Author Topic: Space Truck: Space Station Construction Requirements - Speculation  (Read 5580 times)

Offline Norm38

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The Space Shuttle built ISS, with American modules that were for the most part designed to fit the existing dimensions of the cargo bay.  With Shuttle retired, the next orbital station will be built by something else. Possibly an ITS derivative. We don't need to focus on ITS exclusively, but it's a useful starting point for the discussion.

Maybe a dedicated thread is overkill, but I wanted to start a discussion on cargo bay dimensions, the size and functionality of modules that allows, and how that impacts other vehicle parameters such as overall diameter.

Is it best to stick with ISS type dimensions?  Or something more square (squat)? If you are designing a new space station, fuel depot, etc (not just Bigalow modules), what are your cargo bay requirements? What does a space truck have to look like to get the job done?

Dimensions
Shuttle Bay:       18 x 4.6m dia.     300m3
Zvezda:             13.1 x 4.1m dia.  173m3
Kibo:                 11.2 x 4.6m dia.  186m3
Bigalow "990"     20 x 10m dia.      1570m3  -  Not going to fit ITSy

ITSy Option:     10m x 7m dia.     385m3


Image credit to lamontagne
« Last Edit: 08/29/2017 07:23 PM by Norm38 »

Offline RonM

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It's not going to be design the cargo bay for the space station modules, it's going to be what can we fit in the cargo bay of the space truck.

What do you mean by more square?

Offline Lar

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The shuttle payload bay is long and narrow. ITSy's cargo area is squatter (more square). That's my guess.
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Offline DOCinCT

Not all modules were launched via Shuttle.  The largest module , Zvezda, was a Proton M and measured 43ft x 13.5ft.  The longest Shuttle module was Kibo at 36.7ft and the largest diameter, Leonardo, was 15 ft.

Offline Norm38

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Could Shuttle have carried Zvezda? It fits.
Maybe FH is used to launch big self propelled modules, I'm curious about the cargo bay.

Looks like the ITSy bay could be 15m long but 7-8m in diameter. ~600m3.  But could be only 10m x 7m, 385m3.

Shuttle was 300m3, Kibo 186m3.  Roughly.

Offline Space Ghost 1962

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Shuttle payloads also were designed to be trunnion mounted for the Shuttle to accept loads through load paths via the sides of the cargo bay vertically, as well as cases where return loads could be accepted horizontally through spars.

It is unclear the facility of a BFS/ITS/ITSy payload bay. Suffice to say that fat/wide payloads aren't currently very desirable, especially with a sole platform to fly them.

And no, Shuttle likely would not have been able to fly Zvezda for various reasons. First, it was designed to be launched by Proton. Yes it could have been modified, but to no advantage.

You have existing FH/F9/EELV/other payloads. Apart from SX unique needs, the "paying" payloads will "look" like the existing ones. With few exceptions.

This will only change when multiple vehicles start flying with superset sizes/capacities/capabilities. And then the lag times will be 4-5 years after flight proven. Because that's how long it will take to factor them in.

Offline M_Puckett

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The Space Shuttle built the ISS the way it did because we did not have a Saturn V class launcher to launch Skylab or bigger class modules.

It was a thing of necessity, not a thing of optimization.

If you have a 9M ITS, Launch 8M modules under a 9M faring, not in a cargo bay.

Or launch something Bigelow that inflates to 15M.

Offline Roy_H

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I envision a rotating space station with a non-rotating core for spaceship docking, manufacturing and experimenting in a weightless environment. The living area would be in the outer ring which would rotate at 1 or 2 rpm and consist of Bigelow 990 modules strung end to end in a circle. For 2 rpm this would be about 36 modules. Of course there is no such thing as a Bigelow 990, but my proposal would use this size about 10m dia and 18 to 20m long. This size works well to allow a central sidewalk size walkway to run continuously through all the modules, with each module having an upstairs living quarters and a "basement" below for utilities, water, electrical service etc. The main floor would have common living areas and offices. Agricultural modules would not have the upper living level.

So, to get back to the question in this thread, I think this style module would have to be pre-fabricated on earth and sent up with floors and rooms installed so that means pre-inflated. Cargo bay would therefore have to be slightly larger than 10m dia and 20m long.
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Online Coastal Ron

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You have existing FH/F9/EELV/other payloads. Apart from SX unique needs, the "paying" payloads will "look" like the existing ones. With few exceptions.

This will only change when multiple vehicles start flying with superset sizes/capacities/capabilities. And then the lag times will be 4-5 years after flight proven. Because that's how long it will take to factor them in.

A good point, and one that I've echoed in the past.

We need to focus more on what can be done with commodity transportation, because historically it has been the cost of doing things in space that has been the greatest barrier, not technology. And I think our experience with the ISS has shown that we have not yet reached the maximum size potential of structures that are assembled from components that can fit on the current worldwide fleet of commercial launchers.

For Ariane 5 and Falcon 9/H they can carry payloads up to 4.5m in diameter within their fairings, and at least 6.7m in length, but to make sure more international launchers can be used it would be better to assume a slightly small diameter (JAXA H-IIB is likely 4.4M diameter capable).

And while the least expensive option would be to standardize on the least expensive launch provider(s), I would advocate that it would be better overall to involve as many nations as possible and anticipate that some launches would be done by higher cost providers. In other words spread the launch participation as much as possible, and by getting more companies, individuals and nations involved the in-space costs will likely be lower over the long run.

Then, as capabilities average up in size, the average payload size can be increased. So this approach is not limiting, but ensures the highest level of participation from the beginning.

My $0.02
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline SweetWater

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Is it best to stick with ISS type dimensions?  Or something more square (squat)? If you are designing a new space station, fuel depot, etc (not just Bigalow modules), what are your cargo bay requirements? What does a space truck have to look like to get the job done?

I think it probably depends on what the purpose of the station is. A fuel depot is going to look very different from a station that caters to space tourists, and a station designed for microgravity science is going to look very different from one with other science objectives.

Also, it is worth remembering that many of the Russian components for the ISS performed autonomous rendezvous and docking with the station. There is no reason to assume that the ITS will assume a shuttle-like role in delivering modules to a future station. I think it is far more likely that a re-usable first stage (the ITS booster, New Glenn, etc.) will boost modules to orbit, and they will rendezvous with the station themselves and then either perform autonomous docking or a robot arm on the station will conduct berthing operations.

Offline Norm38

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If you have a 9M ITS, Launch 8M modules under a 9M faring, not in a cargo bay.

How many different versions will they build?  If the portion of the ship that contains the cargo bay is essential for re-entry, then it can't simply shed fairings.  And the whole point of full reuse is to not drop fairings. If a 5m fairing costs $6mil, then 9m is at least $20mil.  A lot to throw away per mission.

Offline Norm38

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I think it is far more likely that a re-usable first stage (the ITS booster, New Glenn, etc.) will boost modules to orbit, and they will rendezvous with the station themselves and then either perform autonomous docking or a robot arm on the station will conduct berthing operations.

Any LEO station module that has to include propulsion can always fly itself into position, not an issue.  But does every module need propulsion?  Could ISS have been assembled from something like Cygnus modules?  Does the propulsion portion stay attached forever, or does it detatch and reenter?  What about things like the solar arrays and trusses?  Are they all self-propelled?
Fuel, engines, attitude control, navigation, power.  A lot of extra hardware, mass and cost, per module.

I am looking at this from a commodity aspect.  Assume SpaceX is flying the 9m ITSy at the rates they want to fly it. Assume its the lowest cost option. Does it make sense to launch smaller self-propelled modules on more expensive rockets, or to launch larger more capable modules on ITSy?  If so, what will engineers do with that capability?
« Last Edit: 08/29/2017 02:32 PM by Norm38 »

Offline Lar

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If you want to minimize cost but feel you need propulsion on all modules, it probably ought to be modular so that it can be detached from modules as they are emplaced, and either reattached in a central place to be used for stationkeeping (after being refueled) or put in a cargo bay and returned to earth.
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Offline guckyfan

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If you want to minimize cost but feel you need propulsion on all modules, it probably ought to be modular so that it can be detached from modules as they are emplaced, and either reattached in a central place to be used for stationkeeping (after being refueled) or put in a cargo bay and returned to earth.

Or use them as tugs to place more modules.

Online Coastal Ron

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Any LEO station module that has to include propulsion can always fly itself into position, not an issue.  But does every module need propulsion?

No. If we use the terrestrial analogy of how we move cargo around today, we would use some form of reusable tug to grab the cargo out of the delivery vehicle and either store it for later or move it to the construction site. Different analogies would be either a tug/tractor (for longer distances) or a forklift (for short distances).

Quote
Could ISS have been assembled from something like Cygnus modules?

I think there would need to be dedicated construction assets that would need to be put in place before construction starts, such as a housing module (I'm assuming humans will be required), construction arms and mobility systems, and tugs (plus whatever infrastructure they require). Then you'd be ready to accept material deliveries from Earth (or wherever) and be able to assemble or attach them to whatever you're building.

Quote
Does the propulsion portion stay attached forever, or does it detatch and reenter?

As of today we don't have a 100% reusable transportation system to space and back to Earth. So as of today there would be a lot of waste. Hopefully that can change with the ITS and other reusable systems, but if we wanted to build something big in space today we should price into it a lot of expendable hardware.

Quote
I am looking at this from a commodity aspect.  Assume SpaceX is flying the 9m ITSy at the rates they want to fly it. Assume its the lowest cost option. Does it make sense to launch smaller self-propelled modules on more expensive rockets, or to launch larger more capable modules on ITSy?  If so, what will engineers do with that capability?

Depends on what is being built, but I think the faster we standardize on modular in-space construction using reusable transportation systems, the faster we'll be able to expand out into space.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Online Cherokee43v6

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In my opinion, the best 'Space Truck' design currently is what SpaceX and Blue Origin are doing/attempting.  Reusable unmanned flight.

Second best is pure cargo heavy lift like SLS delivering high volume/high mass modules for on-orbit assembly.

Combining 'manned' cockpits with in-space cargo delivery is heading down the road of the same set of bad compromises that caused the Shuttle to never live up to its hype.

If a manned presence is required, then a Dragon, Starliner, Dream Chaser, or Orion should fly them separately.
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Online wannamoonbase

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In my opinion, the best 'Space Truck' design currently is what SpaceX and Blue Origin are doing/attempting.  Reusable unmanned flight.

Second best is pure cargo heavy lift like SLS delivering high volume/high mass modules for on-orbit assembly.

Combining 'manned' cockpits with in-space cargo delivery is heading down the road of the same set of bad compromises that caused the Shuttle to never live up to its hype.

If a manned presence is required, then a Dragon, Starliner, Dream Chaser, or Orion should fly them separately.

Completely agree.  In an age where we're going to have robot cars driving us around we don't need a crewed cargo carrying spacecraft.
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Offline Norm38

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Combining 'manned' cockpits with in-space cargo delivery is heading down the road of the same set of bad compromises that caused the Shuttle to never live up to its hype.

The problems with Shuttle's architecture had nothing to do with having crew on board. And ISS probably wouldn't exist if Shuttle had been unmanned.  What would have hosted the assembly crew for a week?
Cargo vehicles don't have to be manned of course, but that's not the deal breaker.

Offline BobHk

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Well we don't NEED crew on board a automated cargo delivery... even station assembly can be automated to a degree to reduce human casualty probability, every accommodation to crew reduces the size of the module delivered.  A series of fifty ton bigelow like expandable modules strung together would be cool but every thing put up there has to have a mission whether its fuel depot, science, or tourism.  How big does it (station, delivery system for minimum sized modules) need to be? 

Offline Roy_H

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Combining 'manned' cockpits with in-space cargo delivery is heading down the road of the same set of bad compromises that caused the Shuttle to never live up to its hype.

The problems with Shuttle's architecture had nothing to do with having crew on board. And ISS probably wouldn't exist if Shuttle had been unmanned.  What would have hosted the assembly crew for a week?
Cargo vehicles don't have to be manned of course, but that's not the deal breaker.

NASA's original idea was to have a much smaller Shuttle for astronauts only (a larger than Dream Chaser would allow living for week or so) and send all the ISS modules up on a new rocket. It became a political decision when the budget for two new designs was not allowed so they combined it into one big shuttle.
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Offline Space Ghost 1962

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What is currently being discussed is non traditional payloads, of the kind used for HSF/exploration.

The scope is large LV that way exceed the traditional payloads. The issues relate to how to encapsulate/deliver the payloads for the mission.

Large, infrequent payloads may require fairing's of unusual size that are a considerable cost to develop qualify. Or, like BFS/ITS/Dragon, have same as part of SC. Likewise, GNC/props for prox ops.

Using a tug is not for free. Having integral props/GNC to a SC means you don't have to endure significant risk of the tug not being available/on-orbit/phased/oriented, able to dock/insert/KOS/handoff/exit, plus the costs of maintaining the tug as an independent mission/ops/replenishment. It complicates the picture w/o possibly improving the missions that depend on it.

(Where tugs (and depots) begin to get useful is when you have a mature situation, like possibly a DSG. But even for the life of the ISS, the desirability of such has been minimal.

Your best model for a trucking service would be exploration logistical support for DSG near Moon/Mars/etc, and looking at alternatives to build DSG/etc as currently in plan.

(There are still significant political "sacred cows" - obviously the stupid anemic (GTOW) solids on SLS, SLS primes, t and the need for HSF assembly where robotic/automated is far more mass efficient/safer. Will skip these.)

Lets suppose we have 10+ assembly payloads to deliver cislunar to the same place with a tug. And we have a tug that does this 2-3 times before replenishment. Instead of the 10 FH "direct delivery" missions, you'd have  1 FH + 13-15 F9 missions plus the development of a tug, which will likely be the cost of 5+ FH missions. Easier to do the 10 FH missions.

Now, what if we needed 100+ assembly payloads to the same place with say 5-6 before replenishment? Different story.

Don't build a trucking line until you have something for it to do. Duh.
Anyone know how many assembly payloads for ISS (not logistics!)?

Offline CuddlyRocket

I think it probably depends on what the purpose of the station is.

This is the fundamental issue. First decide the reason you want a space station.

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For Ariane 5 and Falcon 9/H they can carry payloads up to 4.5m in diameter within their fairings, and at least 6.7m in length, but to make sure more international launchers can be used it would be better to assume a slightly small diameter (JAXA H-IIB is likely 4.4M diameter capable).

(somewhat dated) Reference on fairing diameters

Angara is 2.9m. Proton will supposedly get a 5m fairing in 2020.

Orion - the first and only manned not-too-deep-space craft

Offline Norm38

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People seem to be missing the question I'm asking.  SpaceX is going to build ITS / ITSy.  It will be crew rated, it will carry people and carry cargo.  The plan is for it to be fully reusable.  Sending up cargo on ITS(y) and crew up on Dragon2 with an expendable second stage seems to be more expensive and wasteful.
If crew and cargo on the same vehicle is a bad idea (or unnecessary), then send up two ITS(y).  The crewed version can be the construction shack that supports the initial assembly, spacewalks, etc.  While the cargo version brings up the modules. 

It doesn't matter if it's the most optimal solution by performance if it's the lowest cost to orbit.  SpaceX is going to build it, and they want to fly it a lot to drive down cost.  And I don't see how it makes sense to design a custom launcher around a space station. Unique one-use vehicles are not low cost.

So assuming this is built, it's flying and hauling cargo, how do people want to use it? If you can give input now on a cargo bay, what are the requirements?
Or is the answer really "No thanks, we'll keep flying on expendable or only partly reusable EELVs"??

Online savuporo

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Or is the answer really "No thanks, we'll keep flying on expendable or only partly reusable EELVs"??

The answer is, learn the right lessons from past mistakes, and learn from the successes as well.

Commercial comsat market has decent flexibility in delivering payloads ( yeah, a bit late sometimes, but sometimes ahead of the schedule too ) partly because there is some commonality between payload fairings and interfaces. In other words, you can have a redundancy plan for delivering your very valuable asset on multiple providers

Whereas a project like ISS construction was severely screwed by having its only launcher grounded - and immediately retired after the project was cut down to bare minimum viable configuration.
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Online Cherokee43v6

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People seem to be missing the question I'm asking.  SpaceX is going to build ITS / ITSy.  It will be crew rated, it will carry people and carry cargo.  The plan is for it to be fully reusable.  Sending up cargo on ITS(y) and crew up on Dragon2 with an expendable second stage seems to be more expensive and wasteful.
If crew and cargo on the same vehicle is a bad idea (or unnecessary), then send up two ITS(y).  The crewed version can be the construction shack that supports the initial assembly, spacewalks, etc.  While the cargo version brings up the modules. 

It doesn't matter if it's the most optimal solution by performance if it's the lowest cost to orbit.  SpaceX is going to build it, and they want to fly it a lot to drive down cost.  And I don't see how it makes sense to design a custom launcher around a space station. Unique one-use vehicles are not low cost.

So assuming this is built, it's flying and hauling cargo, how do people want to use it? If you can give input now on a cargo bay, what are the requirements?
Or is the answer really "No thanks, we'll keep flying on expendable or only partly reusable EELVs"??

Lets start by defining 'cargo'.

There is a difference between what a 'truck' hauls and what a specialized heavy-hauler carries.  For FedEx/UPS, sure, use up the extra space in the manned rocket.  But when SpaceX moves an F9 from Hawthorne to Kennedy, they don't use a 53' box or flatbed.

When you start talking Space Station Modules and other big ticket items that will spend their entire lives exposed to space anyway, why create the extra risk modalities involved in putting them in a crew-carrier?  As said, if crew is needed, send them up on the dedicated crew vehicle to meet up with the modules on-site.
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Offline Norm38

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When you start talking Space Station Modules and other big ticket items that will spend their entire lives exposed to space anyway, why create the extra risk modalities involved in putting them in a crew-carrier?  As said, if crew is needed, send them up on the dedicated crew vehicle to meet up with the modules on-site.

The cargo version can be unmanned if that's best.  But as the image in the first post shows, crew and cargo versions will probably have identical mold lines, so that the launch and re-entry profiles are identical.
Modules designed for space need protection through Max Q.  There are either massive fairings with their issues, or a cargo bay. I think the cargo bay wins out.

So the consensus is that SpaceX and Blue Origin need to work together to define an industry standard for cargo and get two ships flying before anyone will use it for anything but comsats?

I guess SpaceX could use it to build their own fuel depot and not be concerned they're reliant on only their own hardware.
« Last Edit: 08/30/2017 07:05 PM by Norm38 »

Offline BobHk

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission. 

Offline philw1776

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission.

If I understand your proposal correctly, S1 going to LEO, it won't work even if S1 could get there because S1 is not designed for anything even close to LEO re-entry velocities.  Throw away an expensive S1 per launch.
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Offline BobHk

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission.

If I understand your proposal correctly, S1 going to LEO, it won't work even if S1 could get there because S1 is not designed for anything even close to LEO re-entry velocities.  Throw away an expensive S1 per launch.

That really depends on the module doesnt it?  Max weight with no engine of its own wouldn't work.  Expendable second stage booster for the module would, depending on orbit you want. 

Using the 2nd stage fuelling ship concept or people transport (converted to carry up cargo) for this kind of mission seems to be another Shuttle rabbit hole... a special kind of waste of resources all its own.

Online Cherokee43v6

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Okay, let's look from a different angle then.

What is a 'payload bay' actually good for as a 'primary resource'?

The primary purpose of the payload bay is to streamline a large vehicle that goes both up and down through the atmosphere.  Primarlily down.  Thus the purpose of a payload bay is to bring cargo FROM orbit to the ground.

What are you bringing down that requires that scale of downmass capability?

If you have no downmass to bring down, why waste resources on a 'payload bay' when the same base vehicle can lift multiple tens of tons more mass up in a more traditional configuration.

As an example, the Space Shuttle was an approximately 120 tons to LEO system... capable of delivering a mere 20 tons of cargo.  So with this example, you're wasting 100 potential usable on-orbit tons for unnecessary structure.

Now, I will admit that if you have a large scale product coming down from orbit, then a payload bay is very desirable.  However I think in 40 years of flight, the shuttle was used that way twice.  Two mis-deployed satellites, and the LDEF.  Otherwise, it was bringing back what it took up on the same flight.
« Last Edit: 09/02/2017 03:54 PM by Cherokee43v6 »
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Online AncientU

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Okay, let's look from a different angle then.

What is a 'payload bay' actually good for as a 'primary resource'?

The primary purpose of the payload bay is to streamline a large vehicle that goes both up and down through the atmosphere.  Primarlily downThus the purpose of a payload bay is to bring cargo FROM orbit to the ground.

What are you bringing down that requires that scale of downmass capability?

If you have no downmass to bring down, why waste resources on a 'payload bay' when the same base vehicle can lift multiple tens of tons more mass up in a more traditional configuration.

As an example, the Space Shuttle was an approximately 120 tons to LEO system... capable of delivering a mere 20 tons of cargo.  So with this example, you're wasting 100 potential usable on-orbit tons for unnecessary structure.

Now, I will admit that if you have a large scale product coming down from orbit, then a payload bay is very desirable.  However I think in 40 years of flight, the shuttle was used that way twice.  Two mis-deployed satellites, and the LDEF.  Otherwise, it was bringing back what it took up on the same flight.

Don't agree.  The payload bay needs to ensure structural integrity of the ship as it enters atmosphere and descends.  Bring stuff down is an extra benefit.
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Online Cherokee43v6

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Okay, let's look from a different angle then.

What is a 'payload bay' actually good for as a 'primary resource'?

The primary purpose of the payload bay is to streamline a large vehicle that goes both up and down through the atmosphere.  Primarlily downThus the purpose of a payload bay is to bring cargo FROM orbit to the ground.

What are you bringing down that requires that scale of downmass capability?

If you have no downmass to bring down, why waste resources on a 'payload bay' when the same base vehicle can lift multiple tens of tons more mass up in a more traditional configuration.

As an example, the Space Shuttle was an approximately 120 tons to LEO system... capable of delivering a mere 20 tons of cargo.  So with this example, you're wasting 100 potential usable on-orbit tons for unnecessary structure.

Now, I will admit that if you have a large scale product coming down from orbit, then a payload bay is very desirable.  However I think in 40 years of flight, the shuttle was used that way twice.  Two mis-deployed satellites, and the LDEF.  Otherwise, it was bringing back what it took up on the same flight.

Don't agree.  The payload bay needs to ensure structural integrity of the ship as it enters atmosphere and descends.  Bring stuff down is an extra benefit.

I'd point at the F9 stage one and argue otherwise.  Lack of a 'payload bay' doesn't affect it's structure.

Also, I'll add, that if you don't need a payload bay to bring stuff back then there is no need for all that structure.
« Last Edit: 09/02/2017 05:06 PM by Cherokee43v6 »
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Online savuporo

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...With Shuttle retired, the next orbital station will be built by something else..

Coming back to thread opening, the next orbital station program is already underway and yes, it will be launched by EELV-sized launchers.
Larger core module than ever before though, at around 22 tons, reportedly.

Quote
Length of the module is 18.1m, it is cylindrical with a maximum diameter of 4.2m and an on orbit mass between 20 and 22 thousand kilograms.
« Last Edit: 09/02/2017 05:55 PM by savuporo »
Orion - the first and only manned not-too-deep-space craft

Offline oldAtlas_Eguy

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Ok lets review SpaceX policies and how they impact how things are designed from a systems standpoint.

SpaceX does not create designs that incur additional costs if not absolutely required.

This then impacts the ground handling, GSE hardware and software, and the launch and processing procedures. Each of which if you have to have major differences incurs actually a very significant development cost prior to even the first launch. Plus incurring even more costs for making these changes compatible with systems that must be there for the Mars goals and vehicle designs is also a  nonstarter. So mold lines, lift points, shapes, sizes, weights, props, umbilical and ground software should be the same for the Space Truck as for the Mars vehicles (tanker and Mars ITSy). Proposing something else just will not happen.

Within these constraints is a fairly wide range of possibilities. The Space Truck would be more kin to the tanker ITSy version than the Mars ship ITSy version. If you need personnel and personnel supplies or other equipment that fits in the ITSy Mars ship and needs personnel to help in its installation then use the existing ITSy Mars ship design. A new design for personnel carrier is not needed.

Now as to a secondary vehicle for 100mt large contiguous payloads look to BO and the New Armstrong to provide this. It will likely also be a lifting body US fully reusable vehicle of about the same size. But it may have widely different versions such as a 3 stage one where a much smaller Lunar Vehicle is the 3rd stage on top of a reusable second stage. And then also a different version of that second stage for delivery of very large payloads to LEO. So if a significant payload size is defined with a significant amount of launch activity (more than 1 every other year) like 5-10 times per year, then additional commercial launchers will emerge to handle it possibly at even cheaper prices than the ITSy Space Truck.

Offline Norm38

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What is a 'payload bay' actually good for as a 'primary resource'?

The primary purpose of the payload bay is to streamline a large vehicle that goes both up and down through the atmosphere.  Primarlily down.  Thus the purpose of a payload bay is to bring cargo FROM orbit to the ground.

The primary purpose is to keep the second stage in one piece, to not shed parts on the way to orbit, and to give the cargo version the same re-entry profile as the crewed version. If you're talking about dropping fairings, then the second stage is a completely different craft. Why do you want that?

This is going to be a fully reusable vehicle and it's not optimized on performance, but cost. 
The SLS system will be able to put 100MT into LEO in one launch. But it's expendable and very expensive.  If a cargo ITSy can put 20MT into LEO per launch, and 5 ITSy launches cost less than one SLS launch, then what is gained by going expendable? Unless there is some function that cannot be broken down into 20MT chunks, lower cost will win out.
« Last Edit: 09/03/2017 02:30 PM by Norm38 »

Offline Norm38

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Coming back to thread opening, the next orbital station program is already underway and yes, it will be launched by EELV-sized launchers.
Larger core module than ever before though, at around 22 tons, reportedly.

1/6th the size of ISS, 1/2 that of MIR. And China isn't going to use SpaceX for launches anyway. EELV is what they have to work with. To the point that was made earlier, yes anyone designing a station today has to base it on expendable EELVs. But it'll be interesting to see what happens once the ITSy and New Glenn class RLVs are flying.

Offline BobHk

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission.

If I understand your proposal correctly, S1 going to LEO, it won't work even if S1 could get there because S1 is not designed for anything even close to LEO re-entry velocities.  Throw away an expensive S1 per launch.

You proceed from a false assumption.  THe S1, being reusable, is not thrown away.  You simply launch something its capable of putting into LEO on its own or something with a 2nd stage motor and fuel to get it to its location.

Redesigning the crew and fuel ships SpaceX plans to be cargo carriers will result in just another 'shuttle' design with too many compromises.

Offline philw1776

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission.

If I understand your proposal correctly, S1 going to LEO, it won't work even if S1 could get there because S1 is not designed for anything even close to LEO re-entry velocities.  Throw away an expensive S1 per launch.

You proceed from a false assumption.  THe S1, being reusable, is not thrown away.  You simply launch something its capable of putting into LEO on its own or something with a 2nd stage motor and fuel to get it to its location.

Redesigning the crew and fuel ships SpaceX plans to be cargo carriers will result in just another 'shuttle' design with too many compromises.

The whatever with engines and fuel that launches Bigelow into LEO gets expended.
Simply use an ITSy to launch whatever as ITSy S2 returns for re-use.

S1 is designed for relatively slow re-entry velocities around 2.5 Km/sec, nowhere near 8.5 Km/sec.
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Offline the_other_Doug

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Why bother using anything but ITS/ITSy S1 Booster when you can have an expandable Bigelow made to order fit on top and launched into orbit?  You get larger modules into orbit that way.  Dont need human crew for the mission.

If I understand your proposal correctly, S1 going to LEO, it won't work even if S1 could get there because S1 is not designed for anything even close to LEO re-entry velocities.  Throw away an expensive S1 per launch.

You proceed from a false assumption.  THe S1, being reusable, is not thrown away.  You simply launch something its capable of putting into LEO on its own or something with a 2nd stage motor and fuel to get it to its location.

Redesigning the crew and fuel ships SpaceX plans to be cargo carriers will result in just another 'shuttle' design with too many compromises.

The whatever with engines and fuel that launches Bigelow into LEO gets expended.
Simply use an ITSy to launch whatever as ITSy S2 returns for re-use.

S1 is designed for relatively slow re-entry velocities around 2.5 Km/sec, nowhere near 8.5 Km/sec.

Or, to put it more plainly, the ITS (or ITSy) Stage 1 can't place a non-propulsive payload directly into orbit and also be recovered.  It won't be able to stand the far more extreme heating of re-entering the atmosphere from orbital velocities than from the much slower staging velocities it will see when carrying a propulsive upper stage to where whatever Stage 2 you put on it can then get itself into orbit.

This is not to say you could not use an ITS or ITSy S1 to put a non-propulsive payload int orbit.  But you would be treating that S1 as expendable -- not what you're trying to do with that hardware.  ;)
-Doug  (With my shield, not yet upon it)

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