Michel Van said:
in the wonderful alternate history scenario "Eyes Turned Skywards" we discus the option of a "Super Saturn" and change on Launch Pad 39 A&B
http://www.alternatehistory.com/discussion/showthread.php?t=208954
here my reply on that topic:
According the Boeing "integrated Manned Interplanetary Spacecraft" documents.
they needed A Saturn V-25(S)U, 40 ft Stretch S-IC with 5 x upgraded F-1 (1.8 million pounds thrust) , strengthened standard length S-II with 5xJ-2S.
For heavy payload this Saturn is equipped with 4 Solid booster (4 segment 156 inch ø weight each 1.38 million pound, total lift off thrust 72,338.40 kN
For safety reason the SRB are Not install inside VAB but on Launch pad 39 A B C
the Pads are modified for new task, like High extension on launch platform tower, module device structure (also for NERVA engine check),
they launch platform must be protected for Fire and Sound pressure of SRB and Saturn-IC stage during lift-off
the crawlers require uprating for bigger mass, it have to role from VAB to Pads.
also the launch platform is strengthened to take the heavier Saturn.
oddly the Launch Pad only modification is for to survive the Blast in case the Saturn explode on launch pad or above if
and bigger blast pit for SRB, to take thrust of72,338.40 kN or 7374 tons
in short: Launch Pad 39 A&B can take Saturn C-8 and Saturn V-23(L) especially because no use of Solid booster
Very good, but the decision to stack the SRB's at the pad rather than in the VAB wasn't safety related (as much)... it was the fact that it was simply IMPOSSIBLE to move a vehicle with FOUR SRB's stacked on the pad in the VAB using the crawlers... they simply couldn't handle that much weight, period.
As it was, the shuttle SRB's were SO heavy that the tower had to come off the MLP's, hence the FSS and RSS at 39A and B for the shuttle program versus the "clean pad" approach with the LUT on the MLP as was done with Apollo/Saturn. The crawlers could BARELY handle the weight of the PAIR of loaded shuttle SRB's with the ~100 ton orbiter and the ET (don't remember the empty weight of the ET offhand) along with the weight of the MLP itself.
This was going to be a real killer with Ares V as well... the 5.5 segment boosters planned for the Ares V basically broke the bank-- the 5 segment boosters along with the heavier core vehicle had already maxed out the crawler and crawlerway capabilities as it was. Going bigger just made the problems worse.
There have been lots of four-SRB proposals around over the years-- I USED to have some on my hard drive (before it melted and lost everything for me without a backup) that showed basically a shuttle stack ET-type core vehicle with four SRB's... but the problem with all these proposals were, they took NO account of ground processing, stacking, or moving to the pad. These were the show stoppers.
In the case of the four-SRB-equipped Saturn V variants, the plan was to stack the Saturn V in the VAB normally on its modified MLP, without the SRB's. The vehicle and platform would then be moved to the pad and set up there, while the crawler returned and hauled back a "solid stacking facility" designed to interface with the pad and MLP structures, and which was "parked" in a parking lot adjacent to the crawlerway, much as the Mobile Service Structure was stored and hauled to the pads via the crawler. The "SSF" would be set up on the pad by the crawler, which would then go back to shuttle out the solid booster segments to the pad, where they'd be lifted off the crawler's strongback, erected vertically via cranes, and stacked adjacent to the Saturn V on the pad. The connections would be made with the base segments and the pad, and with the Saturn V vehicle itself, and the subsequent segments stacked atop them until the boosters were completed. The facility would then be rotated or rearranged to stack the other pair of boosters on the other side of the Saturn V. Then the crawler would haul away the SSF back to its parking area, and bring a modified MSS back from its parking spot and erect it around the Saturn V/SRB stack, which would then be used for the final checkout and preparation of the Saturn V for launch. Afterwards it too would be removed via crawler back to its parking spot for the launch.
All of this complex ground operations to prepare for each flight, as well as the additional costs to engineer all the support equipment and modify the existing equipment to handle such a vehicle, was IMHO not particularly realistic... the funding would never appear for any of it and it shouldn't have passed the "smell test" from day one... IMHO it would have been better and cheaper to simply divide up the cargoes and launch more existing rockets (Saturn V's) without the modifications for large SRB's. Either that, or if the modules couldn't be broken down or launched empty and tanked in orbit, then a LIQUID rocket booster would have made MUCH more sense. Unlike SOLID rocket boosters, LRB's are stacked and moved EMPTY, and thus add very little additional weight to the stack and MLP for the crawler to carry over the crawlerway. This means that they are FAR more versatile and scalable for MUCH larger payloads than a solid-boosted vehicle is. Plus, since the LRB's are handled, stacked, and transported empty, there is none of the safety hazards and concerns of handling extremely heavy SRB's FILLED WITH MIXED PROPELLANTS inside the VAB. Liquid boosters made it possible for the Soviet Buran shuttle and Energia booster rocket to be horizontally integrated in the assembly building, hauled by rail to the pad, and then erected vertically for launch... heavy SRB's would have made that impossible, but their much lighter LIQUID Zenit boosters made it straightforward to do it that way...
Just one of the reasons why the F-1B powered advanced boosters being researched for possible replacements for the five-segment SLS boosters is a superior idea...
Later! OL JR
