NASA Study Summary: "Design Studies of Very Large Solid Rockets(1961)"

[luke strawwalker]

Howdy, howdy...

Here's another jewel from April 9, 1961 (three days before Yuri Gagarin "threw down the glove" to the US in manned spaceflight). The study is entitled "Summary of Final Report on Studies of Very Large Solid Fuel Rockets" by Grand Central Rocket Company, Redlands, CA. (never heard of them... ) It's a summary itself of a series of studies done by GCR for NASA relating to the possibility of clustering large SRMs for exploration class rockets. Two vehicles are proposed- a "one million pound" class vehicle with about the same performance as a Saturn C-2, with 3 120 inch (outside dia.) SRM's for the first stage, with an "S-II" (not the Saturn V S-II that was 396 inches in diameter and powered by 5 J-2 engines of 200,000 lbs thrust each, with 930,000 lbs of propellants, but the "original" S-II stage in the early Saturn Vehicle studies-- 260 inches in diameter, powered by 4 J-2 engines) second stage, and an "S-IV" third stage, similar to the S-IV used on the Saturn I Block II, but with 2 RL-10's instead of 6.

The second proposed vehicle was the "ten million pound class" vehicle designed to deliver about the same payload to lunar orbit as a Saturn V, well, as proposals at the time though, which was a payload of 130,000 lbs. This vehicle proposal used NO LESS THAN SIXTEEN! 120 inch SRMs clustered in the first stage, with a cluster of four SRMs in the second stage, with a 2X early "S-II" third stage, with a roughly equivalent to the S-IVB fourth stage! It also has a brief section discussing stacking and launch of the vehicles. The one million pound class rocket would launch from slightly modified Saturn pads (Complex 34) and the ten million pound class would need it's own new launch complex (what later became Complex 39).

It's an interesting read and would make NEAT looking models for sport flying or future/fantasy scale, or to go along with a Saturn V, just for history's sake-- nobody at the launch field would have any idea what it was!

Enjoy the study-- pics to come... OL JR

[luke strawwalker]

OK... first pic is the three motor "one million pound class" rocket, Vehicle No. 1 as it's called in the study. Has 3 120 inch (external dia-116 inside dia) SRMs clustered for the first stage, and an early Saturn study "S-II" stage (260 inch diameter like the S-IVB, but powered by four J-2 engines, and of course long enough to hold enough fuel for all of them) and used an S-IV stage (221 inch diameter, 6 RL-10 engines) for the third stage. It would have orbited a payload of 60,000 lbs to a 300 n.mi. LEO (figures would have been higher for the "standard" 100 n. mi. "parking orbit")

Second pic is the "head end" of the motors where they're joined together with the interstage ring to connect to the upper stages.

Third pic is the business end, er, nozzle end of the stage-- note the six support points for the 'hold down posts' from the launch pad...

Fourth pic is the sideview of the upper half of the first stage, from the interstage down the SRM casings.

Fifth pic is the sideview from the lower half of the first stage, down the casings toward the end of the nozzles (the last part of the nozzles is in pic three above on the left side).

More to come! OL JR

[luke strawwalker]

The first pic is the "ten million pound class" Vehicle No. 2 as it's known in the study. The first stage is a SIXTEEN! motor cluster of 120 inch, five-segment motors (the one m. lb. Vehicle. No. 1 uses three segment motors) arranged in a center engine with five nested around it pentagonally, with ten clustered around those five in an outer ring, for a total of 16. The second stage is FOUR of the 120 inch, 5-segment SRMs identical to the first stage (except with vacuum nozzles) clustered together, the third stage is a 6 J-2 powered upscaled version of the S-II stage, probably similar in size to the Saturn V S-II stage, and the fourth stage is an S-II stage similar to the second stage of the Vehicle No. 1 second stage, but powered by a pair of J-2's instead of four. This vehicle would have been able of delivering 130,000 lbs to lunar trajectory.

Two different arrangements were investigates for the 16 motor cluster arrangement in the first stage. Arrangement "A" was a 4 x 4 x 8 (four center, surrounded by 4 more, with 8 on the outer ring) but it was found to be heavier because of the larger truss structure and more 'dead space' between boosters. Arrangement "B" was selected, it's a 1 x 5 x 10 (one center, five surrounding it, ten on the outer ring) because there is less dead space between motors and thus the truss structure is smaller and lighter (spider beams).

The third pic is partial view of the head end of the sixteen motor cluster...

The fourth pic is the other half of the third pic, showing the other half of the head end of the sixteen motor cluster, along with the top of the sideview of the head end of the motors, where the fwd skirt and interstage would go...

The fifth pic is the nozzle end of the stage-- the center six nozzles (center engine and five inner circle engines) would have straight nozzles, the outer ten motors would have their nozzles canted outward from the centerline of the rocket, so they were all thrusting through the burnout CG of the rocket, to minimize side-thrust and rates at burnout and staging.

More to come... OL JR

[luke strawwalker]

The first pic is the nozzle end side view of the sixteen motor cluster. Here you can see the inner nozzles are aligned with the vehicle centerline and the outer nozzles are canted away from the centerline. Nozzle dimensions are given on the drawing...

The second pic is the second stage SRM nozzles-- a four 120 inch five-segment SRM cluster was used on the second stage of the #2 vehicle, and the nozzles were all canted away from the centerline to thrust through the burnout CG to minimize rates at stage seperation. Here the aero-fairing for the interstage can be seen, covering the much larger vacuum upper stage nozzles.

This third pic shows the early date of the study-- it proposes using JET VANES in the nozzle walls for TVC-- something used on the German V-2 rocket and the Redstone rocket, but replaced by gimbaled nozzles on nearly everything else. Since gimbaled nozzles for SRMs were a bit of a 'black art' at the time, I guess they figured this was the next best thing. Using fins was discussed, but no planforms or sizes were noted in the study. There was also brief discussion of using liquid-injection TVC like that which was being perfected for Polaris at about the same time. Polaris also used a single-nozzle SRM for it's first stage, and how to accomplish TVC was quite a problem-- the solution was to inject nitrogen tetroxide through radially-located nozzles situated around the nozzle, like numbers on a clock. Each nozzle was controlled by its own valve, which was controlled by the guidance system. When a correction to the trajectory was needed, the guidance system would open the correct valve, which would inject fluid into the exhaust stream coming from the nozzle, diverting it toward the other side of the nozzle, in effect "gimbaling" the fixed nozzle by pushing the exhaust stream from side to side with injected fluid. It worked beautifully and was later adopted for use on TITAN III-C, which had fixed nozzles on it's 120 inch SRBs. This system was considered too 'unreliable' and too early in it's development to be used on this vehicle (at the time of this study, anyway).

The fourth pic is a cutaway of the head end of the motor, and some details of the segment joints. These motors were designed to use tapered locking pin joints. The tapered locking pins would be held in by bolts.

The fifth pic is the nozzle end of the motor, with some details...

More to come... OL JR

[luke strawwalker]

The first pic is showing the launch pad setup for the 3 motor cluster for the No. 1 vehicle... A six-armed hold-down support structure would be installed on the pad over the flame hole and then the motor cluster would be stacked on top of it. Once completed, the upper stages would be installed, almost identically to how early Saturn I's and IB's were stacked at Complex 34 all the way up to Apollo 7. (It wasn't until Skylab that Saturn IB's would launch from the 'milkstool' at LC-39).

The second pic is another launch pad pic showing some details of the three motor cluster setup-- the three nozzle segments were bolted together and then lowered onto the pad and secured as a unit, and then the SRMs were stacked atop them one segment at a time.

The third pic shows the support/holddown arms for the sixteen motor cluster-- it would require a LOT of support arms to hold that kind of weight!

The fourth pic is showing GCR's idea of a partially sunken pad, where part of it was constructed below ground level, to reduce crane heights needed for stacking the sixteen motor first stage cluster and four motor second stage cluster for their Vehicle no. 2. Wonder if they thought about the fact that the pads are only 4 feet above sea level (IIRC) and practically on the beach?? Constructing an 'underground pad' in those conditions would have been fun...

The fifth pic is the segment handling dolly that would have been used during propellant casting and for moving the segments around the factory-- very similar to what ATK uses for segments today...

More to come! OL JR

[luke strawwalker]

Okay, here's the last four pics... 'nuther one in the bag!

The first pic is the segment tranporter that would have been used to move segments to storage or to test stands for static tests. Looks like an old Bucyrus-Erie highway scraper to me! LOL

The second pic is the plans for the segment transporter...

The third pic is the plans for transporting the segments by highway across the US from the California casting plant to KSC. There was also discussion of transport by barge and ship, or possibly rail. Air transport was ruled out due to the weight.

The fourth and final pic isn't from this study, but it's kinda fitting I include it, if only for compare/contrast... These SRM's have a MUCH shorter burn duration that the boosters for Titan III-C (which were about two minutes or so, these were about 45-55 seconds!) but the fact that they're both 120 inch SRM's is fascinating in itself... I don't know if there was any 'history' between these SRM's and the Titan III SRM's, but it's interesting nonetheless... it also proves that solid rocket stages could have been built from the Titan III-C SRMs, because with their longer burn time they would have worked even better than these did (assuming the thrust was similar-- which I haven't compared yet). I doubt that a 16 Titan III-C SRM cluster would have replaced the S-IC stage on Saturn V anytime soon, (or would have ever been taken seriously) but it's quite possible a 3 or 4 120 inch Titan III-C SRM first stage could have found a place under an S-IVB stage as a Saturn IB replacement... such things were proposed several times...

Later! OL JR

[luke strawwalker]

Here's one other pic I found that was mixed up with some others... it's of the Vehicle No. 1 proposal showing the first stage complete in sideview and both endviews...

Also wanted to attach a pic from another study, of the "S-II" stage referred to in this study several times... It's an early version of the S-II stage as designed for use on the Saturn C-3 vehicle.

Sorry I missed that one! Later! OL JR