Space station impact shielding.

"Martha Adams" wrote in message
...
"OM" wrote in message
...
On Fri, 27 Mar 2009 22:52:01 EDT, "Jorge R. Frank"
wrote:

When they were built, did NASA ask
that the modules have a minimum level of impact survivability?

Yes, I did.

....Have you had your shielding upgraded, Jorge?

:-) :-)

OM

--

]=====================================[
] OMBlog - http://www.io.com/~o_m/omworld [
] Let's face it: Sometimes you *need* [
] an obnoxious opinion in your day! [
]=====================================[

==================================================

Where is our moderator? This appears to be a personal attack by "OM" upon
the writer of a previous message.

Titeotwawki -- mha [sci.space.tech 2009 Mar 28]


I was originally going to reply to the original poster but figured this it
would be better to address this in the group.

As our original post had stated:

"Personal attacks generally will NOT be tolerated. Quips at others expense
or ribbing may be tolerated as long as they are not the main point of the
post and are specific to the points being addressed."

Strictly speaking, the S/N of OM's post is on the low side, and for that
reason one could argue it should be rejected. However, our intent is not to
stifle discussion completely.

But it is hardly a personal attack. It definitely falls under ribbing and
quips.

If Jorge does feel attacked, he is more than welcome to email the moderators
and we will address it privately.

In general in order to not pollute the newsgroup, we would prefer questions
be addressed directly to the moderators.

If you have further questions, please address privately.

In any case, let's focus more on technical content. This particular
discussion, while interesting, is lacking in attributions to source
documentation and the like, which is the sort of stuff I know personally I'd
like to see in a .tech discussion.

Thanks.

--
Greg Moore
Ask me about lily, an RPI based CMC.

"Jorge R. Frank" wrote:

:Fred J. McCall wrote:
: "Jorge R. Frank" wrote:
:
: :Alain Fournier wrote:
: :
: : Does anyone know about what kind of impact the space station can
: : survive? Surely this has been analyzed. I would imagine that it can
: : withstand a fleck of paint hitting at 5 km/s but not a 1 kg piece of
: : metal hitting at the same speed.
: :
: :Approximately 1 cm is the upper limit.
: :
:
: But 1 cm moving at what relative speed with what mass?
:
:1 cm aluminum sphere hitting at a right angle (~11 km/s), IIRC.
:

Ah. Thanks.

:
:
: Whipple has gotten his name on the shielding principle, but it's
: really just the same sort of scheme that has been used on armored
: vehicles for decades. It leaves me wondering whether application of
: other techniques from armored vehicles could be adapted somehow.
:
: Blazer armor for space vehicles, anyone?
:
:Possibly, but armored vehicle applications are a lot less
:weight-sensitive...
:

True, but something similar to Blazer might actually save weight when
compared to metal or ceramic offering the same protection.

I know that Blazer is actually intended to work against Munroe Effect
warheads, but it seems to me something similar could be used to help
slow down projectiles. Rather than explosive blocks intended to
disrupt plasma jets, perhaps a 'honeycomb' of small shaped charges
that would rapidly decrease particle velocity normal to the protected
surface, leading to generally smaller velocities of impact with the
spaced protection underneath.

I believe there has been research done on explosive 'sandwiches' that
would cause rapid lateral displacement between two adjacent layers of
spaced armor to help protect against long-rod penetrators. That sort
of approach might work here, too.

Probably be hideously expensive to fabricate, though, as well as being
a safety concern for anything outside the station. Not to mention
having to replace a section every time you get a strike and the
explosive is triggered.

--
"We come into the world and take our chances.
Fate is just the weight of circumstances.
That's the way that Lady Luck dances.
Roll the bones...."
-- "Roll The Bones", Rush

On Mar 30, 3:50 am, Fred J. McCall wrote:
"Jorge R. Frank" wrote:


True, but something similar to Blazer might actually save weight when
compared to metal or ceramic offering the same protection.

I know that Blazer is actually intended to work against Munroe Effect
warheads, but it seems to me something similar could be used to help
slow down projectiles. Rather than explosive blocks intended to
disrupt plasma jets, perhaps a 'honeycomb' of small shaped charges
that would rapidly decrease particle velocity normal to the protected
surface, leading to generally smaller velocities of impact with the
spaced protection underneath.

I believe there has been research done on explosive 'sandwiches' that
would cause rapid lateral displacement between two adjacent layers of
spaced armor to help protect against long-rod penetrators. That sort
of approach might work here, too.

Probably be hideously expensive to fabricate, though, as well as being
a safety concern for anything outside the station. Not to mention
having to replace a section every time you get a strike and the
explosive is triggered.

I think you are underestimating the differences. A long needle
penetrator has a velocity in the 1.6km/s range. much faster and they
tend to shatter or deform unfavorably for amour penetration. While in
orbit we are getting up to 14km/s and even higher for objects with
earth escape velocity. Forget reactive amour, that speck of paint or
nut has a lot more energy than explosive per kg (23x TNT) and will
have a lot more momentum than any reactive plate can hope to get.

The advantage of such high velocity impacts is that you can break them
up with a thin shield. A wipple shield in fact. The particle hits the
shield and explodes into a hot jet of smaller particles that then
impact a more solid shield over a larger area. Giotto used this to
great effect in its very close flyby of Halley's Comet. The wipple
shield in this case was 1 mm of Al.

But otherwise there really is no equivalent with earth based amour.
They do totally different things.

Greg

delt0r wrote:

:On Mar 30, 3:50 am, Fred J. McCall wrote:
: "Jorge R. Frank" wrote:
:
:
: True, but something similar to Blazer might actually save weight when
: compared to metal or ceramic offering the same protection.
:
: I know that Blazer is actually intended to work against Munroe Effect
: warheads, but it seems to me something similar could be used to help
: slow down projectiles. Rather than explosive blocks intended to
: disrupt plasma jets, perhaps a 'honeycomb' of small shaped charges
: that would rapidly decrease particle velocity normal to the protected
: surface, leading to generally smaller velocities of impact with the
: spaced protection underneath.
:
: I believe there has been research done on explosive 'sandwiches' that
: would cause rapid lateral displacement between two adjacent layers of
: spaced armor to help protect against long-rod penetrators. That sort
: of approach might work here, too.
:
: Probably be hideously expensive to fabricate, though, as well as being
: a safety concern for anything outside the station. Not to mention
: having to replace a section every time you get a strike and the
: explosive is triggered.
:
:I think you are underestimating the differences. A long needle
enetrator has a velocity in the 1.6km/s range. much faster and they
:tend to shatter or deform unfavorably for amour penetration. While in
rbit we are getting up to 14km/s and even higher for objects with
:earth escape velocity. Forget reactive amour, that speck of paint or
:nut has a lot more energy than explosive per kg (23x TNT) and will
:have a lot more momentum than any reactive plate can hope to get.
:

But that's not necessarily so. An explosive with a sufficiently high
detonation velocity would radically reduce (or outright eliminate) the
velocity vector of the impinging particle normal to the bulkhead
surface. Explosives like Octanitrocubane have detonation velocities
above 10 km/sec.

:The advantage of such high velocity impacts is that you can break them
:up with a thin shield. A wipple shield in fact. The particle hits the
:shield and explodes into a hot jet of smaller particles that then
:impact a more solid shield over a larger area. Giotto used this to
:great effect in its very close flyby of Halley's Comet. The wipple
:shield in this case was 1 mm of Al.
:
:But otherwise there really is no equivalent with earth based amour.
:They do totally different things.
:

Not so much. 'Armor' is armor and the principles are quite similar.

There are reasons why 'Blazer' for spacecraft probably isn't a great
idea, but your objections are not among them.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw

On Apr 4, 2:27 pm, Fred J. McCall wrote:
delt0r wrote:

:On Mar 30, 3:50 am, Fred J. McCall wrote:
: "Jorge R. Frank" wrote:
:
:
: True, but something similar to Blazer might actually save weight when
: compared to metal or ceramic offering the same protection.
:
: I know that Blazer is actually intended to work against Munroe Effect
: warheads, but it seems to me something similar could be used to help
: slow down projectiles. Rather than explosive blocks intended to
: disrupt plasma jets, perhaps a 'honeycomb' of small shaped charges
: that would rapidly decrease particle velocity normal to the protected
: surface, leading to generally smaller velocities of impact with the
: spaced protection underneath.
:
: I believe there has been research done on explosive 'sandwiches' that
: would cause rapid lateral displacement between two adjacent layers of
: spaced armor to help protect against long-rod penetrators. That sort
: of approach might work here, too.
:
: Probably be hideously expensive to fabricate, though, as well as being
: a safety concern for anything outside the station. Not to mention
: having to replace a section every time you get a strike and the
: explosive is triggered.
:
:I think you are underestimating the differences. A long needle
enetrator has a velocity in the 1.6km/s range. much faster and they
:tend to shatter or deform unfavorably for amour penetration. While in
rbit we are getting up to 14km/s and even higher for objects with
:earth escape velocity. Forget reactive amour, that speck of paint or
:nut has a lot more energy than explosive per kg (23x TNT) and will
:have a lot more momentum than any reactive plate can hope to get.
:

But that's not necessarily so. An explosive with a sufficiently high
detonation velocity would radically reduce (or outright eliminate) the
velocity vector of the impinging particle normal to the bulkhead
surface. Explosives like Octanitrocubane have detonation velocities
above 10 km/sec.

The "velocity" of dentonation is not the same as the gas or shock
velocity and is more a mesure of chemical reaction speed. The velocity
of the shock wave and gases are generally less by a large amout and is
strongly dependend on the physical configuration. It also does not
tell you anything about the momentum or energy.

The claims I made are supported by research and some of this
information is publicy avalible. Ultra High velocity projectiles are
much harder to stop with tradtional armour ideas and is a active area
of resurch with the military. Well stop is not the right word.
Bascialy that energy has to go somewhere, as does that momentum. That
momentum tends to mean the energy is going to end up in the target.
This is not a new idea which is why there is work on things like rail
guns.

:But otherwise there really is no equivalent with earth based amour.
:They do totally different things.
:

Not so much. 'Armor' is armor and the principles are quite similar.

There are reasons why 'Blazer' for spacecraft probably isn't a great
idea, but your objections are not among them.

Why do you think reactive "Blazer" armour, which may be very effective
agaist RPGs, is going to be any good in this setting? Its not that
effective agaist long neddle penetrators for a start.

delt0r wrote:

:On Apr 4, 2:27 pm, Fred J. McCall wrote:
: delt0r wrote:
:
: :On Mar 30, 3:50 am, Fred J. McCall wrote:
: : "Jorge R. Frank" wrote:
: :
: :
: : True, but something similar to Blazer might actually save weight when
: : compared to metal or ceramic offering the same protection.
: :
: : I know that Blazer is actually intended to work against Munroe Effect
: : warheads, but it seems to me something similar could be used to help
: : slow down projectiles. Rather than explosive blocks intended to
: : disrupt plasma jets, perhaps a 'honeycomb' of small shaped charges
: : that would rapidly decrease particle velocity normal to the protected
: : surface, leading to generally smaller velocities of impact with the
: : spaced protection underneath.
: :
: : I believe there has been research done on explosive 'sandwiches' that
: : would cause rapid lateral displacement between two adjacent layers of
: : spaced armor to help protect against long-rod penetrators. That sort
: : of approach might work here, too.
: :
: : Probably be hideously expensive to fabricate, though, as well as being
: : a safety concern for anything outside the station. Not to mention
: : having to replace a section every time you get a strike and the
: : explosive is triggered.
: :
: :I think you are underestimating the differences. A long needle
: enetrator has a velocity in the 1.6km/s range. much faster and they
: :tend to shatter or deform unfavorably for amour penetration. While in
: rbit we are getting up to 14km/s and even higher for objects with
: :earth escape velocity. Forget reactive amour, that speck of paint or
: :nut has a lot more energy than explosive per kg (23x TNT) and will
: :have a lot more momentum than any reactive plate can hope to get.
: :
:
: But that's not necessarily so. An explosive with a sufficiently high
: detonation velocity would radically reduce (or outright eliminate) the
: velocity vector of the impinging particle normal to the bulkhead
: surface. Explosives like Octanitrocubane have detonation velocities
: above 10 km/sec.
:
:The "velocity" of dentonation is not the same as the gas or shock
:velocity ...
:

Yes, I know.

:
:... and is more a mesure of chemical reaction speed.
:

Not so. It is the speed at which the detonation shock wave passes
through the explosive. Composition certainly comes into play, but it
is largely a product of explosive density (packing), particle size,
charge diameter, and degree of confinement.

:
:The velocity
f the shock wave and gases are generally less by a large amout ...
:

For some potentially small definition of "large amout [sic]".

:
:... and is
:strongly dependend on the physical configuration.
:

Quite so, which sort of disagrees with your earlier statement about it
being a measure of chemical reaction speed.

:
:It also does not
:tell you anything about the momentum or energy.
:

Well, it tells you SOMETHING. It just doesn't tell you everything,
which is why concepts like brisance exist.

:
:The claims I made are supported by research and some of this
:information is publicy avalible. Ultra High velocity projectiles are
:much harder to stop with tradtional armour ideas ...
:

This is unsurprising, since they are "much harder to stop", period.

:
:... and is a active area
f resurch with the military.
:

Yes, I know, which is why I mentioned the 'explosive lateral plate'
idea that has been floated for stopping high speed penetrators.

:
:Well stop is not the right word.
:Bascialy that energy has to go somewhere, as does that momentum.
:

Gee, conservation of energy and momentum. Who'd a thunk it?

:
:That
:momentum tends to mean the energy is going to end up in the target.
:

Well, it certainly is unless you somehow divert it or cause it to be
used up prior to arrival at the target. Remember, it is the energy
and momentum OF THE SYSTEM that is of concern, which is why the idea
of explosive armor is workable. It adds opposite momentum, reducing
the momentum of what arrives at the target.

:
:This is not a new idea which is why there is work on things like rail
:guns.
:

It's also why there is work on things like the lateral explosive plate
armor I mentioned.

: :But otherwise there really is no equivalent with earth based amour.
: :They do totally different things.
: :
:
: Not so much. 'Armor' is armor and the principles are quite similar.
:
: There are reasons why 'Blazer' for spacecraft probably isn't a great
: idea, but your objections are not among them.
:
:Why do you think reactive "Blazer" armour, which may be very effective
:agaist RPGs, is going to be any good in this setting? Its not that
:effective agaist long neddle penetrators for a start.
:

Let's try repeating what I started with, which renders your preceding
paragraph rather moot:

"I know that Blazer is actually intended to work against Munroe Effect
warheads, but it seems to me something similar could be used to help
slow down projectiles."

See what I mean? One is left wondering who you're asking your
question of, since my very first statement said "something similar"
and pointed out that Blazer itself is only intended to be effective
against Munroe Effect warheads.

--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw