Apr 042011
 

Diagrams of the last “official” Orion design, featuring a pair of Philco Mars landers. At least some thought was given to lofting the Orion sub-orbitally using an uprated S-IC booster stage, and letting it put itself directly onto a trans-Mars trajectory using the nuclear pulse engine.

The book is still chugging along.

 Posted by at 5:29 pm
Mar 122011
 

Now that I am, seemingly, well and truly on the mend, with my lungs no longer trying to turn themselves inside out, I’ve been back to banging away on my Nuclear Pulse Propulsion book. Yes, I’m kinda behind on this, Yes, that’s nothing especially new.

So far, I’m sitting at 270 pages. I fully expect it to be somewhere north of 350 pages when complete, maybe 400 depending onwhether or not all the images will get in, and how big they’ll be reproduced.

 Posted by at 11:39 pm
Dec 032010
 

Still working the Orion pulse unit & M388 “Davy Crockett” nuclear projectile drawings, but they are now at a point where it’s not embarassing to show ’em. The pulse unit is from the General Atomic design for the 10-meter USAF vehicle, and had a yield of about 1 kiloton. The M388 used a version of the W54 warhead, and had a yield of only 0.01 to 0.02 kilotons. However, other versions of the same basic W54 warhead had yields of up to a kiloton. The Davy Crockett dialed it back for two main reasons:

1) Low yield like this means *really* filthy. The Davy Crockett was designed to make a mass of the foreseen Soviet invasion of western Europe through the Fulda Gap; nuking the bejeebers out of the troops and turning the region into a frighteningly radioactive wasteland was thought to be an effective way of slowing the tide.

2) The range of the M388: pathetic. Down to one slim kilometer. While one can survive a 1 kiloton nuclear blast at a range of one kilometer… one would not want to try.

The Orion was to use existing nuclear explosive designs in the early stages, so it’s safe to assume that the W54 – which, as it happens, was designed by the same guy who designed the pulse units – was the expected basic nuclear explosive. And a comparison of the pulse unit to the M388 shows that they compare quite nicely.

The interior of the M388 as shown here is a bit sparse. Oddly, the DoD is not especially forthcoming with technical information regarding the interior configurations of their nuclear weapons. Strange. Additionally, posted below are three half-ass decent photos… the best versions of ’em I could scrape off the Intarweb tubes. Even with actual units on display at the museums at West Point and Fort Benning (and an oddly painted one at Aberdeen), there are surprisingly few photos of this thing on line.

Anybody near Fort Benning or West Point, and have a camera?

Now, be honest: who *wouldn’t* want one of these hanging from the ceiling, or sitting on the coffee table? Or loaded with a big solid rocket motor and a chute? Or stuck on the end of a big-ass spud gun?

 Posted by at 2:27 am
Nov 272010
 

For those trying to keep up with my fabulous rate of writing progress… the project that has been keeping me busiest of late is a particular chapter in my “Nuclear Pulse Propulsion” book… specifically, the chapter on the design of the Orion pulse units. Of course the most interesting part of the design of the pulse unit – the atom bomb at its core – is safely classified, with just about every meaningful diagram, dimension, mass or detail redacted from the available documentation. However, enough data is available to piece together outlines of several of the designs. And I’ve been dealving into the declassified literature on atomic bomb design to try to re-create what the pulse unit A-Bombs may have been. And you know what?

Atom bomb design is neato.

There’s enough info out there that a trained chimp like me could produce a fairly decent preliminary design for a basic A-Bomb.  I suspect it might only blast itself to flinders and scatter fallout over a few city blocks, but the *next* design might work just fine. The only thing keeping Jihadist jackasses from building their own bombs is… uranium 235 and plutonium 239 are damned hard to come by. Probably easier to simply buy one from North Korea or some drunken Russian military commander with gambling debts.

This chapter should prove to be pretty interesting.

 Posted by at 1:41 am
Sep 272010
 

And here we get to some of the designs that can be considered “kinda big.” First up is the “Enzmann Starship.” It seems to have caught the imagination of a notable fraction of the space-nut population in the early 1970’s; it certainly looked like the first practical, well-thought-out manned starship design. And while a fair deal of really good art and diagrams was produced, the numbers… they don’t seem to add up so well. It’s been a challenge to determine just how much engineering rigor went into this design. The C-size drawing for this beast is 1/2400 scale.

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And here is yet another one from Dandrige Cole, an internal-nuclear pulse vehicle that was meant to be a wholly self-supporting space colony, on the same order of size as Babylon 5. But able to move itself about. C-size drawing is 1/6000 scale.

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The next step up is also a step down. Johndale Solem’s Medusa is a recent design for an Orion-type craft that uses a lightweight spinnaker instead of a solid pusher plate; in order to gain enough distance from the nuclear detonations so that the plastic cables and “sail” don’t get fried by the nuclear radiation, the dimensions are measured in kilometers.  But the core vehicle itself is relatively really quite small. The scale on the C-size drawing is 1/30,000.

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And last up is far and away the largest space vehicle that I’ve ever seen seriously considered (at least that I can recall). It is a Bond/Martin design for a nuclear-pulse-propelled “world ship,” big enough to carry complete ecosystems on journeys lasting millenia, to colonise and terraform alien worlds. While the design is admittedly wholly hypothetical, and was meant more as an excercise to see what might be possible with a vaster industrial infrastructure but with physics and engineering we know today, the math behind the concept seems sound, and is more detailed than many other designs I’ve seen.

The C-size drawing is scaled at 1/600,000.

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Note in the closeup of the engine section that the largest of the other vehicles are mere specks in comparison. In fact, even though the acceleration was a small fraction of a G, and would have lasted for decades, the pulse units themselves would have been astounding feats of engineering. More massive than the Orion Battleship, each pulse unit would have had a yield measured in *gigatons.* One every five seconds.

Two versions were contemplated… a “dry world” with a large hollow rotating cylinder with a terrestrial ecosystem on the inside; and a “wet world” with a much smaller cylinder, sized to support an ocean a kilometer deep (perhaps overly deep, IMO). The “wet world” would have, unsurprisingly, been notably more massive, and would have required the greatest propellant supply and most powerful (34+ gigaton) pulse units, massing over 7,000 tons each.

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That little purple line? Fifty kilometers.

With the possible exception of the Medusa, these designs are well beyond our current capabilities. But a damned good way to improve our capabilities is to have something to strive for. Spacecraft such as these can fire the imagination in a way that rinky-dink little capsules cannot. Spacecraft so large that they have their own weather, that can carry not just humanity but all the forms of life on Earth, to other solar systems… how can you look at that and not be inspired, even if just a little bit?

Far more info than this, on far more projects than these, will be presented in the “Nuclear Pulse Propulsion” book.

 Posted by at 11:12 pm
Sep 272010
 

Something I’ve long noticed is that when someone in the aerospace world – as opposed to science fiction (author or fanboy) – envisions a truly large spacecraft, it’s almost always  powered by some form of nuclear pulse propulsion. Whether it’s driven by dirty A-bombs, cleaner H-bombs, really clean pure fusion devices or far-futuristic anti-matter initiated fusion detonations, the fact seems to be that discrete detonations of nuclear pulse units seems to be the way to go. In contrast, theoretically “better” propulsion systems like steady-state fusion or fusion-free antimatter reactions tend to have fewer designs for really large vehicles. A few designs like various laser/maser sails and the”Valkyrie”-type starship are non-nuke pulse designs, but they seem to be the exception.

In support of my “Nuclear Pulse Propulsion” book, I’m working on a whole bunch of layout drawings. They are all being sized to fit on standard C-size sheets; while the book almost certainly won’t be anywhere near that big (your average road atlas ain’t that big), I want them standardized anyway. Each design has its own sheet, at a scale that allows the design to be shown well. But I also have some scale comparison sheets with multiple designs shown side by side.

Tonight I decided to take some of the representative larger vehicles and put them all to scale on one sheet.  As will be seen, some people dream *big.*

First… the smallest practical orion, the 10-meter design, next to a Space Shuttle. Even being the smallest design, it’s still really big compared to the usual stuff we’ve bothered to send into space. The C-size drawing for this vehicle is 1/100 scale:

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Next, the 4,000 ton “battleship” design. The C-size drawing for this is at 1/250 scale:

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From here, the next step is pretty big. The 4,000 ton Orion is the largest design available to me where detailed engineering design work was known to be carried out. The designs that follow tend to be notional… some of them the vague handwavings of aerospace professionals, others carried out at least at the mathematical scale.

Next is the (Martin Co.) Dandrige Cole “Aldebaran” design for a single stage to orbit cargo lifter. Given a poorly described propulsion system that seems to have consisted of an airbreathing nuclear internal-pulse engine, it was vastly larger than the battleship. The C-size drawing is 1/1200 scale.

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The next is another Cole design, basically a small free-roaming space colony. The landing gear is to allow it to touch down on asteroids and small moons and such, presumably for exploration and mining operations. The drawing is 1/1500 scale.

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Coming soon: Part 2, where Our Hero (that’s me) describes the vehicles that are measured in kilometers. The scales for the C-size drawings for the vehicles to come start at 1/2400 scale and wander on up to 1/600,000 scale. With pulse unit yields measured in “did I read that right? Holy Crap!” units.

Yeah.

 Posted by at 1:30 am
Aug 292010
 

Forging ahead on this project, working multiple angles at once. One project currently in works is collating all my NPP-based CAD drawings, and figuring out what more I need to do. As it turns out, I’ve a fair amount yet to do.

It is my expectation that the book will be loaded with diagrams, both new ones of my own creation, and as many of the original diagrams as possible. Additionally, it is my hope that a good deal of new color artwork will be created for the book. But that particular decision is a ways off yet.

I’ve taken the widely separated and sometimes densely-mashed-together CAD drawings and started to put them into their own C-sized sheets with a proper border. Below you can see a bunch of ’em… not a one of which I’d declare finished. Hopefully the resolution is high enough to make them look appealing, and low enough to be damned frustrating, so that you are left with an overwhelming urger to see to it that this book project is completed. If that urge causes you to shower me with cash, so much the better…

Depending upon the detail and interestingness of the design being shown, several sheets could be devoted to it. For example, seen here are external views of the Orion Battleship, inboard profiles of it, the first starts at external views showing all the primary ports and doors open and views of the landing boats.

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If interested, take a look at the first one with the list of subjects. Note the apparently random distribution of drawing numbers to topics; this is because I listed topics in the order in which they occured to me, not because of any particular logic. If I’ve forgotten something (and I know I have… I need to put the Orion from “Orion Shall Rise” on there), let me know.

NOTE: Once again, the topic of the book is nuclear pulse propulsion, not “starships” or “nuclear propulsion.”

 

 Posted by at 5:37 pm
Aug 262010
 

For the forthcoming “nuclear pulse propulsion” book, one of the later chapters will deal with post-Orion projects. One such concept is the “Enzmann starship,” which called for a vast ball of solid hydrogen to serve as the fuel for a nuclear-pulse starship. While a lot of the numbers for it do not currently make a lick of sense (you couldn’t physically cram the mass of hydrogen into the volume available… the density is off; and the performance of a fusion pulse vehicle is inadequate to attain the 0.9C velocities often touted for the concept), it’s nevertheless an interesting and engaging concept.

All of the designs discussed in the book will be diagrammed, as accurately as possible. There are actually three different “Enzmann Starship” concepts that will be shown; this is an in-progress diagram of the second (and best known) design.

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 Posted by at 9:21 pm
Apr 112010
 

The best known approach to using detonations as a form of space propulsion is the Orion, which uses nuclear bombs  to provide a “kick in the pants” to a spacecraft. But over the years the use of conventional chemical explosives to drive a ship has also been proposed. Early on, in the era before Tsiolkovsky and Goddard, the use of gunpowder and dynamite bombs seemed to make a measure of sense. But after the 1920’s or so, solid and liquid fuel rockets proved themselves far superior to such crude explosive system. The specific impulse of even a mundane rocket typically well exceeds the Isp of an explosive system, with far less danger, complexity, weight and cost. Still, the idea continued to be of interest. Recently, “pulse detonation engines” have proven of substantial interest. These use conventional liquid propellants, but do not burn them in a continuous fashion… instead the propellants are mixed and then detonated. In this case, the explosive system provides *higher* specific impulses than the equivalently-fueled rockets.

But the use of dedicated high explosives for propulsion may still be of interest. Blog reader Michael Holt recently provided a link to a NASA document that discusses the concept and provides data tables on a wide range of proposed explosives. As expected, the Isp’s available are generally fairly unimpressive; note also that these are the theoretical maximums, with percentage losses certain.

One of the more impressive explosives listed is 1,3-diamino-2,4,6-trinitrobenzene (DATNB, C6H5N5O6). Density is a good 1.65 grams per cubic centimeter, and theoretical Isp is 501 seconds… well in excess of conventional hydrogen/oxygen.

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Explosives as propellant offer a few advantages, but a lot of disadvantages. The three most important disadvatages:

1) The propulsion system must be considerably heavier and more complex than an equivalent rocket

2) The risk of the whole ship being blasted into vapor

3) Cost.

In my view, #3 is the killer. I don;t know how much it would cost to buy, say, one hundred tons of 1,3-diamino-2,4,6-trinitrobenzene… but I can’t imagine it’d be cheap. Even with the cost of petroleum far higher than it used to be, kerosene is still less than a dollar a pound. Explosives will always have a hard time competing with that.

 Posted by at 2:14 pm