The encyclopedia astronautica page on the S-ID has some interesting information... there's on sentence that sorta makes the point better than anything else... "At very minimal cost (36 months leadtime and $ 150 million) the United States could have attained a payload capability and level of reusability similar to that of the space shuttle."
Now you figure the costs on THAT compared to the costs and nearly a decade of shuttle development from "go" to first flight, with only 4 missions flown during that time with leftover Apollo hardware, and it's easy to see how much further along we'd be now. Looking at it from the cost of operations standpoint, the costs for S-ID would have been a HUGE savings over shuttle-- Basically it's a 33 foot ET (yeah, WAY worse mass fraction, but that could have been improved over time, just as the ET's was with the LWT and SLWT programs) with 5 F-1's (which were kinda expensive, but that too could have been rectified with an "F-1S" type program to make them cheaper while incorporating the F-1A 1.8 m lb smaller turbine upgrade without breaking the bank) and even tossing the outer 4 might have been cheaper in the long run, as shuttle refurb costs and SSME refurb costs have proven that reusability is practically a wash cost-wise with a cost-efficient throwaway design, perhaps more expensive than a cheap throw-away engine. Sure you'd have had the extra costs of an Apollo or "Apollo II" spacecraft on every MANNED flight, but then again, you could have launched the thing unmanned on quite a few missions and foregone that expense and the danger to do menial stuff like Challenger was doing, which ultimately led to the "light coming on" to the folly of using a MANNED vehicle to perform simple satellite launches better done by UNMANNED vehicles (which incidentally also improved the schedule for satellite launches since the constraints are much lower for unmanned rockets than a manned vehicle, and the satellite design didn't have to be altered for the manned vehicle like it did with shuttle. Then there's the SRB costs, which have proven to be VERY expensive (as the Columbia stand-down proved-- IIRC over a half-billion a year just to keep the lights on and the infrastructure in place whether you're actually making and flying anything or not!) Just saving that added element of the program would have freed up a lot of cash to do interesting stuff. Then there's the 'downmass' issue, which many 'shuttle huggers' decry as the biggest loss to US spaceflight capabilities since we quit going to the moon... Ok, perhaps; S-ID would have been a disposable core vehicle (likely completely expendable as it's questionable whether recovering the outboard F-1's would have been worth the effort and cost) and would have carried a capsule of some sort in manned mode, either further production of Apollo, or a redesigned follow on "Apollo II" of some sort (which could have been made reusable had the desire been there (like the early CEV/Orion proposals were to be). Heck a manned spaceplane wasn't out of the question, either, as something Dyna-Soar like could have been built, or the HL-20 or something like it, or for that matter something akin to the shuttle, or even the early shuttle proposals like Faget's short wing "fluffy" shuttle (which was quite similar to the X-37B if you really look at it) if you figure mankind would have really missed something had it not had runway landings for our spacecraft for the last 30 years...
(no matter how much it's set back exploration). Had a successor to Apollo been designed with affordability in mind, or perhaps reuse if a sharp pencil could show it was ACTUALLY going to be a good investment, program costs could have been cut quite a bit. If the same 'cost cutting/production streamlining" type program been applied to the S-ID and S-IVB, costs could have been cut there too. Downmass could have been addressed, had it been needed, by either building a dedicated 'payload return module' based on the Apollo/II capsule, or having an 'experimental' program to create a winged spaceplane for cargo return or even develop large heat shields in the 10 meter range for payload return (which would have been VERY handy for a Mars mission whenever it was undertaken!) or even a biconic heat shield that could double as a payload fairing (nose cone) on the S-ID itself... another technology that would have been VERY handy to have at Mars, even for unmanned missions, which is something NASA's talked about and produced lots of pretty pictures of but never done...
With S-ID we could have launched roughly the equivalent of TWO ISS modules at once, or one larger module, so building up a sizeable space station in short order wouldn't have been too difficult. Those modules COULD have been 33 feet in diameter if desired, as a study I need to summarize soon will show. Even sticking to a smaller diameter, perhaps, like Skylab (which was 3.5 times too heavy for S-ID to be launched all at once), based on 260 inch diameter, or even going 'clean sheet' as with ISS, any kind of station we wanted was possible. Keeping the S-IVB, or even the S-II around, would have really opened the doors to a lot of possibilities.
It's really a shame... the wasted possibilities... even had there been a long 'lean time' in the 70's when the budget wouldn't support a lot of missions or deep-space exploration, just keeping the technology alive, improving it, and sustaining it for better days would have been an EXCELLENT investment. Now we find ourselves having come full circle... 30 years after the space shuttle, we're trying to re-create Apollo/Saturn, only cheaper and better, but doing it with shuttle components that have proven themselves to be very costly... (in a few years after the last shuttles flown the program is wound down and 'in the can' to use a filmmaking term, the ultimate costs of the shuttle program will be known (as much as they can ever be- on a program this huge, there are SO many different accounting methods and how the money was allocated to intrinsically linked programs like ISS that 'share expenses' we will NEVER know the EXACT cost of the shuttle program) but by what's known already, shuttle costs, from the metric of TOTAL PROGRAM COSTS from day one to today, divided out over the number of shuttle flights, puts the cost per shuttle flight at around a BILLION DOLLARS... MUCH more expensive than Apollo/Saturn! Heck, Saturn V would have been quite a bargain at that price, even considering it's "expensive" nature (that could have been corrected through a cost-cutting/manufacturing streamlining/improvement program). So I don't buy the 'We could never have afforded it" paradigm... SSME development alone cost more than S-ID would have...
True, F-1 is outdated NOW, but it's needed-- a 1.5-2 m lb thrust kerosene first stage engine would solve a LOT of problems! (which is why I hope SpaceX can build their Merlin 2). We COULD have replaced F-1/F-1A with a large pintle-injected regenerative-cooled ~2 m lb class rocket engine (Merlin 2) in the 80's and had we applied it to a cost-streamlined S-ID we could have cut costs to a FRACTION of shuttle costs, reusable or not! Part of shuttle's huge costs is the SRB line-- basically 2 kinds of rocket engines (SSME and SRB) and the infrastructure to make and support both. The new program is talking about THREE systems-- 5-seg SRB's, SSME (or other large first stage engine), and J-2X-- that alone should prove it's going to be A LOT more expensive than shuttle. S-ID would have had F-1 (or successor) and J-2 (or successor), and J-2 COULD have been mothballed in the short term during the lean times of the 70's if necessary (without the huge costs of shuttle development I think it could have been kept alive-- it's cheaper to keep mfg. what you already are tooled up to make and have the blueprints for than to design, test, completely retool, and build something entirely new). Just really sad...
Later! OL JR
