Orion drive and related physics

[SomeGuy123]

Just now, Buster Charlie said:

That's my point. My Reply is simply that I don't have to 'convince' anyone about the Orion Drive, i'm not in a position to make a difference in this, i'm just chatting about the technical side.

 

What really liquided me off about lost potential is, not just the payload size, but the fact that it could put said huge payload into mars orbit in FOUR WEEKS, not you know, a year or two.

This alone is why I think we're not serious about space exploration unless we explore fission drives.

 

AS far as cancer, you'd probably get more cancer deaths from stone construction and burning coal (they release radioisotopes) 

Or, there are saner policies regarding death.  We could figure out how to preserve the brains of terminal cancer patients.  Then we could accept a few extra deaths because they are just temporary.  

[Buster Charlie]

1 minute ago, SomeGuy123 said:

Or, there are saner policies regarding death.  We could figure out how to preserve the brains of terminal cancer patients.  Then we could accept a few extra deaths because they are just temporary.  

There are worse things than death, you know like living in a society that gave up on itself in the 70's ;P

 

Seriously, where is my supersonic southwest flight?

[lobe]

Earlier I the thread I noticed there was mention of how to cool the propulsion plate. Is there a way to use cooling pipes to drive turbine dynamos for power? Storing up the heat energy as electrical energy in flywheels, batteries, or fuel cells?

[Nothalogh]

1 hour ago, SomeGuy123 said:

To be fair, they are strongly related.  Orion drive's best use case is for putting immense heavy payloads into orbit.  The heavier the better.  (heavier payloads, you can use bigger and more efficient nukes that cause less fallout)

If we as a society valued space exploration enough, we would have done this decades ago, and just accepted a few extra deaths from cancer.  

We could have orbiting towns by now or lunar cities.

It is in light of that overwhelming potential of Orion that I have come to regard the various policies that brought about its demise, as nothing short of treason against the human species

[SomeGuy123]

3 hours ago, lobe said:

Earlier I the thread I noticed there was mention of how to cool the propulsion plate. Is there a way to use cooling pipes to drive turbine dynamos for power? Storing up the heat energy as electrical energy in flywheels, batteries, or fuel cells?

That doesn't help you cool it.  All it does is let you use the waste heat in a secondary role.  Thermodynamics dictates this.  If there is 1 gigajoule of waste heat applied to the plate, you can either pump it away and send it straight to radiators to vent to space, or you can send it through a heat engine to make electricity and then radiate all the heat to space.

The total heat radiated to space is the same because the electricity - used to run stuff in the spacecraft - all eventually becomes waste heat.

Edited February 21, 2016 by SomeGuy123

[Bill Phil]

13 hours ago, PB666 said:

The C14 issue is about detecting frauds, notably frauds produced just after WWII when there was an attempt to cash in on American wealth in some European countries. Some of those paintings are still out there, haven't hit the market yet.

Yeah. But total megatonnage detonated in th atmo is near to or in the thousands. This one flight would produce 30 kilotons in the atmosphere in one flight. A tiny percentage of the tests.

[lobe]

Shouldn't it cool it? Energy (thermal) is being taken from the system by being converted to other energy (kinetic/electric). The fluid would cool/condense as it passes through the turbine/thermoelectric cell and then flow back to the plate to gather more heat to continue.

[SomeGuy123]

5 minutes ago, Bill Phil said:

Yeah. But total megatonnage detonated in th atmo is near to or in the thousands. This one flight would produce 30 kilotons in the atmosphere in one flight. A tiny percentage of the tests.

Dirtier bomb cores, though.  The smaller fission only 0.3 kiloton devices leave a larger proportion of their fuel unburnt.  I don't know how to correct for this factor, but it isn't the same as 30/1000 compared to a 1 megaton device.

4 minutes ago, lobe said:

Shouldn't it cool it? Energy (thermal) is being taken from the system by being converted to other energy (kinetic/electric). The fluid would cool/condense as it passes through the turbine/thermoelectric cell and then flow back to the plate to gather more heat to continue.

See my reply above.  Almost all the electricity if it's used internally becomes heat.  It depends on the process.  Run a computer - 100% becomes heat, with the side effect of bit rearrangement.  Run a light, unless the light escapes out windows to space, again, mostly heat.    Now, if the light is shining on a hydroponics bay, 10% or so of the light energy is absorbed and used to synthesize sugars.  Of course, then the crew will eventually eat the product and emit heat, and in the end it's again 100% heat.  Run a pump?  Fluid gets pumped somewhere but it later slows down and releases the energy as heat.  You can safely just assume 100% conversion to heat unless you are doing something that emits to space.

So you need coolant pipes and radiators, and the same amount of both whether you vent all the waste to heat immediately or convert it to electricity in the meantime.

Wow, this reminds me of the novel Footfall, where one of the characters dies heroically repairing some steam lines - no doubt used for this very purpose - repairing the ship enough that it can finish it's attack run on the alien starship.

Edited February 21, 2016 by SomeGuy123

[Bill Phil]

Just now, SomeGuy123 said:

Dirtier bomb cores, though.  The smaller fission only 0.3 kiloton devices leave a larger proportion of their fuel unburnt.  I don't know how to correct for this factor, but it isn't the same as 30/1000 compared to a 1 megaton device.

I don't think so. That's more un ignited material.

30 kilotons is only equal to 30,000 tons of TNT. Megatons are a million tons of TNT, and that means that we've set off, as a species, about 1 billion tons of TNT worth of nukes.

0.15 kilotons, actually.

A higher proportion, but also a much smaller amount of fuel in general. By how much? Idk. But it's not nearly as bad as The Trinity test, the Nagasaki Bombing, and the Hiroshima bombing combined.  That's nearly a total of 50 kilotons. Compared to one launch's 30.

[SomeGuy123]

Just now, Bill Phil said:

I don't think so. That's more un ignited material.

30 kilotons is only equal to 30,000 tons of TNT. Megatons are a million tons of TNT, and that means that we've set off, as a species, about 1 billion tons of TNT worth of nukes.

0.15 kilotons, actually.

A higher proportion, but also a much smaller amount of fuel in general. By how much? Idk. But it's not nearly as bad as The Trinity test, the Nagasaki Bombing, and the Hiroshima bombing combined.  That's nearly a total of 50 kilotons. Compared to one launch's 30.

Sure.  And a tiny amount of additional people inhale just enough fragments to get lung cancer.  Out of those people, they might not develop the cancer til they hit 55 or 65 or so (body becomes weaker with age at stopping cancer) and die at 60 or 70 instead of 80.  So their lives are shortened by a decade or 2 - it's not like they would be alive forever if this hadn't happened.  

[lobe]

Yes but the heating could be drawn out over a longer length of time than just letting the plate deal with it. The thrust isn't going to be continuous, may an hour "burn" at most. The heat could boil/convect a fluid, which would flow to the turbine, cooling the fluid, then the force of acceleration would draw the fluid back. The energy from the dynamo flows into a storage device which would release the energy over a longer period of time powering the systems on the space craft.

 

Edit: I didn't see your full explanation. I didn't say you would need radiators, just the size of the radiator wouldn't need to be rediculous.

Edited February 21, 2016 by lobe
Correction

[SomeGuy123]

32 minutes ago, lobe said:

Yes but the heating could be drawn out over a longer length of time than just letting the plate deal with it. The thrust isn't going to be continuous, may an hour "burn" at most. The heat could boil/convect a fluid, which would flow to the turbine, cooling the fluid, then the force of acceleration would draw the fluid back. The energy from the dynamo flows into a storage device which would release the energy over a longer period of time powering the systems on the space craft.

lobe, you're going to be better served by pumping the fluid directly to the radiators.  More bang for your kilogram(which doesn't matter much with Orion), less complex of a system.  

A separate system would provide power for the ship.  Might just be solar panels you'd unfurl when you are done setting off nukes, while you run on fuel cells in the meantime.  (fuel cells would convert H2 + O2 to water, and you electrolyze it back after your solar cells are deployed)

A nuclear reactor - basically a copy of one off of a submarine - might make logical sense, but (1) water doesn't quite boil the same way in zero g and (2) the jarring of the bomb detonations might burst critical cooling pipes, causing a meltdown.  Furled solar panels seem like they would be safer and more reliable - if the vibration breaks a few or bends the mechanisms, you could repair them.

You would of course need nuclear energy for trips out to Jupiter and beyond.

Edited February 21, 2016 by SomeGuy123

[Temstar]

1 hour ago, SomeGuy123 said:

Wow, this reminds me of the novel Footfall, where one of the characters dies heroically repairing some steam lines - no doubt used for this very purpose - repairing the ship enough that it can finish it's attack run on the alien starship.

The water on Michael is a heat sink since radiators would rapidly be shot off in combat. They fire some of that super heated water out as steam through giant RCS rocket nozzles.

[Bill Phil]

2 hours ago, SomeGuy123 said:

Sure.  And a tiny amount of additional people inhale just enough fragments to get lung cancer.  Out of those people, they might not develop the cancer til they hit 55 or 65 or so (body becomes weaker with age at stopping cancer) and die at 60 or 70 instead of 80.  So their lives are shortened by a decade or 2 - it's not like they would be alive forever if this hadn't happened.  

And yet this has already occurred, since much more than 30 kilotons have been set off since 1945. Very little difference, if you add the tiny amount of Fallout that an Orion launch will add. Even a dozen, maybe even a hundred, launches won't do as much damage as Hiroshima and Nagasaki. Especially if the launch site is extremely isolated.

It's essentially a mid ranged explosion of the W54's possible yields. 

Edited February 21, 2016 by Bill Phil

[Buster Charlie]

6 minutes ago, Bill Phil said:

And yet this has already occurred, since much more than 30 kilotons have been set off since 1945. Very little difference, if you add the tiny amount of Fallout that an Orion launch will add. Even a dozen, maybe even a hundred, launches won't do as much damage as Hiroshima and Nagasaki. Especially if the launch site is extremely isolated.

It's essentially a mid ranged explosion of the W54's possible yields. 

• 
  Artificial Radiation Belt Lifetime
  From Aerospace Projects Review Volume 1, Number 4
• 
  Artificial Radiation Belt
  Do not launch Orion from anywhere within the "Trapping Region"
  From Aerospace Projects Review Volume 1, Number 4

Detonating pulse units in space near Terra can create nasty artificial radiation belts. The explosion can pump electrons into the magnetosphere, creating the belt.

There are two factors: detonation altitude from Terra's surface, and magnetic latitude in Terra's magnetic field. If the detonation is within 6,700 kilometers of Terra's surface (i.e., further than 2 Terran radii from Terra's center) and at a magnetic latitude from 0° to 40°, the radiation belt can last for years. Above 2 Terran radii the radiation belt will last for only weeks, and from latitude 80° to 90°, the radiation belt will last for only a few minutes.

The military discovered this the hard way with the Starfish Prime nuclear test. The instant auroras were very pretty. The instant EMP was very scary, larger than expected (but the test was using a 1.4 megaton nuke, not a 0.001 megaton pulse unit). The artificial radiation belt that showed up a few days later was a very rude surprise. About one-third of all low orbiting satellites were eventually destroyed by the radiation belt.

The radiation belts are harmless to people on Terra, but astronauts in orbit and satellites are at risk.

 

Looking at the info I quote above, I'd like to also point out that as I've mentioned before there is such a ridiculous efficiency of this system in the atmosphere (because you can get away with even smaller bombs for the same amount of thrust) that it would be worth it to give up the traditional launch site requirements (Equatorial launches, near infrastructure). I don't know if you can launch nuclear rockets from the south pole, but certainly it'd probably avoid killing that many civilians.  On the other hand I think the north end of Alaska might be nice. We could really liquid off the russians and launch them from that tiny island in the berring sea that is right off their coast.

 

[Bill Phil]

It's likely that the launch will be near the poles. Preferably the magnetic poles, but Canada would probably get mad...

And of course there's the part about using much smaller bomba than the Starfish test.

[SomeGuy123]

Launching from the middle of the ocean or antarctica really could kill zero people from the fallout.  Poison is about the dosage and the cloud would be so diffuse thousands of miles away where the nearest people are to be harmless.  Shame this wouldn't stop the complainers..

[Elukka]

If you worked to minimize the fallout you could get to the point where the only fallout comes from the vaporized pulse units themselves. Most fallout comes from detonating nukes close to the ground, releasing tonnes of irradiated dust. It's easy to think of ways to mitigate that - launch from a pool, the ocean, a big steel plate. There's a number of possible solutions.

Edited February 21, 2016 by Elukka

[Bill Phil]

5 hours ago, SomeGuy123 said:

Launching from the middle of the ocean or antarctica really could kill zero people from the fallout.  Poison is about the dosage and the cloud would be so diffuse thousands of miles away where the nearest people are to be harmless.  Shame this wouldn't stop the complainers..

Yeah, but you'd need to make sure that ship traffic is clear at least 250 kilometers away. And the radiation would still harm ocean life...

[PB666]

4 hours ago, Bill Phil said:

Yeah, but you'd need to make sure that ship traffic is clear at least 250 kilometers away. And the radiation would still harm ocean life...

Has anyone asked the question yet can you get the near 2 g of acceleration required to launch (although for the game I don't use 2 g, I use 1.4 to 1.5 and rely on more aerodynamic vehicles).

If the pulse and reload time is a minute and your impulse last 10 seconds thats  20g to get 2g. I don't think this device can launch. The other problem, you would have to use a design that did not use plutonium, as taking this to antartica would be a violation of nuclear proliferation treaties.

 

[Bill Phil]

17 minutes ago, PB666 said:

Has anyone asked the question yet can you get the near 2 g of acceleration required to launch (although for the game I don't use 2 g, I use 1.4 to 1.5 and rely on more aerodynamic vehicles).

If the pulse and reload time is a minute and your impulse last 10 seconds thats  20g to get 2g. I don't think this device can launch. The other problem, you would have to use a design that did not use plutonium, as taking this to antartica would be a violation of nuclear proliferation treaties.

 

The pulse is one second, I think.

[SomeGuy123]

What about landing?  I know the basic idea of Orion for launches from Earth is to make gigantic vessels, crammed full of supplies and equipment, and get them into orbit all in one go.  They might be unmanned, which would mean you wouldn't have to worry about injuries to the crew from the gamma rays of each blast.  

But suppose you did want to land.  Is it possible?

[magnemoe]

19 minutes ago, SomeGuy123 said:

What about landing?  I know the basic idea of Orion for launches from Earth is to make gigantic vessels, crammed full of supplies and equipment, and get them into orbit all in one go.  They might be unmanned, which would mean you wouldn't have to worry about injuries to the crew from the gamma rays of each blast.  

But suppose you did want to land.  Is it possible?

You would need other engines for final decent, not sure how smart it would be to do an braking burn with nukes in atmosphere eiter. 

[PB666]

16 minutes ago, magnemoe said:

You would need other engines for final decent, not sure how smart it would be to do an braking burn with nukes in atmosphere eiter. 

lol. yeah the DoD didnt think the liberty ships would be damaged by the h-bomb, little did they know it wasn't the damage they should have been worried about.

No one has answered my question, suppose we allow them to build a really nice facility close to the North Pole at 2 km alt. Does the drive produce adequate g-forces in the atmosphere?

 

[Nothalogh]

7 minutes ago, PB666 said:

lol. yeah the DoD didnt think the liberty ships would be damaged by the h-bomb, little did they know it wasn't the damage they should have been worried about.

No one has answered my question, suppose we allow them to build a really nice facility close to the North Pole at 2 km alt. Does the drive produce adequate g-forces in the atmosphere?

 

In atmo, it produces more thrust than in vac.

The design of the shock absorption system was to moderate the acceleration per pulse to 2 G, with if I recall correctly, 2 to 3 pulses per second