Some ATL US Space Program questions, with pictures.

I've been doing some work on a rewrite of 'Seeing Further' and decided to go with a near OTL STS shuttle (save for a pair of jet engines in the wing roots for more cross range), and needed an HLV for a Mars mission (nuclear). So I've done some math and design for an SLS lite, by merely sticking the STS engines to the bottom of the external tank and add the payload on top.

wCE2291.png

Shuttle parts are from the NASA 3D model repository.

With slightly more fuel in the main stage tank, this baby can lift 120 tonnes into a 205x205 km@28.5° orbit. And its still 100 tonnes into a 500x500km@28.5° orbit. Even have a version with an additional NERVA 2 powered second stage, that increased the throw weight to 165 tonnes to 205km@28.5°and 150 tonnes to 500km@28.5° or 70 tonnes straight to Mars.

Also, an idea of mine would get a space station up and running right quick, but have to check some things real quick.
If its using the Shuttle Main tank as a wet workshop. Its been done. :p
 
I've been doing some work on a rewrite of 'Seeing Further' and decided to go with a near OTL STS shuttle (save for a pair of jet engines in the wing roots for more cross range), and needed an HLV for a Mars mission (nuclear). So I've done some math and design for an SLS lite, by merely sticking the STS engines to the bottom of the external tank and add the payload on top.

With slightly more fuel in the main stage tank, this baby can lift 120 tonnes into a 205x205 km@28.5° orbit. And its still 100 tonnes into a 500x500km@28.5° orbit. Even have a version with an additional NERVA 2 powered second stage, that increased the throw weight to 165 tonnes to 205km@28.5°and 150 tonnes to 500km@28.5° or 70 tonnes straight to Mars.


If its using the Shuttle Main tank as a wet workshop. Its been done. :p
Heard the terms "Wet & Dry" in relation to orbital workshops, but what does that mean? Not quite, as I planned to be able to use the ET like that anyway, but my idea is for quite a bit faster construction.
 
I've been doing some work on a rewrite of 'Seeing Further' and decided to go with a near OTL STS shuttle (save for a pair of jet engines in the wing roots for more cross range), and needed an HLV for a Mars mission (nuclear). So I've done some math and design for an SLS lite, by merely sticking the STS engines to the bottom of the external tank and add the payload on top.

wCE2291.png

Shuttle parts are from the NASA 3D model repository.

With slightly more fuel in the main stage tank, this baby can lift 120 tonnes into a 205x205 km@28.5° orbit. And its still 100 tonnes into a 500x500km@28.5° orbit. Even have a version with an additional NERVA 2 powered second stage, that increased the throw weight to 165 tonnes to 205km@28.5°and 150 tonnes to 500km@28.5° or 70 tonnes straight to Mars.

For a design like that, you appear to have a larger propellant load in the main tanks of the Core Stage, and I can't help but think a 4th engine would be needed for it, a circularisation stage atop the core stage for a final kick plus might also help.

And in such a case, you're better off just using that design for both cargo and shuttle, which means the Orbiter in this instance would lack the SSME engines, aka Energia-Buran.

Buran-1511.jpg



Heard the terms "Wet & Dry" in relation to orbital workshops, but what does that mean? Not quite, as I planned to be able to use the ET like that anyway, but my idea is for quite a bit faster construction.

Wet Workshop refers to a Stage (Usually the Saturn S-IVB) which sends itself into Orbit, and then is outfitted to serve as a workshop once there.

Dry Workshops are built and checked out on the ground before launch. Essentially Skylab, Salyut, Mir, etc.
 
Heard the terms "Wet & Dry" in relation to orbital workshops, but what does that mean? Not quite, as I planned to be able to use the ET like that anyway, but my idea is for quite a bit faster construction.
The Wet/Dry workshop concept was developed during the 1950s to use existing rockets that had expanded their fuels as stations by opening up the tanks, meaning that they were 'wet' during ascent. A dry workshop is 'Dry' during ascent, the best example is Skylab.
For a design like that, you appear to have a larger propellant load in the main tanks of the Core Stage, and I can't help but think a 4th engine would be needed for it, a circularisation stage atop the core stage for a final kick plus might also help.
As I said, SLS lite, the Math certainly checks out, no fourth engine needed. Heck, based on Silberbird a four engine even dropped the payload. And the propellant load is only marginally larger.
And in such a case, you're better off just using that design for both cargo and shuttle, which means the Orbiter in this instance would lack the SSME engines, aka Energia-Buran.

Buran-1511.jpg
Actually not a bad idea. The Timeline is still in work after all... :p

Though it makes using the external tanks as wet workshops a tad harder. :p
 
So what would we call a structure that is lofted as an "outer hull" for the ET or payload. What I mean is, say you are willing, on most missions, to put a cylindrical sheath around the ET (and this does mean the shackle points would be to this sheath, and not the ET itself), and then once in orbit, you have a hollow cylinder that is slightly bigger than the ET in diameter (and perhaps one for the payload, as well), that can serve as readymade space station components, so every launch that includes these “sleeves” will have less of a payload, but more and earlier, Space Station modules.

I will post an image later, showing the notional concept, including the use of “Double Fronts” during ascent and orbital injection, where the first “Front” is detached during an EVA, and placed on the back, thus completing the enclosed space.

On this type of launch, the payload would be very limited, but now you would have a great honking place to put future payloads into. As well, you would still have the empty ET, and OSS up in orbit. If you had a bigger than OTL version of the ET, such that it’s “Sheath” would be able to function as a working ‘garage/maintenance bay’ for the OTL sized ET and OSS, then experiments in orbital retro fitting and refueling, pre-staging of parts, fuel, components and such, for outward bound future mission could begin almost from the very first launches.

Also, such a notional “Bigger than OTL ET”, could be fitted with a scaled up return capsule for larger objects to be returned in a cost effective manner to Earth. Did someone mention SSME’s?
 
Removing wings off the shuttle changes the Center of Gravity/Center of Pressure balance you need for stability under power
 
It does, and no help for it, however, this notional OSS is either going to be stacked with, and hear is as good as any place to rename what in OTL was called the External Tank, but ITTL would really be a LR, or in space where it doesn't matter, or am I wrong on this?

Here is a once again crappy image to attempt to convey my idea for an ATL Space program shuttle stack.
wSH2wB2l.jpg

On the Left is the OTL, in the Center is where I am trying to show the concept of blunt, non-areodynamic tops to the LR and OSS, where scalable cargo/payloads would be attached, and then On the right is where I make a poor attempt to render TTL Orbital Space Shuttle, in green.
 
Can someone give me some technical info the the weights for a notional "outer hull" sheathing system as described up thread? It would need to be able to fit around the OTL External Tank (ITTL: Liquid Rocket), be sufficiently strong to bear the stresses of launch, and be capable of use as a Space Station Module.

Doable, or way out there and impossible?
 
Though it makes using the external tanks as wet workshops a tad harder. :p

I see one big issue with the usage of the ETs as wet workshop. The foam. It'll be like popcorn once it gets into orbit (since it'll be separating from the ET), and that will become a big issue and I would drastically worry about the chances of damage that could occur to the Shuttle's TPS.
 
Heard the terms "Wet & Dry" in relation to orbital workshops, but what does that mean? Not quite, as I planned to be able to use the ET like that anyway, but my idea is for quite a bit faster construction.

It's worth noting that "wet workshops" have never panned out. It turns out that the difficulty and expense of re-fitting the tanks (which require long hours of EVA work by highly, highly paid astronauts who only get to the work site by being lofted into space on billion-dollar rockets.

It has been far cheaper in practice to launch whole dry workshops that are pre-built on Earth by mere high paid workers who don't need to go on an EVA to work inside the construction site and can commute to work in a $9000 car.

Can someone give me some technical info the the weights for a notional "outer hull" sheathing system as described up thread? It would need to be able to fit around the OTL External Tank (ITTL: Liquid Rocket), be sufficiently strong to bear the stresses of launch, and be capable of use as a Space Station Module.

Doable, or way out there and impossible?

Well, how thick is the cylinder, what materials does it use, is it single or double walled (a double wall is the usual micro-meteor protection system)?

I think the main issue with wrapping the station walls around the ET for launch is it then begs the question of how the SRBs attach and how the orbiter attaches.

fasquardon
 
Yep, the SRB and OSS are going to have to be attached to the "Outer Hull", so it needs to fit like a glove around the LR, and needs to augment the structural strength of the whole.

As for the materials and its needed thickness, I have to leave that to folks better informed than myself. Say we took the basic form of the ET, and as TTL OSS doesn't draw fuel from it, it can be quite a bit more streamlined (and the OTL Space Shuttle Main Engines would now be Liquid Rocket Main Engines).

For ease of discussion, lets have TTL LR a flat 30' diameter, and the notional shell needs to fit that and yet be sturdy enough to bear the stresses during launch, so some kind in internal surface integration/lock mechanism is going to be needed between the two. If we assume that the same material as the OTL ET is used, and it's diameter is large enough to provide the double walled construction needed to serve as a prebuilt Space Station Module, what kind of a mass are we talking about? Is it even possible, or would this notional shell be more than the total payload capacity of the OTL system?

If it doesn't take up all of the payload, but rather only a large portion of it, would we see the ATL US Space Program just continually lofting additional modules with the majority of launches?
 
Yep, the SRB and OSS are going to have to be attached to the "Outer Hull", so it needs to fit like a glove around the LR, and needs to augment the structural strength of the whole.

As for the materials and its needed thickness, I have to leave that to folks better informed than myself. Say we took the basic form of the ET, and as TTL OSS doesn't draw fuel from it, it can be quite a bit more streamlined (and the OTL Space Shuttle Main Engines would now be Liquid Rocket Main Engines).
As a rough guess, the wall would need about 6mm of aluminum. That'd add about 22 metric tons of aluminum, plus bracing between the two walls. It could easily knock up to 30 tons off the payload once you account for some kind of sealing ring around your proposed removable ends and the structure to convey loads and act as a replacement for the ET. Once on orbit, it'd be days or weeks of intensely manual EVA to unbolt the ends of this notional container, pull the ET out, and bolt the ends back on. In the end, all you gain is a giant empty can not much different than an ET with altered insulation for much more work. It's not really worth bothering with. If you need a module that large for a one-off mission and already have room for an inline payload fairing on the stack, it's much batter to just fit out the module on the ground and launch it in the fairing. If you want to try and make a module out of something you fly every flight, using the basic ET as your base is far better. Even there, as others mentioned, it's been such a pain when previously studied that it's never actually been done in practice. Shear volume on orbit has never been enough of a problem to warrant it when crew time--the major resource such a wet workshop consumes--is actually the most limited factor.
 
As a rough guess, the wall would need about 6mm of aluminum. That'd add about 22 metric tons of aluminum, plus bracing between the two walls. It could easily knock up to 30 tons off the payload once you account for some kind of sealing ring around your proposed removable ends and the structure to convey loads and act as a replacement for the ET.
Awesome, and thanks for the information. So for a significant portion of the mission payload, we get a large, reusable Space Station Module, plus a payload to put inside it, all in one go?

Once in orbit, it'd be days or weeks of intensely manual EVA to unbolt the ends of this notional container, pull the ET out, and bolt the ends back on.
I have trouble with these figures, could you clarify why it would take so long to separate them? I don't know the reasons that would make this assessment likely, so if you explained them, then I might be able to propose some time saving alternatives/improvements. I would expect to have an EVA component of most missions, and definitely all that involved using such a "Sheathing" to comprise large, cheap, reusable Space Station Modules.

In the end, all you gain is a giant empty can not much different than an ET with altered insulation for much more work. It's not really worth bothering with. If you need a module that large for a one-off mission and already have room for an inline payload fairing on the stack, it's much better to just fit out the module on the ground and launch it in the fairing. If you want to try and make a module out of something you fly every flight, using the basic ET as your base is far better.
If your so inclined, please provide a detailed explanation of this, as my idea for an ATL US Space Program would involve an ongoing mission to steadily expand the US presence in space, and that as an integral portion of this would include labor-saving, power tools designed to be used in zero/micro G environments, as such would be needed nearly every mission excluding resupply missions.
For instance, having watched the repair video for the Hubble, I was like, "How could they possibly have done it that way, when there could have been a much easier effort had they lofted a reusable repair bay to conduct the work inside of?"

I wouldn't see much in the way of One-Off uses, as once we have paid the cost to get the thing into orbit, leaving it there under-utilized would simply be seen as something for a future mission to correct.

Even there, as others mentioned, it's been such a pain when previously studied that it's never actually been done in practice. Shear volume on orbit has never been enough of a problem to warrant it when crew time--the major resource such a wet workshop consumes--is actually the most limited factor.
This would change, though, would it not, if such work was not handled as a one-off, do it a couple times over the course of the entire program kinda thing, but rather as an every mission kinda thing. In other words, they would take the time to think things through, and provide the labor saving tools and equipment to make these tasks far less time consuming and tedious, since they would be doing such things on most missions.

Like providing the equivalent of an auto mechanic with a "dolly on wheels" to service the underside of a car, or the equivalent of the lumberjacks belt to climb trees, so too would I see the astronauts being equipped with the tools of the trade.
 
Another question pops into my head, how much weight is saved by changing the OTL Space Shuttle to my notional Orbital Space Shuttle, as seen in post #27?
 
Awesome, and thanks for the information. So for a significant portion of the mission payload, we get a large, reusable Space Station Module, plus a payload to put inside it, all in one go?
Something like half to two thirds the mission payload, really. I realized that while I accounted for the walls, I didn't account for the antiradiation protection between them, which is usually about 10 cm of polyurethane. That'd raise the total mass of such a module by about 50 metric tons, to a total of 70 metric tons--more than 3/4 of the payload of a Shuttle-derived heavy. Cutting down that foam could make it "only" half, but thats still far, far too much to throw away when station volume is not the driving factor for utilization of a space station.

I have trouble with these figures, could you clarify why it would take so long to separate them? I don't know the reasons that would make this assessment likely, so if you explained them, then I might be able to propose some time saving alternatives/improvements. I would expect to have an EVA component of most missions, and definitely all that involved using such a "Sheathing" to comprise large, cheap, reusable Space Station Modules.
Sure. EVA is slow, painfully so. Spacesuits are, by their nature, incredibly bulky, and space as an environment requires thinking ahead and carefully planning out ones work. Read about the recent EVA-37 on ISS. It was a seven hour EVA, but the main accomplishments would have taken perhaps a third that time on the ground in gravity and pressure, unhampered by gloves that barely flex and more. It'd probably be a solid EVA day just to prepare the end for removal, unbolt the end (which could run to 30 or more individual bolts to ensure a proper seal--one every few feet if not more--move it and latch it out of the way. Then there's a day or so to extract the ET from the inside of the can (and how exactly are you moving 30+ tons of external tank?), discard it or whatever, then another day or so to bolt the ends back one. Then you'd need to remove aerodynamic and thermal protection from any docking port in the module, inspect the interior, check that it will will hold pressure, and this just gets you to the point of having an empty aluminum can the size of a house--it doesn't even begin to approach the work of routing air ducts and power cabling, actually pressurizing the volume, or beginning to install internal floors and the like--something that takes days or weeks when finishing a building on the ground, much less when trying to assemble one IKEA-style in spacesuits when all the bolts want to drift away.

If your so inclined, please provide a detailed explanation of this, as my idea for an ATL US Space Program would involve an ongoing mission to steadily expand the US presence in space, and that as an integral portion of this would include labor-saving, power tools designed to be used in zero/micro G environments, as such would be needed nearly every mission excluding resupply missions. For instance, having watched the repair video for the Hubble, I was like, "How could they possibly have done it that way, when there could have been a much easier effort had they lofted a reusable repair bay to conduct the work inside of?"
They did loft one: the Space Shuttle. The main function of the payload bay on such missions was acting as a support and access structure for working on payloads (indeed, Hubble servicing is one of perhaps a double handful of missions this capacity was ever used as intended). Now a large, pressurizable one? That'd run far heavier, at least were it to have been large enough to put Hubble into without retracting its solar arrays--larger than the OTL Shuttle payload bay, and also acting as a giant airlock.

This would change, though, would it not, if such work was not handled as a one-off, do it a couple times over the course of the entire program kinda thing, but rather as an every mission kinda thing. In other words, they would take the time to think things through, and provide the labor saving tools and equipment to make these tasks far less time consuming and tedious, since they would be doing such things on most missions.
They did take the time to think things through and provide the best tools they could. Every hour of EVA on orbit receives tens or hundreds of hours of support on the ground, including simulation training with the crew before they go to space to act out the mission in advance. They still are as much of a pain as they are because space is hard. This is why it's better whenever possible to install hardware into a module before launch, or in pre-integrated chunks like ISS Payload Racks. You can then use the tens and hundreds of ground labor hours to do the work, not the 1 or 2 hours of EVA time they'd be able to support and easily accomplish orders of magnitude more.

Another question pops into my head, how much weight is saved by changing the OTL Space Shuttle to my notional Orbital Space Shuttle, as seen in post #27?
Your OSS, being about the same size as something like the HL-42 minishuttle, would be of roughly similar mass--28-30 tons, maybe more if it's still carrying the SSME. If it's not carrying the SSME, I'd move the entire stack to an "inline configuration" with the orbiter at the nose, so it is only required on flights carrying a manned payload and it is protected from foam or ice falling from the rest of the rocket. Adding that to the proposed ET wrapper (~50-70 metric tons) and that's basically the payload of an entire SDHLV stack, which runs about 80-90 metric tons without a second stage and maybe 120 tons with one.
 
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I got to get offline here real quick, so just a short reply for now, and thanks for taking the time to explain it to me.

Something like half to two thirds the mission payload, really. I realized that while I accounted for the walls, I didn't account for the antiradiation protection between them, which is usually about 10 cm of polyurethane. That'd raise the total mass of such a module by about 50 metric tons, to a total of 70 metric tons--more than 3/4 of the payload of a Shuttle-derived heavy. Cutting down that foam could make it "only" half, but thats still far, far too much to throw away when station volume is not the driving factor for utilization of a space station.
Well, I have to say that is dissappointing, lol. I was getting all excited about the prospects for using the "Sheathing" method to get a large Space Station built on the cheap. Just what was the payload max for an OTL SS stack?
 
I got to get offline here real quick, so just a short reply for now, and thanks for taking the time to explain it to me.

Well, I have to say that is dissappointing, lol. I was getting all excited about the prospects for using the "Sheathing" method to get a large Space Station built on the cheap. Just what was the payload max for an OTL SS stack?
It reached orbit with a gross mass of about 105-110 metric tons--80 metric tons empty for the Orbiter, plus 7ish tons of OMS propellant, then 25ish metric tons of payload. For a Shuttle-Derived HLV, you still need to carry about 12 tons of the Orbiter mass for the SSME, plus 10-15 tons of structure to support them as a thrust structure, so most SDHLVs you see talk about 70-90 metric tons, depending on their particular assumptions.
 
So a quick look puts the OTL shuttle at 80 some odd tons by itself, and if I got my OSS in at 30 tons, I would just about be breaking even?
 
Ok, so my 30 ish ton OSS, with an identical (Or less) fuel load for the OMS, but no SSME as it doesn't have them, and then the 50-70 tons for the sheathing...

So it would be kinda sorta close?

I really want to include the "Sheathing" thing in my ATL, mainly for coolness factor, something like, "I thought of this" kinda thing. I got the Budget side beat (Or at least I think I do), so costs are going to be far less of a problem.
 
Last post before I got to go for a few hours, On the change over from an ET to a Liquid Rocket, with the shuttle no longer having the SSME, will I need to have two different OSS's, so I can have one with the fuel from the old Apollo CSM to get the advantages of on orbit station?
 
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