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Gunship from Larry Niven and Jerry Pournelle's novel Footfall. See my related post Michael for additional detail.
Image featured on Winchell Chung’s Atomic Rockets site, Michael Nuclear Pulse Propulsion Battleship Scroll down at the link.
Featured on Realistic Spaceship Illustrations Blog, Link: here
“They take one of the main guns off a Navy ship. Wrap a spaceship around it. Not a lot of ship, just enough to steer it. Add an automatic loader and nuclear weapons for shells. Steer it with TV.” —from Footfall, pg. 354
In the novel these Gunships are referred to as “Stovepipe’s.” I was far less concerned with designing to match that narrative description than I was with designing the most compact spacecraft possible capable of the mission described. Michaels construction (including all its auxiliary spacecraft and subsystems) takes place in secret under wartime conditions, perhaps the moniker is derived from a code name picked randomly (that’s how the 1958 Project Orion was named), or perhaps dockworkers handling the vehicle sections, packed in featureless cylindrical shipping containers strapped to pallets, named the craft, and it stuck. See Aldo Spadoni’s commentary on character-delivered descriptions on my Michael post.
I built my Gunship around the 5"/54 caliber Mark 45 gun.
The nuclear round fired by the Gunship would be something akin to the UCLR1 Swift, a 622 mm long, 127 mm diameter nuclear shell, weighing in at 43.5 kg.
In 1958 a fusion warhead was developed and tested. At its test it yielded only 190 tons; it failed to achieve fusion and only the initial fission explosion worked correctly. There are unconfirmed reports that work on similar concepts continued into the 1970s and resulted in a one-kiloton warhead design for 5-inch (127 mm) naval gun rounds, these, however, were never deployed as operational weapons. See paragraph 9 (not counting the bulleted list) under United States Nuclear Artillery.
Gunship Crew & Crew Module
The text of the novel is unclear on the number of crew manning the Gunships, but my opinion is no more than 2 would be required, and dialogue in the novel tends to back this up. The loading mechanism is automated, so only targeting and piloting skills are involved. Considering urgency involved in readying Michael, I doubt an entirely new capsule, man-rated for spaceflight, would be considered. Michaels designers would fall back on tried and tested designs and modify them as required. In this case a stripped down Gemini spacecraft and its Equipment Module fits the bill nicely. The life support system matches the mission requirements. Leave off the heat shield (these are one-way missions), and reaction control system—the capsule never operates separate from the Gunship rig. Mount targeting and firing controls for the gun. Probably a single hatch rather than Gemini’s double hatch, and internal flat-screen displays rather than viewports—looking on this battle with naked eyes would leave the astronaut seared, radiation burned, and blinded.
“The exhausts of the gunboats were bright and yellow: solid fuel rockets.” —from Footfall, pg. 454
Eight SRBs akin to the GEM-40 allow options: they could be fired in pairs, allowing four separate burns, or two burns of 4, or a single burn of all eight – needs depending. The SRBs are strapped around a ten foot diameter 40 foot long core containing ample tank stowage for hypergolic reaction control propellants, pressurization gas, and nitrogen for clearing the breech and gun barrel. The reaction control system is used to aim the gun; propellant expenditure would be prodigious.
1UCRL - University of California Radiation Laboratory
Ah, SO cool.
And a great nod to classic science fiction (double bonus!)
I've had a fictional gun used I dreamed up as a teenager I call an "orbital hypercannon" which takes the multi-charge chamber design of of the WWII Nazi V3 "Vergeltungswaffen" concept (later refined and improved by Gerald Bull) and scale it up to use nuclear charges along the barrel length to continuously accelerate the projectile.
The barrel extends five kilometers kilometers and superconductive magnets powered by the fusion detonations add additional acceleration to the sabot round as it is driven down the barrel by oxygen-hydrogen propellant ignited by the nuclear blasts.
I'm hoping to come up with a story one day where I can use the thing and even have some mockups of a 3D model partly done.
I've actually read a fanfiction that used something similar in a Mass Effect AU in which the Protheans didn't give us any Eezo, just one hell of a warning.
You'll find the relevant bits in chapter 14. Search term is "archer"
Hmmm. Using this weapon to propel a micro-singularity would be pretty cool.
We're going to need bigger bombs.
I actually got motivated to go back and look at my model. I had stopped after designing a breech and loading mechanism to allow for on-the-fly builds of customizable munitions. So I'm taking a stab at finishing it up.
Again, your models are perfect.
By the way, great work! Now I can't help but picture "Stovepipes" like this when reading the battle scenes.
Words in a row, they are not just a decorative feature. They contain information, and links to even more information.
The novel came out in 1985. The story takes place in the (then) far flung future year 1995. So all of the technology I've selected is technology which existed before, or was contemporary at, the time of the story setting.
Footfall is arguably one of the best alien invasion novels ever written. If you haven't read the novel I highly recommend it, it's a great read.
This spacecraft is one of 14 Gunships which, along with 4 Space Shuttles, are mounted to a larger carrier spacecraft, the nuclear pulse propulsion battleship Michael. See my related post Michael for additional detail on the carrier spacecraft.
All of the rationale behind the design, the circumstances of its construction, why particular choices might be made, is described in the text right below the picture.
The use of a Gemini capsule in a US design makes sense, they did use a surplus Gemini hatch for the Skylab airlocks and might have leftover MOL parts and tooling in MDD's warehouses. (Grumman's LM might be an option too, but it doesn't have acceleration couches, has more limited scope for expansion and altered systems...and it's far less rugged.)
The GEM-40s are an odd choice, I picture it using something derived from the LGM-30 Minuteman III or LGM-118 Peacemaker
I wonder if a 203mm (8") or 155mm (6") gun might have been a better option, considering the performance of available nuclear artillery shells. (Apparently there was some work with 125mm nuclear artillery, such as the UCRL Swift, but there's not much certainty on their actual deployment.) I guess the W74, W75, W82, and Swift were introduced in this timeline. On the other hand, the 125mm offers a better rate of fire...and target saturation is key here.
I considered the Mark 16 8"/55 caliber gun, but the rate of fire (10 rounds per minute) compared to the 20 rounds per minute for the 5"/54 caliber Mark 45 gun made the choice for me. BAE Systems Armaments Systems 155 mm 6" Advanced Gun System for the Zumwalt-class destroyer suffers the same 10 rounds per minute limitation—and doesn't fit the novels time-frame.
The 5"/54 caliber Mark 45 gun was best fit to the combat-lifespan of the Gunship in the novel, which is measured in (very few) minutes, and as you say, target saturation is key.
I can see the LGM-30 Minuteman III as a viable alternative, mounting an alternative Gunship with the LGM-118 Peacemaker as booster would be problematic due to constrained physical space available for mounting the vehicle on the carrier spacecraft, see my post here Michael.
Yeah. The Midgetman-derived GEMs are probably the best bet, using the Alt-90s setting.