Author Topic: Bigelow Aerospace Update and Discussion Thread (3)  (Read 382143 times)

Online jabe

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Re: Bigelow Aerospace Update Thread (3)
« Reply #40 on: 01/17/2013 04:40 PM »
so from the video it seems BEAM will inflate in all directions.  Does this mean the BEAM won't have a solid "beam" going down middle?   I always thought it would have to minimize torque.  But since nothing is on other side of BEAM after it is docked it seems to make sense it doesn't really need one.
jb

Offline guckyfan

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Re: Bigelow Aerospace Update Thread (3)
« Reply #41 on: 01/17/2013 05:17 PM »
so from the video it seems BEAM will inflate in all directions.  Does this mean the BEAM won't have a solid "beam" going down middle?   I always thought it would have to minimize torque.  But since nothing is on other side of BEAM after it is docked it seems to make sense it doesn't really need one.
jb

I saw that too in the animation. I imagine there could be a telescopic core that would extend when the module is inflated.


Offline mr. mark

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Re: Bigelow Aerospace Update Thread (3)
« Reply #42 on: 01/17/2013 05:32 PM »
Not sure if the BEAM module's specs were reported. Here is some more data.

"BEAM is a cylindrical module, like all other ISS modules, and is about somewhat similar in size to the US Harmony module, as BEAM is about 4 meters (13 feet) long and 3.2 meters (10.5 feet) wide; Harmony 7.2 meters (24 ft) in length, and it has a diameter of 4.4 meters (14 ft). But weight is where the two vastly differ: Harmony weighs in 14,288 kilograms (31,500 lb), while BEAM weighs roughly 1,360 kg (3,000 pounds). And that is the big advantage of inflatable structures for use in space: their mass and volume are relatively small when launched, reducing launch costs".

Read more: http://www.universetoday.com/99486/nasa-to-beam-up-inflatable-space-station-module/#ixzz2IG72NNi1

 

Offline mmeijeri

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Re: Bigelow Aerospace Update Thread (3)
« Reply #43 on: 01/17/2013 05:38 PM »
Does that count all the equipment inside Harmony? If not, then it's not a fair comparison, except perhaps for crew quarters.
« Last Edit: 01/17/2013 05:42 PM by mmeijeri »
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Offline e of pi

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Re: Bigelow Aerospace Update Thread (3)
« Reply #44 on: 01/17/2013 06:27 PM »
I think Harmony's a poor point of comparison anyway--it's a node, and thus contains 6 CBMs, to BEAM's one. I think an MPLM would make a better comparison.

MPLM: 6.4m long, 4.6m diameter, essentially cylindrical.
BEAM: 4m long, 3.3m diameter, but very "pumpkin shaped."

An MPLM masses 4,082 kg, and has a volume of about 109 cubic meters. BEAM is maybe 25ish: an ellipsoid 4m long by 3.2 by 3.2 would be 21, BEAM has a bit more volume than that would. So, the MPLM masses about 40.8 kg/m^3, while BEAM masses 54/m^3. Obviously, treating this like a density isn't the most valid method, since there's the old square-cube law at work but...I dunno. Not incredibly impressed.

Offline A_M_Swallow

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Re: Bigelow Aerospace Update Thread (3)
« Reply #45 on: 01/17/2013 06:42 PM »
If you are going to modify the BEAM you could simply fly a Genesis II.  It already has solar arrays.
http://www.bigelowaerospace.com/genesis-2-specs.php

I think Genesis 2 is smaller than BEAM, isn't it?  It also doesn't come with pre-designed end plates for the docking interface and the connection to the launcher's U/S.

Mr Mark - "BEAM is about 4 meters (13 feet) long and 3.2 meters (10.5
feet) wide"

Genesis II from web page - length 4.4 meters and diameter 2.54 meters.
11.5 cubic meters usable volume and skin shell is 6 inches thick.

So BEAM is shorter but wider.

The Genesis II must have had some connection to the LV to permit the Russians to launch it.

Docking ports are needed, possibly one of the reasons Bigelow has gone on to the BA-330.

Offline Nathan

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Re: Bigelow Aerospace Update Thread (3)
« Reply #46 on: 01/17/2013 06:57 PM »
I think Harmony's a poor point of comparison anyway--it's a node, and thus contains 6 CBMs, to BEAM's one.

Furthermore, five of Harmony's six CBM's are active CBMs, much heavier than the passive CBM on BEAM. I  agree it's a silly comparison.
I don't think it is worth comparing to any of the other main modules. Maybe the small Russian pirs would be better. If it must be done.
But this is purely a test module that NASA wants in order to evaluate the concept. Being able to pack a module into a smaller space allows better use of the launch vehicles capacity if nothing else.
I like that the module essentially could expand dragons crew volume - kinda like zubrins mars mission architecture using a dragon rider.
Given finite cash, if we want to go to Mars then we should go to Mars.

Offline Elmar Moelzer

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Re: Bigelow Aerospace Update Thread (3)
« Reply #47 on: 01/17/2013 07:04 PM »
Inflatable structures clearly become more efficient the larger the volume is. A smaller module will have less weight advantages than a larger would. Just saying.

Offline Robotbeat

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Re: Bigelow Aerospace Update Thread (3)
« Reply #48 on: 01/17/2013 07:07 PM »
Inflatable structures clearly become more efficient the larger the volume is. A smaller module will have less weight advantages than a larger would. Just saying.
It's likely to be true, but it isn't totally clear. Remember, if you're limited by material strength, the mass per volume of a pressure vessel is essentially independent of the size of the pressure vessel for the same shape.
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Online rklaehn

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Re: Bigelow Aerospace Update Thread (3)
« Reply #49 on: 01/17/2013 07:13 PM »
Inflatable structures clearly become more efficient the larger the volume is. A smaller module will have less weight advantages than a larger would. Just saying.
It's likely to be true, but it isn't totally clear. Remember, if you're limited by material strength, the mass per volume of a pressure vessel is essentially independent of the size of the pressure vessel for the same shape.

If you make some reasonable assumptions about tensile strength, the mass of such a small module is absolutely dominated by the shielding mass, which scales with surface area. Only for really large diameters does the pressure vessel mass (which scales with volume) become relevant.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline Robotbeat

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Re: Bigelow Aerospace Update Thread (3)
« Reply #50 on: 01/17/2013 07:14 PM »
Inflatable structures clearly become more efficient the larger the volume is. A smaller module will have less weight advantages than a larger would. Just saying.
It's likely to be true, but it isn't totally clear. Remember, if you're limited by material strength, the mass per volume of a pressure vessel is essentially independent of the size of the pressure vessel for the same shape.

If you make some reasonable assumptions about tensile strength, the mass of such a small module is absolutely dominated by the shielding mass, which scales with surface area. Only for really large diameters does the pressure vessel mass (which scales with volume) become relevant.
That is true about shielding mass. Except shielding mass isn't that great, either, unless you're talking about GCR, which I suspect you are.

Also, I'm not sure you're including the large factor of safety you might want for a permanently occupied vessel.
« Last Edit: 01/17/2013 07:15 PM by Robotbeat »
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Online rklaehn

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Re: Bigelow Aerospace Update Thread (3)
« Reply #51 on: 01/17/2013 07:42 PM »
Inflatable structures clearly become more efficient the larger the volume is. A smaller module will have less weight advantages than a larger would. Just saying.
It's likely to be true, but it isn't totally clear. Remember, if you're limited by material strength, the mass per volume of a pressure vessel is essentially independent of the size of the pressure vessel for the same shape.

If you make some reasonable assumptions about tensile strength, the mass of such a small module is absolutely dominated by the shielding mass, which scales with surface area. Only for really large diameters does the pressure vessel mass (which scales with volume) become relevant.
That is true about shielding mass. Except shielding mass isn't that great, either, unless you're talking about GCR, which I suspect you are.

Also, I'm not sure you're including the large factor of safety you might want for a permanently occupied vessel.

Even with a large safety factor, the mass of a pure pressure vessel is very low. The specific mass (mass per volume) of a spherical pressure vessel according to wikipedia is

mass/volume = 3/2*pressure*material_density/material_tensile_strength

Assume a material with a tensile strength of 1GPa and a density of 1000kg/m^3. Then the specific mass of a spherical pressure vessel would be 3/2*100000*1000/1e9 = 0.15kg/m^3. Even if you add a very generous safety factor of 20, that is only 3kg/m^3 or 60kg for a bigelow beam module.
Try the ISS 3D visualization at http://www.heavens-above.com/ISS_3D.aspx

Offline JasonAW3

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Re: Bigelow Aerospace Update Thread (3)
« Reply #52 on: 01/17/2013 08:16 PM »
Apparently, Bigelow plans to have two BEAM units ready by 2016.  One is the spare, of course, but that got me thinking.

Possible BEAM Application
HSF Mission Module

* Modified BEAM with Dragonrider- or CST-100-derived life support on the opposite side to the docking port;
* Base permanently attached to Falcon-9 upper stage, which will also provide RCS and, through Dragon-type solar arrays, electrical power;
* Dragon rides on top of BEAM or, if a Bigelow mission, the module will be enclosed with a SpaceX-standard 5.2m PLF.  Alternate launch vehicle is either EELV-M (Delta-IV (5,4) or Atlas-V-5x2);
* Central spine of module has five or six 'flower petal' work station mountings that fold out to the full width of the module from flush against the spine as the module inflates.

The module could fly underneath a Dragon when launched by Falcon Heavy for a single launch multi-week mission.  Application: Lower-cost space tourism or short-term science.  The module could also fly attached to a Golden Spike-style Centaur EDS as the hab module for a lunar fly-around or orbiter mission.

Reason for being: Possible Bigelow competitor to DragonLab.

Nice idea.

     Add an inflatable heat shield and a parachute pack at the end of the mission and it could be recovered and reused.  (Heck, might even be usable as an emergency Lifeboat for the ISS or other stations).

Just a thought.

Jason
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Offline JasonAW3

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Re: Bigelow Aerospace Update Thread (3)
« Reply #53 on: 01/17/2013 08:24 PM »
Interesting. But how would it go from inside the HTV to outside the station?

It also raises another question: why not make it an expendable inflated trash can to be taken down with Dragon?
1- Dragon carries one empty BEAM in the trunk
2- The inflatable module is moved to a docking port
3- It stays there for as long as required, being loaded with high volume, low weight garbage
4- Another Dragon visiting the station would take it on its trunk to be disposed

So....

     They are essentially using it as a big Hefty Trash Bag...

Hmmmm...


Jason
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Online jabe

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Re: Bigelow Aerospace Update Thread (3)
« Reply #54 on: 01/17/2013 09:25 PM »
So....

     They are essentially using it as a big Hefty Trash Bag...

Hmmmm...
Jason
seems like a good start..get all parties comfortable with the idea of using inflatables.  keeping door closed allows for leak checks etc.  then go to next phase whichever that is..for ~$18 million a cheap deal
jb
« Last Edit: 01/17/2013 09:26 PM by jabe »

Offline mr. mark

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Re: Bigelow Aerospace Update Thread (3)
« Reply #55 on: 01/18/2013 09:25 PM »
BEAM also planned for Bigelow station.

“BEAM would be excellent for EVA [extra-vehicular activity],” Bigelow told TPM, referring to the technical term for activities conducted by humans outside of space craft and habitations like BEAM. “You could accomodate three people in space suits in there very easily. From a practical standpoint, you’d be able to move more people outside of the station at once to do whatever it is they need to do.

http://idealab.talkingpointsmemo.com/2013/01/inflatable-spacecrafts-other-goal-space-walks-for-tourists.php

Offline go4mars

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Re: Bigelow Aerospace Update Thread (3)
« Reply #56 on: 01/18/2013 09:46 PM »
“BEAM would be excellent for EVA” Bigelow told TPM, ..“You could accomodate three people in space suits in there very easily.
I assume he means put 3 astros in there in their fancy dress, hang on to beam with the robot arm, then vent and unlatch the whole thing? 

Quote
would allow for less nitrogen and oxygen to escape into the vacuum of outer space — which happens every time a current airlock door is opened.
  Is he talking about this specific one?  Or a new one that has an airlock in the side of it (or does he mean the whole thing is the airlock)? 
« Last Edit: 01/18/2013 09:50 PM by go4mars »
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Offline mr. mark

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Re: Bigelow Aerospace Update Thread (3)
« Reply #57 on: 01/18/2013 09:50 PM »
No, Bigelow is planning to use BEAM as a spacious airlock that can accommodate up to 3 astronauts. Also the current BEAM will not have this feature so no to the ISS beam. It would be used on Bigelow's station.
« Last Edit: 01/18/2013 09:57 PM by mr. mark »

Offline go4mars

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Re: Bigelow Aerospace Update Thread (3)
« Reply #58 on: 01/18/2013 09:57 PM »
No, Bigelow is planning to use BEAM as a spacious airlock that can accommodate up to 3 astronauts.
It wasn't clear to me whether he means that BEAM is the airlock, or has a door in the side of it. 
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Offline mr. mark

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Re: Bigelow Aerospace Update Thread (3)
« Reply #59 on: 01/18/2013 10:00 PM »
Yes, he's saying BEAM would be the airlock. I'm not sure how effective this would be.

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