Author Topic: What's Happening at Bigelow? (Read 429290 times)

Jason1701 · « **Reply #600 on:** 05/10/2011 09:41 pm »

Another update. The fancy curves seem to be a viewing area.

http://www.bigelowaerospace.com/prosper.php

Prober · « **Reply #601 on:** 05/11/2011 04:42 pm »

More on the NASA Feb. visit:

http://www.lvrj.com/business/las-vegas-entrepreneur-wants-to-upgrade-space-modules-115356329.html

SpacemanSpiff · « **Reply #602 on:** 05/12/2011 06:11 am »

The limit on the inflated shell diameter is dependent on the diameter of the launch vehicle fairing that the payload must fit within. This is always your number one constraint for a space vehicle that does not possess it's own pressure shell.
Cheers,
SS

Quote from: joek on 04/15/2011 08:21 pm

Quote from: baldusi on 04/12/2011 03:30 pm
If you want to do a 100m Diameters, it might be difficult, but not unfeasible. A good question is how many folds can take a bigelow wall.

Interesting question. I'd also like to know the primary constraint on the inflated shell diameter and the fold geometry.

In the attached, the image on the right is the original TransHab fold geometry; the left is from the most recent NASA ISS Inflatable Module Mission presentation.

TransHab fold geometry was specifically intended to minimize folds; new geometry suggests it may be less of an issue today. (Assuming the new diagram is close to reality.)

edit: the other left

joek · « **Reply #603 on:** 05/12/2011 06:22 am »

Quote from: SpacemanSpiff on 05/12/2011 06:11 am

The limit on the inflated shell diameter is dependent on the diameter of the launch vehicle fairing that the payload must fit within. This is always your number one constraint for a space vehicle that does not possess it's own pressure shell.

Can you expand on that please? Do you have data you can share? Specifically, ratio of core diameter vs. shell packed diameter vs. shell inflated diameter? Thanks.

SpacemanSpiff · « **Reply #604 on:** 05/12/2011 06:24 am »

In order for them to show you anything you'd have to sign a non-disclosure agreement. This guy is king of the IP.

Quote from: Robotbeat on 04/19/2011 12:52 am

I don't think the symposium was very media-friendly. I think I remember hearing that photography was not allowed for the Bigelow stuff.

joek · « **Reply #605 on:** 05/12/2011 07:13 am »

Quote from: SpacemanSpiff on 05/12/2011 06:24 am

In order for them to show you anything you'd have to sign a non-disclosure agreement. This guy is king of the IP.

Understood. Anyone who has followed Bigelow understands that they are tight (as are most high-tech/bleeding-edge enterprises). Short of all of us signing an NDA or stating "it's secret", can you contribute to the collective knowledge that isn't otherwise known with credible sources?

edit: Or at least sources with a creditable hypothesis?

beancounter · « **Reply #606 on:** 05/12/2011 07:20 am »

Quote from: Prober on 05/11/2011 04:42 pm

More on the NASA Feb. visit:

http://www.lvrj.com/business/las-vegas-entrepreneur-wants-to-upgrade-space-modules-115356329.html

Ok so the spend is now up from $180m to $215m. That's starting to get close to half of what he says he's willing to spend. I wonder how dependant on NASA largess Bigelow is or is he simply attempting to get a bit more funding to accelerate things or save money that he have to spend in any case?

docmordrid · « **Reply #607 on:** 05/12/2011 07:56 am »

I would think a large amount of recent expendatures is that 180,000 sq/ft expansion they're building in Nevada. Once that's finished & outfitted they can get down to brass tacks.

baldusi · « **Reply #608 on:** 05/12/2011 03:10 pm »

Quote from: SpacemanSpiff on 05/12/2011 06:11 am

The limit on the inflated shell diameter is dependent on the diameter of the launch vehicle fairing that the payload must fit within. This is always your number one constraint for a space vehicle that does not possess it's own pressure shell.

In my experience, thin walled pressure vessels are constrained by the tensile strength of the wall material. As you increase the diameter, you increase the tensile effort, and thus you reach a maximum (for a given safety margin). But here we want to do a toroid, so the question was more how much could you fit. A back of the envelope calculation was that a 2m ID tube, plus a .3m wall thickness, in a 50m torus, was around 350m³. A Falcon 9 fairing is in the order of a 130m³.
An 8.4m fairing (ID 7.6m, with a 20m length) would have around 950m³. That is around the total wall volume of a 120m x 2m ID toroid. Of course here we have no structure and no equipment, and the wall is arbitrarily foldable (though incompressible). I a HLV is ever developed, a 50m toroid for centripetal gravity could be developed. If you launched it in segments, then you'd be running into tensile strength problems.

Robotbeat · « **Reply #609 on:** 05/12/2011 03:46 pm »

Quote from: baldusi on 05/12/2011 03:10 pm

Quote from: SpacemanSpiff on 05/12/2011 06:11 am
The limit on the inflated shell diameter is dependent on the diameter of the launch vehicle fairing that the payload must fit within. This is always your number one constraint for a space vehicle that does not possess it's own pressure shell.
In my experience, thin walled pressure vessels are constrained by the tensile strength of the wall material. As you increase the diameter, you increase the tensile effort, and thus you reach a maximum (for a given safety margin). But here we want to do a toroid, so the question was more how much could you fit. A back of the envelope calculation was that a 2m ID tube, plus a .3m wall thickness, in a 50m torus, was around 350m³. A Falcon 9 fairing is in the order of a 130m³.
An 8.4m fairing (ID 7.6m, with a 20m length) would have around 950m³. That is around the total wall volume of a 120m x 2m ID toroid. Of course here we have no structure and no equipment, and the wall is arbitrarily foldable (though incompressible). I a HLV is ever developed, a 50m toroid for centripetal gravity could be developed. If you launched it in segments, then you'd be running into tensile strength problems.

Tensile strength isn't the limit. You can always increase wall thickness.

ChefPat · « **Reply #610 on:** 05/12/2011 04:02 pm »

This Pic from the Nautilus-X thread shows a test torus that might be deployed in the ISS.
Figuring a greater diameter of 60 feet & a lesser diameter of around 10 feet, how big a faring would be needed to put it in LEO?

baldusi · « **Reply #611 on:** 05/12/2011 04:04 pm »

Quote from: Robotbeat on 05/12/2011 03:46 pm

Tensile strength isn't the limit. You can always increase wall thickness.

The rate of increase of wall thickness is higher than the inner id, until eventually it stops being a thin walled PV. In any case the original question was which were the limits in outer diameter of a torus. Is it volume, is it material strength, is it vibrations, weight, material foldability?

Bill White · « **Reply #612 on:** 05/12/2011 04:04 pm »

Quote from: ChefPat on 05/12/2011 04:02 pm

This Pic from the Nautilus-X thread shows a test torus that might be deployed in the ISS.
Figuring a greater diameter of 60 feet & a lesser diameter of around 10 feet, how big a faring would be needed to put it in LEO?

A question about this design.

Would it be feasible to launch the torus in a linear configuration and then attach the ends to form a torus after arriving in LEO?

baldusi · « **Reply #613 on:** 05/12/2011 04:11 pm »

Quote from: ChefPat on 05/12/2011 04:02 pm

This Pic from the Nautilus-X thread shows a test torus that might be deployed in the ISS.
Figuring a greater diameter of 60 feet & a lesser diameter of around 10 feet, how big a faring would be needed to put it in LEO?

If you mean that the outer diameter of the torus is 18m, an the inner diameter of the section of the tube is 2.5m. And assuming that the walls are 0.3m thick. I get around 160m³ of wall. Again, no hard parts, no compression, infinite foldability. A Falcon 5m fairing is around 130m³, plus a small maneuvering engine. So Bigelow modules should actually be volume constrained. At least for this sizes.

ChefPat · « **Reply #614 on:** 05/12/2011 04:14 pm »

Quote from: Bill White on 05/12/2011 04:04 pm

Quote from: ChefPat on 05/12/2011 04:02 pm
This Pic from the Nautilus-X thread shows a test torus that might be deployed in the ISS.
Figuring a greater diameter of 60 feet & a lesser diameter of around 10 feet, how big a faring would be needed to put it in LEO?

A question about this design.

Would it be feasible to launch the torus in a linear configuration and then attach the ends to form a torus after arriving in LEO?

That certainly seems the way to go, but I have no idea whether it would work that way or not.
Maybe it would just take some hands on assembly?

ChefPat · « **Reply #615 on:** 05/12/2011 04:18 pm »

Quote from: baldusi on 05/12/2011 04:11 pm

If you mean that the outer diameter of the torus is 18m, an the inner diameter of the section of the tube is 2.5m. And assuming that the walls are 0.3m thick. I get around 160m³ of wall. Again, no hard parts, no compression, infinite foldability. A Falcon 5m fairing is around 130m³, plus a small maneuvering engine. So Bigelow modules should actually be volume constrained. At least for this sizes.

Is a 5m faring necessarily the largest diameter faring that can fit on a 3.6m body? If not, what is the largest that could be lifted to LEO?

baldusi · « **Reply #616 on:** 05/12/2011 04:28 pm »

Well, ULA has said they could even fit a 7.2m fairing in their 3.9m Atlas V body. At client's cost, of course. So I don't really know. Besides, the Payloads not only weight a lot, they are drag, and lot's of that. A 5m has a 19.6m² of area (I'm assuming the cx to be equal for any size). A 7.2m would have 40.7m². That would at least double your drag. Probably lower your maxQ significantly. And since the Merlin 1 isn't throttlable you might have a problem there. Atlas V's RD-180 can throttle and thus can keep a lower maxQ, at the expense of performance, of course.
Here the LV should be whatever NASA comes with for a HLV. I would assume that a 8.4m fairing (from the ET's width), would give you at least 7.6m of ID. And you can have twice that length before it starts to taper. That would be 15.2m. That could give you a 220m³ plus the top taper. Since this assumes the OD of the main stage, then it's quite possible that it could be made much longer. Your limiting factor would probably be VIB doors.

Downix · « **Reply #617 on:** 05/12/2011 05:09 pm »

Ok, studying the picture a bit. The central hub is about 2/3 the size of the module it is attached to. Those modules are 4.4m wide, so, applying this would give a hub size of ~3m. The hub is the widest hard point to be concerned about. To either side, you have support structures which collapse, fold up in a way ideal for transport. The walkthrough thicker support also has a telescoping capacity it appears in this picture, which means it can be shortened. This appears to allow that to be reduced in length by a third for storage. It appears at full length to be 1.5x the central hubs diameter, so would be 4.5m. Assuming that the hard point of the ring at the end of this walkthrough point is the same width as the central hub, the diameter of the interior can be determined. The diameter of the ring as it attaches to that point appears to be the same as that of the section itself it appears, so would also be 3m, plenty to stand up in.

So, let us add it up at this point, to build a radius. Half of the hub would be 1.5m. Adding the connection would give us an additional 4.5m, for 6m. Adding 3m would give us a radius of 9m, for a total diameter of 18m. But now let us collapse it.

3m core, adding the deflated sections and drawing the two telescoping pieces on each side in would be drawn down to just under 4.4m. Moving the access tunnel into storage position reduces it's length to 3m, so adding in the hub, tunnel, and ring link you get 9m. The bottom section in the picture appears to be linked through a hard point, non-telescoping. But it's hard point is also thin, ideal to move up and out of the way when deflated. So, my thought was that this would be the piece that required spacewalk assembly. When deflated, the ring would be folded down along the side of the hub, rather than on the bottom. It would therefore still fit under a 5m long fairing on an Atlas with the Centaur. Once on-site, it would then have the bottom ring and structure attached, the access tunnel extended, then the whole thing inflated.

joek · « **Reply #618 on:** 05/13/2011 01:01 am »

To answer the questions about size and PLF constraints for the NAUTLIUS ISS centrifuge demo (really belongs in the NAUTILUS thread)...

Torus is spec'd at 30ft OD (they also show figures for 40ft OD so may be TBD), with 50in cross section (ID). Self-deploying and IVA for final construction (no EVA). Launch on Delta IV or Atlas V; presumably existing PLF's are sufficient. See:

NAUTILUS-X (slide 11, 13, 16)
http://spirit.as.utexas.edu/~fiso/telecon/Holderman-Henderson_1-26-11/Holderman_1-26-11.ppt

TAAT Study Team Applications and Plans (slide 13)
http://spirit.as.utexas.edu/~fiso/telecon/Holderman-Henderson_1-26-11/Henderson_1-26-11.ppt

edit: correct links.

ChefPat · « **Reply #619 on:** 05/13/2011 03:28 am »

Quote from: joek on 05/13/2011 01:01 am

To answer the questions about size and PLF constraints for the NAUTLIUS ISS centrifuge demo (really belongs in the NAUTILUS thread)...

Torus is spec'd at 30ft OD (they also show figures for 40ft OD so may be TBD), with 50in cross section (ID). Self-deploying and IVA for final construction (no EVA). Launch on Delta IV or Atlas V; presumably existing PLF's are sufficient. See:

We weren't talking about the Demo model. We were discussing the dimensions of the possible full size model.
The Demo model was proposed by Bigelow. I think it would be safe to assume that if the Bigelow Demo design is validated in those tests, Bigelow will build the full size model.