Niether article was trying to detail a comprehensive architecture for a lunar program.
Not with simple engine count.Last I heard, six RS-68s per 140 tons atop Ares V still costs less than 21 thrown away on seven flights for D-IV 'heavy.'According to Cooke, the upgrade to Ares V amounts to an extra engine, a cross-beam being moved, and an extra half segment for the SRB. No big deal. No laws of physics being broken.All less daunting than trying to get VentureStar or DC-X to work full scale.
The 90% curve is pretty consistent throughout the industry. Most major elements in the space business which are built on a year-to-year basis seems to fall within a few percent of it, so it's not a bad guideline for any first-order estimates like this.Ross.