I have changed my concept pic by reversing the spaceships so that radius is increased by length of the engine section. Note that this is opposite hanging direction as in ITS video so this may not be an improvement.
The other structure that has been discussed is to have a pressurised tunnel made from Bigelow-skin, with tensile cables running down the walls putting the tube under compression. Each component is strong enough to support the loads individually, but when you combine the tensile and compression elements, you get a much more rigid system. As a bonus, you have a pressurised tube to transfer between modules (and repair the cables). Avoiding the "elevator", which would need to be a mini-spaceship, with two docking events for every trip.
5. Crew lives under 1 g and > 90% cosmic ray shielding.
That will learn me to leave an old thread favourite un-read for a while!Loved reading the latest posts. Love your work mikelepage!Thank you Nasaspaceflight A few points.1) I'm not so sure the old Gemini experiment applies as the amount of AG was so small."Despite the oscillations in the tether and other spacecraft issues, these did settle down temporarily after 20 minutes or so, and for a brief time a teeny, tiny bit of artificial gravity was observed in the Gemini capsule. How much gravity? About 0.0005 g with 0.15 revolutions per minute. Some time later the tether was released." https://blogs.scientificamerican.com/life-unbounded/watch-the-first-artificial-gravity-experiment/2) I like structures such as trusses. Nothing potentially flopping about in an emergency. (So long as the emergency is not greater than the load the truss can take of course.) I presume Mike's idea will lock in place after deployment.
I added one more B330 module on each end, since it almost doubles pressurized 1g volume
I dont want to reduce the diameter too much because I think the experience itself of building large structures in space that can rotate at 1g and not fall apart is an important function of such near-term station.
But not a "realistic" one. The people within NASA (and similar agencies around the world) who want AG research are not a dominant faction. Therefore any proposal needs to be small enough not to make waves. Larger than ISS, which was the major development program for two decades? No.
I added one more B330 module on each end, since it almost doubles pressurized 1g volume of the station for very little additional structure.
I estimate it should take a dozen BFR launches to construct this station, with launches being mostly volume rather than mass constrained.
Quote from: blasphemer on 07/14/2018 10:33 amI added one more B330 moduleThe Bigelow B330 is designed for zero-G only, and inflatables are not a good idea when you need to take structural loads.
I added one more B330 module
Quote from: Coastal Ron on 07/14/2018 07:55 pmQuote from: blasphemer on 07/14/2018 10:33 amI added one more B330 moduleThe Bigelow B330 is designed for zero-G only, and inflatables are not a good idea when you need to take structural loads.Why not? The walls can support at least 10 tonnes per square metre, a US ton per square foot. It's hardly a weak structure.
I think even Bigelow Aerospace has stopped using the term inflatable, in favour of expandable, to get away from the notion of a balloon which can pop.
The main advantage of expandables is the extra volume once inflated (The fairing for a BA2100 is only 8m wide) and better micrometeorite protection.
The main advantage of solid modules is that the on-orbit setup period is much reduced, because you already installed everything into the module while it was on the ground - including some facilities which might be impossible/very difficult to install in an expandable once on-orbit.
I don't understand this fascination with designing in zero-G components into micro-gravity structures. The Bigelow B330 is designed for zero-G only, and inflatables are not a good idea when you need to take structural loads.
They are designed for zero-G uses, so they are ill-suited for artificial gravity applications.
The BA2100 is only a concept
Plus, with the availability of upcoming large-diameter launchers like the New Glenn and BFS, the need for expandables is reduced.
So let's focus on the requirements - how much space is needed to prove out at micro-gravity station?
(IMO, if humans require a full 1g at very low RPMs, we might as well end the manned space program until someone invents some magitech that fundamentally changes the rules.)
But I agree that using a B330 is not ideal. If we assume the station will be constructed by BFS, then its payload bay has a volume of 825 m3, a lot more than interior of an expanded B330. There must be a better way to utilize that space. Note that BA 2100 at 17.8m length is too big to fit. I would really like to use a module sized exactly to fit into non-cylindrical BFS payload bay, either rigid or expandable, something like this:https://forum.nasaspaceflight.com/index.php?topic=44127.msg1748690#msg1748690Sadly I dont see any such model in Sketchup warehouse..
Most people use BA-330's and BA-2100 because the numbers exist. Deployed length and width, and launch mass. Even price, for the BA-330. Makes it easier to use in a what-if compared to proposing a custom hab.
Quote from: Coastal Ron on 07/15/2018 06:09 amThey are designed for zero-G uses, so they are ill-suited for artificial gravity applications.You keep saying it, but you've said nothing that demonstrates it.
They can handle loads of 10 tonnes per square metre. Bet your roof and floor can't, and yet your home manages to stand up under a whole 1g.
Quote from: Coastal Ron on 07/15/2018 06:09 amThe BA2100 is only a concept...But, when speaking of Bigelow's concepts, its also worth noting that they've proposed their modules for Lunar bases, ie, under (some) gravity. So they're open to fitting modules to purpose.
Quote from: Coastal Ron on 07/15/2018 06:09 amPlus, with the availability of upcoming large-diameter launchers like the New Glenn and BFS, the need for expandables is reduced.There's a mass-efficiency issue. Hab modules are mostly empty space. A module that would fill the BFS's payload area would probably not mass 150 tonnes. So if you shrink the empty space, you can use that spare mass to ship ancillary systems. Solar panels, radiators, etc, etc.
Quote from: Coastal Ron on 07/15/2018 06:09 amSo let's focus on the requirements - how much space is needed to prove out at micro-gravity station?Micro? If you meant spin, the it depends on what you are trying to prove. The basics only require animal studies. In theory a stand-alone Dragon-Lab module rotating around its "vertical" axis.
What humans need to know can only be found out by experimenting on humans. And since setting up colonies on our Moon and on Mars is of HUGE interest, then what we should focus on first is artificial gravity space stations that can provide a minimum of 1/3 G, with the option of operating at 1/6 G too. They also need to be sized in order for humans to actually live and work on them for periods of at least a year, or however long it takes to do studies to see if micro-gravity environments mitigate some or all of the effects of zero-G.Because the goal has to be that we need to find out as soon as possible how humanity will be able to expand out into space while not only surviving, but thriving. Otherwise, why else should we spend money on sending humans to space?