Atomic Aircraft

[Larry Dighera]

Let's see, all we need is a water tank, steam boiler, turbine, some
uranium 235 or plutonium 239, plenty of lead shielding, a condenser,
and the will to cope with the radiation hazard in the event of a
mishap. Containment? We don't need no stinkin' containment. :-)

But weight isn't an issue in the micro gravity of space ...



http://www.newscientist.com/article/mg19225780.006-atomic-aircraft.html

Atomic Aircraft
18 November 2006
NewScientist.com news service

ENTHUSIASM for the nuclear-powered bomber project in the United States
blows alternately hot and cold. Mr. R. E. Gross, chairman of Lockheed
Aircraft, one of the two companies with contracts to develop the
airframes (the other being Convair) has said recently that if the
American government were to give the "go ahead signal", Lockheed could
have an aircraft ready to make its first flight in the mid-1960s.

The type of aircraft the company has in mind would have the shielded
crew cabin in the nose, the reactor in the tail as far from the crew
as possible, a small tankage of conventional turbine fuel for take-off
and landing so that the reactor was only at full power in the air and
never near the ground, and thin straight wings free from the
encumbrances of fuel tanks, engines or undercarriage gear. The Air
Force wants atomic bombers of this kind for the same reason that the
Navy wanted atomic submarines: they could range the world without
refuelling.

But the Air Force faces one great technical difficulty that did not
trouble the Navy - weight. Even when the weight of reactor shielding
is cut to the minimum by concentrating on a radiation-proof cabin for
the crew rather than trying to block all escape of radiation from the
reactor, it still remains the biggest barrier to getting an atomic
aircraft off the ground. Mr. Donald Quarles, who was until recently
Secretary for Air, told a Congressional Committee earlier this summer
that reactor weight had increased so much above original estimates
that any plans for putting the aircraft themselves into production
should be dropped while designers went right back to what he called
"reactor fundamentals". And this was when the US Government was
spending roughly £70 millions a year on the project. This evidence
could be read as meaning that the aircraft companies will not get the
green light they want until there is a technical breakthrough leading
to lightweight reactor design.

These facts should be borne in mind when Britain is criticised for the
absence of a similar project here. In spite of the unlimited range
that only a nuclear plant can give, some scientists believe it is not
a development that should be undertaken at this stage. Mr. Cleveland,
who is in charge of Lockheed's atomic design, has himself suggested
there are serious health problems connected with the maintenance of
atomic aircraft because of the radiation leakage. Other experts have
pointed to the hazard that would follow the crash of an atomic
aircraft, whose reactor would almost inevitably be cracked open,
making rescue all but impossible and, if there were a fire, spreading
fission products downwind from the wreckage.

This article was originally published in New Scientist on 11 July 1957

[Gig 601XL Builder]

Nuclear-powered drone aircraft on drawing board
a.. 19:00 19 February 2003 Exclusive from New Scientist Print Edition.


The US Air Force is examining the feasibility of a nuclear-powered version
of an unmanned aircraft. The USAF hopes that such a vehicle will be able to
"loiter" in the air for months without refuelling, striking at will when a
target comes into its sights.

But the idea is bound to raise serious concerns about the wisdom of flying
radioactive material in a combat aircraft. If shot down, for instance, would
an anti-aircraft gunner in effect be detonating a dirty bomb?

It raises political questions, too. Having Unmanned Aerial Vehicles (UAVs)
almost constantly flying over a region would amount to a new form of
military intimidation, especially if they were armed, says Ian Bellamy, an
arms control expert at Lancaster University in Britain.

But right now, there seems no stopping the proliferation of UAVs, fuelled by
their runaway success in the Kosovo and Afghanistan conflicts. The big
attraction of UAVs is that they do not put pilots' lives at risk, and they
are now the norm for many reconnaissance and even attack missions.

The endurance of a future nuclear-powered UAV would offer military planners
an option they might find hard to turn down. Last week, the Pentagon
allocated $1 billion of its 2004 budget for further development of both
armed and unarmed UAVs.

Feasibility studies
The US Air Force Research Laboratory (AFRL) has funded at least two
feasibility studies on nuclear-powered versions of the Northrop-Grumman
Global Hawk UAV (pictured). The latest study, revealed earlier in February
at an aerospace technology conference in Albuquerque, New Mexico, concluded
that a nuclear engine could extend the UAV's flight time from hours to
months.

But nuclear-powered planes are not a new idea. In the 1950s, both the US and
the USSR tried to develop nuclear propulsion systems for piloted aircraft.
The plans were eventually scrapped because it would have cost too much to
protect the crew from the on-board nuclear reactor, as well as making the
aircraft too heavy.

The AFRL now has other ideas, though. Instead of a conventional fission
reactor, it is focusing on a type of power generator called a quantum
nucleonic reactor. This obtains energy by using X-rays to encourage
particles in the nuclei of radioactive hafnium-178 to jump down several
energy levels, liberating energy in the form of gamma rays. A nuclear UAV
would generate thrust by using the energy of these gamma rays to produce a
jet of heated air.

The military interest was triggered by research published in 1999 by Carl
Collins and colleagues at the University of Texas at Dallas. They found that
by shining X-rays onto certain types of hafnium they could get it to release
60 times as much energy as they put in (New Scientist print edition, 3 July
1999).

Tightly controlled reaction
The reaction works because a proportion of the hafnium nuclei are "isomers"
in which some neutrons and protons sit in higher energy levels than normal.
X-ray bombardment makes them release this energy and drop down to a more
stable energy level.

So the AFRL has since been looking at ways in which quantum nucleonics could
be used for propulsion. "Our directorate is being cautious about it. Right
now they want to understand the physics," says Christopher Hamilton at the
Wright Patterson Air Force Base in Ohio, who conducted the latest nuclear
UAV study.

The AFRL says the quantum nucleonic reactor is considered safer than a
fission one because the reaction is very tightly controlled. "It's
radioactive, but as soon as you take away the X-ray power source its gamma
ray production is reduced dramatically, so it's not as dangerous [as when
it's active]," says Hamilton.

Paul Stares, an analyst with the US Institute of Peace in Washington DC,
wonders what would happen if a nuclear UAV crashed. But Hamilton insists
that although hafnium has a half-life of 31 years, which according to
Britain's National Radiological Protection Board is equivalent to the highly
radioactive caesium-137, the structural composition of hafnium hinders the
release of this radiation.

"It's probably something you would want to stay away from but it's not going
to kill you," claims Hamilton.





"Larry Dighera" > wrote in message
...
>
> Let's see, all we need is a water tank, steam boiler, turbine, some
> uranium 235 or plutonium 239, plenty of lead shielding, a condenser,
> and the will to cope with the radiation hazard in the event of a
> mishap. Containment? We don't need no stinkin' containment. :-)
>
> But weight isn't an issue in the micro gravity of space ...
>
>
>SNIP<

[Kev]

Larry Dighera wrote:
> ENTHUSIASM for the nuclear-powered bomber project in the United States
> blows alternately hot and cold. Mr. R. E. Gross, chairman of Lockheed
> Aircraft, one of the two companies with contracts to develop the
> airframes (the other being Convair) has said recently that if the
> American government were to give the "go ahead signal", Lockheed could
> have an aircraft ready to make its first flight in the mid-1960s.
>
> This article was originally published in New Scientist on 11 July 1957

Yep, when I was a kid, I remember building a (Revell?) model of a
prototype atomic bomber. We were so convinced back then that we'd
have atomic-powered everything... both automobiles and rocket ships to
the moon.

Thanks for the memories!
Kev

[Jay Beckman]

"Kev" > wrote in message
oups.com...
>
> Larry Dighera wrote:
>> ENTHUSIASM for the nuclear-powered bomber project in the United States
>> blows alternately hot and cold. Mr. R. E. Gross, chairman of Lockheed
>> Aircraft, one of the two companies with contracts to develop the
>> airframes (the other being Convair) has said recently that if the
>> American government were to give the "go ahead signal", Lockheed could
>> have an aircraft ready to make its first flight in the mid-1960s.
>>
>> This article was originally published in New Scientist on 11 July 1957
>
> Yep, when I was a kid, I remember building a (Revell?) model of a
> prototype atomic bomber. We were so convinced back then that we'd
> have atomic-powered everything... both automobiles and rocket ships to
> the moon.
>
> Thanks for the memories!
> Kev
>

Didn't the USAF take a working (albeit small) reactor aloft in a B29 "back
in the day?"

Jay B

[quietguy]

Kev wrote:
> Yep, when I was a kid, I remember building a (Revell?) model of a
> prototype atomic bomber. We were so convinced back then that we'd
> have atomic-powered everything... both automobiles and rocket ships to
> the moon.

Circa 1960 I built two different atomic-powered bomber models. One was
by Aurora and had a single engine and a parasitic fighter for defense;
the other, by Hawk, had two engines on the wingtips, canard stabilators
and a pair of parasitic fighters. The closest anyone came to building
a real one was when a working reactor was flown in the bomb-bay of a
B-36 in 1955 to test the feasibility of a lightweight reactor with
minimal shielding. That was when little was known about the long-term
effects of even low radiation doses; atomic bombs were also being
considered for use in massive excavation projects such as dams and
canals. Imagine the fallout!

[Jay Beckman]

"quietguy" > wrote in message
oups.com...
>
> Kev wrote:
>> Yep, when I was a kid, I remember building a (Revell?) model of a
>> prototype atomic bomber. We were so convinced back then that we'd
>> have atomic-powered everything... both automobiles and rocket ships to
>> the moon.
>
> Circa 1960 I built two different atomic-powered bomber models. One was
> by Aurora and had a single engine and a parasitic fighter for defense;
> the other, by Hawk, had two engines on the wingtips, canard stabilators
> and a pair of parasitic fighters. The closest anyone came to building
> a real one was when a working reactor was flown in the bomb-bay of a
> B-36 in 1955 to test the feasibility of a lightweight reactor with
> minimal shielding. That was when little was known about the long-term
> effects of even low radiation doses; atomic bombs were also being
> considered for use in massive excavation projects such as dams and
> canals. Imagine the fallout!
>

I stand corrected, it was a B36 not a B29...

Jay B

[tom418]

Yeah, I remember watching "The Jettsons" every Saturday morning and looking
forward to having my own space ship! LOL!
"Kev" > wrote in message
oups.com...
>
> Larry Dighera wrote:
> > ENTHUSIASM for the nuclear-powered bomber project in the United States
> > blows alternately hot and cold. Mr. R. E. Gross, chairman of Lockheed
> > Aircraft, one of the two companies with contracts to develop the
> > airframes (the other being Convair) has said recently that if the
> > American government were to give the "go ahead signal", Lockheed could
> > have an aircraft ready to make its first flight in the mid-1960s.
> >
> > This article was originally published in New Scientist on 11 July 1957
>
> Yep, when I was a kid, I remember building a (Revell?) model of a
> prototype atomic bomber. We were so convinced back then that we'd
> have atomic-powered everything... both automobiles and rocket ships to
> the moon.
>
> Thanks for the memories!
> Kev
>

[Laurence Doering]

On Wed, 20 Dec 2006 11:25:14 -0700, Jay Beckman > wrote:
>
> Didn't the USAF take a working (albeit small) reactor aloft in a B29 "back
> in the day?"

It was a B-36, not a B-29. One B-36H was modified to carry a 1
megawatt air-cooled nuclear reactor in its aft bomb bay. The
aircraft (redesignated NB-36H) made 47 test flights between
1955 and 1957, totalling 215 hours of flight time, with the
reactor critical for 89 of those hours.

The reactor did not provide power to the aircraft -- the
purpose of this program was to test shielding and radiation
effects on aircraft systems, and to demonstrate that it was
possible to fly a nuclear reactor around without irradiating
the aircraft's crew or the surrounding area.

The NB-36 was scrapped in 1958 after the USAF's nuclear-
powered aircraft program was abandoned.


ljd

[Larry Dighera]

On Wed, 20 Dec 2006 09:56:40 -0600, "Gig 601XL Builder"
<wrDOTgiaconaATcox.net> wrote in >:

>Instead of a conventional fission
>reactor, it is focusing on a type of power generator called a quantum
>nucleonic reactor. This obtains energy by using X-rays to encourage
>particles in the nuclei of radioactive hafnium-178 to jump down several
>energy levels, liberating energy in the form of gamma rays. A nuclear UAV
>would generate thrust by using the energy of these gamma rays to produce a
>jet of heated air.

Interesting.

http://en.wikipedia.org/wiki/Hafnium

So, it seems hafnium-178m2 is radioactive with a half-life of 31
years, equivalent to cesium-137. Are the byproducts subsequent to
X-ray bombardment radioactive also?

It would appear that the whole DARPA hafnium fandango is bunkum:


Conflicting Results on a Long-Lived Nuclear Isomer of Hafnium Have
Wider Implications
http://www.physicstoday.org/vol-57/iss-5/p21.html



Scary Things Come in Small Packages
The Pentagon says what Carl Collins is cooking up in his lab could
power the most devastating bomb this side of a nuke. A long list
of heavyweight physicists calls that dangerous bunk.

http://www.washingtonpost.com/ac2/wp-dyn?pagename=article&contentId=A22099-2004Mar24&notFound=true



Ultimately, even the mavens’ attempts to repeat their earlier
favorable experiment were disappointing. In time – perhaps too
much time, it was only last year – annoyed scientists and aghast
politicians delivered a coup de grace. Bang! The lifeless body of
Pentagon-funded hafnium isomer research slumped to the laboratory
floor, its white coat sullied by Texas dust and latté spills. It
had breathed its last. Maybe.

http://agonist.org/20060709/a_journey_through_the_pentagon_s_scientific_underw orld

[Danny Deger]

"Larry Dighera" > wrote in message
...
> snip

> But weight isn't an issue in the micro gravity of space ...
>
>

You can not be any more wrong about this. In space craft design, weight is
EVERYTHING.

Danny Deger

[Montblack]

("Danny Deger" wrote)
>> But weight isn't an issue in the micro gravity of space ...
>
> You can not be any more wrong about this. In space craft design, weight
> is EVERYTHING.


For getting your payload (one time) up to space, after that weight is much
less of an issue. <g>


Montblack

[Gig 601XL Builder]

"quietguy" > wrote in message
oups.com...

>
> Circa 1960 I built two different atomic-powered bomber models.

Shouldn't that read, "Circa 1960 I built two different models of
atomic-powered bombers." Otherwise I have to ask, do you glow in the dark
now?

[Montblack]

("Gig 601XL Builder" wrote)
> Shouldn't that read, "Circa 1960 I built two different models of
> atomic-powered bombers." Otherwise I have to ask, do you glow in the dark
> now?


"Let's go up to the schoolyard and blow up models with firecrackers."

"Naw, we'll simply shut off the reactor core's main 'coolant valve' in my
B-36, then sit back and watch what happens."

Ok, but if I get radiation sickness, I'm telling mom!"

(...you could still do that kind of thing in the 60's, and early 70's.
Actually it was encouraged - "Don't blow those things off around here, the
baby's sleeping. Why don't you run on up to the schoolyard if you're going
to be making a racket!")


Montblack

[Kev]

Montblack wrote:
> ("Danny Deger" wrote)
> > You can not be any more wrong about this. In space craft design, weight
> > is EVERYTHING.
>
> For getting your payload (one time) up to space, after that weight is much
> less of an issue. <g>

But then there was the infamous Project Orion in the '50s, which was a
spaceship designed to be pushed along by multiple atomic blasts. It
was envisioned to hold 200 crew, weigh thousands of tons, and be able
to get to Mars and back in four weeks (!!!). I think they planned to
use two Saturn V's to launch it, in case people objected to using the
atomic blasts inside the atmosphere.

http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion

http://www.space.com/spacelibrary/books/library_projectorion_020709.html

Gotta love those wacky rocket scientists.

Kev

[[email protected]]

Larry Dighera > wrote:
> Let's see, all we need is a water tank, steam boiler, turbine, some
> uranium 235 or plutonium 239, plenty of lead shielding, a condenser,
> and the will to cope with the radiation hazard in the event of a
> mishap.

The original concept may have been slightly different:

"Or: nuclear reactor... air comes rushing in the front... heated up by
nuclear reaction... out the back it goes... Boom! Through the air --
it's an airplane." (p. 181 of ISBN 0-393-31604-1 )

The patent on this concept was sold to the US government for one dollar
(in cookies) in the mid-1940s.

Matt Roberds

[Larry Dighera]

On Wed, 20 Dec 2006 14:33:32 -0600, "Danny Deger"
> wrote in
>:

>
>"Larry Dighera" > wrote in message
...
>> snip
>
>> But weight isn't an issue in the micro gravity of space ...
>>
>>
>
>You can not be any more wrong about this. In space craft design, weight is
>EVERYTHING.
>

Only during launch.

[Neil Gould]

Recently, Kev > posted:

> Montblack wrote:
>> ("Danny Deger" wrote)
>>> You can not be any more wrong about this. In space craft design,
>>> weight is EVERYTHING.
>>
>> For getting your payload (one time) up to space, after that weight
>> is much less of an issue. <g>
>
> But then there was the infamous Project Orion in the '50s, which was a
> spaceship designed to be pushed along by multiple atomic blasts. It
> was envisioned to hold 200 crew, weigh thousands of tons, and be able
> to get to Mars and back in four weeks (!!!). I think they planned to
> use two Saturn V's to launch it, in case people objected to using the
> atomic blasts inside the atmosphere.
>
IIRC, Project Orion intended to launch from Earth with successive atomic
blasts, as well. Interesting what can be imagined when one is unencumbered
by reality.

Neil

[Gig 601XL Builder]

"Montblack" > wrote in message
...
> ("Gig 601XL Builder" wrote)
>> Shouldn't that read, "Circa 1960 I built two different models of
>> atomic-powered bombers." Otherwise I have to ask, do you glow in the dark
>> now?
>
>
> "Let's go up to the schoolyard and blow up models with firecrackers."
>
> "Naw, we'll simply shut off the reactor core's main 'coolant valve' in my
> B-36, then sit back and watch what happens."
>
> Ok, but if I get radiation sickness, I'm telling mom!"
>
> (...you could still do that kind of thing in the 60's, and early 70's.
> Actually it was encouraged - "Don't blow those things off around here, the
> baby's sleeping. Why don't you run on up to the schoolyard if you're going
> to be making a racket!")
>

Ah, yes. The good old days before bicycle helmets and the when children were
told to be home by the time the street lights come on. And yes too we were
given medium order explosives and told to go have fun.

My wife and I were talking just this morning how as children my friends and
I would have tortured any kid who was wearing a bike helmet.

[Ron Natalie]

Montblack wrote:
> ("Danny Deger" wrote)
>>> But weight isn't an issue in the micro gravity of space ...
>> You can not be any more wrong about this. In space craft design, weight
>> is EVERYTHING.
>
>
> For getting your payload (one time) up to space, after that weight is much
> less of an issue. <g>
>
>
> Montblack
>
>
You're still wrong. There's no free lunch. Even things in
orbit will eventually fall back to earth unless you keep kicking
them back. The ISS uses thrusters for both keeping the orbit
from degrading and (in coordination with gyroscopes) to hold
the proper orientation. Objects in space still have MASS.
The amount of thruster fuel consumed depends on the mass.

[Gig 601XL Builder]

"Ron Natalie" > wrote in message
...
> Montblack wrote:
>> ("Danny Deger" wrote)
>>>> But weight isn't an issue in the micro gravity of space ...
>>> You can not be any more wrong about this. In space craft design, weight
>>> is EVERYTHING.
>>
>>
>> For getting your payload (one time) up to space, after that weight is
>> much less of an issue. <g>
>>
>>
>> Montblack
> You're still wrong. There's no free lunch. Even things in
> orbit will eventually fall back to earth unless you keep kicking
> them back. The ISS uses thrusters for both keeping the orbit
> from degrading and (in coordination with gyroscopes) to hold
> the proper orientation. Objects in space still have MASS.
> The amount of thruster fuel consumed depends on the mass.

So the question is would a nuclear powered engine, once in space, provide
enough energy to be more efficient than a more conventional power source. I
think the answer might be yes for high earth orbit and as the craft moved
farther away from the earth gravity well it would be even more efficient.

[Ron Natalie]

Gig 601XL Builder wrote:

>
> So the question is would a nuclear powered engine, once in space, provide
> enough energy to be more efficient than a more conventional power source. I
> think the answer might be yes for high earth orbit and as the craft moved
> farther away from the earth gravity well it would be even more efficient.
>
>
Huh? What do you need the engine for? If it's for propulsion then
the mass is going to be important, the force needed to be applied is
proportional of the mass. If you are just using it for other power
purposes, then it doesn't necessarily make a difference.

[Ron Wanttaja]

On Thu, 21 Dec 2006 07:49:28 GMT, Larry Dighera > wrote:

>On Wed, 20 Dec 2006 14:33:32 -0600, "Danny Deger"
> wrote in
>:
>
>>
>>"Larry Dighera" > wrote in message
...
>>> snip
>>
>>> But weight isn't an issue in the micro gravity of space ...
>>
>>You can not be any more wrong about this. In space craft design, weight is
>>EVERYTHING.
>
>Only during launch.

Only if you never, EVER need to use thrust again, once your booster shuts down.
If you plan on keeping a precise orbit or are charting a course to another body
in space, then you'll want to keep the weight down to minimize the expenditure
of onboard fuel. Also, if you're going to want to point the vehicle in any
particular direction, lower weight will let you get away with smaller/lighter
attitude control devices and/or use less fuel to do it.

Ron Wanttaja

[Gig 601XL Builder]

"Ron Natalie" > wrote in message
...
> Gig 601XL Builder wrote:
>
>>
>> So the question is would a nuclear powered engine, once in space, provide
>> enough energy to be more efficient than a more conventional power source.
>> I think the answer might be yes for high earth orbit and as the craft
>> moved farther away from the earth gravity well it would be even more
>> efficient.
> Huh? What do you need the engine for? If it's for propulsion then
> the mass is going to be important, the force needed to be applied is
> proportional of the mass. If you are just using it for other power
> purposes, then it doesn't necessarily make a difference.

My comment was made in a world where nuke propulsion isn't going to be used
for launches in the foreseeable future. So the question was would a nuclear
propulsion unit give you enough power to make up for the added mass of the
unit. I would assume if you were going to go to the trouble of putting a
nuke in there you'd use it for all power needs from propulsion to the
lights.

[Larry Dighera]

On Thu, 21 Dec 2006 07:33:48 -0800, Ron Wanttaja
> wrote in
>:

>On Thu, 21 Dec 2006 07:49:28 GMT, Larry Dighera > wrote:
>
>>On Wed, 20 Dec 2006 14:33:32 -0600, "Danny Deger"
> wrote in
>:
>>
>>>
>>>"Larry Dighera" > wrote in message
...
>>>> snip
>>>
>>>> But weight isn't an issue in the micro gravity of space ...
>>>
>>>You can not be any more wrong about this. In space craft design, weight is
>>>EVERYTHING.
>>
>>Only during launch.
>
>Only if you never, EVER need to use thrust again, once your booster shuts down.
>If you plan on keeping a precise orbit or are charting a course to another body
>in space, then you'll want to keep the weight down to minimize the expenditure
>of onboard fuel. Also, if you're going to want to point the vehicle in any
>particular direction, lower weight will let you get away with smaller/lighter
>attitude control devices and/or use less fuel to do it.
>
>Ron Wanttaja

What would you estimate the ratio between the quantity of fuel
expended during launch to the amount of fuel needed to accomplish the
things that you mention?

[Jose[_1_]]

>>You can not be any more wrong about this. In space craft design, weight is
>>EVERYTHING.
> Only during launch.

After which mass is everything.

Jose
--
"There are 3 secrets to the perfect landing. Unfortunately, nobody knows
what they are." - (mike).
for Email, make the obvious change in the address.

[Larry Dighera]

On Thu, 21 Dec 2006 16:49:42 GMT, Jose >
wrote in >:

>>>You can not be any more wrong about this. In space craft design, weight is
>>>EVERYTHING.
>> Only during launch.
>
>After which mass is everything.

It would seem that, the mass or weight become a lot more insignificant
after the Earth's gravitational field's influence on the space craft
is reduced as a result of the increased distance between the Earth and
the space craft. But that whole discussion fails to address the issue
implicit in the question of using atomic fission for propulsion of an
aerial vehicle within the Earth's atmosphere.

Apparently the weight of a conventional atomic fission reactor and its
necessary shielding, not to mention the weight of the "steam engine"
components, make the prospect of atomic aircraft all but entirely
unfeasible for terrestrial navigation. That weight limitation would
largely be overcome in a vehicle designed for use in space under
micro-gravity conditions where there is no necessity to rely upon
aerodynamic lift to support it. So if one has the power available to
boost a heavy reactor and the requisite shielding into space, if a
suitable nuclear powered rocket can be devised, the use of nuclear
propulsion may be feasible for space travel, despite its apparent
limitations for use in conventional winged aircraft operating within
the Earth's atmosphere.

However, if a small nuclear fission reactor used to power a Sterling
engine, such as those currently used in space, could be made light
enough, powerful enough and still adequately shielded, perhaps the
dream (nightmare?) of atomic aircraft would be achievable.

Here's some information about what NASA successfully has accomplished
with nuclear power:


http://www.grc.nasa.gov/WWW/tmsb/index.html
The Thermo-Mechanical Systems Branch (5490) is responsible for
planning, conducting and directing research and technology
development to advance the state-of-the-art in a variety of
thermal systems for space, aerospace, as well as non-aerospace
applications. The systems of interest include thermal energy
conversion for power systems and solar thermal propulsion systems.
The effort involves working at the component level to develop the
technology, the subsystem level to verify the performance of the
technology, and the system level to ensure that the appropriate
system level impact is achieved with the integrated technology.
System analysis is used to identify high-impact technology areas,
define the critical aspects of the technology that need to be
developed, and characterize the system level impact of the
technology. Specific technology areas of interest include:

Dynamic Power Systems: Brayton, Rankine and Stirling Convertors,
Solar Receivers and Thermal Energy Storage
Primary Solar Concentrators: Thin film, SRP and Rigid
Secondary Solar Concentrators: Refractive and Reflective
Thermal Management: Radiators, Electronics Packaging, and Heat
Pipe Technology


http://www.grc.nasa.gov/WWW/tmsb/stirling.html
Animation of a 55 We Stirling TDC
(click on image to view)


http://www.grc.nasa.gov/WWW/tmsb/stirling/doc/stirl_radisotope.html
AVAILABLE TODAY FOR TOMORROW'S NEEDS
NASA Glenn Research Center and the Department of Energy (DOE) are
developing a Stirling convertor for an advanced radioisotope power
system to provide spacecraft on-board electric power for NASA deep
space missions. Stirling is being evaluated as an alternative to
replace Radioisotope Thermoelectric Generators (RTGs) with a
high-efficiency power source. The efficiency of the Stirling
system, in excess of 20%, will reduce the necessary isotope
inventory by a factor of at least 3 compared to RTGs. Stirling is
the most developed convertor option of the advanced power concepts
under consideration [1,2].


http://www.grc.nasa.gov/WWW/tmsb/stirling/doc/stirling_bckgrd.html
However, about this time NASA became interested in development of
free-piston Stirling engines for space power applications. These
engines use helium as the working fluid, drive linear alternators
to produce electricity and are hermetically sealed. These 12.5 kWe
per cylinder engines were intended for use with a nuclear reactor
power system; the Space Demonstrator Engine (or SPDE) was the
earliest 12.5 kWe per cylinder engine that was designed, built and
tested by MTI. A later engine of this size, the Component Test
Power Convertor (or CTPC), used a "Starfish" heat-pipe heater
head, instead of the pumped-loop used by the SPDE. Recently, in
the 1992-93 time period, this work was terminated due to the
termination of the related SP-100 nuclear power system work and
NASA's new emphasis on "better, faster, cheaper" systems and
missions.


http://www.spacedaily.com/news/outerplanets-00a2.html
Europa Orbiter was replanned to use a new "Sterling" nuclear
generator design which would use less plutonium



http://www.cndyorks.gn.apc.org/yspace/articles/boeing_lockheed_offer.htm
Boeing, Lockheed Offer NASA Two Choices for Nuclear Power


http://powerweb.grc.nasa.gov/doc/marsairplane.html
On February 1, 1999, NASA Administrator Daniel Goldin, announced
the "Mars Airplane Micromission," which would have been the first
NASA micromission program to launch on an Ariane 5 rocket. The
flight would have the first Mars airplane arriving on the Red
Planet around December 17, 2003, the centennial of the Wright
brother's first flight. A team composed of members from four NASA
centers (Ames, Dryden, Langley, and Glenn) was formed to generate
conceptual designs for the micromission airplane.


From the information provided at those web pages, perhaps it would be
possible to deduce whether the current state of technology would
enable the development of atomic powered aircraft today.
Unfortunately, the political and environmental concerns are probably
insurmountable even if the technology is now adequate.

[Jose[_1_]]

> It would seem that, the mass or weight become a lot more insignificant
> after the Earth's gravitational field's influence on the space craft
> is reduced as a result of the increased distance between the Earth and
> the space craft.

The mass of a spacecraft directly impacts the energy needed to change
course and attitude, and thus the fuel required during the journey.

> Unfortunately, the political and environmental concerns are probably
> insurmountable even if the technology is now adequate.

Rightly so. Technology may be up to the task, but nuclear reactors
increase the degree to which human error (a constant) or human evil
(also a constant) would impact the world. We are actually getting to
the point where the old cartoons of the mad scientist flying to the moon
to blow up the earth could actually come to pass, in some form.

Jose
--
"There are 3 secrets to the perfect landing. Unfortunately, nobody knows
what they are." - (mike).
for Email, make the obvious change in the address.

[Capt. Geoffrey Thorpe]

"Kev" > wrote in message
oups.com...
>
> Montblack wrote:
>> ("Danny Deger" wrote)
>> > You can not be any more wrong about this. In space craft design,
>> > weight
>> > is EVERYTHING.
>>
>> For getting your payload (one time) up to space, after that weight is
>> much
>> less of an issue. <g>
>
> But then there was the infamous Project Orion in the '50s, which was a
> spaceship designed to be pushed along by multiple atomic blasts. It
> was envisioned to hold 200 crew, weigh thousands of tons, and be able
> to get to Mars and back in four weeks (!!!). I think they planned to
> use two Saturn V's to launch it, in case people objected to using the
> atomic blasts inside the atmosphere.
>
> http://en.wikipedia.org/wiki/Nuclear_pulse_propulsion
>
> http://www.space.com/spacelibrary/books/library_projectorion_020709.html
>
> Gotta love those wacky rocket scientists.
>
> Kev
>

Orion was nothing

http://www.merkle.com/pluto/pluto.html

Radioactive fallout from the exhaust was a _feature_ of this thing - not a
problem!

--
Geoff
The Sea Hawk at Wow Way d0t Com
remove spaces and make the obvious substitutions to reply by mail
When immigration is outlawed, only outlaws will immigrate.

[Ron Wanttaja]

On Thu, 21 Dec 2006 16:09:47 GMT, Larry Dighera > wrote:


>>>>You can not be any more wrong about this. In space craft design, weight is
>>>>EVERYTHING.
>>>
>>>Only during launch.
>>
>>Only if you never, EVER need to use thrust again, once your booster shuts down.
>>If you plan on keeping a precise orbit or are charting a course to another body
>>in space, then you'll want to keep the weight down to minimize the expenditure
>>of onboard fuel. Also, if you're going to want to point the vehicle in any
>>particular direction, lower weight will let you get away with smaller/lighter
>>attitude control devices and/or use less fuel to do it.
>
>What would you estimate the ratio between the quantity of fuel
>expended during launch to the amount of fuel needed to accomplish the
>things that you mention?

Low...*but*: For every pound of additional fuel you'll need on orbit, you'll
burn twenty additional pounds of propellant to put it there. Ditto for every
pound of upgraded attitude control hardware. And you *cannot* refuel. Darn
right you'll design your space vehicle to minimize the consumption of on-orbit
fuel, just because it costs so much to get it up there.

You can't ignore launch weight for a spacecraft any more than you can ignore
wing design for an aircraft.

Ron Wanttaja