No, it is to create as much volume as possible because people are going to live in that volume for months, especially if the module is intended to be an option for deep space missions.For launching space station modules, most launchers are fairing limited, not mass limited. The non-expanded BA-330 can just barely fit inside the standard fairing of the Falcon Heavy, even though it is only half of the maximum payload mass-wise. If you're going to send up anything with a decent volume in a single launch on a reasonably cheap rocket, inflatable modules are very nice to have.
Actually not Kevlar but rather Vectran which NASA has lots of experience with. Spacesuits (EMU)among other things. So far as I have been able to discover there is no aluminum in the BA skins. In fact the lack of aluminum is one of the advantages since there is no secondary radiation generated thus reducing overall radiation exposure.
Quote from: Kansan52 on 04/01/2015 04:03 amThe Bigelow modules are tougher than aluminum cans as people have posted. Since "alunimium cans" have hardly proved fragile in space flight and how well the Genesis modules have stood up to spacelfight is not public knowledge AFAIK, I would see this as an unsubstantiated claim by the advocates.QuoteThey will not want the BA 300's fully outfitted as the occupants will bring their experiments. The racks will be based on current ISS racks.Which meands that all claims about the supposed mass advantages on inflatbale structures are specious.QuoteAnd the ISS modules were not fully equipped but, if memory serves, it was mass limitations.Some were, some weren't. But I find it strange how fitting something out in space is a parsed as an advanatage for inflatables and a fault for rigid structuresQuoteAlso, like it has been posted, BA 300 is designed plus, as I understand it, being constructed. Any ISS type module hasn't bent metal yet. Time is money.Is BA330 being built? There are lots of mockups.
The Bigelow modules are tougher than aluminum cans as people have posted.
They will not want the BA 300's fully outfitted as the occupants will bring their experiments. The racks will be based on current ISS racks.
And the ISS modules were not fully equipped but, if memory serves, it was mass limitations.
Also, like it has been posted, BA 300 is designed plus, as I understand it, being constructed. Any ISS type module hasn't bent metal yet. Time is money.
Quote from: Norm Hartnett on 04/01/2015 03:53 amActually not Kevlar but rather Vectran which NASA has lots of experience with. Spacesuits (EMU)among other things. So far as I have been able to discover there is no aluminum in the BA skins. In fact the lack of aluminum is one of the advantages since there is no secondary radiation generated thus reducing overall radiation exposure.The secondary radiation issue is, I suspect over stated as all materials will generate some secondary radiation and even an inflatable willcontain a substantial amount of structural and system aluminium. Besides, aluminium is used for radiation shielding, so is hardly a viability.
Quote from: Kansan52 on 04/01/2015 04:03 amThe Bigelow modules are tougher than aluminum cans as people have posted. Since "alunimium cans" have hardly proved fragile in space flight and how well the Genesis modules have stood up to spacelfight is not public knowledge AFAIK, I would see this as an unsubstantiated claim by the advocates.
QuoteThey will not want the BA 300's fully outfitted as the occupants will bring their experiments. The racks will be based on current ISS racks.Which meands that all claims about the supposed mass advantages on inflatbale structures are specious.
QuoteAnd the ISS modules were not fully equipped but, if memory serves, it was mass limitations.Some were, some weren't. But I find it strange how fitting something out in space is a parsed as an advanatage for inflatables and a fault for rigid structuresQuoteAlso, like it has been posted, BA 300 is designed plus, as I understand it, being constructed. Any ISS type module hasn't bent metal yet. Time is money.Is BA330 being built? There are lots of mockups.
Quote from: Dalhousie on 04/01/2015 04:47 amQuote from: Kansan52 on 04/01/2015 04:03 amThe Bigelow modules are tougher than aluminum cans as people have posted. Since "alunimium cans" have hardly proved fragile in space flight and how well the Genesis modules have stood up to spacelfight is not public knowledge AFAIK, I would see this as an unsubstantiated claim by the advocates.There are numerous Nasa videos that seem to indicate otherwise. There are tests that have been done that have indicated that a hit from even a pebble sized meteor could cause substantile damage to the ISS, versus the Bigelow module which gives and deforms much like bullet resistant body armor does. Currently, Nasa is using, what in effect is, Spaced Armor to mitigate debris damage. While this has proven effective in the past, even they admit that it's not perfect. Neither is the Bigelow Module either, but it can take a more sizable impact than could the ISS before potentile pressure failure.
QuoteIs BA330 being built? There are lots of mockups.Actually, as I understand it, yes, two modules have been currently constructed and one is being used for destructive testing. Pushing the design boundries until they break.
Is BA330 being built? There are lots of mockups.
Quote from: JasonAW3 on 04/01/2015 05:37 pmQuote from: Dalhousie on 04/01/2015 04:47 amQuote from: Kansan52 on 04/01/2015 04:03 amThe Bigelow modules are tougher than aluminum cans as people have posted. Since "alunimium cans" have hardly proved fragile in space flight and how well the Genesis modules have stood up to spacelfight is not public knowledge AFAIK, I would see this as an unsubstantiated claim by the advocates.There are numerous Nasa videos that seem to indicate otherwise. There are tests that have been done that have indicated that a hit from even a pebble sized meteor could cause substantile damage to the ISS, versus the Bigelow module which gives and deforms much like bullet resistant body armor does. Currently, Nasa is using, what in effect is, Spaced Armor to mitigate debris damage. While this has proven effective in the past, even they admit that it's not perfect. Neither is the Bigelow Module either, but it can take a more sizable impact than could the ISS before potentile pressure failure.A pebble sized meteor is huge. A very much doubt a Bigelow inflatable will survive that either. remember two that a Bigelow module still has a lot of external equipment such as antennae, solar panels and radiators which will be just as vulnerable as a those of conventional station.
After some thought I realized that the answer to your original question “Are inflatable modules even necessary for private space stations?” is, self-evidently, yes.Why? Because no other private party is attempting to create a space station of any kind. No other private party has spent significant money nor have they orbited one, let alone two, test space craft. No private party has talked NASA into testing a prototype on the ISS.Why? Economics and vision. (I believe.)Inflatable modules are necessary for private space stations because no one else is building any other sort of private space station.“if there is a business case for private space stations, why these would be necessary?”Because Bigelow Aerospace is the only one building private space stations and inflatables are what they believe will work. Presumably they know what they're doing.I suspect that's not the answer you were looking for but it is the reality.BEAM probably isn't necessary to BA's business plan but it certainly can't hurt and may provide a kick start to investment and customer orders.
Because Bigelow Aerospace is the only one building private space stations and inflatables are what they believe will work. Presumably they know what they're doing.
I am sceptical as well. An inflatible station means the entire hull must be flexible/expandle. I suspect that severly limits you in the materials you can use and in the overall design. A non-inflatible station needs a rigid hull but you can fit it with whatever protection etc. you like.
Btw, why not use composites for the hull instead of aluminium?
The solid hull needs added protection, so I don't see its advantage.
I'll take a guess here that composites are too brittle, and difficult to repair. And probably very expensive.
For deep space additional radiation shielding would be necessary, for example plastics, water tanks etc. The question is whether such additional protection could easily be designed to be flexible (as a fabric) such that it is expandable and if yes, how much more costly it would be.
ISS modules also have bumpers (aluminum sheets) placed at a standoff which causes incoming particles to disintegrate before they hit the inner wall.
Quote from: cosmicvoid on 04/02/2015 07:51 amI'll take a guess here that composites are too brittle, and difficult to repair. And probably very expensive.They could be too brittle in the event of an impact. I do not agree on cost though, composite pressure tanks from what I know are cheaper than metal ones.
Bigelow plans to add radiation shielding by Velcro bladders of water attached to inside of wall. Given its large internal diameter, layering these shielding bladders shouldn't be an issue. As technology improves the shielding bladders can be changed for something better.
We use these pools for short-term storage because water is a really good radiation shield. How good? Well, according to a report on the topic prepared for the DoE back in 1977, a layer of water 7 centimeters thick reduces the ionizing radiation (rays and particles) transmitted through it by half (the remainder is captured or moderated to non-ionizing energy levels, mainly heat).
{snip}When you look at the SkyLab II trades on interior configuration, you find the same configuration as the BA-2100, i.e. three "floors". The big difference is that in an 8.4m aluminum can, all the equipment and ECLSS is already installed and routed on the comfortable gravity well of Earth's surface, while a BA-2100 would need a lot of ducting and installation. Things as silly as ventilation ducting, with the required power and data would eat a lot of crew time in installation. Is is worth the savings in mass if you have to spend an extra six months on orbit (or even more) doing simple installations?