Orion Drives

[Skgoa]

But that is a topic of later discussion. Orion drives I could see working well for moving in a straight line, but how would you turn a ship powered by an Orion Drive? Would you just have conventional rocket engines strapped to various portions of the ship, or would you have a nuke cannon that allows you to precisely detonate nukes behind you that would allow you to redirect your starship?

Also, braking. How would one brake using an Orion Drive?

Any change in velocity in any direction would be achieved by rotating the ship* to the appropriate orientation and firing the main engine.

* probably by small "rocket" engines scattered around the ship's surface.

[Shroom Man 777]

Fascinating. I had not realised Stuart was a published author. Thanks.

There's even an audiobook of Armageddon. Check it out.

[RRoan]

It's worth noting that the pulse units used in Orion drives are, although definitely of serious destructive potential, not weapons. They are very specialized directed-blast devices optimized for spaceship propulsion, and are generally of very low yield compared to most modern nuclear weapons. The 4000-ton Orion (known simply as the Interplanetary Ship) would launch using 150-ton devices and would use devices of progressively higher yield until it was using 5-kiloton devices in orbit. You certainly can't use normal nuclear weapons as pulse units. There actually were design studies on weaponized nuclear shaped charges known as "Casaba Howitzers", but those studies remain classified to this day.

Fallout can be kept to a minimum using thermonuclear devices optimized for low fallout, although you're still using 800 or so pulse units to get your spacecraft into orbit . There were numerous proposals for lofting Orions to very high altitudes or even orbit with chemical boosters such as the proposed NEXUS rocket family, which is notable for making the Saturn V look like a cute little children's toy. Although Orion certainly does make for spacecraft with downright salivating performance seeing as how its ISP outstrips ion drives and it has ludicrous amounts of thrust, it still makes for a very, very effective launch vehicle on its own. The 10,000-ton Orion would be cost-competitive (in terms of dollars per kilogram to orbit) with modern rockets even if it cost several tens of billions of dollars per launch.

They even calculated the additional deaths from cancer that you could expect per launch if you didn't loft it with a chemical rocket. If I remember right it was supposed to be less than 5-10 eventual deaths each, which isn't too bad.

[Sarevok]

Calculations of fallout related deaths are always "iffy". I dont think using nuclear pulse propulsion on Earth is a practical or politically idea. But I have to question people claiming with blatant surety that each launch is going to kill 5 individuals. I always take statistical correlation like this with a big grain of salt.

[Dalton]

The Daban Urnud. Apparently it can pivot, but not easily; since the ship is a habitat for four different parallel-universe strains of humanity, the living areas are half-full orbs of water that rotate to provide artificial gravity.

[TsarAD]

Wouldn't a cargo orion be exceptional for boosting construction material into space? A few Orion launches would be a great way to get, lets say, a space solar industry going.

[Dalton]

Wouldn't a cargo orion be exceptional for boosting construction material into space? A few Orion launches would be a great way to get, lets say, a space solar industry going.

I hope you've found a good, solid patch of land somewhere out there in some remote corner where there's not a lot of wind but is still close to the equator.

[RRoan]

To be honest, the large Orion concepts have such high performance that it doesn't make a huge difference if you were to launch them from, say, Antarctica.

[Terralthra]

You might still fry optical sensors or other delicate equipment.

EMP is an atmospheric/magnetospheric effect. In deep space, there is no significant EMP.

[Sarevok]

He is not talking abou EMP but the intense flash of radiation produced by nuclear explosions. That could certain damage optics and perhaps more significantly harm the eyesight of anyone looking at it.

[Sithking Zero]

Plus, the whole, you know, the whole "Radiation," and "Cancers," thing. Maybe it's just me, but being in any proximity to a nuclear device is an experience I'd rather avoid.

But you guys know me; I'm weird like that.

[Simon_Jester]

Arguably, all the big issues with Orion involve the user- the drive simply cannot be entrusted to anyone ever. Even though the propulsion bombs themselves are not particularly effective nuclear weapons, the technology to make them unavoidably requires having the ability to make effective weapons from the same materials, by solving a simpler engineering problem.

Give it to a private organization and the problem is obvious: private manufacture of nuclear weapons. If I tried to count all the failure modes for that I suspect I'd be here all night.

Give it to a government and the situation is a bit less clear-cut; there are plenty of governments the world de facto trusts with nuclear weapons, after all. But Orion offers a number of strategic advantages: massive, rapid spacelift capability that could be used for powerful military applications.

One easy example: I can use an Orion ship, or a small fleet of them, to very rapidly launch a fleet of SDI-type satellites. If that defense net is good enough that even your best nuclear first strike could not reliably overwhelm it to ruin my nation, I now have the power to dictate terms to you or threaten to start a nuclear war which you will predictably lose- in that your nation will be ruined while mine will be at worst damaged.

Or I could orbit a huge number of kinetic impactors and be dropping Thor rods on your nation's missile silos and airbases before you figure out what's hit you. Or... something, some X-factor that cannot be easily predicted in advance without knowing the details of the enemy's secret weapon programs, but that has the effect of drastically weakening your ability to deter me from doing things you don't like.

An Orion launch, unlike almost anything else, has the capacity to alter the nuclear balance of power between major states in an afternoon, without directly triggering a nuclear exchange the way that a mass launch of missiles would.

This isn't such a big deal as it was in the Cold War, but it's still very significant, and will no doubt remain so.

[Skgoa]

Two things:

1) Whats your definition of "big issue"? Nobody has even come close to demonstrating that this concept even works the way nuke wankers claim it does. I can guarantee you that like in any engineering project of this scale issues WILL come up, that - while maybe not insurmountable - will make the development and construction of any Orion-driven ship a very very long and costly endeavour. (Such little things like shrappnel being launched by the force of the blast from the front of the pusher plate into the actual ship.) It might just not be worth the effort.
But even if we ignore the fact that its all still only a pipe dream at the moment AND ignore that no one would be idiotic enough to even seriously propose this... we still have the teensy tiny little problem of the "proposed" Orion ships being constructions that on a sheer physical scale dwarf everything we have ever sent into space. We will have SSTO, space elevators, orbital construction etc. a long time before Orion-driven ships become cost effective.
I think I had already said it in another thread, but its worth repeating: we will NEVER EVER* see an Orion launch vehicle.


2) IMHO your analysis of Orion being a game changer in the field of launch vehicles is flawed, because (in addition to what I wrote above) you did not take into account that the same amount of payload can be launched by just using a huge number of conventional rockets. Lets not forget what a huge investment in terms of money, materiel and opportunity cost an Orion ship would mean. Actually, rockets would even be better, since you could launch to many different orbits at the same time, while your Orion ship would waste quite a lot of time changing orbits. (Keep in mind that it can't fire it's main engine near the satelites it just deployed.)



* Well, unless the reason for it is something like a meteor hurtling towards us or something unexpectable like that...