luke strawwalker
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Here's an interesting Bellcomm study from 1969 on the possibility of producing a low-cost S-IVB stage for use on an "Intermediate Launch Vehicle" to be used for launching Air Force and NASA payloads in the 1970's.
The Air Force, in usual form, was proposing their own vehicle, using new 156 inch solid rocket boosters and an all-new 15 foot diameter Titan-based core vehicle, using a storable propellant first stage, and an all-new 15 foot diameter LH2 powered second stage using a J-2 engine... only 15% smaller than the S-IVB itself, but a completely new from scratch stage... (about as stupid as it gets-- dump something you already have that works great and is completely manrated, for something that's an all new development project from square one.) Alternatively, the Air Force proposed developing a new solid rocket motor cluster first stage comprised of FOUR of the new 156 inch SRM's strapped together to make a first stage, with the new LH2 upper stage atop it.
NASA plans included the 260 inch large monolithic SRM being developed by Aerojet General (which was test fired upside down in a silo constructed in southern Florida in a subscale test) and also several iterations of the "Interim Launch Vehicle" (ILV) proposals using Saturn derivative vehicles like INT-20, which would have paired a Saturn V S-IC stage first stage with fewer F-1 engines (depending on the version) and an S-IVB second stage, among others.
The study centers on the fact that the S-IVB second stage, which was designed and built with dry mass being the critical design criteria, along with restart capability, for the lunar mission, was coming in at about TWICE the cost of any of the other proposed first stages under consideration, INCLUDING S-IC. McDonnell Douglas, the contractor in charge of S-IVB development and construction, had made a series of proposals to enable a lower-cost S-IVB, including more automated and simplified production, and not test-firing the individual stages before flight. Using various approaches to cutting costs, it was felt that using the existing Saturn-derived technologies to build simplified and cheaper versions of the S-IVB could result in an ILV rocket with a cost of about $200 per pound to 100 nautical mile low Earth orbit (LEO). This was roughly commensurate with the best overly-optimistic (as cited in the report) cost projections from the Air Force for their new proposed launcher, using already existing and manrated stages and equipment.
It's a fascinating look into what "might have been". Unfortunately, the powers that be chose to dump virtually all the existing Saturn development work and infrastructure and start from scratch with the Space Shuttle, and ended up in bed with the Air Force to win approval and badly needed funding for the shuttle program, and hopelessly compromised the design to meet Air Force "requirements" that never materialized anyway, resulting in a fundamentally flawed vehicle incapable of meeting the original goals planned for it.
Enjoy! OL JR
View attachment Low Cost SIVB Study Summary.txt
The Air Force, in usual form, was proposing their own vehicle, using new 156 inch solid rocket boosters and an all-new 15 foot diameter Titan-based core vehicle, using a storable propellant first stage, and an all-new 15 foot diameter LH2 powered second stage using a J-2 engine... only 15% smaller than the S-IVB itself, but a completely new from scratch stage... (about as stupid as it gets-- dump something you already have that works great and is completely manrated, for something that's an all new development project from square one.) Alternatively, the Air Force proposed developing a new solid rocket motor cluster first stage comprised of FOUR of the new 156 inch SRM's strapped together to make a first stage, with the new LH2 upper stage atop it.
NASA plans included the 260 inch large monolithic SRM being developed by Aerojet General (which was test fired upside down in a silo constructed in southern Florida in a subscale test) and also several iterations of the "Interim Launch Vehicle" (ILV) proposals using Saturn derivative vehicles like INT-20, which would have paired a Saturn V S-IC stage first stage with fewer F-1 engines (depending on the version) and an S-IVB second stage, among others.
The study centers on the fact that the S-IVB second stage, which was designed and built with dry mass being the critical design criteria, along with restart capability, for the lunar mission, was coming in at about TWICE the cost of any of the other proposed first stages under consideration, INCLUDING S-IC. McDonnell Douglas, the contractor in charge of S-IVB development and construction, had made a series of proposals to enable a lower-cost S-IVB, including more automated and simplified production, and not test-firing the individual stages before flight. Using various approaches to cutting costs, it was felt that using the existing Saturn-derived technologies to build simplified and cheaper versions of the S-IVB could result in an ILV rocket with a cost of about $200 per pound to 100 nautical mile low Earth orbit (LEO). This was roughly commensurate with the best overly-optimistic (as cited in the report) cost projections from the Air Force for their new proposed launcher, using already existing and manrated stages and equipment.
It's a fascinating look into what "might have been". Unfortunately, the powers that be chose to dump virtually all the existing Saturn development work and infrastructure and start from scratch with the Space Shuttle, and ended up in bed with the Air Force to win approval and badly needed funding for the shuttle program, and hopelessly compromised the design to meet Air Force "requirements" that never materialized anyway, resulting in a fundamentally flawed vehicle incapable of meeting the original goals planned for it.
Enjoy! OL JR
View attachment Low Cost SIVB Study Summary.txt