{snip}Considering all that, if there was a case for a private space station, why not just contract someone like Boeing, EADS Astrium, Mitsubishi or indeed one of the Russian aerospace firms to just make such a monolithic station and launch it on a Ariane V/Proton? I highly doubt this is beyond their technical capabilities.
Necessary? No.Desirable? Yes.The BA 330 has about the same interior space as Skylab, a station that required a Saturn V to launch and yet itself weighs like a third the weight of Skylab.3 times the volume for a given lift is nothing to sneeze at.
The proposed business model for private space stations proposed by Bigelow is that people will rent them out for weeks at time, not the months even year of the ISS. They're not even deep space missions. In fact, mission to Tiangong 1 were carried out for periods of two weeks, with it's pressurized volume being only 15m3...90-100 cubic meters is gigantic by comparison.Sure inflatable space stations would be nice to have..My own thinking about it is that it doesn't really matter too much if private stations are hard hulled or inflatable, that the biggest problems are the lack of transport and the fact the biggest potential customer already owns a gigantic space station. SpaceX, if it were so inclined probably could apply it's experience of making rockets and capsules into a private station it could launch on Falcon Heavy and resupply with it's two vehicles. Low Earth orbit might be a place they test out human-systems for going to Mars, but get other customers to help pay for it. I in fact wouldn't rule that out after the satellite constellation announcement, though I doubt it.
I am not sure how they use the walls, but i am sure it requires assembly if they're usable in a conventional way at all.
They're not even deep space missions.
Inflatable modules are a very interesting technology that will have to work all the kinks out before being fully deployed
There is tons of experience across several corporations over the world in building monolithic metal modules, but very little experience with inflatable space stations.
Why is it all that desirable to the point you'd wait until the tech came along to do such a station?
Once launched, isn't an inflatable space station essentially a house with no furnishings? <snip>
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.
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.
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?
SpinCalc is your friend! As you can see on that site, you really need something like 10m of radius (20m diameter) to get somewhere comfortable to simulate even Mars gravity. An inflatable might be the key, but probably not in the balloon configuration, but rather in something like a torus or so.If you did had a torus with 20.3m of outer diameter, 2m of pressurized space, and 0.3m of wall thickness, you could pack in 400mł with a 70% efficiency. That would fit (tightly) within the 6.5m x 25m fairing that ULA said can do in a Delta IV Heavy. Only issue is that it would have to weight less than 90kg/mł so that the launcher could actually orbit it.Given that even polypropylene is something like 900kg/mł, I believe that we would be mass limited for anything "big" than volume constrained.
rpm = v/c
Quote from: Norm Hartnett on 04/07/2015 07:40 pmrpm = v/cRevolutions per Second = v/cRevolutions per Minute = 60 * v/cHence:rpm Earth = 18 rpmrpm Mars = 11 rpmrpm Lunar = 8 rpm
Earth rpm as a bit fast but if the mice do do look out of the window they should be all right at Mars and Lunar rpm.We already have living quarters for rodents. It will have to be fitted onto a wheel or torus.http://www.nasa.gov/mission_pages/station/research/news/rodent_research
Inflatabilty is not a requirement for any space station.It's more of an issue than a solution to a critical need.BA modules may get there first, though, because of past circumstances and hype.More probably, the first comercial LEO space station will have a big X painted on it's side, and it will be testing key technologies needed for a trip to mars.
Is BA330 being built? There are lots of mockups.QuoteQuoteActually, 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.Thank you.
QuoteActually, 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.Thank you.
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.
Quote from: dror on 04/08/2015 06:36 pmInflatabilty is not a requirement for any space station.It's more of an issue than a solution to a critical need.BA modules may get there first, though, because of past circumstances and hype.More probably, the first comercial LEO space station will have a big X painted on it's side, and it will be testing key technologies needed for a trip to mars.Anyone knows the ISS aluminum wall width? I've calculated that if it is more than 1.1cm wide then the fabric construction is lighter per unit of surface.
Quote from: baldusi on 04/08/2015 08:16 pmQuote from: dror on 04/08/2015 06:36 pmInflatabilty is not a requirement for any space station.It's more of an issue than a solution to a critical need.BA modules may get there first, though, because of past circumstances and hype.More probably, the first comercial LEO space station will have a big X painted on it's side, and it will be testing key technologies needed for a trip to mars.Anyone knows the ISS aluminum wall width? I've calculated that if it is more than 1.1cm wide then the fabric construction is lighter per unit of surface."2mm aluminum pressure shell" plus unspecified graphite-epoxy shield thickness- in figure 10 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060026214.pdf"The walls are about 10 cm thick and consist of an inner and outer shell of aluminum (density= 2.7 grams per cubic centimeter) about 0.3 cm thick. In between the two walls is polyurethane to improve radiation shielding of the astronauts inside."- http://spacemath.gsfc.nasa.gov/Modules/8Mod6Prob1.pdf"The thickness of outer wall is estimated as 1,5 g/cm (2)"- http://adsabs.harvard.edu/abs/2014cosp...40E3366T"the bullet's effect on the ATV's 3-millimeter-thick aluminum wall "- http://spacenews.com/41022atv-shielding-takes-a-bullet-to-show-space-stations-stopping-power/"The ISS is largely composed of thin-walled aluminum modules, from 1.27 millimeters (0.05 inches) to 7 millimeters (0.27 inches) thick. The air pressure from within exerts the force to keep the walls rigid."- http://www.21stcentech.com/developed-artificial-gravity-human-space-flights/
Quote from: Burninate on 04/08/2015 08:54 pmQuote from: baldusi on 04/08/2015 08:16 pmQuote from: dror on 04/08/2015 06:36 pmInflatabilty is not a requirement for any space station.It's more of an issue than a solution to a critical need.BA modules may get there first, though, because of past circumstances and hype.More probably, the first comercial LEO space station will have a big X painted on it's side, and it will be testing key technologies needed for a trip to mars.Anyone knows the ISS aluminum wall width? I've calculated that if it is more than 1.1cm wide then the fabric construction is lighter per unit of surface."2mm aluminum pressure shell" plus unspecified graphite-epoxy shield thickness- in figure 10 of http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060026214.pdf"The walls are about 10 cm thick and consist of an inner and outer shell of aluminum (density= 2.7 grams per cubic centimeter) about 0.3 cm thick. In between the two walls is polyurethane to improve radiation shielding of the astronauts inside."- http://spacemath.gsfc.nasa.gov/Modules/8Mod6Prob1.pdf"The thickness of outer wall is estimated as 1,5 g/cm (2)"- http://adsabs.harvard.edu/abs/2014cosp...40E3366T"the bullet's effect on the ATV's 3-millimeter-thick aluminum wall "- http://spacenews.com/41022atv-shielding-takes-a-bullet-to-show-space-stations-stopping-power/"The ISS is largely composed of thin-walled aluminum modules, from 1.27 millimeters (0.05 inches) to 7 millimeters (0.27 inches) thick. The air pressure from within exerts the force to keep the walls rigid."- http://www.21stcentech.com/developed-artificial-gravity-human-space-flights/On the last point; So in point of fact, the CANS are actually inflated as well?
I was looking for something that would fit inside the B330 which would eliminate a wheel. I considered the possibility of a module but the only thing I could come up with was putting the module on rails running around the interior circumference of the B330. This causes all sorts of problems not the least of which is maintaining the habitat.
In addition to the volume and storage benefits, TransHab provides superior radiation and micrometeoroid protection than conventional aluminum modules.
IV. TESTING Hypervelocity Impact Testing (M/OD Protectioni: A variety of hypervelocity impact tests, using different size pruticles at speeds ranging between 2.5 through 11 km/s, have verified the TransHab multi-shock shield. Initial ballistic limit equations have been developed from these test for use in sh ield optimization. As an example this sub-scale and full-scale testing has demonstrated that the TransHab shield can stop a 1.7cm diameter aluminum particle traveling at 7 km/s fired at both 0 and 45 degree angles. The results of these tests have verified that the TransHab MlOD shield would exceed the ISS M/OD shield requirement for a habitation module.
The TransHab inflatable technology development program has proven that not only are inflatable structures a viable option, but they also offer significant advantages over conventional metallic structures.