self-patching walls for micro-meteors

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A.W.R. - 31 Jul 2005 03:40 GMT

If one wanted to have a wall between vacuum and .15 Oxygen atm (or 1
atm air if you wish), what material will after a micro-meteor passes
through patch itself??? This is rather than the thick wall or shield
defense against micro-meteors.

1. With "1 thin metal wall", you get some stretching of metal then
puncture with no sealing. Or is this wrong?

2. With "super-stretchable film" might one get long tube of stretched
film then puncture, so somehow the tube seals itself either by being
flatly pressed against remaining air by pressure or due to
self-adhesion?? I know its hard to get stretching due to super-speed
of meteor but possible at all??

3. With film that doesn't stretch but is "multi-layer" film or metal
walls lying next to dozens of other layers, if one allowed layers to
shift might not the layers post-strike shift to seal and avoid complete
path to space??? Layers shouldn't stretch, which would block any
shifting. I know hard to imagine layers of material any of which could
be pressure wall, but maybe imagine metal tubes inside each other slide
on top of each other while heated so later contract and pressurize
(this idea is getting complicated...)

4. Is there some goop that could be put in between layers or maybe put
in "goop-bags" like bubblewrap that any meteor would go through and
thus immediately apply to any puncture, thus sealing it (so don't try
to fight meteor with this wall, use thin wall and then patch
afterward). Of course goop-bags would block transparent walls.

5. Finally, how about using "floating goo-balls" that would be sucked
to hole to space and plug the leak, maybe in splat-ball shells to keep
goo-balls from sticking??? Use many floaters or a few big rubber
balls, to minimize time?

6. Or is there no such thing as a passive patching option, and "active
human or robot patcher" always needed.

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Ian Stirling - 02 Aug 2005 12:54 GMT

> If one wanted to have a wall between vacuum and .15 Oxygen atm (or 1
> atm air if you wish), what material will after a micro-meteor passes
[quoted text clipped - 3 lines]
> 1. With "1 thin metal wall", you get some stretching of metal then
> puncture with no sealing. Or is this wrong?

No stretching, it's too fast an event, you just get vapourisation of the
metal, and a hole/crater punched, depending on the size.

> 2. With "super-stretchable film" might one get long tube of stretched
> film then puncture, so somehow the tube seals itself either by being
> flatly pressed against remaining air by pressure or due to
> self-adhesion?? I know its hard to get stretching due to super-speed
> of meteor but possible at all??

No.
Basically, you can't get stretching unless the incoming impulse is several
times less than the speed f sound in the material.

> 3. With film that doesn't stretch but is "multi-layer" film or metal
> walls lying next to dozens of other layers, if one allowed layers to
[quoted text clipped - 4 lines]
> on top of each other while heated so later contract and pressurize
> (this idea is getting complicated...)

And sounds heavy.
-

> 4. Is there some goop that could be put in between layers or maybe put
> in "goop-bags" like bubblewrap that any meteor would go through and
> thus immediately apply to any puncture, thus sealing it (so don't try
> to fight meteor with this wall, use thin wall and then patch
> afterward). Of course goop-bags would block transparent walls.

You then have to figure out something that won't leak out of the hole too.

> 5. Finally, how about using "floating goo-balls" that would be sucked
> to hole to space and plug the leak, maybe in splat-ball shells to keep
> goo-balls from sticking??? Use many floaters or a few big rubber
> balls, to minimize time?

This will complicate ventilation - you don't want the balls going into
filters, ...
You need to insulate the hull.
If you don't, you get severe condensation on the inside of the hull,
and stuff growing in that moisture, which is bad for several reasons.
You need this insulation on the outside anyway, so it's not that big
a stretch to add some debris barrier layers.

Any sort of floating system means also that you can't bolt anything to
walls.

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Jeff Findley - 02 Aug 2005 22:06 GMT

It's wrong. At the speeds a micrometeorite would hit your wall, you don't
get "stretching then puncture", you get an effect that's more like an
explosion.

I would think this woudn't be possible.

This idea is similar to the multi-layered protection already used on
spacecraft, but they typically use very high strength fabrics separated by
some amount of space. If you're layers are all togehter, the pieces made by
the object hitting the first layer don't have time to spread out. You want
them to spread out so that the next layer takes the impact over a larger
area. You then add as many layers as needed to get the protection desired.

If you read a bit about the subject, you'll find that your ideas aren't
original and you'll find out why some work and some don't.

Jeff

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Aristotle - 04 Aug 2005 20:45 GMT

We have been in space for nearly fifty years. Over that time how many
objects have been launced and how amy have been severly damaged or
destroyed by meteors? One? maybe two? And if there were any, none
have been manned craft, which tend to be more robustly built.

The danger of collision is extremely small and one has to balnce the
potential risk with the cost of avoiding that risk. Some of your
passive systems sound interesting. But they would to the weight and
will increase both the cost of the craft and its launching.

>If one wanted to have a wall between vacuum and .15 Oxygen atm (or 1
>atm air if you wish), what material will after a micro-meteor passes
[quoted text clipped - 32 lines]
>6. Or is there no such thing as a passive patching option, and "active
>human or robot patcher" always needed.

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Space Forum / Space Flight / August 2005

self-patching walls for micro-meteors