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View Full Version : NASA Study Summary: "SATURN V DERIVATIVES"(1968)


luke strawwalker
04-08-2011, 01:44 AM
Here's a brief study (more like a white paper) from 1968-- "Saturn V Derivatives". Much of what it discusses has been covered in other studies, such as the INT 20 and 21 vehicles, and the uprated Saturn V with 4 SRM boosters strapped on the first stage... BUT there is ONE concept that I've not seen anywhere else before... The "Saturn S-ID".

This concept vehicle would have taken a standard S-IC Saturn V first stage and totally reworked the thrust structure, to turn it into a 3 or 5 F-1 powered "MEGA-ATLAS" of sorts... The rocket would lift off under the power of all it's F-1 engines (3-5 depending on the payload) and fly normally until 70% of the propellants were gone. The outer 2 or 4 engines would shut down, their fuel valves would close, and then the outer skirt and thrust structure, with the fins and fairings, would jettison. The center engine, attached to a conical thrust structure at the base of the S-ID stage, would keep thrusting and push the entire S-ID stage with it's payload to LEO. The payload capacity would have been 50,000 lbs with the five engine variant. Basically, shuttle size payloads, with no shuttle-- only a single S-ID stage! The outer ring of booster engines could have theoretically been made recoverable (though no discussion was made of this in this study, but it mentioned a Boeing study that fleshed out the concept). The payload would have been even greater had the stage fuel tanks been enlarged.

Another "what if" that never happened but should have...

Here's the summary, and the pics to follow...

More to come! OL JR

luke strawwalker
04-08-2011, 01:46 AM
Ok... the first pic is the Saturn V derivative family... the first vehicle is the regular Saturn V, capable of orbiting 275,000 lbs. The second vehicle is the "A" vehicle (S-IC/S-IVB) capable of orbiting 132,000 lbs. The third vehicle is S-ID stage and a half to orbit concept, a modified S-IC with the new thrust structure, capable of orbiting 50,000 lbs (about 2/3 more than Saturn IB). The fourth vehicle is the "C" derivative, which takes the S-ID stage and a half and adds an S-IVB stage on top, capable of orbiting 180,000 lbs. The fifth vehicle is a beefed up S-IC or S-ID based vehicle with beefed up S-II and S-IVB stages and perhaps a propellant tank stretch, to handle 4 SRMs, in this case, 120 inch Titan III-C SRMs, capable of orbiting 400,000 lbs. The sixth vehicle is the same vehicle as the last one, but strengthened and fitted with 156 inch SRMs, capable of orbiting 500,000 lbs. The last pic is the same vehicle strengthened to handle 260 inch SRMs capable of launching 700,000 lbs. to orbit...

The second pic is the "A" vehicle... pop the center F-1 off the S-C, plug the lines, slap the S-IVB on top, presto there ya go. Instant 132,000 lbs to LEO or 32,000 lbs to the moon. "SEO" is geosynchronous orbit.

The third pic is the "B" vehicle, or S-ID. Basically rework the thrust structure by mounting the center engine on a cylinder attached to a new conical thrust structure on the back of the stage, to transfer the thrust to the vehicle skin. Rework the outboard engine thrust structure cross beams with a cylinder in the center large enough to clear the center engine, by removing the cruciform where the center engine USED to be mounted. Make the aft structure seperable from the fuel tank/new thrust structure joint where the outboard engines transfer their thrust to the vehicle structure, install seperation devices into the propellant lines so they can sever at staging and fall free, install gimbals on the center engine and rework the IU in a 33 foot ring to fit the top of the stage, and to handle the vehicle modes for proper control, and presto- instant 1.5 stage to orbit "mega-Atlas" capable of orbiting 50,000 pounds without an engine upgrade or tank stretch. Do the tank stretch and you up the payload. Uprate the F-1's and you REALLY up the payload!

The fourth pic is the "C" derivative-- put the S-IVB on top of your new S-ID stage, and presto-- 180,000 lbs to LEO, or 45,000 lbs to the moon.

The fifth pic is the "D" derivative, the actual "upgrade" beyond Saturn V. This is pretty much what was discussed in the other uprating studies in more detail. Strengthen everything quite a bit, stretch the propellant tanks, and slap on 4 SRMs of your favorite flavor-- off the shelf 120 inch Titan III-C boosters, 156 inch SRMs, or the 260 inch SRMs tested by Aerojet as possible first stage replacement for Saturn IB.

More to come... OL JR

luke strawwalker
04-08-2011, 01:48 AM
Ok... the first pic is a chart from the study... I know, doesn't have much to do with modeling the thing, but it does shed some insight into some of the conclusions and thinking... this one has a lot going on... The solid curved areas at the top of the chart are the performance envelopes of the various SRM equipped Saturn V's. Moving DOWN the chart, toward the curved line at the bottom of the 'wedges' created by the lower line, the lower line shows the maximum core propellant tank stretches beyond which no further increase in performance occurs. The left edge of the chart shows the maximum payload envelope size for the vehicle, which of course gets shorter as the fuel tanks get longer, with the 410 foot height limit being fixed. As you move from left to right, you can see the increase in payload capability to LEO, as shown at the bottom of the chart. The width of the 'wedge' for each vehicle shows the increase in payload capability starting on the left with a basic unchanged (but beefed up) Saturn V with the SRM's, to the full tank-stretched beefed up Saturn V with the same SRM's at the lower right, or "point" of the wedge. Each step to the right is going up to the next largest size SRM, from the 120 inch, to the 156 inch, to the 260 inch. The dotted line defines the same fields and values for the vehicles, if they ALSO incorporated the uprated liquid engines in the stages, the F-1A and J-2S.
As I said, a LOT going on in this chart, but you can also "pick-n-choose" your favorite variant and favorite options and see what the performance would be... quite interesting graph and a TON of information in it! Even shows how much you can stretch the tanks before you hit diminishing returns.

The second pic is the development cost picture for all the variants... if done piecemeal one at a time, versus a combined project doing all the work at once and qualifying all the vehicles at once, which was actually cheaper...

The third pic is an artist concept of the S-ID at staging. It reproduced with almost UNUSABLE quality, so I sent it over to Paint and reworked it into something actually viewable. Not perfect but 'good enough'...

Well, that's it for this one...

Later! OL JR

blackshire
04-08-2011, 03:14 AM
The S-1D embodied what I had wondered about ever since I first saw the original (five-engine) Atlas ICBM design proposal, in which the outer four engines were dropped and the center engine was the sustainer. It also reminded me of something I once asked my uncle Dan (who developed a gaseous hydrogen leak detector for the Saturn V's interstage areas while at Boeing): Could the S-IC by itself achieve SSTO (Single-Stage-To-Orbit) with a smaller payload? He answered that it very likely could, but that the payload would be small and the acceleration (going from the pad to low Earth orbit in just 2-1/2 minutes!) would be quite high.

luke strawwalker
04-08-2011, 11:24 AM
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... :rolleyes: (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 :)

gpoehlein
04-08-2011, 12:35 PM
This is some really cool stuff, JR - I've always loved the Saturn V (probably even more than I like the Shuttle) and this stuff just makes me want to model some of these - maybe in paper! Thanks for posting these!

Greg

blackshire
04-08-2011, 03:00 PM
The S-1D report inspired a couple of thoughts. Because an S-1D (or its equivalent if built today, by someone like SpaceX) stage would quite possibly use rare metals such as niobium (the Falcon vehicles' Kestrel and Vacuum Merlin engines' nozzles are made of niobium), it might be worthwhile to design such stages to be "salvageable" rather than reusable. As long as they would float after impact (which has been not uncommonly observed with expendable first stages after impact), any kind of vessel that is capable of towing a barge or another disabled vessel could tow the spent stages back to a collection site. The launch vehicle operator wouldn't even have to maintain two specialized ships like the SRB retrieval ships, but could simply contract with existing barge towing firms to retrieve the first stages.

A heavy, MCD (Minimum Cost Design) pressure-fed first stage of this type would be robust enough to be reusable, and it could also be recovered in this way. (McDonnell-Douglas' Phase B Double Prime Space Shuttle design had a beefy, seven-engine [975,000 lb thrust each] LOX/propane pressure-fed reusable first stage, on top of which the delta-winged orbiter with its [smaller] external tank would have been mounted [the orbiter's main engines would have ignited after staging]. That LOX/propane reusable booster would also have made possible a whole host of heavy-lift launch vehicles by substituting various upper stages for the orbiter/ET combination.)

I know that such operations (fishing "salvageable" or reusable boosters out of the sea) are not elegant or airline-like, but as the Shuttle has hopefully made clear to NASA, rockets and spacecraft are not airplanes and they should not be expected to operate as such.

Regarding down-mass, the biconic heat shield (that doubles as an ascent payload fairing) sounds like a very good idea. To placate the "Shuttle-huggers" (I like that term!) who pine for the down-mass capability of the orbiter's large payload bay, this capability could be retained (and even increased) if desired by developing a large re-entry cargo carrier that would look like an enlarged Atlas D or Titan I ICBM re-entry vehicle (a cylindrical body with a blunt conical nose and a flared conical aft stabilizing skirt). It could parachute into the ocean or, perhaps, touch down horizontally on land by means of a large parafoil. To simplify and lighten its structure (and to make it easier to waterproof the vehicle for ocean landings), it could have a rear loading/unloading hatch instead of longitudinal payload bay doors.

luke strawwalker
04-10-2011, 01:48 AM
Good points there...

I dunno about pressure fed designs... That's one of those paradigms that just has never caught on... kinda like "big dumb booster"... (hehe... always thought that was kind of a stupid sounding name... hard to get Congress to pony up when you ask them for funding to build something with the word "dumb" in it... LOL:) The problem with pressure-fed engines is the chamber pressure is SHARPLY limited by the need for the TANK PRESSURE TO BE HIGHER. Therefore, you're stuck with either LOW PRESSURE ENGINES (and chamber pressure and ISP are intrinsically related via fuel burn efficiency and exhaust velocity/temperature of combustion and all that) or you up the pressure to gain some more power and efficiency out of your engines, but RAPIDLY run into a wall of MASSIVE TANK STRENGTHENING, meaning your tank weight soon eats up all your payload, OR BOTH (massive tanks AND underpowered low-efficiency engines). There is a reason that pressure-fed engines have always pretty much been last in line except for when absolute simplicity and "it's GOT to work FIRST TIME, EVERY TIME, NO MATTER WHAT" type reliability is required (like SPS, LM descent/ascent stages, OAMS, etc.) where efficiency or power is at best a secondary concern. That's why pressure fed hasn't been developed for first stage propulsion that I can recall...

Not saying you can't "brute force it"... If you've ever read about "Sea Dragon" it's well worth a read-- there's a thread about it the HLV section at nasaspaceflight.com/forums... HUGE multi-million pound SINGLE PRESSURE FED RP-1/LOX engine on both stages, ~ a million pounds to orbit depending what version you're looking at... built out of ordinary steel and aluminum BY SHIPBUILDERS; basic pressure-hull type construction, not finely tuned highly refined aeronautically engineered structures-- cheap and dirty, with the operative word being CHEAP! That was Bob Truax's idea, anyway, too bad it was never given a shot (though I saw something awhile back, a video, of a rocket towed out to sea, stood vertical in the water by flooding a ballast tank under/behind the engines, and then launched from in the water... kinda like a floating SLBM... So why not?? Seems like the most realistic method to launch a large 10 m lbs plus rocket... simply because of the acoustics impact... NASA won't be launching anything over about 11 million lbs thrust from KSC simply because they could never afford to replace every window for 100 miles around after every launch... it's either build a "super heavy" floating launch complex farther out at sea or, go to the 'tow it out to sea, float it upright, fill the tanks, and launch" type paradigm...

At any rate, perhaps with better materials and technology pressure fed could be made to work-- FLOX or some other exotic propellant combinations, or perhaps thrust-augmented nozzles that essentially add 'afterburners' to a rocket engine and multiply the thrust, might be just the ticket around the 'low pressure engine' efficiency problem.

As to recovery of niobium nozzles or other things, SpaceX seems to be working toward that goal... working on first stage recovery (which will always be easiest due to the velocities and altitudes involved are so much lower) and even talking about possibly recovering second stages from near-orbital velicities and altitudes... (I'll believe it when I see it... :) ) Until then, tossing niobium nozzles on expendable upper stages doesn't seem to worry them too much (or hacksawing off the bottom of the nozzle if it cracks! LOL:) )

It'd be interesting to see a modern S-ID version by SpaceX... SpaceX is really in a great position, by developing a highly efficient fairly inexpensive kerosene liquid engine based on pintle injection... I'd LOVE to see a 1.5-2 million pound class Merlin 2 engine on a Saturn-ID stage setup... Heck for that matter I'd love to see the numbers on such a setup powered by RD-180's... The RD-180's and the Merlin 2 would UNDOUBTEDLY put the F-1 to shame... I freely admit to having been an unrepentant "F-1 hugger" for a long time... UNTIL I really started reading up and found out that the F-1 is VERY outdated, and it's performance and design has been eclipsed in nearly every area except perhaps in pure raw maximum thrust (at least for the 1.8 m lb F-1A-- RD-180 can already almost match F-1 for thrust). RD-180 is a MUCH more efficient engine ISP-wise than F-1, which would make a S-ID THAT MUCH MORE CAPABLE than the design was with F-1! Presuming Merlin 2 would have the same ballpark efficiency (or higher) than RD-180, and have more thrust (it's supposed to AT LEAST be a match for F-1A, at 1.8 m lbs thrust) that would make a S-ID a virtual SLAM DUNK! If the thing could lift off under the power of the outer four engines GROUNDLIT and the center engine AIRLIT, with a more vacuum-optimized nozzle, performance would increase substantially... but note that S-ID's performance even with ALL REGULAR GROUNDLIT SEA-LEVEL EXANSION RATIO F-1's (which robs performance at altitude) was still NOTHING TO SNEEZE AT!

Combine ET tank super-lightweight construction mass fractions in the core sustainer stage, with high-thrust kerolox booster engines in a jettison thrust structure with high thrust- high efficiency kerolox boosters and you'd have a world beater IMHO... nothing could touch it! Try the idea out with Merlin 1D's as a subscale test vehicle...

That I'd love to see...

We're going to HAVE to figure out biconic heat shields sooner or later anyway, if we ever plan to actually land folks on Mars... the masses and sizes are simply too huge for regular solid spherical section heat shields to ever work or be feasible to launch from Earth's surface-- unless you make them folding or ballutes or something esoteric like that... A biconic can be launched as the nosecone/payload fairing of the vehicle. They basically glide (but at a very low lift-drag and very low cross-range-- maybe 'controlled fall' is a more correct term... If large downmass is a 'requirement' at some point, teaming up to prove biconic research at the same time just makes good sense...
OL JR :)

blackshire
04-10-2011, 08:35 AM
The French Diamant A, Diamant B, and Diamant BP.4 satellite launch vehicles (see: http://www.astronautix.com/lvs/diamant.htm ) all had pressure-fed liquid propellant first stages (with solid propellant upper stages). Tank pressurization was achieved by means of a chemical gas generator. The Diamant A's first stage burned nitric acid and turpentine, while the uprated first stages of the Diamant B and Diamant BP.4 used N2O4 and UDMH.

Like the *much* larger Truax Sea Dragon (I was hoping you'd mention that one, as it's one of my favorite MCD proposals), a Diamant-type vehicle could also be launched directly from a sea or lake. The U.S. Navy pioneered the concept with the Sea Bee (see: http://www.astronautix.com/lvs/seabee.htm ), a modified Aerobee liquid propellant sounding rocket that was launched from the ocean, recovered, refurbished, and re-launched successfully. According to the article, "This proved to be so simple that the cost of turn-around was found to be about 7% of the cost of a new unit."

Admiral Robert Truax designed several sea-launched, all-pressure-fed MCD satellite launch vehicles of various sizes and payload capabilities (see: http://www.astronautix.com/fam/seanched.htm ). Some were expendable while others were reusable. Their robust structures (more like submarine hulls than rockets) readily lent themselves to being reusable--like a football, their already-strong tankage would be made even stronger by the internal gas pressure from their residual propellants.

SpaceX's Falcon 9 second stages could be recovered from orbit using inflatable heat shields (see: http://www.nasa.gov/topics/aeronautics/features/irve.html ). The NASA IRVE inflatable heat shield has only been tested in a suborbital flight thus far, but it could be used for returning Earth-orbiting satellites as well as for lowering Mars landers and rovers to the planet's surface.

In February 2000, Russia orbited a test satellite using the then-new Soyuz U-Fregat launch vehicle; both the satellite and the Fregat upper stage were fitted with inflatable heat shields (see: http://www.esa.int/esapub/bulletin/bullet103/marraffa103.pdf and http://www.spaceflight.esa.int/irdt/factsheet.pdf ). The IRDT test satellite was found intact (although its heat shield tore and partially deflated during descent) but the larger Fregat stage was never located--it was believed to have been stolen by locals for scrap metal! Also, the Russian Mars-96 lander (lost in the launch failure) had been equipped with an inflatable heat shield for entering Mars' atmosphere.

The S-1D definitely sounds like a design type that should be pursued. There is no need to try to "re-invent the Saturn V" (or this modification of it, in this case) down to the original alloys and fasteners; rather, new vehicles of similar configuration (such as those you described) using current or soon-to-be-developed LOX/kerosene rocket engines and Shuttle ET tankage would provide reliable heavy-lift capability without trying to re-purpose the Shuttle's expensive SSMEs and SRBs.

luke strawwalker
04-10-2011, 03:34 PM
I KNEW I'd seen something similar to S-ID in recent memory, but it took a bit of "looking thru the files" to find it and jog my memory!

Here's some pics of some interesting proposals... too bad they never seem to gain much traction...

The first is a recent proposal from someone on nasaspaceflight.com/forums about using the shuttle ET and SSME's to build the modern-day equivalent of an S-ID/uber-Atlas. The problem is, the performance isn't that great. You've got to upsize the ET considerably to feed 6 SSME's even though 4 are dropped along the way in a (presumably) reusable thrust structure. The other 2 continue on with the core to near-orbital velocities to drop the payload for self-insertion into orbit. The other problem is, the SSME is just too low a thrust engine for this application-- you really need a million-pound PLUS thrust engine to make this work-- and SSME is only like 400,000 lbs thrust or so. The RS-68 has higher thrust (758,000 lbs, about half F-1) but it's ISP is much lower than SSME, and therefore requires even BIGGER tankage to feed the thirsty beasts! Besides, as I've said before, the low density of hydrogen REALLY kills you in this type application-- for a vehicle like this to work, you really need denser fuels like kerosene, even though the ISP of kerosene engines isn't that great and so it takes more kerosene to get the job done, the desity difference actually helps you by keeping your tank sizes smaller (and improving mass fractions). IF S-ID could work with fairly low-ISP engines like F-1, then it would work that much better with RD-180's or a substantially equivalent Merlin 2, or properly downsized vehicle using Merlin 1D's. RS-84 is another terrific possibility for such a vehicle-- and they were DESIGNED to be reused! Put reusable RS-84 in the recoverable booster pod and either a "throwaway" RS-84 or RD-170 in the center sustainer position, and there ya go-- modern S-ID with reusable engines for the booster section, and no need for heavy, expensive SRBs.

One of the big reasons that NO shuttle replacement NASA is likely to support is going to be affordable is because of the necessity of paying for both SRB's AND relatively-low thrust core engines... then of course upper stage engines are required as well if you want to do anything BEO, unless you use large-ish clusters of RL-10 series engines, or develop RL-60... If you can ditch the costs of SRB's, and get set up to use a 1 million pound plus first stage engine, either kerosene or hydrogen (but of course kerosene would be better in this application) they'd be in a LOT better shape. The 1.5 stage solution really lends itself to reusability of the booster engines, while negating the need for reusability for the core, while still leaving the door open to possibly using inflatable heat shields or other such recovery techniques to reuse the core or it's components at some later date... Plus, if you can design the upper stage so that it basically only has to insert itself into a parking orbit, without a lengthy burn like S-IVB did (burning half it's fuel along the way to parking orbit) you effectively double the mass fraction of the upper stage and greatly increase the payload capability through TLI, while still having the option to put big payloads into LEO with just the core, or, if the first stage thrust is sufficient to lift even larger payloads with a fully-fuelled second stage, use the second stage as an ascent stage to insert very large payloads into LEO.

That would really be the way to go to get costs down. With SpaceX vowing to do cross-feed capability on their Falcon 9 Heavy, that puts them in a good position to develop a 1.5 stage vehicle-- since highly reliable disconnects are required for propellant cross-feed of strap-on boosters that are jettisoned in flight, much like the booster section of Atlas or any other 1.5 stage...

The second, third, fourth, and fifth pics are the same idea as in the first pic, but dating back to the NLS studies done after the Challenger accident when there was considerable doubt whether shuttle would continue or be phased out... The NLS program was an effort to see what could be developed using the shuttle components to construct a new family of vehicles capable of performing manned missions. When it became apparent shuttle WOULD continue, NLS morphed into an effort to supplement shuttle capabilities with higher-payload partially-expendable vehicles built from shuttle components to share costs, and finally to an effort to show itself capable of performing national security missions for DOD, probably in an effort to get the Air Force and DOD to cost-share in the development and use to justify it. DOD distanced themselves from anything shuttle or shuttle derived after the Challenger-induced national security payload launch crisis and elected to go with Titan IV as a national security launcher and then replace it (since it was as expensive as shuttle) with EELV's in an effort to cut costs. (That's one reason why DOD wants NASA to "keep it's hands off" the EELV's NOW-- they put a lot of money into developing them and don't want NASA "messing around with them" and changing things for manrating them, which usually means system changes and complications that increases costs and failure risks for unmanned national security launches...)

Later! OL JR :)

blackshire
04-11-2011, 12:48 AM
Although it was never built, Philip Bono at Douglas Aircraft (he was an early SSTO advocate) designed a vehicle called ROOST (Reusable One-stage Orbital Space Truck, see: http://www.astronautix.com/lvs/roost.htm and http://www.astronautix.com/lvs/roostisi.htm ) that was planned to have a 1,000,000+ pound payload capability to orbit. The LOX/LH2 powered vehicle would have been recovered using an inflatable heat shield (not shown in these articles, but illustrated in this July 1963 "Popular Science" article, "How to Bring a Booster Back Alive," see: http://books.google.com/books?id=pSADAAAAMBAJ&pg=PA80&lpg=PA80&dq=ROOST+Reusable+One-stage+Orbital+Space+Truck&source=bl&ots=IuamvJTTo7&sig=ELD3dSE2OElahznrOj2ESH0_Nbs&hl=en&ei=ipOiTd_YAaHhiAK_x63uAg&sa=X&oi=book_result&ct=result&resnum=10&ved=0CFEQ6AEwCQ ) that would have been inflated with the residual gaseous hydrogen from the ROOST vehicle's LH2 tank. Being buoyant after re-entry with hot (400 degrees) hydrogen gas inside its inflatable heat shield, the craft would have slowly drifted down to the ocean as the hydrogen cooled.

The S-ID core could use this method for recovery and reuse (using gaseous oxygen). One version of ROOST was "non-buoyant," which (presumably) used gaseous oxygen instead of gaseous hydrogen to inflate its heat shield.

The NLS never impressed me for the reason you mentioned--the SSME just isn't powerful enough.

luke strawwalker
04-11-2011, 10:07 AM
Don't forget SASSTO... :) S-IVB with a plug nozzle capable of flying up to orbit and back down from orbit...

Shades of Blofeld's capsule stealing rocket in "You Only Live Twice"... :chuckle:

Later! OL JR :)

blackshire
04-12-2011, 06:06 AM
Don't forget SASSTO... :) S-IVB with a plug nozzle capable of flying up to orbit and back down from orbit...

Shades of Blofeld's capsule stealing rocket in "You Only Live Twice"... :chuckle:

Later! OL JR :)Indeed--and that was just the "baby" of Philip Bono's SSTO design family--his later Hyperion, Ithacus, ROMBUS, and Pegasus VTOVL (Vertical Take-Off, Vertical Landing) SSTO vehicles (see: http://www.astronautix.com/fam/ssto.htm ) were very large. I think an SSTO launch vehicle is doable (even the Titan II's first stage can do SSTO, albeit with very little payload), and an expendable SSTO launch vehicle could be the first step (psychologically [to prove that it *can* be done] as well as in terms of engineering and operational experience) toward developing a reusable SSTO spaceship. Even before then, a reusable 'SSTO-type' VTOVL sounding rocket ("Single-Stage-To-Altitude," in this case) like Masten Space Systems' XA-1.0 (see: http://www.google.com/#sclient=psy&hl=en&site=&source=hp&q=Masten+XA-1.0&btnG=Google+Search&aq=f&aqi=&aql=&oq=Masten+XA-1.0&bav=on.2,or.r_gc.r_pw.&fp=e7df6ea8d325b7b2 ) would help build operational experience and confidence for developing a reusable SSTO spaceship.

blackshire
04-12-2011, 06:32 AM
Also, the SASSTO article on astronautix.com (see: http://www.astronautix.com/lvs/sassto.htm ) has text and diagrams on a SASSTO variant intended as an improved Saturn IB and Saturn V upper stage! This paragraph says:

"Since SASSTO was loosely based on the Saturn S-IV-B rocket stage, Douglas also proposed an expendable version for use as a more capable upper stage with the Saturn IB and Saturn V launch vehicles. The expendable SASSTO stage would have had a burnout mass of 7,400kg and carried 85,729kg of oxygen+hydrogen propellant. The stage was thus of a much more lightweight construction than the standard S-IV-B (12,949kg + 104,326kg LOX,LH2) and the new aerospike engine would have been more efficient as well (464s specific impulse vs. 426s for the J-2 engine). Consequently, the Saturn V's payload capability would have been boosted by 8-11t as well. The Saturn IB's basic 15876-kilogram payload capability to a 185km orbit would have increased to 23814-25855kg depending on whether SASSTO would be flown in expendable or reusable mode. The latter version was known as SARRA (Saturn Application Retrieval and Rescue Apparatus) and was intended for returning stranded Apollo crews from the lunar surface."

For a SASSTO (or ROMBUS, Ithacus, or Pegasus) flying scale model using a working plug nozzle rocket engine, numerous Quest MicroMaxx motors could be used to thrust against the plug nozzle...