Problems with Problems With The Orion Spacecraft #9: Stress
bombardmentforce
The ship's structure itself ... has to be able to take the stress of
sitting next to a bunch of exploding nuclear bombs. Even with shock
absorbers, it would be under repeated stress of a type not experienced
by any vehicle we have ever built. The ability of a battleship to
survive the strain of firing its own guns was the subject of a
considerable amount of development efforts in the early 20th century,
and that strain would be dramatically less than the strain experienced
by an Orion. -POS
----
Fact:
"Both the pulse frequency and the acceleration profile are reasonably
well simulated by a child's backyard swing operating through an arc
65deg each way from vertical". GA-5009 Volume 1 page 14
Quoted in Project Orion Page 179
http://spacebombardment.blogspot.com/2005/10/problems-with-problems-with-orion_21.html
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19650058729_1965058729.pdf
Tux Wonder-Dog
Fact: Based on my recall of Footfall and my knowledge of thermonuclear tests
in the Pacific and elsewhere: Taking off in Orion would be one hell of an
experience. Quite literally.
It would start out as a pseudo-underground explosion, with the bomb being
only metres away from the spacecraft's "bumper". Think vitrification.
Think sublimation of metal. Think superhot gaseous vitrified rock and
metal gases spewing out all sides.
And you need to fire another within the next few seconds to maintain your
momentum so you won't fall back down to the ground again.
Designing a hatchway that can be blocked against subliming metal and yet
pass a functioning thermonuclear device through, is beyond _my_
capabilities. I presume the Cavalry in those circumstances get Superman -
Jor-El - to throw them in, albeit from a safe distance? I missed seeing
Jor-El in Footfall - perhaps Niven and Pournelle couldn't pay him enough
for a cameo deus ex machina appearance? ;)
Wesley Parish
(And note: that factoid about the child's swing, fails to make the link
between the child's swing and the thermonuclear explosion. The energy
released in a thermonuclear explosion is orders of magnitude vaster than
that expended in a child's swing.
And that's the crux of the matter. If that vast instantaneous pulse of
energy is to be absorbed to pass it on to the spacecraft, then it will be
like being inside a battleship while firing a broadside. Except that
battleship will have it helluva lot easier. And if it isn't passed on to
the spacecraft, then it has been wasted. No ifs, no buts.)
--
"Good, late in to more rewarding well." "Well, you tonight. And I was
lookintelligent woman of Ming home. I trust you with a tender silence." I
get a word into my hands, a different and unbelike, probably - 'she
fortunate fat woman', wrong word. I think to me, I justupid.
Let not emacs meta-X dissociate-press write your romantic dialogs...!!!
Henry Spencer
Tux Wonder-Dog <wes.p...@paradise.net.nz> wrote:
>It would start out as a pseudo-underground explosion, with the bomb being
>only metres away from the spacecraft's "bumper". Think vitrification.
>Think sublimation of metal. Think superhot gaseous vitrified rock and
>metal gases spewing out all sides.
The ship would be up on towers, not flat on the ground, for launch. The
initial bomb would be a small one, with bomb size ramping up thereafter.
These would not be bare bombs, but packages with ablative propellant
incorporated, so what would strike the pusher plate would be a jet of
vaporized propellant, chosen by design to be within the limits of what the
plate could take. (For a technical overview, see the paper on Orion and
nuclear-pulse propulsion in the May/June 2002 issue of the AIAA's Journal
of Propulsion and Power.)
The plate surface would be sprayed with, roughly speaking, grease before
each explosion; the plate itself would not ablate. This was tested, and
it was effective enough to eliminate any need to make the plate itself out
of anything exotic.
>And you need to fire another within the next few seconds to maintain your
>momentum so you won't fall back down to the ground again.
Correct. It's a bad day for any vertical-takeoff vehicle if the engine
cuts out just after takeoff.
>Designing a hatchway that can be blocked against subliming metal and yet
>pass a functioning thermonuclear device through, is beyond _my_
>capabilities.
See above -- no exotic materials required. And they would be fission
devices, not fusion, barring the hypothetical pure-fusion bombs that some
of the Orion designers were hoping for.
Fast-acting mechanical devices are not magic. The best of the supersonic
interceptors of the late 1950s could open weapons-bay doors, toss out a
long-range air-to-air missile, and close the doors again, in something
like 300 milliseconds, despite a supersonic slipstream.
>...I missed seeing Jor-El in Footfall ...
Note that Footfall is fiction, and should not be used as a textbook on
Orion design. George Dyson's book "Project Orion" is a better source.
>(And note: that factoid about the child's swing, fails to make the link
>between the child's swing and the thermonuclear explosion. The energy
>released in a thermonuclear explosion is orders of magnitude vaster than
>that expended in a child's swing.
The principles, however, remain the same. The shock-absorber system is
resonant at a particular frequency, like the swing. You toss out bombs at
that frequency. A charge for a battleship gun has orders of magnitude
more energy than that of a .22 rifle, but the same physics applies to
both, although the engineering is a bit harder for the big one.
>And that's the crux of the matter. If that vast instantaneous pulse of
>energy is to be absorbed to pass it on to the spacecraft, then it will be
>like being inside a battleship while firing a broadside. Except that
>battleship will have it helluva lot easier.
No, the battleship has it a lot worse -- it has nowhere near the
shock-absorber stroke that an Orion would. The recoil stroke for a
battleship gun is severely limited by the requirement that the whole
motion fit within a cramped turret even when the guns are elevated at a
high angle. (You can't just make the turrets bigger because their walls
and roof are thick armor, and they're already enormously heavy -- one of
the problems cited with schemes to do major revisions to the Iowa-class
battleships was that the USN apparently no longer has a shipyard crane
that can lift one of those turrets.)
--
spsystems.net is temporarily off the air; | Henry Spencer
mail to henry at zoo.utoronto.ca instead. | he...@spsystems.net
Derek Lyons
>In article <435a...@clear.net.nz>,
>Tux Wonder-Dog <wes.p...@paradise.net.nz> wrote:
>
>The plate surface would be sprayed with, roughly speaking, grease before
>each explosion; the plate itself would not ablate. This was tested, and
>it was effective enough to eliminate any need to make the plate itself out
>of anything exotic.
Tested at small scale - it's one of the Big Unknowns for a full scale
Orion. (There are a couple of unanswered questions about design
principles and details IIRC. No showstoppers, but contrary to the
handwaving of bombardmentfarce, we can't build one from a standing
start - a non trivial amount of development must be done first.)
>>And that's the crux of the matter. If that vast instantaneous pulse of
>>energy is to be absorbed to pass it on to the spacecraft, then it will be
>>like being inside a battleship while firing a broadside. Except that
>>battleship will have it helluva lot easier.
>
>No, the battleship has it a lot worse -- it has nowhere near the
>shock-absorber stroke that an Orion would.
Yet big-gun recoil absorbers are fairly simple and compact devices.
>The recoil stroke for a battleship gun is severely limited by the
>requirement that the whole motion fit within a cramped turret even when
>the guns are elevated at a high angle. (You can't just make the turrets
>bigger because their walls and roof are thick armor, and they're already
>enormously heavy --
Which is why 'modern' (I.E. early 1930's) big guns push the trunnions
as far forward as possible - right against the mantlet plate. When
you look at the back of one of the Iowa's guns, most of what you see
is a honkin' big counterweight. This combo allows you to increase the
length of the recoil stroke without materially increasing the size of
the turret.
>one of the problems cited with schemes to do major revisions to the Iowa-class
>battleships was that the USN apparently no longer has a shipyard crane that can
>lift one of those turrets.)
That's a bit of a red herring - as the turrets were not lifted on in
one piece in the first place. They are designed to come apart for
regunning or to repair battle damage. It's a non trivial job, but
it's doable. (In the second place, at least one of the cranes used
for such jobs is still operational about 10 blocks from where I sit.)
D.
--
Touch-twice life. Eat. Drink. Laugh.
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Henry Spencer
Derek Lyons <fair...@gmail.com> wrote:
>... (There are a couple of unanswered questions about design
>principles and details IIRC. No showstoppers, but contrary to the
>handwaving of bombardmentfarce, we can't build one from a standing
>start - a non trivial amount of development must be done first.)
No question about that. Outside reviewers consistently thought the Orion
enthusiasts were being seriously optimistic about schedule and budget,
with a lot of optimism about incompletely-solved problems.
>>one of the problems cited with schemes to do major revisions to the Iowa-class
>>battleships was that the USN apparently no longer has a shipyard crane that
>>can lift one of those turrets.)
>
>That's a bit of a red herring - as the turrets were not lifted on in
>one piece in the first place... (In the second place, at least one of
>the cranes used for such jobs is still operational...
Note that I said it had been cited -- I didn't say I believed it. :-)
(I *thought* at the time that it had a smell of technical rationalization
for a decision made on political grounds...)
Derek Lyons
Fiscal grounds mostly - the varied conversions would have been
*extremely* expensive for very little return in the way of combat
power. (There's some doubt as to whether some of them would have even
been possible - the hull girder was 'prestressed' to account for the
weight of the turrets, as well as the balance and stability curves.
Removing them would have had all manner of interesting effects.)
The Navy was not unanimous in it's admiration of the battlewagons.
Pat Flannery
Henry Spencer wrote:
>In article <435b381f...@supernews.seanet.com>,
>Derek Lyons <fair...@gmail.com> wrote:
>
>
>>... (There are a couple of unanswered questions about design
>>principles and details IIRC. No showstoppers, but contrary to the
>>handwaving of bombardmentfarce, we can't build one from a standing
>>start - a non trivial amount of development must be done first.)
>>
>>
>
>No question about that. Outside reviewers consistently thought the Orion
>enthusiasts were being seriously optimistic about schedule and budget,
>with a lot of optimism about incompletely-solved problems.
>
>
Here's something _very_ interesting from that Orion .pdf that Rusty found:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770085619_1977085619.pdf
If you go over to page 134 of the report (pdf page 146) you will run
into LENS (Low Energy Nuclear Source); a very low yield nuclear device
that will is to be detonated near the pusher plate to check out how it
behaves...nothing unusual in that...except that LENS is a....ready for
this? "the LENS system, which is a very-low-yield "gun-type" plutonium
assembly (see Fig. 7. 10)."
You heard it here first- a gun assembly nuclear device employing
plutonium, not uranium, as its fissile material.
That was supposed to be impossible due to a unstable isotope of
plutonium (Pu-240) that would cause it to pre-react if gun assembly was
used, and which was supposed to not be separable from the Pu-239.
Well, either the Orion team made a major slip in their report, or by
1964 we knew how to separate Pu-239 and Pu-240.
Pat
Jack Linthicum
You are aware that the original launch point for Orion was either at
Torrey Pines or Point Loma in the San Diego area. They had to leave TP
when their test shots, with C4, distrubed the neighbors. Think what the
real deal, even in a 'shallow silo', would have done for property
values?
Paul F. Dietz
> You heard it here first- a gun assembly nuclear device employing
> plutonium, not uranium, as its fissile material.
> That was supposed to be impossible due to a unstable isotope of
> plutonium (Pu-240) that would cause it to pre-react if gun assembly was
> used, and which was supposed to not be separable from the Pu-239.
> Well, either the Orion team made a major slip in their report, or by
> 1964 we knew how to separate Pu-239 and Pu-240.
... or maybe that pre-reacting is perfectly acceptable
in the low yield situation here?
Paul
Jack Linthicum
One of Ted Taylor's 'grails' was finding the least amount of
fissionable material that would explode. Page 54 in the paperback
Project Orion, show he was thinking about this before Orion. IIRC one
of his later statements mentioned a fissionable quantity the size of a
stick of gum. You just have to compress it.
Herb Schaltegger
(in article <1130154994.5...@g47g2000cwa.googlegroups.com>):
> IIRC one
> of his later statements mentioned a fissionable quantity the size of a
> stick of gum. You just have to compress it.
Talk about understating the technical complexities . . . :-/
--
"Fame may be fleeting but obscurity is forever." ~Anonymous
"I believe as little as possible and know as much as I can."
~Todd Stuart Phillips
<www.angryherb.net>
Jack Linthicum
You must not be conversant with Ted Taylor. TRy Jamie McPhee's The
Curve of Binding Energy. Taylor goes from a source the size of a
softball (not specified whether the 12, 13 or 20 inch circumference)
page 108, 20 pounds weight page 109, a small cantelope page 148, one
gram was converted to energy in the Nagasaki bomb, page 163, home-made
about the size of a golf bag page 193, the gum reference is to a stick
of U-235 that size which 10% of the energy contained therein would
bring down the World Trade Center, when it was still standing, page 15.
All the nuke people hate Taylor as he kind of makes their brain strains
into easy exercises.
John Schilling
>Here's something _very_ interesting from that Orion .pdf that Rusty found:
>http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770085619_1977085619.pdf
>If you go over to page 134 of the report (pdf page 146) you will run
>into LENS (Low Energy Nuclear Source); a very low yield nuclear device
>that will is to be detonated near the pusher plate to check out how it
>behaves...nothing unusual in that...except that LENS is a....ready for
>this? "the LENS system, which is a very-low-yield "gun-type" plutonium
>assembly (see Fig. 7. 10)."
>You heard it here first- a gun assembly nuclear device employing
>plutonium, not uranium, as its fissile material.
>That was supposed to be impossible due to a unstable isotope of
>plutonium (Pu-240) that would cause it to pre-react if gun assembly was
>used, and which was supposed to not be separable from the Pu-239.
>Well, either the Orion team made a major slip in their report, or by
>1964 we knew how to separate Pu-239 and Pu-240.
Or they were paying attention to the *Very Low Yield* part.
This is not something we heard here first. It has been publicly known
for about sixty years now, that what happens if you try to build a Pu
gun is that it predetonates, resulting in a very low yield. Normally,
this is undesirable behavior and we thus don't build a plutonium gun.
If a very low yield is what you actually *want*, go ahead and buuld
the gun - it's a simple and reliable, if somewhat heavy, way to get
a very low nuclear yield.
--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
*schi...@spock.usc.edu * for success" *
*661-951-9107 or 661-275-6795 * -58th Rule of Acquisition *
Pat Flannery
Paul F. Dietz wrote:
>>
>> Well, either the Orion team made a major slip in their report, or by
>> 1964 we knew how to separate Pu-239 and Pu-240.
>
>
> ... or maybe that pre-reacting is perfectly acceptable
> in the low yield situation here?
From what I read, what would happen is that the plutonium would go
molten and start to vaporize before it could be detonated- you would
probably end up with a dirty bomb more than a true nuclear bomb. I
wouldn't want to be the guys who had to retrieve the pusher plate, as it
would probably have been sprayed with plutonium if that happened.
I was always suspicious of that stated inability to separate Pu-239 and
Pu-240; our isotope separation technology is a lot more advanced
nowadays than in W.W. II.
Pat
Pat Flannery
John Schilling wrote:
>Or they were paying attention to the *Very Low Yield* part.
>
>This is not something we heard here first. It has been publicly known
>for about sixty years now, that what happens if you try to build a Pu
>gun is that it predetonates, resulting in a very low yield. Normally,
>this is undesirable behavior and we thus don't build a plutonium gun.
>If a very low yield is what you actually *want*, go ahead and buuld
>the gun - it's a simple and reliable, if somewhat heavy, way to get
>a very low nuclear yield.
>
>
Wouldn't you end up with very inefficient fission and a lot of
unfissioned plutonium getting sprayed around?
They intended to use the LENS for several tests up to and including a
test of a 10 meter diameter pusher plate in a large semi-buried vacuum
chamber around 100 feet in diameter by 250 feet tall.
The way the report describes LENS makes it sound like it's something
that already existed at the time of the report's writing.
It uses a barrel of tungsten or uranium inserted into a cylindrical
reflector assembly.
By varying the speed of impact and the diameter and shape of the
plutonium core, you can vary the energy released.
I don't know what the upper end of efficiency for this system is, but
the report puts the lower end at 1% of the total potential energy
contained in the fissioning plutonium.
Pat
Derek Lyons
>The way the report describes LENS makes it sound like it's something
>that already existed at the time of the report's writing.
As Henry pointed out - the Orion folks were somewhat on the optimistic
side in their assumptions and their reports. This had lead people
like bombardmentfarce to believe the program was much further along
than it was in reality.
Thomas Womack
Jack Linthicum <jackli...@earthlink.net> wrote:
>You must not be conversant with Ted Taylor. TRy Jamie McPhee's The
>Curve of Binding Energy. Taylor goes from a source the size of a
>softball (not specified whether the 12, 13 or 20 inch circumference)
>page 108, 20 pounds weight page 109, a small cantelope page 148, one
>gram was converted to energy in the Nagasaki bomb, page 163, home-made
>about the size of a golf bag page 193, the gum reference is to a stick
>of U-235 that size which 10% of the energy contained therein would
>bring down the World Trade Center, when it was still standing, page 15.
>All the nuke people hate Taylor as he kind of makes their brain strains
>into easy exercises.
It's at least moderately marvellous that there was a person in the
world who was to nuclear weapons design what the master-smiths of
Japan were to swords; the kind of person whose intuitive understanding
of implosion made him a living national treasure.
It's possibly also marvellous that there was but one, he is dead, and
his like unexpected to return.
[though Aldermaston is very strongly hiring at the moment, if anyone
here's a security-clearable Brit with an interest in very large-scale
computing and not concerned about building what can only be either
exercises in engineering masturbation or tools of genocide; I'm afraid
I match only #1 and #2, and #3 is something of a deal-breaker]
Tom
Sander Vesik
> [though Aldermaston is very strongly hiring at the moment, if anyone
> here's a security-clearable Brit with an interest in very large-scale
> computing and not concerned about building what can only be either
> exercises in engineering masturbation or tools of genocide; I'm afraid
> I match only #1 and #2, and #3 is something of a deal-breaker]
Well, its not preceicely a secret why their budget nearly doubled even if
the PM will not publicly say it yet.
>
> Tom
>
>
>
--
Sander
+++ Out of cheese error +++
Kelly McDonald sympatico.ca>
wrote:
The "Super" grade Pu produced at Hanford during WWII was some of the
most pure reactor Pu produced, largely due to the rapid fuel cycles
they used at the time. It is a real balancing act, the longer you
leave the U-238 slugs in the reactor, the more Pu-239 will be bred,
but more Pu-240,241, and 242 will be produced as well. You can get
fairly pure Pu-239 if you change the slugs out quickly, but then the
costs go up dramatically, as you need to shut down the reactor,
extract the slugs and put them through chemical seperation each time.
This "Super" grade Pu was just barely on the edge for an extremely
large scale gun weapon, in which two sub-critical masses would be
fired at one another. It was huge, heavy and was still very suceptable
to a fizzle. This was why the whole idea was discarded as it would not
have lead to a practical weapon, and would have been horribly
inefficient. Not the kind of device I could see being used on an Orion
Standard seperation techniques can be used to seperate Pu240,241,242
out of Pu239, but because the mass ratio is much smaller it is much
harder to do. I suspect the AVLIS could probably be used to great
effect here. This part of the movie "The Manhattan Project" (The one
where a kid builds an a-bomb), wasn't that far off.
Kelly McDonald
John Schilling
>
>
>
>John Schilling wrote:
>
>>Or they were paying attention to the *Very Low Yield* part.
>>
>>This is not something we heard here first. It has been publicly known
>>for about sixty years now, that what happens if you try to build a Pu
>>gun is that it predetonates, resulting in a very low yield. Normally,
>>this is undesirable behavior and we thus don't build a plutonium gun.
>>If a very low yield is what you actually *want*, go ahead and buuld
>>the gun - it's a simple and reliable, if somewhat heavy, way to get
>>a very low nuclear yield.
>Wouldn't you end up with very inefficient fission and a lot of
>unfissioned plutonium getting sprayed around?
Yes, precisely. Now, just what were you imagining a very low yield
nuclear explosion would be, if *not* "very inefficient fission an a
lot of unfissioned plutonium getting sprayed around"?
Well, OK, the early Orion proponents imagined that they'd get fusion
explosions of whatever yield they needed from the Fission-Free Hydrogen
Bombs That Were Going To Be Invented Any Day Now, Really!, but that
seems to have not worked out real well. The techniques that actually
work to produce nuclear explosions start with a critical mass[1] of
highly enriched uranium and/or plutonium, and a full critical mass
efficiently fissioned results in a high-yield explosion.
[1] An imprecise term that incorporates lots of assumptions about things
like geometry, compression, and tamping, but is measured in kilograms,
not grams, for any currently plausible arrangement of these.
Sander Vesik
>
> Well, OK, the early Orion proponents imagined that they'd get fusion
> explosions of whatever yield they needed from the Fission-Free Hydrogen
> Bombs That Were Going To Be Invented Any Day Now, Really!, but that
> seems to have not worked out real well. The techniques that actually
> work to produce nuclear explosions start with a critical mass[1] of
> highly enriched uranium and/or plutonium, and a full critical mass
> efficiently fissioned results in a high-yield explosion.
>
>
> [1] An imprecise term that incorporates lots of assumptions about things
> like geometry, compression, and tamping, but is measured in kilograms,
> not grams, for any currently plausible arrangement of these.
>
Hmmm.... I though concentrated solution of Plutonium Nitrate in a good
reflector would be critical near a kilogram ? No idea if it would be
usable in a weapon or if you would need a special geometry.
Derek Lyons
>This "Super" grade Pu was just barely on the edge for an extremely
>large scale gun weapon, in which two sub-critical masses would be
>fired at one another. It was huge, heavy and was still very suceptable
>to a fizzle. This was why the whole idea was discarded as it would not
>have lead to a practical weapon, and would have been horribly
>inefficient. Not the kind of device I could see being used on an Orion
This was intended to be the first 'stage', fired beneath the craft
while it rested on the launch towers. As it was never loaded aboard
the craft, the 'normal' limits on PPU's do not apply.
Tux Wonder-Dog
> In article <11lq9oe...@corp.supernews.com>, Pat Flannery says...
>>
>>
>>
>>John Schilling wrote:
>>
>>>Or they were paying attention to the *Very Low Yield* part.
>>>
>>>This is not something we heard here first. It has been publicly known
>>>for about sixty years now, that what happens if you try to build a Pu
>>>gun is that it predetonates, resulting in a very low yield. Normally,
>>>this is undesirable behavior and we thus don't build a plutonium gun.
>>>If a very low yield is what you actually *want*, go ahead and buuld
>>>the gun - it's a simple and reliable, if somewhat heavy, way to get
>>>a very low nuclear yield.
>
>>Wouldn't you end up with very inefficient fission and a lot of
>>unfissioned plutonium getting sprayed around?
>
> Yes, precisely. Now, just what were you imagining a very low yield
> nuclear explosion would be, if *not* "very inefficient fission an a
> lot of unfissioned plutonium getting sprayed around"?
And a very effective way of killing off one's neighbours!
Just think what that'd do for property values!
>
> Well, OK, the early Orion proponents imagined that they'd get fusion
> explosions of whatever yield they needed from the Fission-Free Hydrogen
> Bombs That Were Going To Be Invented Any Day Now, Really!, but that
> seems to have not worked out real well. The techniques that actually
> work to produce nuclear explosions start with a critical mass[1] of
> highly enriched uranium and/or plutonium, and a full critical mass
> efficiently fissioned results in a high-yield explosion.
>
>
> [1] An imprecise term that incorporates lots of assumptions about things
> like geometry, compression, and tamping, but is measured in kilograms,
> not grams, for any currently plausible arrangement of these.
>
>
--
Tux Wonder-Dog
I imagine the accountants would've had a rahter different opinion of them.
Consider it from that point of view - a battlewagon is a huge investment.
Its weaponry are in modern terms, short range, so you have to get up
relatively close to the enmy to do any harm. The damage it is capable of
doing is thus, less than ships of a lesser cost. At the same time, it is a
hugely inviting target, so it is costing the navy an extra magnitude of
cost in defending it, a cost which it does not return since its offensive
capability is reduced by comparison.
So if an enemy can tie up a battlewagon, it can bleed said battlewagon's
navy and country while suffering comparatively minor damage itself.
Useful thing to remember when you write the Great SF Space War Opera! ;)
>
> D.
Wesley Parish
bombardmentforce
>only metres away from the spacecraft's "bumper".
Here's the first fireball at .1 -.94 ms, actual distance to plate
should be about 5r.
http://spacebombardment.blogspot.com/2005/10/orion-designs-compared-to-launch.html
Here's the drawing at .5 sec...
http://spacebombardment.blogspot.com/2005/10/orion-designs-compared-to-launch_18.html
This is assuming a tower or cable supported initial position. The first
pulse could be chemical, but at the same 20kt energy level to loft this
571,000 ton ship.
Pat Flannery
Sander Vesik wrote:
>Hmmm.... I though concentrated solution of Plutonium Nitrate in a good
>reflector would be critical near a kilogram ? No idea if it would be
>usable in a weapon or if you would need a special geometry.
>
>
In the LENS system the blast gets projected out of the barrel at the
test target. In this concept one can see the germ of the Casaba Howitzer
concept as well as the Orion's nuclear propulsion bomblets that shoot a
cloud of vaporized tungsten and beryllium oxide upwards at the pusher plate.
Pat
bombardmentforce
about, doesn't show up in Carey Sublette's FAQ.
http://nuclearweaponarchive.org/Nwfaq/Nfaq0.html
Tough name to google for, does this Atomic Shotgun sound familiar to
anyone else here?
Carey Sublette
"John Schilling" <schi...@spock.usc.edu> wrote in message
news:djjhj...@drn.newsguy.com...
> In article <11lq9oe...@corp.supernews.com>, Pat Flannery says...
>>
>>
>>
>>John Schilling wrote:
>>
>>>Or they were paying attention to the *Very Low Yield* part.
>>>
>>>This is not something we heard here first. It has been publicly known
>>>for about sixty years now, that what happens if you try to build a Pu
>>>gun is that it predetonates, resulting in a very low yield. Normally,
>>>this is undesirable behavior and we thus don't build a plutonium gun.
>>>If a very low yield is what you actually *want*, go ahead and buuld
>>>the gun - it's a simple and reliable, if somewhat heavy, way to get
>>>a very low nuclear yield.
>
>>Wouldn't you end up with very inefficient fission and a lot of
>>unfissioned plutonium getting sprayed around?
>
> Yes, precisely. Now, just what were you imagining a very low yield
> nuclear explosion would be, if *not* "very inefficient fission an a
> lot of unfissioned plutonium getting sprayed around"?
Further diagram 7.10 makes it clear that the plutonium gun is firing into a
vacuum tank (probably built very much like Jumbo, but with a removable
liner).
Since essentially none of the plutonium will have been fissioned as these
things are usually reckoned (efficiency would be something like 0.001%) they
undoubtedly planned on recovering the plutonium and refabricating for reuse
over and over.
Carey Sublette
Pat Flannery
Carey Sublette wrote:
>Further diagram 7.10 makes it clear that the plutonium gun is firing into a
>vacuum tank (probably built very much like Jumbo, but with a removable
>liner).
>
>Since essentially none of the plutonium will have been fissioned as these
>things are usually reckoned (efficiency would be something like 0.001%) they
>undoubtedly planned on recovering the plutonium and refabricating for reuse
>over and over.
>
>
There has to be some fission going on, as the point of the LENS tests is
to expose the pusher plate to radiation to see how it reacts; otherwise
you could use high explosives instead. (as some of the other planned
tests were going to.)
Pat
Tux Wonder-Dog
There you go. 20 000 tons of HE to lift a 571 000 ton spaceship.
Did you actually read what you'd written? kt is a measuring term. It
relates to a specific form of High Explosive. I doubt it relates to
gunpowder ;)
So, unless the people organizing this have a HE with greater explosive power
per ounce, they are going to need every ounce of said 20 000 tons of HE.
I bet at this point, the people they were trying to seel this idea gave each
other a significant look as if to say, let's humour these people, let's let
them try to explain their way out of this!
Wesley Parish
P.S. And "tonne" versus "ton"? Which one? A ton is an Imperial
measurement; a tonne is metric. A kiloton is an Imperial unit in a metric
wrapper. How many spacecraft do we need to lose before we decide which one
to use consistently?
Carey Sublette
"Pat Flannery" <fla...@daktel.com> wrote in message
news:11m0mr6...@corp.supernews.com...
Yes, something like 0.001% of it (see what I said above). That would be
roughly a 1 ton yield out of 6 kg of plutonium.
This is a tiny, tiny amount - you can measure the radioactivity of the
products easily but it would be virtually impossible to detect the mass loss
directly. It is so small that process losses in reclamation and
refabrication would vastly exceed it.
bombardmentforce
funding was to small to develop LENS to the point where it cheaper to
use in testing than ordinary small nukes, what program was the idea
part of?
bombardmentforce
http://print.google.com/print?hl=en&id=r_Gu4f0QxrkC&pg=PA55&lpg=PA55&...
Here's a table of Orion designs from 50 tons to 10,000. Sea level
pulses operate at higher efficiency because of the ram effect, so the
ratio is one ton of energy per about 30 tons of ship. Vacuum charges
range up to 1.6 tons of yield per ton of ship.
>they are going to need every ounce of said 20 000 tons of HE.
Or three tons for the smallest test vehicle, on a tower under the
plate.
Karl Johanson
> The "Super" grade Pu produced at Hanford during WWII was some of the
> most pure reactor Pu produced, largely due to the rapid fuel cycles
> they used at the time. It is a real balancing act, the longer you
> leave the U-238 slugs in the reactor, the more Pu-239 will be bred,
> but more Pu-240,241, and 242 will be produced as well.
You have a higher alpha flux from the Plutonium, compared to Uranium.
This can complicate enrichment if you want to use light elements like
Beryllium or Aluminium, as they can emit neutrons if exposed to alphas.
bombardmentforce
True, especially in the larger space charges, we have clear information
about how they work and the tightly focused shape of the forward
plasma. Their backward lobe is unfocused.
>the pictures and diagrams of the blasts that you photoshop are
Rough drafts, we don't have a drawing of the six times less massize
http://spacebombardment.blogspot.com/2005/10/orion-isp-at-low-altitude.html
sea level pulse units, so errors like this, at 1.25 seconds, remain to
be corrected.
http://spacebombardment.blogspot.com/2005/10/orion-designs-compared-to-launch_27.html
I need to fix the section between the explosion center and the plate to
get the focused, rammed, air to the plate sooner, a torroidal fireball
seems like a good start.