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Inflatable Space Stations

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Re: Inflatable Space Stations

#21

Post by simonh »

Retric wrote: post #10
voakbasda wrote: post #8

This is a really nice article that covers the history of space habitats, but it also made me realize that the future of habitable structures has questionable value outside of space tourism. We have entered an age where humanoid robots are beginning to do many tasks that we thought were exclusively in our domain. At our current pace, I expect they will be able to outperform us in most work settings within a decade or…

The vast majority of work done in space is already done by machines. Humanoid robots are potentially useful when operating in human environments, but that doesn’t really apply if we’re never sending humans to these locations.

Agreed, for space being humanoid is optional. Legs are superfluous for a start. However the issue with current automated systems we’re sending out there is they are function specific, and not very adaptable to novel or unanticipated activities.

This is why sending humans is often advantageous, we can do lots of different and new things. The ideal multipurpose space robot may not have to be humanoid, but it would need to replicate or ideally exceed this kind of flexibility of function.

Re: Inflatable Space Stations

#22

Post by udfalkso »

xixixao wrote: post #16
maxcan wrote: post #5

I never understand why the rotating station concepts seem to all have rigid tethers, either in the form of a central boom or a rigid circular structure. It would seem like you could get a much larger diameter, so less rotational velocity and more comfort, by attaching rigid, or inflatable in this case, structures with a tether. Compressive loads are non existent, you just need to resist tensile loads. Maybe I'll go a…

See Project Hail Mary.

And Seveneves

Re: Inflatable Space Stations

#23

Post by CableNinja »

pixl97 wrote: post #15
zackmorris wrote: post #14

Earlier quoted context omitted.

Ya I really like their airship to orbit concept. I asked AI about lift to drag (L/D) ratios in plasma at 10,000-17,5000 mph (5-8 km/s) and it suggested that lifting bodies achieve between about a 1:1 and 3:1 L/D ratio. If we assume the generous 3:1 L/D ratio, that would seem to make a single-stage to orbit space plane possible. A bit off-topic, but an aerospike engine is half of a rocket nozzle, with a virtual half c…

Pretty sure it's Scott Manley that did an episode on the aerospike and just how hard they are to get to work right. Needless to say, getting anything to go to space is hard.

Aerospikes are hard because you cant control the external pressure. At altitude A you have X atmospheric pressure, but at altitude B, Y pressure, that pressure is what keeps the exhaust against the surfave and exerting force, you can only design an aerospike for a certain effecient operational altitude and outside of that its just not great.

A nozzle engine doesnt have to account for this as much because the nozzle is keeping the pressure of the exhaust

Re: Inflatable Space Stations

#25

Post by accrual »

hypertexthero wrote: post #24

I just saw a ship that looks like some of those pictures earlier today: The Beckett-Class science vessel in the Cygnus point of interest by the current Elite Dangerous community goal station at HIP 87621.

On the topic of space games, Kerbal Space Program also had a mod to provide various inflatable space station modules. I loved them - very compact to launch and provided a fun place to float around in IVA on the way to the destination. I brought mine to Moho.

Re: Inflatable Space Stations

#26

Post by dabluecaboose »

CableNinja wrote: post #23
pixl97 wrote: post #15

Earlier quoted context omitted.

Pretty sure it's Scott Manley that did an episode on the aerospike and just how hard they are to get to work right. Needless to say, getting anything to go to space is hard.

Aerospikes are hard because you cant control the external pressure. At altitude A you have X atmospheric pressure, but at altitude B, Y pressure, that pressure is what keeps the exhaust against the surfave and exerting force, you can only design an aerospike for a certain effecient operational altitude and outside of that its just not great. A nozzle engine doesnt have to account for this as much because the nozzle i…

Nozzle engines absolutely have to account for the external pressure. The optimal pressure as the exhaust leaves the bell should be as close as possible to ambient for full thrust.

If the pressure at exhaust is higher than ambient, the exhaust pushes outward against the ambient pressure and you get huge exhaust plumes, and lost efficiency.

Conversely, if the pressure at exhaust is lower, the ambient pressure pushes the exhaust inward into shock diamonds[1] and you, again, lose efficiency.

Engine bells specifically yield their max efficiency at one external pressure/altitude. The reason you see shock diamonds is most often from ground-level testing (or takeoff) of engines that perform best at altitude.

[1] https://en.wikipedia.org/wiki/Shock_diamond

Re: Inflatable Space Stations

#27

Post by JKCalhoun »

Love the painting of the huge toroidal space station—with the houses and forests inside.

I had a thought experiment: if you could ride a bicycle (motorcycle?) against the direction of spin of the station you would essentially be "stationary". You would still have a velocity into the always-sloping-up wheel. What if you rode up a gentle ramp? Could you break away from the surface of the wheel then and become "weightless"?

Re: Inflatable Space Stations

#28

Post by Jeremy1026 »

JKCalhoun wrote: post #27

Love the painting of the huge toroidal space station—with the houses and forests inside. I had a thought experiment: if you could ride a bicycle (motorcycle?) against the direction of spin of the station you would essentially be "stationary". You would still have a velocity into the always-sloping-up wheel. What if you rode up a gentle ramp? Could you break away from the surface of the wheel then and become "weightle…

Sounds like a good question to submit to Randall at xkcd for his What If? series.

Re: Inflatable Space Stations

#29

Post by nrhrjrjrjtntbt »

JKCalhoun wrote: post #27

Love the painting of the huge toroidal space station—with the houses and forests inside. I had a thought experiment: if you could ride a bicycle (motorcycle?) against the direction of spin of the station you would essentially be "stationary". You would still have a velocity into the always-sloping-up wheel. What if you rode up a gentle ramp? Could you break away from the surface of the wheel then and become "weightle…

I think so! I doubt you need the ramp even.

The trick is that the bike is also accelerating (even at constant "speed") due to going in a circle.

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