[1.12.5] Bluedog Design Bureau - Stockalike Saturn, Apollo, and more! (v1.13.0 "Забытый" 13/Aug/2023)

[lemon cup]

2 hours ago, braxfortex said:

I really want to try this mission now.  Docking a dry Skylab with 4 S-IVBs chained together to go to Eve and back (2.5x scale via JNSQ).  Is there a docking ring in BDB or other mod that could enable this?

You can find a 5m diameter “annular truss” docking ring in the mod NearFutureConstruction from Nertea that performs this job very well.

Only problem is that it is wider than the BDB S-IV stage by default, so you will need Tweakscale to make it work 

Edited December 3, 2021 by lemon cup

[Pappystein]

1 hour ago, braxfortex said:

I really want to try this mission now.  Docking a dry Skylab with 4 S-IVBs chained together to go to Eve and back (2.5x scale via JNSQ).  Is there a docking ring in BDB or other mod that could enable this?

The Docking port and serial burn of the S-IVCs is actually for Mars,   But it was also mentioned for Venus and Eros.   As a way to provide a "more robust" experience for the astronauts.

As of this time there are no public plans to make such a set of parts.   But I hope they do come to be.   Based on my reading, all the interconnects (for controlling the various stages) were wired to "shielded" and "un-shielded" portions of the docking ring.  meaning the forks on the active port side (in the middle of the IU) were the "wires" for control connections.   

It would bring me back to the Tinker-Toy space ships that I built back in 2013 with just stock parts in KSP!

 

[Starhelperdude]

On what would the XLR-81 8096C engine (the agena engine with the big bell and lower thrut) have been used?

[Jcking]

6 minutes ago, Starhelperdude said:

On what would the XLR-81 8096C engine (the agena engine with the big bell and lower thrut) have been used?

I believe that engine meant to be the one for Agena 2000, a MMH/MON-3 upperstage for Delta IV and Atlas V of which little is known about.

Edited December 4, 2021 by Jcking

[Starhelperdude]

also, how do I build the ''Gamma'' you can build with the vega parts? Is it used on titan?

[SpaceFace545]

3 minutes ago, Starhelperdude said:

also, how do I build the ''Gamma'' you can build with the vega parts? Is it used on titan?

It’s practically Vega but with no third stage 

[Jcking]

Gamma refers to Gamma Centaur (which the stage has been alternatively referred to as Centaur Junior) is a Vega like third stage, except hydrolox and using a single RL10

Edited December 4, 2021 by Jcking

[Pappystein]

47 minutes ago, Jcking said:

Gamma refers to Gamma Centaur (which the stage has been alternatively referred to as Centaur Junior) is a Vega like third stage, except hydrolox and using a single RL10

Minor correction here, Jcking has it mostly right...   Gamma is a miniature Centaur so sometimes called Centaur JR.  But it is NOT the stage Centaur JR (which would be closer to the HOSS than Centaur) 

I use the HOSS in game to represent CEntaur JR... and the Vega smaller forward dome tank with the Centaur Single Engine mount for Gamma..    NOTE   Do not put a GCU on your Centaur Stage if you are going to do Centaur Gamma...  It belongs on the Gamma stage now.

 

Other than that publicity drawing there is no documented proof that Centaur-JR and Gamma were the same stage...  However there IS proof that Centaur JR was to be a smaller diameter (8ft instead of 10)

The data I am basing this off from is on the DTICs server   AD842594

https://apps.dtic.mil/sti/pdfs/AD0842594.pdf

*realize the above statement in conjunction with the graphic from SpaceLaunchReports made me sound like I was Ed Kyle, I am not *

 

Edited December 4, 2021 by Pappystein

[pTrevTrevs]

 

Apollo 13: Jim Lovell, Eat Your Heart Out:

Apollo 12's spectacular touchdown at Surveyor Crater opened a whole new realm of possibilities for Apollo lunar exploration. Instead of being constricted to broad surveys of the Moon's geographical regions, missions could now focus on specific landmarks or locations of interest. One such location was the Fra Mauro formation, in particular Cone Crater. Fra Mauro was formed by debris ejected from the same impact which created Mare Imbrium, and was therefore not composed of the same material as the surrounding Ocean of Storms. It was, in a sense, an island in that ocean. More intriguing to geologists, however, was what lay underneath Fra Mauro's wrinkled terrain. When the Imbirum impact formed the highlands of Fra Mauro, it covered up the original lunar surface which had originally made up the area, shielding it from whatever impacts and volcanic activity happened afterward. Because of this, scientists believed that a deep study of Fra Mauro would yield valuable information about the Moon's origin, maybe even producing samples of the original lunar crust. Key to this expedition, then, was Cone Crater. Cone is a relatively young crater, but it was thought to be large enough to have punched through the layer of Imbrium ejecta which composed most of the highlands to reach the underlying material. In addition to seeking a deeper glimpse into Cone, Apollo 13 will also be the first lunar mission to not land on a lunar mare, so if all else fails the mission will almost certainly recover a much different collection of sample material than was collected by Apollos 11 and 12. The eager optimism of the science teams is by no means universal, however. The number thirteen has long been an object of superstition and dread, and while it is superstition alone which fuels certain people's doubts about the mission, some have noted the ominous alignment of mission parameters which cause the unlucky number to show up again and again in timetables and plans. The required launch window for Apollo 13 will lead to the Saturn V lifting off at exactly 1:13 local time, in the 24-hour format commonly used by mission itineraries this becomes 13:13. The voyage to the Moon will have the spacecraft entering the Moon's sphere of influence on April 13, 1970, at which point the crew will be far enough away from home that a mission abort would require several days to complete. Additionally, some have raised concerns over the name chosen for the Apollo 13 command module, Odyssey, which refers to "a long journey, fraught with many hazards". Although few real concerns are present as the launch countdown begins, some find themselves more troubled over the perfectly sunny launch of Apollo 13 than the violent and stormy launch of its predecessor a mere five months past...

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Part 1:

At T-minus 43 minutes, Swing Arm 9 is detached from the spacecraft and moved to a standby position approximately six feet from the command module hatch. At T-5:00 the arm will be moved to its fully retracted position to clear the way for the ascending vehicle.

In the meantime the launch umbilical connections begin to fuel and pressurize the cryogenic propellant tanks on the second and third stages of the booster. Three tail service masts at the base of the first stage provide auxiliary power to the vehicle and feed telemetry back to the firing room several miles away.

And at 13:13 on the nose, the call "Tower Clear!" echoes through the LCC at the Cape. Kennedy's work done, the launch director hands off control to Mission Control at the Manned Spacecraft Center in Houston.

The Saturn V assigned to Apollo 13 is SA-508. Although mostly identical to her predecessors, '508 has been slightly modified in order to collect necessary data for the upcoming J-series missions beginning next year. When these extended missions fly they will carry a considerable amount of extra equipment, including extended consumables supplies, the Lunar Roving Vehicle, and the Scientific Instrument Module, all of which will lead to significantly heavier spacecraft, which in turn will require more capable Saturn Vs. To prepare for this, SA-508 has been loaded with more propellant than previous Saturn Vs so NASA can evaluate how the vehicle performs with a heavier launch weight approaching that of the J-class parameters. Because of this, Apollo 13 is noticeably slower to clear the tower than earlier missions, and overall acceleration is slightly reduced.

In order to limit the force of acceleration on the crew during the launch to 3G or less, the center engines of the first and second stages are programmed to shut down earlier than the four outboard engines. Typically this is done shortly before staging, but on Apollo 13 the inboard engine shut down approximately two minutes early. This is believed to have happened because the Saturn guidance computer detected an abnormal intensity of pogo oscillation caused by a cavitation in one of the S-IIs turbopumps, and triggered the early inboard-out to alleviate it. While far from mission critical, the mission required a longer burn of the outboard S-II engines and the S-IVB to compensate.

The S-II inboard malfunction notwithstanding, Apollo 13's launch and TLI proceeded without incident. After the flight, the crew would remark that this shutdown must have been where the number 13 affected the mission. Once settled in the translunar flight profile, Odyssey retrieves the lunar module Aquarius from her adapter. Following this the S-IVB will be redirected to impact the lunar surface to provide seismic data for the Apollo 12 ALSEP, making it the first of the Saturn stages to do so.

Some halfway between the Moon and the Earth the crew experienced a slight mechanical failure when the stirring fan inside one of the cryogenic oxygen tanks failed to operate. While causing concerns of a severed electrical connection at first, no further symptoms were found, and the mission continued ahead. By this point in the program enough missions had been flown that EECOMs could make quantity estimates for remaining consumables based on previous flights, and beginning on the next mission the cryo fans would be removed entirely, having been deemed a potential failure point in the environmental system.

Sorry, but the black cat under the ladder isn't gonna catch me...

Anyway, Odyssey with Aquarius in tow arrives in lunar orbit right on schedule.

By this point, Powered Descent is a familiar routine, and the flight to the hills of Fra Mauro encounters few obstacles. It is noted, however, that the amount of fuel remaining in the descent stage tanks was lower than on Apollo 12, which in turn was lower than on Apollo 11. Upon closer study, it is realized that the growing list of extra equipment being hauled to the lunar surface will eventually cause the LM to burn too much fuel on descent and potentially risk an abort or crash. A solution will be developed for future missions.

Despite the tighter margins, however, the Apollo 13 landing crew proved to be the calmest thus far. The lunar module pilot even found an opportunity to look up from his instruments and snap a photo of the earthrise while awaiting PDI. Ironically, the astronaut responsible for the first earthrise photo is currently flying in the LM's left-hand seat. CDR Roy Kerman was previously the command module pilot on Apollo 8, making him the first person to fly to the Moon twice. In addition to two flights in Project Gemini, this amount of flight time makes him NASA's most experienced astronaut, and few can think of a better choice to command the first visit to the lunar highlands than him.

Gliding silently over Fra Mauro, Aquarius arrives over Cone Crater, which is captured on film by the camera aimed out the LMP's window. Unexpectedly, however, the terrain around the planned landing site it rougher than it appears in orbital photographs, featuring scattered boulders and steeper than expected slopes. Realizing this, the crew level off their descent and search for the earliest suitable landing site downrange of their target. Such a spot is easily found, and in no time at all Aquarius sets down directly over it.

With LM-7 resting comfortably at the base of a Fra Mauro hillside, the most memorable phase of Apollo 13 can now begin.

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Part 2:

Crawling through Aquarius's hatch and down its ladder, Roy Kerman realizes the dream which has chased him ever since his first lunar voyage eighteen months prior. As the gravity of his accomplishment sets in, he raises his outer visor and takes a moment to marvel at the spacecraft which delivered him and his crewmate to the surface of the Moon. Once back in lunar orbit, he will detach the armrest on his side of the cockpit and return it to Earth. After the mission, Roy will have it mounted on a plaque and presented to the Grumman engineers as a sign of thanks.

All these sentimental moments must wait, however; right now there's work to be done.

Having joined the commander on the surface, the LMP begins to prepare the ALSEP for deployment. Like on Apollo 12, the first of two EVAs on the surface is dedicated to deployment of the ALSEP and other activities around the immediate landing site. 

Apollo 13's ALSEP features a new experiment station. the Lunar Ionographer is designed to measure the levels of charged particles and solar wind present on the lunar surface, as well as studying the sparse lunar atmosphere. Due to space and weight limitations on the H-class LM, the materials study device flown on Apollo 12 has been excluded in favor of this delicate new instrument.

With its third flag on the Moon, America now possesses all three spots on the victory podium, Gold, Silver, and Bronze. The filthy Europeans can have their FIFA wins, because they'll never make up for missing this.

Before closing out the EVA, the astronauts take a short hike up the hillside towards Cone crater. This traverse is focused primarily on collecting samples that would need to be passed up due to time restrictions on tomorrow's longer expedition. Additionally, by examining the route now, it is hoped that the crew will have an easier time navigating towards Cone the next time they head out. If only it were that simple...

Cresting the top of the hill, the astronauts spot the rim of Cone Crater looming in the distance, although farther away than hoped for. This is likely the best view between the LM and the rim, so the pair study the route they expect to take on tomorrow's journey before returning to Aquarius for the night.

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Part 3:

In the meantime, the lone occupant of Odyssey is much busier than previous CMPs. Apollo 13 is the first mission which involves any real geologically-focused observation from lunar orbit; all previous flights focused on landing site investigation. While Odyssey is tasked with photographing certain prospective sites, it is emphasized that the primary object of interest at a given site is its geological significance rather than its ease of access or practicality. This maxim means that the Apollo 13 photography itinerary features such sites as Littrow Crater (above image), Hadley-Apennine, Aristarchus, and the Marius Hills.

During a pass over Littrow, however, the CMP notices something unexpected; a small valley to the south of Littrow, wedged between the Taurus Mountains and Mare Serenitatis. Looking closer at the valley, he notices features which can only be volcanic in nature. In addition, the large massifs flanking the valley to the north and south appear considerably different than the dark mare-like material of the valley floor. Shifting his gaze northward again, the once-interesting crater Littrow now appears dull and unremarkable by comparison. Eyes glued to Odyssey's window, the CMP snaps off photo after photo until this region, which will become known as Taurus-Littrow, sinks out of sight. When the photos are developed post-mission the geologists will wholeheartedly agree, everything about this site makes it perfect for a landing, while the trajectory engineers balk at the idea of sending a LM down through much mountainous terrain. Despite certain objections, Taurus-Littrow is immediately bumped to the top of the list of prospective landing sites, and soon the original Littrow H-3 site designated for Apollo 14 is abandoned altogether in favor of this new location. As a partial consequence, mission planners also feel that, should Apollo 14 successfully explore this valley the plan for a fourth H-mission will be eliminated. Pending '14's success, Apollo 15 will be reclassified from the H-4 mission to the J-1 mission, making it the first to carry the LRV and the first to explore a landing site over three days. As a further consequence, Apollo 15's original landing site at the crater Censorinus will also be abandoned, being ruled as unworthy of the investment of a J-mission. By August of 1970 the long-enticing site at Hadley Rille will be tentatively assigned to Apollo 15s flight the following Spring.

Besides studying the lunar surface, Odyssey must also make periodic plane change maneuvers with the SPS to keep its orbital track above Aquarius's landing site, in case a mission abort requires the surface crew to launch and rendezvous early.

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Part 4:

Surface Day 2 has begun, and staggering out of their awkwardly rigged hammocks the crew at Fra Mauro prepares for the trek to Cone crater. Ideally they will reach the crater rim and collect photographs and material from its immediate interior, but should they fail to travel that far they will be compelled to settle for whatever they can find. This is the chief fear in the back of the commander's mind; the poor conditions at the prime landing site forced him to set down farther away from Cone than planned, and should navigation prove difficult they may not have enough oxygen to reach their objective. Even so, confidence and anticipation well up inside him as he descends Aquarius's ladder for the second time.

Following a short check-up on the ALSEP, the two astronauts set off towards Cone, moving as directly as possible towards the crater, fighting to maintain their bearing against treacherous slopes and obstructive boulders.

The ground steadily rises as they pass the high-water mark of the previous day and the lander disappears beneath the hills. The commanding view from the day before is gone now, betraying a much more confusing landscape. The astronauts find themselves easily misdirected, deviating to the left or right of their desired path because of small craters, large pieces of ejecta, and unsafe-looking drifts of soil. As they struggle to summit each new ridge and hope for another sight of their prize, the two gulp down loads of oxygen and strain their suit's cooling systems. Mission controllers soon become worried that the astronauts may overexert themselves and be unable to return to the LM.

Finally, the explorers summit a ridge which allows them some visibility of Cone crater, but to their frustration and astonishment the rim appears even farther away than it did from the earlier ridge. At that moment the flight surgeon in Houston recommends the crew abandon the search; by now they have used over half of their oxygen and their suit's electrical systems are struggling to handle their rising body temperatures. Reluctantly, Apollo 13's crew takes one final look at Cone crater, so close and yet so far. They search for whatever sample materials they can find and begin the disappointing trek back to Aquarius.

After taking a few hours to recover from their ordeal, the crew blasts off from Fra Mauro, by this time eager to rejoin their comrade in orbit and return home.

As Aquarius pitches over, the LMP catches a final glimpse of Cone crater just outside his window, as if it were taunting him. If only he'd had a set of wheels, he would have made it. 

Some time later and all three crewmembers are back aboard Odyssey. The CMP had enjoyed a very successful mission with no issues comparable to his friends' failure to reach Cone. The only notable hiccup was when the MOCR EECOM noticed a momentary decline in cabin pressure right before Odyssey slipped behind the Moon, but whatever fears this may have caused were dispelled when the ship reemerged reading nominal levels. Ultimately the abnormal readings were chalked up as an instrumentation error.

There aren't many historical photos from Apollo 13 that I could recreate this time, but I was able to get one (however uninspired it may be). Farewell Aquarius, and we thank you.

From here on out the mission slowly winds down, typical TEI, typical transearth voyage, and typical reentry, culminating in a splashdown just south of Hawaii some three days later.

Having passed out from the G-forces on his Apollo 8 reentry, Roy Kerman has braced himself for another brutal descent. To his surprise, however, Apollo 13 proves to be the first mission to absolutely nail the ideal reentry corridor. Taking advantage of its lifting body aerodynamics, the command module flies with the relative grace of a magic carpet over the Pacific Ocean, with decceleration barely exceeding 7G.

Anyway, there you have it, the odyssey of Apollo 13, the "failed success", "NASA's darkest hour", or something like that. Whatever, Ron Howard will make a film about it in twenty years and we'll get Ed Harris to learn backwards Spanish for the role of Gene Kerman.; trust me it'll be great.

These are getting pretty long to write up; but I'm really appreciative of all the positive feedback I'm getting from them. Hope y'all continue to enjoy my AARs.

[Thatguywholikesionengines]

Your AARs are absolutely awesome, Trev!

I came here to wonder why the former CADS port, an androgynous, 0.9375 port that I was planning for use on shuttles and a Skylab knockoff, got changed with the development versions to 1.25m, with an appearance more similar to the CBM. I miss my old port, and don't wish to use the Apollo probe/drogue.

[Entr8899]

12 minutes ago, Thatguywholikesionengines said:

Your AARs are absolutely awesome, Trev!

I came here to wonder why the former CADS port, an androgynous, 0.9375 port that I was planning for use on shuttles and a Skylab knockoff, got changed with the development versions to 1.25m, with an appearance more similar to the CBM. I miss my old port, and don't wish to use the Apollo probe/drogue.

Ermm, you can already find an updated version in game, but it's called something else. It's Benjee10's APAS port.

[flamerboy67664]

3 hours ago, pTrevTrevs said:

 

Apollo 13: Jim Lovell, Eat Your Heart Out:

These are getting pretty long to write up; but I'm really appreciative of all the positive feedback I'm getting from them. Hope y'all continue to enjoy my AARs.

Awesome AARs man, but something I noticed with your pics and also previous posts...

I seem to recall from my days of simming whole Apollo missions with AMSO in Orbiter 2006 and reading NASA docs, didn't the crew activate the LM (turning on stuff like antennas and comms, and extending LDG) before LOI to check if the LM is bad and they would go mission abort with the free return trj if so?

[GoldForest]

6 hours ago, Thatguywholikesionengines said:

Your AARs are absolutely awesome, Trev!

I came here to wonder why the former CADS port, an androgynous, 0.9375 port that I was planning for use on shuttles and a Skylab knockoff, got changed with the development versions to 1.25m, with an appearance more similar to the CBM. I miss my old port, and don't wish to use the Apollo probe/drogue.

CADS got changed to reflect ETS CADS which is what it is actually based off of. If you want an APAS port, Habtech has a really nice one.

17 hours ago, Pappystein said:

Oh and here is a picture of the S-IVC docking:

Oh, so it slipped over the J-2? Interesting. 

[TaintedLion]

7 hours ago, pTrevTrevs said:

The only notable hiccup was when the MOCR EECOM noticed a momentary decline in cabin pressure right before Odyssey slipped behind the Moon, but whatever fears this may have caused were dispelled when the ship reemerged reading nominal levels. Ultimately the abnormal readings were chalked up as an instrumentation error.

Is that a little Ocean of Storms reference I pick up there?

[Beccab]

17 hours ago, Pappystein said:

Douglas Saturn IV stage.   A quick and dirty design history, including significant variants.

 

 

 

Something that I have tried to make clear to my readers as I write these “vignettes” on Rocket design has not been well stated.  So I am taking the opportunity to start by talking about History and the most significant failing the average non-historian reader suffers.     Time dilation.    No, in the physical sense, we are not time-traveling here, nor are we approaching the speed of light, the two places where most of you probably think Time Dilation exists. Instead, by looking ‘so far back,’ what you see as a few events that are hard to make sense of has happened over days, months, and years.   A great example: The Titan Rocket.   Titan started in 1955, was first launched in 1959, and completed service in 2005.   The design and fabrication of the relatively simple Titan I took practically five years!    Much of what you, the reader, see on the Titan Rocket is summarized in these bullet points:

 

·         Build a robust alternative to Atlas

 

·         Upgrade said robust alternative to storable fuels

 

·         Upgrade said storable rocket for Gemini program

 

·         Upgrade said rocket again for space launch as the Titan IIIA

 

·         Realize we need MOAR thrust, so add SRMs to Titan IIIA

 

·         Stop, change directions with a different SRM

 

·         Build space station manned spy satellite launched from Titan III

 

·         Realize you need even bigger SRMs for MOL

 

·         Realize a bigger core would make MOL more viable

 

·         MOL Canceled

 

·         Build newer versions of Titan III for future space launch of bigger things

 

·         Completely redesign Titan III into Titan IV

 

·         Completely redesign SRMs (SRMU vs. UA120x)

 

·         Cancel because Toxic Storable fuels are too expensive to replace, and “new things” are coming (regardless that it was a new rocket in 1996)

 

When you look at those bullet points, you see a few decisions.  But each of those decisions resulted from thousands of other choices leading up to each of them.    So realize that what you are about to read is probably the most significant compression of time into a vignette I have yet done.   Also, recognize that much is missing from the NASA published history “Stages to Saturn” by Blisten because of fears of spreading technical knowledge to the enemies of the United States.

 

 

 

Juno V:   Cluster’s revenge?

  Reveal hidden contents

 

 

It is essential to understand that Von Braun did not place much love on Bossart’s ideas about Balloon tanks, did not have a lot of funds, and was limited in what he could design and build by the US Army’s actual needs. The Atlas was testing and entering service.  There were a lot of failures.   Titan was also just about to enter testing, and its classical design was something Von Braun could appreciate.   No magic here, just straightforward structural evolution.  

 

At this juncture, we have the newly minted Defense Advanced Research Agency, abbreviated ARPA or DARPA depending on the year, who decided to look at the next generation of Space booster.   Part of the reason for DARPA’s formation was to create a centralized think tank AWAY from the much-feared and loathed “military-industrial complex.” An isolated place where new ideas could be thought up.   Sort of like a NACA for the Military.   DARPA’s purview was, however, not just limited to the military.   Thus, the organization's name has shed and added the word Defense repeatedly throughout its life.  

 

Anyway, the US Army had just lost its long-range “Ballistic missile Artillery” as part of a Department of defense re-organization.   The Jupiter IRBM moved from the US Army to the USAF, where they already had their preferred Thor that utilized essentially the same engine but had a better performance reserve than the Jupiter.   In this “rapid” change of fortune, the Army Ballistic Missile Agency (or ABMA) and Von Braun had no prospective work, were losing engineers to other jobs, and were still a point of pride for the US Army.   DARPA, looking to the future of space boosters, needed actual rocket scientists.  ABMA had rocket scientists and was a governmental organization.   This looks like a ready match made in heaven with one glaring exception.    The exception?  The almighty dollar $$$.   DARPA did not have the funding to pay for the design and testing of an all-new rocket stage, but they knew they would need such a thing.   Von Braun did some sketching and figured that it would be cheaper to build a stage of the prospective performance with existing tooling already at ABMA.   The only new items would be the engines for said stage and the end webs.   You see, Von Braun figured that if he re-used the tooling to make Jupiter Tanks and Redstone tanks, he could make a new set of tanks in those diameters and combine them to get an appropriate level of fuel to match DARPA’s needs.     

 

Note these new tank structures are NOT Redstone and Jupiter tanks glued together. Instead, they are all new tank designs that use the same fabrication tooling.   IF you made an actual stage out of Redstone rockets and a Jupiter rocket, it would mass significantly more and have substantially less fuel than the Juno V.   Something a few of you have figured out in KSP already.

 

Saturn S-IV stage:

 

For the point of this paper, we will leave Juno V here long before it becomes the Saturn C-1 and C-2 booster.   We now jump ahead to Von Braun, DARPA, and company looking for upper stages to meet performance requirements set out by them.    Having won the contest for the S-IV stage, Douglas Aircraft, at this point meant to be the Orbit insertion stage for the Saturn C-1 and C-2, was intended to have a core diameter of 220” and be powered by 4 of the oncoming LR-119 engines.   The LR-119 would never complete development; even though many sources credit the RL10-A-3 as the LR-119, it is not.   Because of the LR-119 failure looming quickly ahead.  The decision was taken first to upgrade the S-IV stage to accept 6x LR-115 engines, aka the RL10-A-3, and to increase the diameter from 220 inches to 240 inches to accommodate the extra fuel needed for 6 engine operations.      So the specifications as we understand them:

 

S-IV (as designed and mocked up)

 

Mainline diameter= 220”

 

Tapered diameter= 156”

 

Engine qty: 4

 

Engine LR119 (a never completed RL10 development)

 

 

 

S-IV (as-built)

 

Mainline Diameter=240”

 

Tapered Diameter = 156”

 

Engine Qty: 6

 

Engine: RL10-A-3S (this is NOT an LR119!)

 

 

 

The overall height/length of the two S-IV stages as laid out above are about the same, differing only by a few inches.   The main external changes to the Saturn C-1 and C-2 rockets were a completely new “slab side” interstage for the S-IV rather than a conic one as initially planned.   The change in interstage likely resulted in an increase in drag in the transonic regions of flight.  

 

While it is not the reason, it is stated that the change from 4 to 6 engines pushed the need to cut mass from the S-I stage.  This resulted in the re-engineering program that led to the S-IB stage.   The optimized engineering of the S-I stage was not invested in initially as there was no budget for it.   Thus, before selecting the Saturn Rocket as the launch vehicle to the Moon, there was a fiscal need not to optimize S-I.  After choosing the Saturn program to go to the Moon, it became more and more imperative to make the structure more efficient.

 

The S-IV stage would not fly for long on Saturn rockets because of the rapid change from a satellite launcher to a mid-earth orbit to an orbital test of the Apollo program. 

 

We will cover more on the S-IVB latter, but suffice to say, and the S-IV stage was impressive on its own.   The use of a “perfect balsa” insulation…. Being the best insulator for liquid hydrogen then available, Balsa wood gave the S-IV stage the best on-orbit storage of any Liquid Hydrogen tank.    Boiloff still sucked but much less than any then existent alternatives.   Even modern SOFI insulated tanks have a higher boiloff rate than the S-IV’s “Perfect Balsa” insulation!   Of course, the Perfect Balsa was not natural balsa wood but an artificial equivalent that was then hand-fitted to the tank and structures.   The Saturn program would have made extinct the world supply of ACTUAL balsa had it used the real wood.   The man-hours involved in installing the insulation made manufacturing the S-IV and the latter the S-IVB stages very expensive.   The insulation cost will be addressed again in the MLV section below.

 

 

The Saturn S-IVB,  200 and 500 versions:

 

 

 

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The S-IVB development comes from the need to escape the orbit of Earth with a significant payload.   Contracts for the S-IVB were granted to alter the existing S-IV contracts after selecting LOR for the Moon landing in mid-1961.   Two structurally similar stages would be developed under the contract.   The major changes between the two were to support the various RCS, Ullage, and restart capabilities and all of those features were concentrated at the bottom of the stage in the engine mount area.   The S-IVB used the same tanks in both subvariants.   The S-IVB was designed to utilize the same “Perfect Balsa” insulation as its predecessor.  Still, the larger diameter, 260” up from the 220/240” of the S-IV, and the cylindrical shape of the S-IVB would make it slightly more efficient to build than the smaller but more complicated S-IV.   The % of fuel by mass vs. the overall mass was also better.   The S-IVB was a much more efficient S-IV.    While the switch to a Single J-2 lowered the ISP of the stage by a bit, it did so with a significant mass vs thrust reduction, essentially canceling out the gain from the higher ISP RL10 engines.   However, we are adding mass to the already in-efficient S-I rocket stage at launch, making payload only marginally different from the smaller S-IV stage.)  

 

The S-IVB, the most well-known variant of the S-IV family, does not need more accolades or history space here.  Suffice to say, it was a well-engineered stage and became the building block that all future S-IV variants would evolve from.

 

 

 

S-IVC   To Eros, Mars, and Venus or Bust!:

 

 

 

Modular Launch Vehicle (MLV) MS-IVB:

 

 

 

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When Douglas was working on the Slush fueled S-IVC, NASA decided to look beyond Apollo Saturn Applications.  IE what could NASA do with the existing hardware with a minimum of modifications.  Well, as it turns out, there were many things that could be looked at.    Newer engines were available to enter production in the forms of the F-1A, the J-2S and both Rocketdyne and Pratt and Whitney had programs. Further follow-ons to the J-2S in performance if not form on the books as well.   The ADPAE, or J-2T-250K toroidal Aerospike on one contract.   And the LTBE, or J-2L-250k Linear Aerospike, on a different contract for development.  Both would be tested within a few years with great success.  The only result of all this effort was the XRS-2200, a testbed engine.   This was covered a few months back with my articles on the J-2 engine family.   Pratt and Whitney had the RL20 and XLR-129 under development for various reasons at this time as well.    These engines could work with a minor rework to the S-IVB stage.   These engines (including the growth J-2T-400K) could utilize a stretched fuel supply in the S-IVB to increase efficiency.   At the same time, some structural issues that had come to light in the later Apollo missions could be rectified better than the in-field expedients used to improve the payload capabilities of the S-IVB.   Thus resulting in the MS-IVB family.    Things all the MS-IVB have in common a switch from the S-IVB’s “perfect Balsa” insulation to a hybrid “Perfect Balas” and SOFI (spray-on Foam insulation.)   Improvements to the structural design.   Reduction of the number of changes needed to mount different engines.   IE, the engine choice was more modular, and the choice was not tied to a specific stage.  

 

While not a complete list, here are the MS-IVBs as I have them (grouped by length)

 

Basic S-IVB length:  The MS-IVB-1, MS-IVB-4(S)B the last being 11.8% due to extra structural strengthening to use with the AJ-260 SRBs.

 

16.5ft Stretch S-IVB: The MS-IVB-1A, and MS-IVB-3B, and co-incidentally the Douglas S-IVC

 

17.7ft Stretch S-IVB:  MS-IVB-2

 

 

It should be remembered that the Saturn MLV program was a “what can we do with minimal change to what we got” study.    It was not a straight building block to an extensive and varied portfolio of rockets….   Although with limited additional investment and design choices, it COULD HAVE BEEN.

 

 

Oh and here is a picture of the S-IVC docking:

Correct me if I'm wrong, but wouldn't boiloff make most of that mostly unfeasible? Say, maybe they could have prepared a Saturn V on 39a and a second on 39b, then launch something like a week apart and dock a day later, but that's still a long time. It's why Starship uses a depot after all, and iirc hydrogen boiloff is even faster

Edit: talking about the SIVC

Edited December 4, 2021 by Beccab

[GoldForest]

1 hour ago, Beccab said:

Correct me if I'm wrong, but wouldn't boiloff make most of that mostly unfeasible? Say, maybe they could have prepared a Saturn V on 39a and a second on 39b, then launch something like a week apart and dock a day later, but that's still a long time. It's why Starship uses a depot after all, and iirc hydrogen boiloff is even faster

Edit: talking about the SIVC

If I had to guess, the launches would be 24 hours apart, like Atlas Agena + Titan Gemini missions. The first launch is a wetlab and the second launch is the Venus/Mars transfer stage which would dock less than 48 hours later. Just my take on it, I could be wrong.

[Starwaster]

14 minutes ago, GoldForest said:

If I had to guess, the launches would be 24 hours apart, like Atlas Agena + Titan Gemini missions. The first launch is a wetlab and the second launch is the Venus/Mars transfer stage which would dock less than 48 hours later. Just my take on it, I could be wrong.

24 hours between launches is much more likely than a week. No point in leaving a tank full of hydrogen up there for an entire week if you don't have to.

[CobaltWolf]

17 hours ago, braxfortex said:

I really want to try this mission now.  Docking a dry Skylab with 4 S-IVBs chained together to go to Eve and back (2.5x scale via JNSQ).  Is there a docking ring in BDB or other mod that could enable this?

The S-IVC Docking structure is definitely coming at some point, probably along with some sort of radiator system to control the boil off (if only to make planning easier.

 

14 hours ago, Starhelperdude said:

On what would the XLR-81 8096C engine (the agena engine with the big bell and lower thrut) have been used?

If I remember it's from one of the Shuttle Agena or Reusable Agena papers.

 

14 hours ago, Jcking said:

Gamma refers to Gamma Centaur (which the stage has been alternatively referred to as Centaur Junior) is a Vega like third stage, except hydrolox and using a single RL10

If I remember, they literally took the Vega mockup and attached an RL-10 to it.

[Jcking]

2 hours ago, Beccab said:

Correct me if I'm wrong, but wouldn't boiloff make most of that mostly unfeasible? Say, maybe they could have prepared a Saturn V on 39a and a second on 39b, then launch something like a week apart and dock a day later, but that's still a long time. It's why Starship uses a depot after all, and iirc hydrogen boiloff is even faster

Edit: talking about the SIVC

The report (19690006388) quotes a 30 day orbital lifetime, with additional insulation over the standard S-IVB (most notably removal of the internal insulation and replacing it with an external foam insulation)

Edited December 4, 2021 by Jcking

[Pappystein]

15 hours ago, Starhelperdude said:

On what would the XLR-81 8096C engine (the agena engine with the big bell and lower thrut) have been used?

Cobalt has mostly answered the above question.   The actual engine comes from Shuttle Agena documents.   HOWEVER the performance comes from AiAA paper from 20 years latter that I think is a type o given the same Shuttle Agena document quotes a much higher thrust for the same ISP.

15 hours ago, Jcking said:

I believe that engine meant to be the one for Agena 2000, a MMH/MON-3 upperstage for Delta IV and Atlas V of which little is known about.

The LR-81 was not intended for Agena 2000 (yeah I know I was really confused by that myself.)    But the performance cited in the AIAA paper above ARE from Agena 2000 (which was being talked about in the same paper.)

15 hours ago, Jcking said:

Gamma refers to Gamma Centaur (which the stage has been alternatively referred to as Centaur Junior) is a Vega like third stage, except hydrolox and using a single RL10

Did a bit more research after my post above.    I am going to partially retract my statement from above.   Re reading Joe Powel's excellent if abbreviated history of the Vega stage re-kindled a thought... one I just accused everyone else of missing...  Time Dilation.    It appears, and I am concluding without a full set of facts here, that there were TWO teams at Convair working on Centaur JR in the runup to the Atlas F stretch proposals.   The timing of the Atlas F.  With it's H-2 engines and Centaur JR is BEFORE the first centaur launch but around or after the cancellation of Vega.   It seems Gamma is a quick and dirty "alternative" to the scaled down Centaur that Convair was wanting designed.

9 hours ago, Thatguywholikesionengines said:

I came here to wonder why the former CADS port, an androgynous, 0.9375 port that I was planning for use on shuttles and a Skylab knockoff, got changed with the development versions to 1.25m, with an appearance more similar to the CBM. I miss my old port, and don't wish to use the Apollo probe/drogue.

The port you are looking for is Benjee10's C-100 port.   IIRC the BDB team has sourced that port and it is in BDB already.    But, if you are like me, you may want the original port that Benjee10 made (in-case he updates it or similar)

https://github.com/benjee10/Benjee10_sharedAssets/archive/refs/heads/master.zip

The neat thing about the C-100 vs the old CX-Aerospace APAS port that WAS in BDB, is that it is colorful and more forgiving than the old CX one.  Also there is a "right side dot" on one side so you can tell the correct orientation needed to have a perfect dock everytime.

3 hours ago, Beccab said:

Correct me if I'm wrong, but wouldn't boiloff make most of that mostly unfeasible? Say, maybe they could have prepared a Saturn V on 39a and a second on 39b, then launch something like a week apart and dock a day later, but that's still a long time. It's why Starship uses a depot after all, and iirc hydrogen boiloff is even faster

Edit: talking about the SIVC

 

6 minutes ago, Jcking said:

The report (19690006388) quotes a 30 day orbital lifetime, with additional insulation over the standard S-IVB (most notably removal of the internal insulation and replacing it with an external foam insulation)

Ignoring the key factors, Switching to SOFI would actually increase boil-off vs Perfect balsa.       But you have the right of it Jcking.   The biggest benefit of the S-IV stages is they are NOT Balloon tank stages.   They are in fact rather well built pressure vessels. 

The factors of Boil-off:

1. Thermal Boiling of the Liquid Hydrogen
2. Lack of pressure containment to re-force Gaseous Hydrogen to re-liquify
3. lack of structural strength forcing the out-gassing of the gaseous hydrogen

An easy way to visualize Boil-off is your favorite carbonated beverage be it Pop, Seltzer or Soda water.    (YES Faygo invented the bubbly drink we all love, they call it POP thus it is POP not Soda people!  regardless of what Coke or Pepsi, or some states in the Union might say  )

You shake it up and you watch it fizz and fizz in the sealed container....   If you wait a few moments most of the fizz, the gaseous Carbon Dioxide, is mostly re-absorbed into the liquid.   This is because of the higher pressure created by the shaking.    IF the top was open or loose when you did it, you get a jet of carbon Dioxide, along with some Carbonic acid and whatever other fun stuff was in the bottle.   This is Boil-off as a countertop Science experiment.  

In the case of Saturn S-IV stages, the same thing would basically happen.    But in the case of the fragile Centaur balloon tanks...   You HAVE to vent the gaseous Hydrogen because you WILL explode.

Think the Saturn IV stages as a fully sealed  Bottle, and the Centaur a Bottle with the cap twisted 1/4th of the way off.   Do the experiment enough, with the Centaur analog and you are going to have a Fizzy mess everywhere...   

 

Now onto the Specifics of the S-IVC.

1. Improved insulation installation.   I think it is a Hybrid of SOFI and Perfect Balsa but I didn't go far into details on that.  SOFI on the LOX tank would make perfect sense for example.  SOFI is something like 90% as effective as Perfect Balsa
2. Slurry Slush Hydrogen... solid has to translate to liquid before it can boil off.... for the most part....
3. extra Hydrogen due to the semi-solid state of the Hydrogen (more can be lost to boiloff... a perfect burn would deplete LOX before Hydrogen in other words
4. Extra strength designed into the fittings.  Allows for greater pressures in the tanks before venting.

Each of those four points dramatically improve on orbit stay time before Hydrogen loss is endemic.    I would GUESS that the 30 day on orbit time is 30 days until the Hydrogen has depleted enough to not allow a full burn to LOX depletion.

 

Oh and no Kidding, I can give you Hypergolics at the countertop... well more like sidewalk  for science experiments...  All OTC stuff   But you will stain your Concrete purple so I don't suggest it....    Only involves to reagents... one for your aquarium and one for your scrapped knee

 

 

[Pappystein]

Followup thought on Boil-off.   30 days in orbit is enough time that LOX Boil-off would be a concern.  After all this is why the Vega was paired with the 6K stage from TRW.   The Vega actually outperformed Agena B in all critical stages except on orbit fuel stability... because LOX boils off.

[Zorg]

12 hours ago, Thatguywholikesionengines said:

Your AARs are absolutely awesome, Trev!

I came here to wonder why the former CADS port, an androgynous, 0.9375 port that I was planning for use on shuttles and a Skylab knockoff, got changed with the development versions to 1.25m, with an appearance more similar to the CBM. I miss my old port, and don't wish to use the Apollo probe/drogue.

the old CADS was just a real world APAS under a false name. The new one is accurate in size and configuration to the CADS from Eyes Turned Skyward, basically CBM with petals.

With Benjee's permission we have included his excellent 0.9375m APAS in BDB since we knew people would miss the ports in that size. The config file will not conflict with Benjee's own if you install one of his mods either. It should turn up if you search for APAS. Part name is C-100 Androgynous Docking Mechanism

[ballisticfox0]

 

 

[pTrevTrevs]

14 hours ago, flamerboy67664 said:

Awesome AARs man, but something I noticed with your pics and also previous posts...

I seem to recall from my days of simming whole Apollo missions with AMSO in Orbiter 2006 and reading NASA docs, didn't the crew activate the LM (turning on stuff like antennas and comms, and extending LDG) before LOI to check if the LM is bad and they would go mission abort with the free return trj if so?

Uhh, I’ve always understood that the LM was temporarily powered up during the translunar voyage to check it out and give television audiences a tour inside it, but its legs and antennas weren’t deployed until reaching lunar orbit (but before undocking from the CSM). If a problem with the LM had been discovered then the crew could always perform some sort of lunar orbital observation contingency mission and then return to Earth by using the SPS to perform a standard TEI.

 

10 hours ago, TaintedLion said:

Is that a little Ocean of Storms reference I pick up there?

Possibly.

Actually, theOcean of Storms scenario for Apollo 13 is in turn a reference to an actual simulation that had been run during the training for Apollo 13, in which the SimSups threw a cabin depressurization at Ken Mattingly while he was alone in the CSM and Lovell and Haise were “on the surface” in the LM. Flight controllers didn’t pick up on the issue until some 45 minutes later because it was triggered right as Odyssey slipped behind the Moon, but Mattingly noticed the depressurization and donned his spacesuit to wait it out.

[Adam-Kerman]

AARs?

I'm also a bit of a Railroad Person, so AAR is "Association of American Railroads"