Mid 20th century interplanetary cruiser.

a reply to: Saint Exupery

Thanks for the run down about Footfall, I read it so long ago I forgot most of what you described about it.

I do remember the notion of sitting back and throwing rocks and smart rods at ground targets from space.

The aliens got lax or something, right? They got too close too right, like Independence Day?

The book was a work of art, I enjoyed it immensely but stretched my imagination with the bomb powered space craft as a last ditch defense of Earth.

Yo saw Gravity? A space ship needs retros all around it to effectively move in vacuum. not just "landing jets" made of nukes.

I forgot about using shuttles and X-ray beams. Also remember what the (real world) defensive shield using Nike missiles to defend against incoming Soviet ICBM's on the west coast would have looked like in an out and out.

Image search for Nike counter missile batteries

originally posted by: JadeStar
I'd rather channel all of that nuclear energy into Nuclear Ion drives or EM thrusters. Blowing up bombs for propulsion seems like a crude mid 20th century Cold War era idea.

There are far more efficient ways to use the same energy now.

But can they ever lift any substantial payload into orbit?

Thats is what holding mankind back. Earth to orbit cost.

Spending $300 million odd to barely get 100 tons into orbit is just not economical.

Until that price goes down and that payload goes up by a magnitude or more we are stuck with cramped tin cans in LEO

The way thing stand now im skeptical we wont see a man on mars by 2040 and even then it will be a short trip toplant a flag and the return.

Until we finder a better way to break orbit we are stuck with only probes LEO small scale habbitation and if lucky a mars mission and astroid capture mission.

originally posted by: crazyewok

originally posted by: JadeStar
I'd rather channel all of that nuclear energy into Nuclear Ion drives or EM thrusters. Blowing up bombs for propulsion seems like a crude mid 20th century Cold War era idea.

There are far more efficient ways to use the same energy now.

But can they ever lift any substantial payload into orbit?

Thats is what holding mankind back. Earth to orbit cost.

Spending $300 million odd to barely get 100 tons into orbit is just not economical.

Until that price goes down and that payload goes up by a magnitude or more we are stuck with cramped tin cans in LEO

I fully expect that space tourism and things like Britain's Skylon will bring the cost to orbit down in the same way that the cost of air travel came down once it was opened up for the masses.

And then there is always this.....Japanese Company Plans Space Elevator By 2050

That is not what Freeman Dyson told me, it was one of the reasons why he decided not to move forward was because they could not get the bombs clean enough to cut down the risk. a reply to: crazyewok

Actually to save cost the crew that lands on Mars would have to stay for months until planetary alinement occurs again to launch home. So they will have far more time to do many more things than just plant a flag. There is a program of using a lighter than air platform to launch a space craft from over 100,000 feet but such a platform would be massive. I suspect it would be slightly cheaper to use the SLS to assemble the Mars spacecraft in orbit than to build a massive LTA platform.
a reply to: crazyewok

Actually to save cost the crew that lands on Mars would have to stay for months until planetary alinement occurs again to launch home. So they will have far more time to do many more things than just plant a flag. There is a program of using a lighter than air platform to launch a space craft from over 100,000 feet but such a platform would be massive. I suspect it would be slightly cheaper to use the SLS to assemble the Mars spacecraft in orbit than to build a massive LTA platform.
a reply to: crazyewok

originally posted by: intrptr
Yo saw Gravity? A space ship needs retros all around it to effectively move in vacuum. not just "landing jets" made of nukes.
a reply to: Saint Exupery




Yes and Orion would have several thrusters and would have used a light water nuclear reactor to superheat various liquids and turn them into expanding gasses for the needed maneuvering in space. One idea was to use waste water super heated by the reactor to use as fuel for the RCS system as one source since at the time the tech to recycle water like the ISS could did not exist. Though there was a plan to also use the nuclear heat from an exchanger to distil gray water back into clean water.


Image search for Nike counter missile batteries

As for Earth to orbit,

Skyhook? Has there been any sort of thoughts as to this method of reaching orbit?

I read somewhere, don't remember where, about Boeing doing some feasibility studies as to a rotating skyhook, but materials haven't yet been developed that can deal with the obvious stresses involved.

A stationary one would seem to be feasible, but would it be worth the time and effort to develop it?

I've no idea. None.

a reply to: USSGOBLiN
Hi, USSGOBLIN, welcome to ATS…

Yes and Orion would have several thrusters and would have used a light water nuclear reactor to superheat various liquids and turn them into expanding gasses for the needed maneuvering in space. One idea was to use waste water super heated by the reactor to use as fuel for the RCS system as one source since at the time the tech to recycle water like the ISS could did not exist. Though there was a plan to also use the nuclear heat from an exchanger to distil gray water back into clean water.

Nothing "light" about such a reactor. The shielding and cooling plumbing for such would require lifting a large reactor to orbit on a multiple chain reaction of detonations, no?

What a mess of fallout, even if it worked and didn't get destroyed in the process.

One giant, radioactive fireworks display.

I do not think you understand the term "Light water nuclear reactor" perhaps you should look it up. As far as the fall out, well yes and that is partly why the program did not move forward. a reply to: intrptr

originally posted by: USSGOBLiN
That is not what Freeman Dyson told me, it was one of the reasons why he decided not to move forward was because they could not get the bombs clean enough to cut down the risk. a reply to: crazyewok

You're correct:
www.webofstories.com - Project Orion: the question of fallout ...

BUT I think the ot her poster was basing his/her thoguhts on this:
www.spacedaily.com - The Case For Orion...

Based on more modern research the calculated environmental impact of an Orion launch might cause a single fatality on a global scale. That however is assuming a 10,000 ton Orion designed with 60's fission bombs and launched from Nevada with no effort to minimise groundburst fallout.

(note: 1 perosn dies, but many people get cancer)

The idea is obviously outdated today, for the reasons stated by Dyson and more, but I can see why it's still popular. The reason it works is because you're fully using the nuclear chain reaction to create thrust. You're not confining it like in a nuclear reactor. We could use fusion bombs (uses fission trigger) to harness fusion power to greatly increase the effectiveness and also decrease the fallout. Yet we cannot create practical fusion reactors yet. That's the difference.

There's also partial confinement of fusion where the purpose is jetting it out to create thrust. The problem is even this requires a great deal of control. We're still struggling to achieve it for practical purposes.

VASIMR is a precursor to fusion propulsion:
en.wikipedia.org - Variable Specific Impulse Magnetoplasma Rocket...

Here's another project which is trying to go one step further and deal with actual fusion plasmas rather than hot plasma, going from 1 million degrees to 100 million, if I understand correctly:
cosmiclog.nbcnews.com - Scientists develop fusion rocket technology in lab – and aim for Mars...

Slough and his colleagues are working on a system that shoots ringlets of metal into a specially designed magnetic field. The ringlets collapse around a tiny droplet of deuterium, a hydrogen isotope, compressing it so tightly that it produces a fusion reaction for a few millionths of a second. The reaction should result in a significant energy gain.

"It has gain, that's why we're doing it," Slough said. "It's just that the form the energy takes at the end is hot, magnetized metal plasma. ... The problem in the past was, what would you use it for? Because it kinda blows up."

So now I hope I've communicated why Project Orion is still interesting to some people. It harnesses something we struggle to harness. The problem is it does it with bombs, creating proliferation concerns. And given it's more efficient the bigger it's, it could be argued we're not prepared for it. It also leaves fallout which can kill people and has a long sordid history with the public. And as other posters have stated, the blasts can fry satellites.

Regarding VASIMR, Robert Zubrin wrote this rebuttal:
www.marssociety.org - The VASIMR Hoax...

But wait, there’s more. To achieve his much-repeated claim that VASIMR could enable a 39-day one-way transit to Mars, Chang Diaz posits a nuclear reactor system with a power of 200,000 kilowatts and a power-to-mass ratio of 1,000 watts per kilogram. In fact, the largest space nuclear reactor ever built, the Soviet Topaz, had a power of 10 kilowatts and a power-to-mass ratio of 10 watts per kilogram. There is thus no basis whatsoever for believing in the feasibility of Chang Diaz’s fantasy power system.

Space nuclear reactors with power in the range of 50 to 100 kilowatts, and power-to-mass ratios of 20 to 30 watts per kilogram, are feasible, and would be of considerable value in enabling ion-propelled high-data-rate probes to the outer solar system, as well as serving as a reliable source of surface power for a Mars base. However, rather than spend its research dollars on such an actually useful technology, the administration has chosen to fund VASIMR.

No electric propulsion system — neither the inferior VASIMR nor its superior ion-drive competitors — can achieve a quick transit to Mars, because the thrust-to-weight ratio of any realistic power system (even without a payload) is much too low. If generous but potentially realistic numbers are assumed (50 watts per kilogram), Chang Diaz’s hypothetical 200,000-kilowatt nuclear electric spaceship would have a launch mass of 7,700 metric tons, including 4,000 tons of very expensive and very radioactive high-technology reactor system hardware requiring maintenance support from a virtual parallel universe of futuristic orbital infrastructure. Yet it would still get to Mars no quicker than the 6-month transit executed by the Mars Odyssey spacecraft using chemical propulsion in 2001, and which could be readily accomplished by a human crew launched directly to Mars by a heavy-lift booster no more advanced than the (140-ton-to-orbit) Saturn 5 employed to send astronauts to the Moon in the 1960s.

That said, the fact that the administration is not making an effort to develop a space nuclear reactor of any kind, let alone the gigantic super-advanced one needed for the VASIMR hyper drive, demonstrates that the program is being conducted on false premises.

Robert Zubrin created this powerPoint presentation to advance the notion we need nuclear power to get things done in space:
www.nuclearconnect.org - Nuclear Power Applications in Space...

originally posted by: Phage

Recently I talked to an Air Force officer and he told me this project maybe brought back.

With a suitable shock absorber, why not.
Oh, politics. That's why. A whole bunch of nuclear explosions overhead will not be an easy sell.

NASA has been quietly re-examining ORION, under the new name of "External Pulsed Plasma Propulsion". As George Dyson observed, the new name removes most references to "Nuclear", and all references to "Bombs."

www.projectrho.com...

originally posted by: stormbringer1701

originally posted by: Phage

Recently I talked to an Air Force officer and he told me this project maybe brought back.

With a suitable shock absorber, why not.
Oh, politics. That's why. A whole bunch of nuclear explosions overhead will not be an easy sell.

NASA has been quietly re-examining ORION, under the new name of "External Pulsed Plasma Propulsion". As George Dyson observed, the new name removes most references to "Nuclear", and all references to "Bombs."

www.projectrho.com...

I suspect that it would only be a matter of time before those words entered the picture again though. I heard that environmentalists tried to block the launch of Cassini because it was using "nuclear" RTGs and would "ignite Saturn" or some other nonsense?

Is that true?

If so, why didn't they try to block New Horizon's launch?

What about ANTIMATTER?

originally posted by: cavtrooper7
What about ANTIMATTER?

The first antimatter related space propulsion systems are likely to be along the lines of AIMSTAR and ICAN and ICAN II. this is because those designs require just a tiny tiny tiny amount of antimatter to go as far as the Oort cloud and back.

originally posted by: stormbringer1701

originally posted by: cavtrooper7
What about ANTIMATTER?

The first antimatter related space propulsion systems are likely to be along the lines of AIMSTAR and ICAN and ICAN II. this is because those designs require just a tiny tiny tiny amount of antimatter to go as far as the Oort cloud and back.

How much anti-matter are we talking here? a few micrograms?

on a fun side note i just discovered Project Rho's weird astronomy section. I knew about Rho for the engine list and the infamous boom table. but the astronomy page was new to me.

www.projectrho.com...

a sample:

Gliese 436 is a star about 10.1 parsecs away from Terra. In 2004 the Neptune-sized planet Gliese 436 b was discovered orbiting the star.

The weirdness is that the freaking planet is covered in red-hot ice.

There is plenty of water, but the planet's gravity smashes it into something called Ice X (ice-ten). Among its many amusing properties, it has a melting point of over 725°C.

Therefore, despite the fact that the planet's surface is broiling at about 439°C, the blasted ice refuses to melt.

originally posted by: JadeStar

originally posted by: stormbringer1701

originally posted by: cavtrooper7
What about ANTIMATTER?

The first antimatter related space propulsion systems are likely to be along the lines of AIMSTAR and ICAN and ICAN II. this is because those designs require just a tiny tiny tiny amount of antimatter to go as far as the Oort cloud and back.

How much anti-matter are we talking here? a few micrograms?

for one its nanograms. for the other it's a few micrograms.

ICAN II 140 nanograms for a mars trip

source: ffden-2.phys.uaf.edu...