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#1 2016-09-04 14:38:46

Tom Kalbfus
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Project Orion Mars Colony

Suppose the US Government green lighted the construction of an Orion Spaceship and supplied the nuclear warheads for a Mars Colony. Lets say SpaceX wanted to build it, and they also purchased the atomic bomb explosions from the Energy Department, that is the nuclear warheads remain the property of the government until the explode, and when they explode SpaceX then owns the explosions.
Project-Orion-Spacecraft.jpg
So imagine this sitting on a launch pad, the launch director calls up the President of the United States, and he supplies the launch code, and the launch code is good for detonating each atomic bomb within a certain time frame to propel the spaceship into orbit. First a chemical rocket lifts this thing off the launch pad, and when the ship reaches a certain height, spectators at a certain distance see an eerie violet light casting long shadows as the view the spectacle through protective glasses, then another bright light and another, while they watch this spectacle, the blast wave from the first atomic bomb explosion catches up with them, and then another and another, each blast grows fainted as the ship ascends higher and higher, past a certain height, they only see the bright light, as the ship ascends into space.

The lunch site is most likely an island in the South Pacific, the EMP radiation would tend to fry electronics that aren't protected, so we launch his thing where hardly anyone lives. Once in orbit, the Orion uses a low thrust, high specific impulse ion or plasma drive to pull away from Earth, to a safe distance where atomic bombs can once again be used to insert the ship into a trans-Mars injection.

So what do you think can one such spaceship establish one colony on Mars? say with 100 people in it?

I think that it wouldn't need atomic bombs for landing on Mars. Since we're setting up a Mars colony, it would have heat shields and chemical landing rockets to make a soft touchdown. inside would be a bunch of inflatable greenhouses and habs for the colonists to live in.

Last edited by Tom Kalbfus (2016-09-04 14:41:47)

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#2 2016-09-04 15:09:09

GW Johnson
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Re: Project Orion Mars Colony

If you launch from a scaffold over a deep hole,  you can use the nukes to take off.  If one chooses to launch from a remote surface location,  there is no excuse not to go into high orbit immediately to avoid EMP effects on the ground,  or even to escape from Earth to the moon or some other remote parking location in cis-lunar space. 

These things use very small yields while still down in the atmosphere where there really is a blast wave,  like fractional kiloton for a 5000-10,000 ton vehicle.  Once in space where there is no blast wave,  yield required is larger,  like a single-digit few kilotons for that same size vehicle.

The original 1959 concepts called for direct landings,  but using chemically-fuelled "landing boats" makes a lot more sense.  Once in space,  the Orion needs to be an orbit-to-orbit transport.  This is specially important for EMP effects on colony facilities on the surface.  Distance is the "shield" against EMP. 

You should note that Orion ship hulls are built of steel armor plate similar to what is used in naval warships.  They provide quite a bit of innate radiation shielding,  in and of themselves.  Not good enough for GCR,  but good enough for solar flares and that crap in our Van Allen belts. 

Orions run more efficiently (meaning higher Isp) at larger ship masses.  These were planned in 1959 for 5000 to 50,000 tons.  500 is actually too low to achieve good Isp.  10,000+ tons is better.  It is difficult to hold down average thrust to vehicle accelerations in the 2 gee range.  Think 20,000 sec Isp at 20,000 ton mass,  at 2-4 gees vehicle acceleration levels. 

These things are then large enough to spin for artificial gravity by spiralling like a bullet or a football,  instead of end-over-end. 

The original 1959 designs were based on 1953-vintage second-generation fission weapons technology,  modified to be a sort of shaped charge to mostly concentrate released energy into two more-or-less oppositely-directed spikes.  Most people do not know about that.  But that directional quality is precisely what made pulse propulsion technology so outstandingly efficient in the larger size vessels.  Down in the hundreds of tons,  it's really no better than a solid core nuclear thermal rocket.  Size really makes a huge difference. 

Big size like that is exactly what you need to send materials and people to start colonies.  It is entirely inappropriate to small exploration parties. 

Imagine what we could do today with 5th-generation thermonuclear weapons technology so modified into shaped charges.  We're talking about multiple-100-thousand+ ton vessels.  Those are real solar system colonization ships,  and could actually serve as short range interstellar vessels at up to around 5-10% the speed of light,  single stage (even with return).  It would be worth the fallout to build and launch maybe half a dozen of those things,  and then use them for the next 2 or 3 hundred years. 

GW

Last edited by GW Johnson (2016-09-04 15:25:30)


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#3 2016-09-04 16:06:07

Antius
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Re: Project Orion Mars Colony

All we need is the prospect of a planetary disaster.  Or an impending alien invasion.  Or maybe a president that doesn't care too much about international outrage.  Maybe a man like Trump?

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#4 2016-09-04 17:35:48

Tom Kalbfus
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Re: Project Orion Mars Colony

Antius wrote:

All we need is the prospect of a planetary disaster.  Or an impending alien invasion.  Or maybe a president that doesn't care too much about international outrage.  Maybe a man like Trump?

We got that. Nuclear weapons provide their own prospect for planetary disaster, whether we use them in spaceships or not. Not using them does not reduce the threat to our cities. I think Trump could be persuadable if one can make the right arguments. He is a real estate man after all. Mars has plenty of real estate. I think with an Orion, we basically build a prefab colony on Earth, and then launch it into space and land it on Mars. Since nukes are a strategic asset, we probably would need the government' permission to use them, but that doesn't mean that a private entity could not use them. As I said before, the nukes become private property when they explode, before that, they belong to the government. I think the nukes would probably be made specifically for the spaceship, the private user would pay for their manufacture and take possession of them when they explode underneath the spaceship.

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#5 2016-09-04 22:27:44

GW Johnson
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Re: Project Orion Mars Colony

This question has nothing to do with Trump or Clinton or anybody else.  It is merely a question of public will:  do we want to attempt something truly challenging in space like planting colonies,  or not? 

To do something really challenging requires nuclear propulsion.  Colonization efforts require very large effort scales,  and so also very large spacecraft.  Based on the technologies,  science principles,  and materials that we already have in hand,  nuclear pulse propulsion is simply the preferred choice for large colony-planting efforts. 

That does not rule out smaller-scale efforts using chemical propulsion.  Such as the Spacex Falcon-Heavy/Dragon and "Mars Colonial Transporter". 

GW


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#6 2016-09-04 22:40:07

Tom Kalbfus
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Re: Project Orion Mars Colony

How do you know the Mars Colonial Transporter won't be nuclear? Elon Musk hasn't shown it yet, maybe a nuclear Orion Spacecraft is what he has in mind, his company could probably build an Orion, he just needs permission from the government to get those nukes to propel such a spacecraft.

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#7 2016-09-05 03:52:35

elderflower
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Re: Project Orion Mars Colony

Wouldn't an updated nuclear thermal design be more realistic? Nuclear explosions are very unpopular. Hence the restrictions on testing of nuclear weapons.

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#8 2016-09-05 09:46:48

Tom Kalbfus
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Re: Project Orion Mars Colony

I don't see nuclear weapons being restricted, if Russia and the United States are helping the Iranians of all people to get them! If people think nuclear bombs are safe in the hands of Iranian Clerics and Islamic fundamentalists, then I don't see the danger of employing them for space flight. I mean Barack Obama is fine with the Iranians having nukes, so I think nuclear explosions to propel a spaceship into space is much safer than that! I mean I'm just using logic! For one thing, people piloting the spacecraft won't try to kill people with those nukes, and the Iranians will! In fact the Iranians having these nukes is all the more reason to build this spacecraft, as the Iranians will threaten the human race! Their fanaticism and willingness to die along with their possession of nukes is a threat to us all!

Last edited by Tom Kalbfus (2016-09-05 09:48:05)

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#9 2016-09-05 12:01:48

RobertDyck
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Re: Project Orion Mars Colony

The Outer Space Treaty prohibits any weapon of mass destruction in space. Established through the UN, signed and ratified by 104 countries including the United States and Russia. That puts an end to Orion right there.

I found a couple papers from NASA working on micro fusion thrusters. For Star Trek fans, yes the RCS thrusters used by Enterprise D on Star Trek - The Next Generation (ST-TNG) was micro-fusion thrusters. NASA is working on it. My question, could this be scaled up for primary propulsion?
Engineering of the Magnetized Target Fusion Propulsion System - 2002
Magnetized Target Fusion Propulsion: Plasma Injectors for MTF Guns - 2003

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#10 2016-09-05 16:57:47

GW Johnson
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Re: Project Orion Mars Colony

This may be splitting hairs,  but devices that make good pulse propulsion make lousy weapons of mass destruction,  and vice versa. 

As I have indicated before,  the best pulse propulsion devices by far are very directional shaped charges.  The best weapons of mass destruction are very omni-directional.  That's two very different things,  although most laymen refuse to believe,  or perceive,  it. 

Ain't willful ignorance a bitch?

GW

Last edited by GW Johnson (2016-09-05 16:59:03)


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#11 2016-09-05 17:24:29

RobertDyck
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Re: Project Orion Mars Colony

Gary, we're talking about governments of countries. In the 1990s, the United States was not allowed to enter Afghanistan to arrest Osama bin Laden, so they sent in B-52 bombers to drop bombs on Al Qaeda's training camp. Outrage over that was used as recruitment, they ended up with more fighters. They moved training to a cave so dropped bombs could reach them. So Bill Clinton ordered a cruise missile sent into the camp. Of course outrage over that resulted in more recruitment, they ended up with more fighters again. What's the difference between that vs a truck bomb? Just expense of the weapon, no ethical difference.

The reason countries of the UN created the Outer Space Treaty is they don't trust Russia or the US government to send into space charges that can only be used for propulsion. That will be used as a Trojan Horse to launch nuclear weapons in space. "Oops! We dropped one of our propulsion charges right on your national leader's palace! Sorry. It exploded with more force than the bomb dropped on Hiroshima? A charge for space propulsion could never survive entry into the atmosphere, and isn't configured to deliver that kind of destruction? You must be mistaken. But we will send a puppet to become the new leader of your country, a figure head who takes orders from junior functionaries in our national capital."

That's what they're worried about. Even if charges are designed to not be effective, even if they aren't supposed to have atmospheric entry vehicles, such weapons will be launched anyway. Purpose built nuclear weapons, hidden among the propulsion charges.

And you are aware that a nuclear explosive detonated in LEO will cause an EMP that will fry electronics on the ground. So it doesn't even need an entry vehicle to do massive damage.

You realize that Israel's nuclear program started with an American ship carrying enough bomb-grade uranium to fabricate many warheads. This ship was sent into waters close to Israel, and just happened to have no solders onboard to defend it. Then Israeli commandos raided the ship and stole all the uranium. There was an official statement of protest. "Bad Israel!" Slap on wrist. Israel was allowed to keep all the uranium. Do you really think that was an accident? Do you understand now why certain countries treat the United States as no more trustworthy than Russia? Or did you know that? This is what comes to mind when you say "willful ignorance".

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#12 2016-09-05 17:30:29

RobertDyck
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Re: Project Orion Mars Colony

The papers I linked above use nuclear pulse propulsion, but do so in such a way that it can't be used as a bomb. The deuterium and tritium are ejected as plasma at high speed to a central target, creating pressure and heat. That means the pulse can only be used for propulsion, the detonation is too "soft", it's not a "sharp" explosion used for destruction. And most importantly there is no self-contained explosive. The detonation can only occur at the focus of the plasma injectors. So it's only propulsion, cannot be used as a weapon.

Isn't fusion better than fission anyway?

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#13 2016-09-05 17:52:39

GW Johnson
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Re: Project Orion Mars Colony

Sure,  fusion pulse propulsion is better than fission,  although you are talking about hundred-thousand ton ships instead of ten-thousand ton ships.  Scale affects effectiveness,  as I have indicated. 

The EMP thing is mitigated by distance:  no LEO,  only out near the moon. Inverse square law. 

Otherwise,  I think the resistance to explosion propulsion is more emotional than rational.  Not that emotional resistance ain't real,  because it is. 

It may be some time yet before we as a planetary society outgrow this nonsense.  But until we do,  colonization on a mass scale makes no sense anyway.

GW


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#14 2016-09-05 18:02:43

Tom Kalbfus
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Re: Project Orion Mars Colony

RobertDyck wrote:

The Outer Space Treaty prohibits any weapon of mass destruction in space. Established through the UN, signed and ratified by 104 countries including the United States and Russia. That puts an end to Orion right there.

I found a couple papers from NASA working on micro fusion thrusters. For Star Trek fans, yes the RCS thrusters used by Enterprise D on Star Trek - The Next Generation (ST-TNG) was micro-fusion thrusters. NASA is working on it. My question, could this be scaled up for primary propulsion?
Engineering of the Magnetized Target Fusion Propulsion System - 2002
Magnetized Target Fusion Propulsion: Plasma Injectors for MTF Guns - 2003

The UN isn't too popular in this country anyway, it failed to keep nuclear weapons out of the hands of North Korea, and Iran wants some, and our president just sent them $400 million to get started on their Nuclear program so they can target US cities, everyone is cheating and proliferating nuclear weapons anyway, so why should we let a stupid treaty that everyone else is ignoring stop us from building an Orion Space Ship? Not building one is not making any of our cities safer from nuclear attack!

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#15 2016-09-05 18:09:00

Tom Kalbfus
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Re: Project Orion Mars Colony

RobertDyck wrote:

Gary, we're talking about governments of countries. In the 1990s, the United States was not allowed to enter Afghanistan to arrest Osama bin Laden, so they sent in B-52 bombers to drop bombs on Al Qaeda's training camp. Outrage over that was used as recruitment, they ended up with more fighters. They moved training to a cave so dropped bombs could reach them. So Bill Clinton ordered a cruise missile sent into the camp. Of course outrage over that resulted in more recruitment, they ended up with more fighters again. What's the difference between that vs a truck bomb? Just expense of the weapon, no ethical difference.

The reason countries of the UN created the Outer Space Treaty is they don't trust Russia or the US government to send into space charges that can only be used for propulsion. That will be used as a Trojan Horse to launch nuclear weapons in space. "Oops! We dropped one of our propulsion charges right on your national leader's palace! Sorry. It exploded with more force than the bomb dropped on Hiroshima? A charge for space propulsion could never survive entry into the atmosphere, and isn't configured to deliver that kind of destruction? You must be mistaken. But we will send a puppet to become the new leader of your country, a figure head who takes orders from junior functionaries in our national capital."

That's what they're worried about. Even if charges are designed to not be effective, even if they aren't supposed to have atmospheric entry vehicles, such weapons will be launched anyway. Purpose built nuclear weapons, hidden among the propulsion charges.

And you are aware that a nuclear explosive detonated in LEO will cause an EMP that will fry electronics on the ground. So it doesn't even need an entry vehicle to do massive damage.

You realize that Israel's nuclear program started with an American ship carrying enough bomb-grade uranium to fabricate many warheads. This ship was sent into waters close to Israel, and just happened to have no solders onboard to defend it. Then Israeli commandos raided the ship and stole all the uranium. There was an official statement of protest. "Bad Israel!" Slap on wrist. Israel was allowed to keep all the uranium. Do you really think that was an accident? Do you understand now why certain countries treat the United States as no more trustworthy than Russia? Or did you know that? This is what comes to mind when you say "willful ignorance".

Why should we care? Russia isn't our primary enemy, our primary enemy is a bunch of non-nuclear powers that want nuclear weapons so they can attack us, and our government is doing nothing to stop them from getting them. So I guess is no one is worried about a nuclear armed Iran, no one should be worried about an atomic bomb propelled spaceship either! You can't convince me that they are afraid of the US using atomic bombs to propel its spaceships, if they aren't afraid of a nuclear armed Iran. I think Iran is more likely to use atomic bombs on people, that an atomic bomb propelled spaceship.

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#16 2016-09-05 18:11:17

Tom Kalbfus
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Re: Project Orion Mars Colony

GW Johnson wrote:

Sure,  fusion pulse propulsion is better than fission,  although you are talking about hundred-thousand ton ships instead of ten-thousand ton ships.  Scale affects effectiveness,  as I have indicated. 

The EMP thing is mitigated by distance:  no LEO,  only out near the moon. Inverse square law. 

Otherwise,  I think the resistance to explosion propulsion is more emotional than rational.  Not that emotional resistance ain't real,  because it is. 

It may be some time yet before we as a planetary society outgrow this nonsense.  But until we do,  colonization on a mass scale makes no sense anyway.

GW

They don' seem too emotionally resistant to Iran having nuclear weapons, because I see they are doing nothing to stop Iran from getting them, so I guess there is no emotional resistance to nuclear weapons anymore, since people have lost their fear of Iran having them!

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#17 2016-09-06 05:34:11

Antius
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Re: Project Orion Mars Colony

Tom Kalbfus wrote:
GW Johnson wrote:

Sure,  fusion pulse propulsion is better than fission,  although you are talking about hundred-thousand ton ships instead of ten-thousand ton ships.  Scale affects effectiveness,  as I have indicated. 

The EMP thing is mitigated by distance:  no LEO,  only out near the moon. Inverse square law. 

Otherwise,  I think the resistance to explosion propulsion is more emotional than rational.  Not that emotional resistance ain't real,  because it is. 

It may be some time yet before we as a planetary society outgrow this nonsense.  But until we do,  colonization on a mass scale makes no sense anyway.

GW

They don' seem too emotionally resistant to Iran having nuclear weapons, because I see they are doing nothing to stop Iran from getting them, so I guess there is no emotional resistance to nuclear weapons anymore, since people have lost their fear of Iran having them!

Iranian nukes are not a non-issue to the voting public, but they tend to be concerned with issues that threaten them imminently.  People would worry and bother endlessly about the fallout.  It won't matter how small it is, people aren't generally very good at understanding quantitative arguments when it comes to radiation.  What they will understand is that you are exposing them to radiation that could cause them cancer, for the sake of some boondoggle project that they don't understand and aren't interested in.  Every ache and pain they get will be attributed to the fallout from your nuclear rocket.  There would be a tidal wave of international condemnation.

Work on pure fusion propulsion would largely solve the problem, but is unlikely to achieve sufficient power density to be useful for space launch.  Nuclear thermal propulsion would reduce operational fallout, but that advantage would be undone with the first accidental explosion of a NTR.  In any event, it offers very little economic advantage.  The development and operational costs would tend to swamp any operational advantages that you might gain from an NTR SSTO.

Last edited by Antius (2016-09-06 05:42:06)

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#18 2016-09-06 10:06:54

GW Johnson
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Re: Project Orion Mars Colony

The "ready-to-go" version of pulse propulsion technology is the 1959-vintage shaped-charge fission technology.  We can build more compact fission devices today,  that would also be "ready-to-go" technology.  Nothing else is "ready-to-go".  If you wait for technology development,  usually you do not fly.  That's an important lesson from history. 

Consider the 1959 fallout estimate: launching a 10 or 20 thousand ton ship into space from the surface was equivalent in fallout to a 10 megaton warhead test in the atmosphere.  That means we could build and launch a half a dozen of these for less detrimental radiation effects than either Chernobyl or Fukushima.  And THAT comparison might actually help make the case to the public. 

The Starfish Prime shot over Johnston Island in 1962 revealed the EMP effect as a crashed telephone system and a damaged power grid 900 miles away in Hawaii,  before the advent of the more vulnerable solid state electronics.  That was a handful of megatons about 200 miles up. 

BTW, this EMP threat was long ignored,  and still is ignored,  in strategic defense planning (small nukes do more EMP damage than blast/fire damage,  if exploded around 50 miles up,  where heat shields and precision guidance are not needed).

What all that really means is you have be very careful where you build and launch these pulse propulsion things,  and you must fly them straight out into space to very high-altitude orbits to avoid EMP damage on the ground.  Cis-lunar space would be a very good place to base and park these things.  Inverse square reduction really helps a lot with EMP. 

As for Tom's worries about the Iranians,  it remains to be seen whether the nuke deal does any real good (so, yes,  there have been efforts to control Iranian nuke ambitions).  We'll see,  soon enough.

But history does have a little-remembered example to offer about controlling Iranian behavior.  Remember how the US embassy hostages were released almost the moment Reagan was first sworn in? 

Do you remember why?  (Few do,  reporting on that was suppressed.  And still is.)

Reagan privately let the Iranians know that he would nuke Tehran within minutes of taking office,  if those hostages were still held.  Carter would not do that,  which is why they did not release them until Reagan actually took the oath.  But release they did,  and before the nuclear "trigger" could be turned over to him.  They made sure Reagan knew within seconds of being sworn in,  to prevent being destroyed.

Blackmail really does work,  even with evil religious extremists like the Iranian "government". 

GW

Last edited by GW Johnson (2016-09-06 10:14:53)


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#19 2016-09-06 10:55:27

Tom Kalbfus
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Re: Project Orion Mars Colony

Antius wrote:
Tom Kalbfus wrote:
GW Johnson wrote:

Sure,  fusion pulse propulsion is better than fission,  although you are talking about hundred-thousand ton ships instead of ten-thousand ton ships.  Scale affects effectiveness,  as I have indicated. 

The EMP thing is mitigated by distance:  no LEO,  only out near the moon. Inverse square law. 

Otherwise,  I think the resistance to explosion propulsion is more emotional than rational.  Not that emotional resistance ain't real,  because it is. 

It may be some time yet before we as a planetary society outgrow this nonsense.  But until we do,  colonization on a mass scale makes no sense anyway.

GW

They don' seem too emotionally resistant to Iran having nuclear weapons, because I see they are doing nothing to stop Iran from getting them, so I guess there is no emotional resistance to nuclear weapons anymore, since people have lost their fear of Iran having them!

Iranian nukes are not a non-issue to the voting public, but they tend to be concerned with issues that threaten them imminently.  People would worry and bother endlessly about the fallout.  It won't matter how small it is, people aren't generally very good at understanding quantitative arguments when it comes to radiation.  What they will understand is that you are exposing them to radiation that could cause them cancer, for the sake of some boondoggle project that they don't understand and aren't interested in.  Every ache and pain they get will be attributed to the fallout from your nuclear rocket.  There would be a tidal wave of international condemnation.

Work on pure fusion propulsion would largely solve the problem, but is unlikely to achieve sufficient power density to be useful for space launch.  Nuclear thermal propulsion would reduce operational fallout, but that advantage would be undone with the first accidental explosion of a NTR.  In any event, it offers very little economic advantage.  The development and operational costs would tend to swamp any operational advantages that you might gain from an NTR SSTO.

Lets do cost versus benefit. What is the cost of Iran having nuclear weapons?
One is they might start a nuclear war, they could deliberately target US cities, since they have announced their hatred of us time and time again, yet that doesn't seem to bother us, we fine with letting the Iranians develop nuclear weapons despite all their hatred and their "Death to America" chants and all that, and maybe they believe God is on their side, and that God would not let them come to any harm if they launch an all out nuclear missile barrage of the United States, once they feel they have enough nuclear missiles t thoroughly thrash they United States. What's the benefit of Iran having nuclear weapons? I can't see any.

What's the benefit of an Orion Spaceship?
We get cheaper access to space,
we can send enough people to Mars to actually make a difference,
By openly using such nuclear weapons, we demonstrate to the World that we have them and may actually use them, should some nitwit country decide that now is a good time to send out terrorists on a suicide mission to kill American citizens, maybe they'll have second thoughts about that.

The cost is a little extra radioactivity in the air, but if we are so deathly afraid of nuclear weapons, why are we letting the Iranians have them? The only conclusion I can come to is that we aren't deathly afraid of nuclear weapons anymore, that we aren't concerned hat Iran might use them to blow up our cities, for whatever reason, on a nuclear Jihad. So fine, I guess there is no reason not to use them to launch a spacecraft either! Might as well get the benefit of a nuclear spaceship, if we can't get the safety that these nuclear nonproliferation agreements and treaties are supposed to ensure! If the clock is ticking away towards doomsday, and the current administration isn't doing a thing about it, then we might as well try to safe what humanity we can and get some people off the Earth with the same technology that threatens to destroy us!

Last edited by Tom Kalbfus (2016-09-06 10:56:59)

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#20 2016-09-06 11:02:41

Tom Kalbfus
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Re: Project Orion Mars Colony

GW Johnson wrote:

The "ready-to-go" version of pulse propulsion technology is the 1959-vintage shaped-charge fission technology.  We can build more compact fission devices today,  that would also be "ready-to-go" technology.  Nothing else is "ready-to-go".  If you wait for technology development,  usually you do not fly.  That's an important lesson from history. 

Consider the 1959 fallout estimate: launching a 10 or 20 thousand ton ship into space from the surface was equivalent in fallout to a 10 megaton warhead test in the atmosphere.  That means we could build and launch a half a dozen of these for less detrimental radiation effects than either Chernobyl or Fukushima.  And THAT comparison might actually help make the case to the public. 

The Starfish Prime shot over Johnston Island in 1962 revealed the EMP effect as a crashed telephone system and a damaged power grid 900 miles away in Hawaii,  before the advent of the more vulnerable solid state electronics.  That was a handful of megatons about 200 miles up. 

BTW, this EMP threat was long ignored,  and still is ignored,  in strategic defense planning (small nukes do more EMP damage than blast/fire damage,  if exploded around 50 miles up,  where heat shields and precision guidance are not needed).

What all that really means is you have be very careful where you build and launch these pulse propulsion things,  and you must fly them straight out into space to very high-altitude orbits to avoid EMP damage on the ground.  Cis-lunar space would be a very good place to base and park these things.  Inverse square reduction really helps a lot with EMP. 

As for Tom's worries about the Iranians,  it remains to be seen whether the nuke deal does any real good (so, yes,  there have been efforts to control Iranian nuke ambitions).  We'll see,  soon enough.

But history does have a little-remembered example to offer about controlling Iranian behavior.  Remember how the US embassy hostages were released almost the moment Reagan was first sworn in? 

Do you remember why?  (Few do,  reporting on that was suppressed.  And still is.)

Reagan privately let the Iranians know that he would nuke Tehran within minutes of taking office,  if those hostages were still held.  Carter would not do that,  which is why they did not release them until Reagan actually took the oath.  But release they did,  and before the nuclear "trigger" could be turned over to him.  They made sure Reagan knew within seconds of being sworn in,  to prevent being destroyed.

Blackmail really does work,  even with evil religious extremists like the Iranian "government". 

GW

Nuclear pulse technology could also be used to life heavy payloads into space that otherwise couldn't be lifted, such as for instance a mass driver for installation on the Moon. If we want to give O'Neill's vision a shot, and Orion Spacecraft couldn't certainly give it a big boost! We might also have a secondary drive in the Orion spaceship. Use the bombs to get into space, and once in orbit we ignite the secondary drive, such as a large nuclear powered ion or plasma drive, that we couldn't otherwise lift into orbit.

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#21 2016-09-06 12:09:21

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Project Orion Mars Colony

A number of years ago, the President of France said many countries have technology to stop a missile. He said if Iran tried to launch a ballistic missile with a nuclear warhead at Israel, France would stop the missile before it got 10 metres above the ground. And France would then nuke Iran. I had posted on this forum that someone should say that. Yea! But then NATO allies got him to retract that statement.

Israel has nukes. Arab countries are going to panic until they have nukes as a counter threat. But they can't use the Nukes. If Israel does, then Arab nukes would be launched. If any Arab country nukes Israel, then NATO would sanction turning that Arab country into a radioactive hole in the ground. If not French nukes, then the fact France feels that would would give permission for the US to do it. And Israel would definitely launch their unless they were disabled. MAD: Mutual Assured Destruction.

In one war, Arab countries invaded Israel and it looked like they were going to win. Israel ordered deployment of their nuke. A bomber took off for an Arab target with a nuclear bomb. However, a small Israeli force managed to halt progress of a major Arab attack force several times their size, and hold them long enough for Israel's main force to arrive. So the attack was thwarted. Israel recalled their bomber, it turned around and returned to base without dropping the bomb. This demonstrates the danger of just one side having the bomb.

Perhaps a nuclear deterrent would stop wars, stabilize the Middle East. I would prefer neither side have nuclear weapons, but I don't get a say. Just trying to figure out what's going on. Once Israel got nuclear weapons, it was a matter of time before at least one Arab country would too.

My understanding is the Iranian deal would let Iran have nuclear reactors for commercial power only, not weapons. We'll see how that works out.

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#22 2016-09-06 12:37:42

Antius
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From: Cumbria, UK
Registered: 2007-05-22
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Re: Project Orion Mars Colony

Maybe there is a way of separating the fissile and fusion parts of the charge?  A battery of nuclear-pumped lasers providing the trigger needed to ignite the fusion charge.  That way, the fission products remain contained.

Last edited by Antius (2016-09-06 12:40:35)

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#23 2016-09-06 12:49:13

RobertDyck
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From: Winnipeg, Canada
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Re: Project Orion Mars Colony

The NASA papers linked above use plasma injectors to trigger fusion. It doesn't have fission at all. And that means fusion can only occur at the focus of the injectors, so no self-contained explosive. And atmosphere would interfere, it could only detonate in vacuum. It can't be used as a weapon, only for propulsion. Don't know about EMP, though.

This wouldn't work for ground launch. Only in-space propulsion. I'm asking if it could be scaled up as primary propulsion for an unmanned interstellar probe. For Proxima, not Mars.

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#24 2016-09-06 13:00:44

kbd512
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Registered: 2015-01-02
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Re: Project Orion Mars Colony

I would just like to say that I'm not in favor of repeatedly nuking our planet just to put something heavy into orbit.  We did that in the 50's and 60's.  The results were ranged from bad to worse and we're still living with the health effects from poor decision making with nuclear weapons.

I'm not opposed to using solid core NTR's within the Earth's atmosphere.  Once the engines in your lift vehicle have an Isp around 1000s, lot's of things become possible that simply weren't economically feasible using conventional chemical propulsion.  Unfortunately, nobody seems the least bit interested in serious development of these types of rocket engines.  Imagine where we'd be today with left vehicle technology by simply evolving the technologies created for the Apollo program.

Sooner or later, I have a feeling we're going to come full circle and realize that the engineers involved in the Saturn and NERVA programs really were developing the next generation of lift vehicle technologies and everything we've done since that time has ultimately made launch vehicles more unattainably expensive rather than improved upon the efficiency of existing technology.

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#25 2016-09-06 13:39:32

RobertDyck
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From: Winnipeg, Canada
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Re: Project Orion Mars Colony

NASA did update NERVA in 1991, but it was a study and computer simulation only. No hardware built. NERVA was intended to be launched by chemical rockets into Earth orbit, used for Earth departure only.

In 1990 the Air Force developed a project called Timberwind, which was intended for ground launch. Intended for ICBMs to launch nuclear warheads. But anti-nuclear activists learned of it, got Congress to shut it down.

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