large volume space stations for microgravity activites

[redneck]

BEAM expanded 1.85x in length and 1.37x in diameter. Not sure where the figure of an 11.4x increase in volume came from?

So if we start with 8 m diameter and 10 m in length, this gets us to 14.9 m in diameter and 13.7 meters in length.

I'm late catching this bus, but wouldn't 1.85 in length hit 18.5 meters from 10? And the diameter go to almost 11 meters from 8? I don't have a dog in this fight, just confused.

[StraumliBlight]

I'm late catching this bus, but wouldn't 1.85 in length hit 18.5 meters from 10? And the diameter go to almost 11 meters from 8? I don't have a dog in this fight, just confused.

Sierra Space sells a 7m diameter LIFE 1400 station that inflates to 11m and a 9m LIFE 5000 that inflates to 19m.

[DanClemmensen]

Don't assume that a Starship will be free. In other words, you require SpaceX to provide a Starship that will likely never be used again, there is a cost associated with that. And because SpaceX is a for-profit entity, don't expect customized Starships to be cheap.

In fact, likely for the same cost of a modified and one-use only Starship, you can build and ship 8m diameter X 8m long fully outfitted modules that can be assembled into a structure far larger that what you are proposing - with none of the liability that comes from all that useless mass hanging off the end of the habitable area (i.e. the tanks and engines section).

Exactly. For the same cost, we end up with a CLD that is larger than your module (it's the size of the entire Ship payload section) and fully outfitted.

Maybe it wasn't clear, but I said "modules" (i.e. many), not just one. And if there is an assembly line set up for them, for the same cost there could be quite a few.

Do you have any idea how much SpaceX would charge to sell you a Starship? And that even assumes that they would, because they might not. There are ITAR issues, and they may not want their technology to be out of their control.

I don't understand why you are so insistent on using pre-assembled modules delivered by a Starship, when this is EXACTLY what SpaceX wants the market to be.

These Ships can be docked to each other just like your modules.

More money issues you are ignoring, because even if the Starships are just leased, and will eventually return to Earth, they are costing you money. How much? Hard to know, but each one circling in space is lost revenue to SpaceX, so they are going to charge you for that. How large is your budget for that?

Unless you can show a clear and significant cost advantage to refurbishing a Starship into something humans can live in, everyone will go the route they already understand - build modules complete on Earth and ship them up.

The CLD Ship does not need to be refurbished in space. It is fully equipped and habitable when it is launched. The crew will only modify the tanks into a large empty space when someone decides to pay to create this " large volume for microgravity activites". The resulting large volume is a lot larger than any module you can put in a Starship payload bay.

Again, as I mentioned above, you don't get the Starship for free, you have to pay for that regardless if you plan to rip it apart eventually - and you may not be allowed to do that because of ITAR issues that keep SpaceX from selling you that vehicle.

I don't think investors will want to pursue this route because it has high overhead (i.e. you have to rent/lease the Starship that is doing nothing in space). The least risky route for investors is to pay for modules that are delivered to space to form a space station structure. And now with Starship, all of the modules can be returned to Earth for refurbishment when needed, which can't be done with a modified Starship.

Sorry, we seem to be at cross-purposes. I am talking about a CLD that is owned by SpaceX. It's probably a modified version of one of the crew transports for Mars. Like any other CLD, it will stay in LEO and will never return to Earth.

[Twark_Main]

BEAM expanded 1.85x in length and 1.37x in diameter. Not sure where the figure of an 11.4x increase in volume came from?

So if we start with 8 m diameter and 10 m in length, this gets us to CORRECTION: 18.5 m in diameter and 11.0 meters in length.

I'm late catching this bus, but wouldn't 1.85 in length hit 18.5 meters from 10? And the diameter go to almost 11 meters from 8? I don't have a dog in this fight, just confused.

That's what I get for doing math (in my crappy limited phone calculator no less, which doesn't let me just write out the entire expression) in a quick edit! Obviously I flipped the two somehow.

Thanks, I have double-checked the source, re-calculated, and corrected the original post.

[Bob Shaw]

Surely a basic Starship-based LEO large volume habitable platform is basically a parked interplanetary transport craft? Before committing a crew to a Mars trip with no abort capacity along the way it’d be a good idea to prove out life support and other systems close to home and with a docked Dragon on hand for a quick escape. That might well not mean access to propellant tanks but presumably would still involve a larger diameter habitable volume than ever seen before. About the only practical argument against this in LEO would be the (real) MMOD issue which could be mitigated against either with shielding or going to HEO.

In other words, Musk’s Mars ambitions would lead to a new class of habitable LEO volume simply as a by-product of his overall project.

[Twark_Main]

BEAM expanded 1.85x in length and 1.37x in diameter. Not sure where the figure of an 11.4x increase in volume came from?

So if we start with 8 m diameter and 10 m in length, this gets us to CORRECTION: 18.5 m in diameter and 11.0 meters in length.

I'm late catching this bus, but wouldn't 1.85 in length hit 18.5 meters from 10? And the diameter go to almost 11 meters from 8? I don't have a dog in this fight, just confused.

That's what I get for doing math (in my crappy limited phone calculator no less, which doesn't let me just write out the entire expression) in a quick edit! Obviously I flipped the two somehow.

Thanks, I have double-checked the source, re-calculated, and corrected the original post.

Point being, it's not:

a basketball court area to 13 meters high (or a cylinder 19 m diameter by ~20m long)

Shape matters.


Still confused as to where the 11.4x number came from. Since Bigelow is defunct and BEAM is a dead-end we'll probably never know.  Much better to baseline Sierra Nevada's technology which actually has a future.

However their modules have a spine running down the middle, which again may be limiting depending on the application. For sports you can of course just define the rules around any such limitations, but eg for movie production it could make things harder.

[DanClemmensen]

Surely a basic Starship-based LEO large volume habitable platform is basically a parked interplanetary transport craft? Before committing a crew to a Mars trip with no abort capacity along the way it’d be a good idea to prove out life support and other systems close to home and with a docked Dragon on hand for a quick escape. That might well not mean access to propellant tanks but presumably would still involve a larger diameter habitable volume than ever seen before. About the only practical argument against this in LEO would be the (real) MMOD issue which could be mitigated against either with shielding or going to HEO.

In other words, Musk’s Mars ambitions would lead to a new class of habitable LEO volume simply as a by-product of his overall project.

Yep. If you are building 100 Mars Ships, then building an extra one is very cheap, and you gain some experience. However, the missions are sufficiently different that it is useful to customize the CLD. Strip the EDL features to save some mass so you can increase the mass of the fixed lab equipment, etc. Add additional docking ports. Add extra solar panels and hard points for add-on external experimental gear. And of course the special hatch for access to the methane tanks for allow for later conversion of the tanks into that large volume space for microgravity activities that this thread is supposed to be about.

[Twark_Main]

opportunities for space tourism if you could really get out and float (or fly by flapping?) in a really large space, there might be interesting movie opportunities, or even whole fields of entertainment that don't yet exist, like microgravity dance.

If you had a really large space, you might be able to do all kinds of weird microgravity sports.

I've always thought you'd just strap some EDFs (with protective grills) to your arms and fly around that way.

Careful though!  The major risk is that you could get into a spin that's too fast, and then either 1) pass out, or 2) cause injury when you contact the wall or furniture or another person.

I'm reminded of the fact that the major under-appreciated risk in a nuclear blast is just...  getting thrown a short distance and causing a head injury. Humans are disturbingly fragile...


So yeah, only trained sports players with the EDF wrist rockets. Tourists get the backpack version which has nanny software that doesn't let you get in trouble.

[Vultur]

opportunities for space tourism if you could really get out and float (or fly by flapping?) in a really large space, there might be interesting movie opportunities, or even whole fields of entertainment that don't yet exist, like microgravity dance.

If you had a really large space, you might be able to do all kinds of weird microgravity sports.

I've always thought you'd just strap some EDFs (with protective grills) to your arms and fly around that way.

Careful though!  The major risk is that you could get into a spin that's too fast, and then either 1) pass out, or 2) cause injury when you contact the wall or furniture or another person.

I'm reminded of the fact that the major under-appreciated risk in a nuclear blast is just...  getting thrown a short distance and causing a head injury. Humans are disturbingly fragile...


So yeah, only trained sports players with the EDF wrist rockets. Tourists get the backpack version which has nanny software that doesn't let you get in trouble.

I wasn't suggesting that flapping would be the easiest or best means of flight, but that flying "like a bird" would just be something that could be sold to space tourists as a truly unique (not possible on Earth) novelty experience.

IIRC this was done on the Moon in some Heinlein story?

[mikelepage]

Point being, it's not:

a basketball court area to 13 meters high (or a cylinder 19 m diameter by ~20m long)

Shape matters.


Still confused as to where the 11.4x number came from.

Ack. That’s me getting caught out by AI in the search results whilst tired. 16/1.4 =11.4. Actual ratio is 32.86 / 9.45 =3.48.

Yes the BEAM tech is probably sunsetted, but I was wondering about the necessity of the central column in the expanding module, given that BEAM didn’t have it.

[Coastal Ron]

...
In other words, Musk’s Mars ambitions would lead to a new class of habitable LEO volume simply as a by-product of his overall project.

Yep. If you are building 100 Mars Ships, then building an extra one is very cheap...

This is not an accurate statement.

It won't be hideously expensive, like the SLS, but you still have all the same material costs as every other Starship, all the labor, etc. What you save on is amortization of the facilities, cost of inventory (i.e. material won't sit long), and maybe some minor discounts on material (likely no more than a couple of %). But there are plenty of fixed costs that don't change.

However, the missions are sufficiently different that it is useful to customize the CLD. Strip the EDL features to save some mass so you can increase the mass of the fixed lab equipment, etc.

I did a calculation recently to see how much water a reusable Starship could launch to orbit, and I wanted to know if a 8m diameter X 8m tall water container could be filled completely or if the container would max out on weight first. Turns out that the container maxes out with weight first, so based on that you don't need to strip down a standard Starship, because you would have to stuff a cargo container so tightly before you would get close to the maximum payload for a reusable Starship. And that doesn't sound like what you plan to take to orbit.

...
And of course the special hatch for access to the methane tanks for allow for later conversion of the tanks into that large volume space for microgravity activities that this thread is supposed to be about.

There are plenty of ways to get large volume space stations WITHOUT tearing apart the ships you ride to orbit. And Starship is designed to do that already by shipping already built modules to space, then returning to ship even more. That is the least costly way to address this goal.

[edzieba]

Yes the BEAM tech is probably sunsetted, but I was wondering about the necessity of the central column in the expanding module, given that BEAM didn’t have it.

The Transhab-based line continues with Sierra Space's LIFE modules, and Maxime De Jong (who worked on Transhab at NASA and then BEAM for Thin Red Line - who designed manufactured Bigelow's modules) is working on Isotensoid-based inflatables at Max Space, which have axial as well as radial expansion and whose current prototypes are coreless. .

[Twark_Main]

And now for something completely different, a man with two electron beam welding


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