Legless spacesuits

[Joris]

Is there any reason that spacesuits for EVA have always housed the legs of an astronaut in separate legs, and not in a cocoon? You might be able to simplify and/or reduce the mass of your suit. This will cost you some versatility, but legs seem to just flout around on most spacewalks, or they are attached to a robotic arm. In both cases it doesn't seem to matter what degree of freedom your legs have.

The concept seems to have been around for at least 60 years, so I must be missing something. It can't be too expensive to develop, and it seems a more simple design than a basic spacesuit.

[RonM]

Is there any reason that spacesuits for EVA have always housed the legs of an astronaut in separate legs, and not in a cocoon? You might be able to simplify and/or reduce the mass of your suit. This will cost you some versatility, but legs seem to just flout around on most spacewalks, or they are attached to a robotic arm. In both cases it doesn't seem to matter what degree of freedom your legs have.

The concept seems to have been around for at least 60 years, so I must be missing something. It can't be too expensive to develop, and it seems a more simple design than a basic spacesuit.

Seems to me that you might need your legs for getting out and back into your ship.

If you used suitports, you could probably simplify spacesuit design.

[Jim]

they are attached to a robotic arm.

By the legs.

[grondilu]

By the legs.

Astronauts are attached by the joint legs, aren't they?

Independent legs make sense mostly for walking.  And no astronaut has ever walked in space for decades.

[Jim]

Astronauts are attached by the joint legs, aren't they?

You need three points to control your position in space.   Your two hands and your joint legs should be enough, providing your joint legs have still a few degrees of freedom altogether (by this I mean that the part of the suit enveloping the legs would not be rigid, but flexible).

Which means the astronaut's feet in the cocoon have to be rigidly fixed to the interior of the cocoon with no ability to move independently.   Try keeping your feet that way for 8 hours. 

[R7]

This would be a step towards us becoming Daleks. Just say no.

[grondilu]

Which means the astronaut's feet in the cocoon have to be rigidly fixed to the interior of the cocoon with no ability to move independently.   Try keeping your feet that way for 8 hours.

8 hours is a particularly long duration for an EVA.

Also, the legs would not be tightly knot together.  It would be kind of like a sleeping bag, or what hang gliders use.  I've never heard any report that those things were harmful.

[Jim]

8 hours is a particularly long duration for an EVA.

Also, the legs would not be tightly knot together.  It would be kind of like a sleeping bag, or what hang gliders use.  I've never heard any report that those things were harmful.

That is how long they are in the suit.

No, it can't be like that, they have to be some what "knotted together".  The flyer can move his legs in that cocoon and it is not anchored to anything.  An EVA astronaut has his feet anchored in boots.  The boots then can be anchored in foot restraints.   If the cocoon is to be attached to some type of EVA restraint, then there has to be an anchor inside the cocoon for the astronaut's feet.

[grondilu]

The boots then can be anchored in foot restraints.   If the cocoon is to be attached to some type of EVA restraint, then there has to be an anchor inside the cocoon for the astronaut's feet.

So?  Nothing prevents you to design the cocoon with a way to attach feet at the bottom.  Possibly with the ability to disengage if wanted/necessary.  As with say, monoskis:



Not to mention that you don't have to anchor the astronaut by the feet, do you?

[Prober]

Believe this thread will help as it might fit.

http://forum.nasaspaceflight.com/index.php?topic=28369.0

[Patchouli]

Why not attach the astronaut to the arm by the waist or backpack vs the legs?

[Jim]

1.  So?  Nothing prevents you to design the cocoon with a way to attach feet at the bottom.  Possibly with the ability to disengage if wanted/necessary.  As with say, monoskis:


2.  Not to mention that you don't have to anchor the astronaut by the feet, do you?

1.   Those require visual cues to engage and hands to disengage, both which are unavailable in a cocoon.  And if you are going to have boots, might as well as design them into the suit. 

2.  Yes, you do.  It gives the astronaut more freedom of movement through his legs.  Any other attachment is fixed and the astronaut would have to take a break from his work to readjust.

[Jim]

Why not attach the astronaut to the arm by the waist or backpack vs the legs?

Then the astronaut is further beholden to the arm operator for every adjustment for position.  When attached by his feet, he can lean forward, back and side to side and crouch and extend.

[Avron]

Why not attach the astronaut to the arm by the waist or backpack vs the legs?

Then the astronaut is further beholden to the arm operator for every adjustment for position.  When attached by his feet, he can lean forward, back and side to side and crouch and extend.

What would be the benefit to a legless spacesuit..  none that I can see.. 

[grondilu]

1.   And if you are going to have boots, might as well as design them into the suit. 

Yeah.  But they can fit in one envelop.  And they won't be exactly boots.  Rather internal fixation systems.

Basically the fact that the feet may have to be anchored does not imply much about the legs.  That's what I tried to illustrate with the monoski.

What would be the benefit to a legless spacesuit..  none that I can see..

Easier to manufacture, for one.  Possibly more comfortable.  Also maybe less surface area.   But basically whenever something is not useful, it's always good to consider getting rid of it.  Independence of legs seems to qualify.

I may be biased though, since if you'd ask me, I would not put human bodies in space, anyway.

[Jim]

  But basically whenever something is not useful, it's always good to consider getting rid of it.  Independence of legs seems to qualify.

I have shown that it is quite the opposite.  Legs are very useful for EVA.

[grondilu]

I have shown that it is quite the opposite.

Have you?  If you refer to:

Then the astronaut is further beholden to the arm operator for every adjustment for position.  When attached by his feet, he can lean forward, back and side to side and crouch and extend.

then you're talking about a situation when the astronaut has his feet attached together.  There is no need for leg independence then.

Legs are very useful for EVA.

I wrote that independence of legs is (possibly) useless.  Not legs.

[RonM]

I have shown that it is quite the opposite.

Have you?  If you refer to:

Then the astronaut is further beholden to the arm operator for every adjustment for position.  When attached by his feet, he can lean forward, back and side to side and crouch and extend.

then you're talking about a situation when the astronaut has his feet attached together.  There is no need for leg independence then.

Legs are very useful for EVA.

I wrote that independence of legs is (possibly) useless.  Not legs.

If you are still going to use legs to change position, then they need to be independent so the suit can have joints. Flexing a pressurized cocoon over both legs and maintaining that new position would be very difficult and tiring.

I think the future of EVAs will be telepresence. A Robonaut type robot torso attached to an arm and operated virtual reality style by an astronaut safely in the ship.

[grondilu]

If you are still going to use legs to change position, then they need to be independent so the suit can have joints. Flexing a pressurized cocoon over both legs and maintaining that new position would be very difficult and tiring.

Well, that is a good point.  It might be difficult to make a flexible pressurized cocoon indeed.

A Robonaut type robot torso attached to an arm and operated virtual reality style by an astronaut safely in the ship.

Or even better:  on Earth.  At least if we're taking about LEO missions.  But this is off-topic.

[Borklund]

If you are still going to use legs to change position, then they need to be independent so the suit can have joints. Flexing a pressurized cocoon over both legs and maintaining that new position would be very difficult and tiring.

Well, that is a good point.  It might be difficult to make a flexible pressurized cocoon indeed.

It would be more difficult and expensive than making pressurised legged space suits, something that has been done for over 60 years now. Operating in a cocoon would be cumbersome and unnatural. An astronaut would probably tire him/herself out more from unnecessary movement. It's only natural to use your legs independent of one another. Not to mention other issues like numbness and comfort in general. Jim is right.

A Robonaut type robot torso attached to an arm and operated virtual reality style by an astronaut safely in the ship.

Or even better:  on Earth.  At least if we're taking about LEO missions.  But this is off-topic.

Telepresence would probably best be suited for a scenario where the delay in communication is such that robots become inefficient when controlled from Earth, like on Mars. For example, it would be cheaper to launch astronauts in a spacecraft to orbit around Mars or one of its moons (cheaper than landing them on the surface) and then have the crew teleoperate robots on the surface from the confines of the spacecraft in orbit. You'd get a balance of of cheap robotics and expensive (but efficient) human operation. But I digress, this is straying away from the topic at hand.