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SpaceX Discussion Thread


Skylon

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And:

TL;DR:

- Land clearing continues at Roberts Road for Starship ops

- Concrete supports/footings for tower segments are now in place ready for tower construction

- Modifications to one of 39A's commodity tanks are underway, perhaps to support methane. Visible from the air is 4 horizontal CH4 tanks (similar to those in Boca)

- Crane used for pilings is now demantled - this likely means that foundation work for the tower and the launch stand is complete.

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With respect to the EVA suits, it seems like they are heading down the same path I suggested several years ago (and for which I was roundly mocked over at the NSF forums). Build IVA suits, then use those lessons learned to upgrade the IVA suits into something which can provide a very basic level of EVA functionality, without limiting or impairing their IVA role. Then, the combo IVA/EVA suit can be evolved to accept optional add-ons for specific, expanded tasks. One suit per person, but lots of specialized modules for different activities.

For longer or more complex spacewalks, the upgrade module would be a self-contained life support backpack so you didn’t need the tether, and perhaps also magnetic boots/knee pads or grapples to make navigating microgravity less challenging. For lunar surface EVA, overshoes and perhaps mechanical joints around the knees and hips to help avoid suit-ballooning and to help assist with balance.

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Magnetic boots are a terrible idea in my opinion, because humans don't walk by pulling ourselves along a surface with our feet attached to it. We walk by maneuvering our body weight above our feet, which support us like stilts. If you tried to walk without your weight, you would have to put immense strain on your ankles to get anywhere. It would be terribly slow and painful. 

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21 minutes ago, JoeSchmuckatelli said:

... Because your suggestion was 'not the way things are done'?  (some people are wedded to the traditional) 

Or did you get constructive arguments about why they thought it would not work? 

Oh, entirely the former. “That’s dumb! IVA suits are totally different from EVA suits. There’s no way an IVA suit could be the base layer of an EVA suit!”

10 minutes ago, cubinator said:

Magnetic boots are a terrible idea in my opinion, because humans don't walk by pulling ourselves along a surface with our feet attached to it. We walk by maneuvering our body weight above our feet, which support us like stilts. If you tried to walk without your weight, you would have to put immense strain on your ankles to get anywhere. It would be terribly slow and painful. 

Surely there is some way that your legs could be useful during a space walk, right? Otherwise they are just sort of dangling there with no purpose.

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Just now, sevenperforce said:

Oh, entirely the former. “That’s dumb! IVA suits are totally different from EVA suits. There’s no way an IVA suit could be the base layer of an EVA suit!”

Surely there is some way that your legs could be useful during a space walk, right? Otherwise they are just sort of dangling there with no purpose.

A true spaceman’s feet would evolve to function more like another pair of hands, and might be genetically altered to grow a prehensile tail, too.

Or, if we could train chimps to spacewalk, or create superchimps as in Rendezvous With Rama…

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4 minutes ago, sevenperforce said:

Surely there is some way that your legs could be useful during a space walk, right? Otherwise they are just sort of dangling there with no purpose.

Maybe. The kneepads idea is interesting, because that is a way that humans can actually move around, but it would need a more maneuverable suit than has ever been built.

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31 minutes ago, cubinator said:

Maybe. The kneepads idea is interesting, because that is a way that humans can actually move around, but it would need a more maneuverable suit than has ever been built.

Oh, absolutely. And that’s part of the vision. The problem with maneuvering in a fabric suit, fundamentally, is the ballooning effect. If the joints are full of air, they puff up, and you can’t bend them without compressing the air inside your suit. To keep them from puffing up, you can make the fabric very stiff (as with the existing ISS EVA suits), but that makes them harder to bend too.

But if you have an evolved IVA suit with basic EVA functionality, that’s not too bulky, you have a lot of options. You can attach a hard shell “knee pad” that wraps around the fabric of the joint to keep it from puffing, and also has either a magnetic pad or a grapple attached. You could even have the grapple actuated by the ankle. It would take some work to figure out how to move around but it would become natural pretty quickly. 

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5 minutes ago, CatastrophicFailure said:

Would magnetic… bits even work tho? I mean, aren’t the hulls in question either stainless, aluminum, or wrapped in thermal blankets and thus not magnetic?

As I recently discovered, stainless is a special case.  Some SS alloys are magnetic; others are not. It depends on the crystalline structure (simplification). The fun part is that working the metal can change the structure and make it magnetic. 

I recently tested that on my stainless steel kitchen sink. A magnet will not stick to the flat sections, but it will stick to the curved sections that were deformed by the stamping process. The tighter the curve, the more magnetic it ‘felt’ (subjective testing, not quantitative). 

So the hull of Starship at large is probably not magnetic, but those stiffening stringers look stamped. Some well-placed, well-stamped (or well-rolled, or otherwise worked) stringers may work well as rails for magnets stick to. 

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20 hours ago, StrandedonEarth said:

As I recently discovered, stainless is a special case.  Some SS alloys are magnetic; others are not. It depends on the crystalline structure (simplification). The fun part is that working the metal can change the structure and make it magnetic. 

I recently tested that on my stainless steel kitchen sink. A magnet will not stick to the flat sections, but it will stick to the curved sections that were deformed by the stamping process. The tighter the curve, the more magnetic it ‘felt’ (subjective testing, not quantitative). 

So the hull of Starship at large is probably not magnetic, but those stiffening stringers look stamped. Some well-placed, well-stamped (or well-rolled, or otherwise worked) stringers may work well as rails for magnets stick to. 

The steel in your sink is expected to carry far less load than the starship. For sinks you may be able to get away with using as cast steel, but I would expect that they do at least some work hardening, not to mention they are probably using a special grade of steel

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