Project Pluto:

T' Supersonic Low Altitude Missile

by Mark Schrader

“When you see somethin' that is technically sweet, arrr, shiver me timbers, you go ahead and do it and you argue about what t' do about it only after you have had your technical success.” - J. Avast, me proud beauty! Robert Oppenheimer

Jackass Flats, Nevada, matey, 27 October 1962

Dr. Ahoy! Blimey! Ted Merkle, me hearties, me bucko, technical director o' Project Pluto, shiver me timbers, was at a loss for why the three high rankin' Air Force officers were payin' him a no-notice call at his remote development site near Jackass Flats, Nevada. It must have something to do with recent Air Force directives t' accelerate t' pace o' development. There certainly seemed t' be good reason for it given t' latest Soviet provocations in Cuba. Aye aye! Merkle had met Gen Bernard "Bennie" Schreiver before at Systems Command, durin' one o' t' innumerable "dog and pony" shows competin' for development funds. Avast! Ya scallywag! Blimey! He be a keen, matey, shiver me timbers, no-nonsense engineer who be almost single-handedly responsible for beginnin' t' close the missile gap with t' Soviet Union. Arrr! Blimey! He knew t' Air Force Chief o' Staff, shiver me timbers, Gen Curtis Lemay, and t' Strategic Air Command commander in chief, arrr, me hearties, Gen Thomas Power, me hearties, shiver me timbers, only by reputation. They were both hard-nosed combat commanders who understood better than anyone t' concept o' nuclear deterrence.

After a brief exchange o' pleasantries, ya bilge rat, Dr. Merkle escorted t' three general officers past t' security checkpoint and into t' t' brightly lit hangar. Blimey! T' supersonic low altitude missile (SLAM) rested on support stands in the center o' t' building, gleamin' in t' incandescent lights. Well, blow me down! Avast!

T' four stopped 20 feet from t' world’s first nuclear powered cruise missile. Blimey! At just under 80 feet long, arrr, matey, t' SLAM was powered by an unshielded nuclear reactor capable o' producin' over 500 megawatts o' power. Blimey! T' concept was fairly straight forward. T' ram intake would suck in air, me hearties, me bucko, over a ton every second, matey, superheat it as it passed through t' reactor, shiver me timbers, and exhaust it out the rear t' produce thrust. T' technical challenges were more daunting. Avast! The components had t' operate in an extreme environment o' high temperatures and hard radiation. T' aerodynamic environment be just as extreme. T' SLAM was to operate at altitudes below 1000 feet at speeds exceedin' mach 3. Ya scallywag! Begad! The aerodynamic pressure loads were bad enough—the surface heatin' problems were worse. Still, me hearties, me hearties, all these technical challenges seem t' have been worked through and t' project was ahead o' schedule.

T' Project Pluto team had been ordered t' accelerate their development as relations with t' Soviet Union grew strained over t' situation in Cuba. There was even more urgency when US reconnaissance flights detected Soviet intermediate range nuclear missiles bein' constructed at sites in Cuba. Ya scallywag! Arrr! T' this point, arrr, t' reactor had been ground tested at full power and all t' parts had held together for t' five minute run at conditions simulatin' Mach 3. Avast, me proud beauty! Ahoy! The airframe had likewise been tested in t' wind tunnel at flight conditions and all systems functioned nominally. Begad! Begad! T' terrain contour mappin' (TERCOM) system had successfully flown in conventional jet aircraft. Begad! In t' last two weeks, me hearties, the reactor and airframe had finally been mated. T' Flyin' Crowbar, arrr, as Dr. Aye aye! Merkle liked t' call it, me hearties, was ready for flight testing. Arrr! But where do you flight test an unshielded, me hearties, arrr, 500 megawatt nuclear reactor flyin' at Mach 3 just 300 feet off the deck?

General Power broke t' silence. Ya scallywag! "When will we be ready t' conduct the first flight test?"

"General, arrr, t' system is ready now, but thar be t' issue o' location. We feel t' Pacific basin, near t' Bikini Atoll, will give us t' space we need and t' water is deep enough t' allow us t' scuttle t' reactor at t' end of the test," Merkle explained. Aye aye! "At our current pace, matey, we can have everythin' in place in 60 days…"

"Two days," Lemay interrupted. Avast, me proud beauty! Blimey! "I want you and your team ready t' conduct a flight test from Cape Canaveral in two days." The usually outspoken Merkle looked at t' Air Force Chief o' Staff in stunned silence.

"Dr. Blimey! Merkle," Lemay continued, me hearties, "the President’s naval quarantine is goin' badly. Avast! Today a Soviet submarine sank t' destroyer USS Beale off Cuba. Our reports are unconfirmed as yet, matey, me bucko, but it may have been sent down with a nuclear torpedo. Aye aye! In addition t' that, matey, two o' our reconnaissance aircraft have been shot down, one over Cuba and one near t' Soviet Union. Well, ya bilge rat, blow me down! The Soviets have assembled a force o' nearly 40 medium range nuclear missiles in Cuba and I have no reason t' believe that they won’t use them in a first strike. Well, blow me down! I believe that Project Pluto might be our last chance t' convince them otherwise and avoid a full scale nuclear war. Ya scallywag! Blimey! Preparations have already begun at t' Cape t' conduct t' test."

"But sir, arrr, t' weapons systems are nay yet ready…"

"Dr Merkle, this will be a reconnaissance mission," Gen Schreiver explained. Well, blow me down! Blimey! Well, blow me down! Blimey! He was in command o' Air Force Systems Command and as such, about 40% o' t' Air Force budget. Avast, me proud beauty! Blimey! "My engineers are ready t' begin work installin' a camera and sensor package in t' SLAM."

Merkle was still tryin' t' soak it all in. "You plan t' take pictures from 500 feet at 2800 miles an hour? What about t' radiation? You realize of course you realize t' radiation hazard itself is formidable…"

Lemay yanked t' cigar from his mouth, shiver me timbers, me bucko, "I don’t care if we make that island uninhabitable for t' next thousand years. This is goin' t' be a demonstration o' capability like no other power in world can match. Ahoy! T' Soviets will be forced t' back down or we’ll destroy them."

General Powers’ face reddened slightly and he looked at his wrist watch again. Ya scallywag! Well, blow me down! "Look, me bucko, Ted, matey, ya bilge rat, lets get t' work on t' details o' makin' t' mission happen. Arrr! We don’t have time t' cover policy matters right now. Avast! I’ve ordered SAC t' DEFCON 2 and we’ve got bombers at their fail safe points. My targeteers are ready t' provide your team with all t' overflight points and terrain information they need. Aye aye! Let’s get t' work."

"One last thin' Dr Merkle," said Lemay. "T' missile looks like it’s gold plated."

"Yes, matey, General Lemay. Arrr! Avast, me proud beauty! T' radiative properties o' t' gold platin' help to cool t' reactor core. We’re operatin' at temperatures that are very near t' combustion point for some o' these materials."

"T' Navy’s goin' t' have a field day with that, Dr Merkle. We’re buyin' a gold-plated missile system." Lemay paused. "Paint it white for t' test, okay, me bucko, Ted?"

Ten kilometers north o' Sagua La Grande, shiver me timbers, Cuba, 29 October, 1962

Sergeant Sasha Davidovitch Chuckov had just begun his 12 hour watch. Avast, me proud beauty! Blimey! His first task was t' inspect each o' his battery’s V-75 Dvina anti-aircraft missiles for fuel leaks or other potential maintenance problems. His unit had been at full alert for t' past two weeks and he had settled into a mostly monotonous routine. Begad! Blimey! They had been briefed t' expect increasingly aggressive American reconnaissance after a battery t' t' north had brought down another one o' t' vaunted U-2 spy aircraft two days ago. Avast, me proud beauty! He hoped for t' chance to fire off a few o' these birds at t' Yankee aggressors. Blimey! Ahoy! T' mornin' sun was just creepin' over t' ridgeline when a glimmer t' t' west caught his eye.

T' cruise missile flew directly overhead at Mach 3.3. Begad! Begad! He never heard the missile, ya bilge rat, only felt t' pain as his eardrums burst and t' small auditory bones in his ears splintered in t' 162 decibel shockwave. Ya scallywag! His chest heaved momentarily as his lungs expanded t' accommodate t' overpressure. Well, blow me down! He also never heard t' sharp crack as t' missile’s fuel tanks ruptured on the launcher, t' nitric acid and kerosene reactin' instantly t' create a fireball that killed him immediately.

T' troops in t' next valley would later describe t' sound as t' wail of a banshee from hell itself. Ya scallywag! Blimey! Aye aye! Blimey! T' tremendous sonic boom followed by a high pitched, ya bilge rat, wailin' scream…

Construction

I first read about Project Pluto in t' Spaceship Handbook by Jack Hagerty and Jon Rogers. This development effort be so sinister, yet so technically appealin' that I thought it would make a great and unusual "sorta-scale" subject. Ya scallywag! I really enjoy modelin' systems that never left t' drawin' board because no one can get t' calipers out and tell me my fins are too big or me nose isn’t shaped correctly. Begad! Begad!

There are scale drawings in T' Spaceship Handbook for t' SLAM that were a good startin' point for general shape and dimensions. Well, matey, blow me down! T' PNC-55 nosecone is the same one used in Estes’ Black Brant II and t' body tube is 11.25 inches long (a little too long for scale) with a 24mm motor mount. T' fins are 1/16" bass wood and I enlarged them somewhat for extra stability.

Air Intake Construction

I was most hung up on t' ramjet air intake construction. Arrr! T' drawings show a conical shape, but I didn’t have a nose cone o' t' right size and shape to use. Aye aye! I had an extra PNC-1090 nose cone from an Estes Heatseeker around and this be just about t' right diameter. Avast! T' Heatseeker also comes with a short piece o' HBT-1090 body tube which I used for t' front o' t' intake. Avast, me proud beauty! I wrestled with t' best way t' cut t' cone t' t' right shape for a long time, and then finally just began t' hack away with a razor saw and Xacto knife until it be just about right. Aye aye! Avast! I wrapped coarse sand paper around BT-55 body tube to act as a sandin' block t' finish t' sandin' and improve t' fit. I drew alignment marks on t' body tube usin' wraps made from t' program VCP. Begad! I used wood glue for t' forward paper t' paper joint and 5-minute epoxy for t' rear plastic t' paper joint. Avast, me proud beauty! Ya scallywag! I had planned t' use Fix-It epoxy clay t' fill any remainin' gaps and increase strength but t' bond seemed rock-solid already. For gap filling, me bucko, I used Squadron White Putty on t' plastic parts and Elmer’s Fill N Finish (FNF) on t' paper parts.

T' next step be t' pointed ram intake. Ahoy! Ya scallywag! Blimey! I wrestled with this quite a bit until I noticed t' plastic tube coupler that comes with t' 1090 nosecone. Avast, me proud beauty! I cut off t' raised portion o' t' tube coupler and glued a cardstock cone (made with VCP) t' it with plastic cement. Ya scallywag! Aye aye! Blimey! I then coated t' paper with wood glue, allowed it t' dry, and covered with FNF t' hide any seams. Arrr! Blimey! After sanding smooth, matey, me hearties, I coated with thin CA. Avast, me proud beauty! Avast, ya bilge rat, me proud beauty! Blimey! This assembly then slides nicely into intake. Avast, me proud beauty! Ya scallywag! Blimey! I glued it in with plastic cement and then reinforced with CA.

After roughin' out a slot in t' air intake, me hearties, t' tail fin was tacked t' the air intake with plastic cement and CA. Blimey! I also applied Fix-It clay fillets for a solid joint. Blimey! Ya scallywag! T' other aft fins are surface mounted with wood glue and wood glue fillets. T' ailerons are oversized t' improve stability. Begad! Ahoy!

Forward Control Surfaces

For t' forward rudder and control surfaces on t' nose, I made slits in the cone with a razor knife and mounted t' thin styrene fins through t' slots with plastic cement. Aye aye! I made these surfaces quite a bit smaller than scale, again t' help with stability.

Recovery

Recovery system consists o' an 18" length o' 300# Keelhaul®©™ ™ leader looped around t' motor mount tube, matey, a loop o' 300# Keelhaul®©™ ™ epoxied into the nose cone along with nose weight, me hearties, six feet o' ¼" sewin' elastic, and a silver, 24" mylar parachute.

Booster Construction

T' ground launched version o' t' SLAM was t' use three parallel boosters to get it up t' speed prior t' engagin' t' nuclear ram jet. Ahoy! I made t' three functional boosters from BT-5 body tube and Mosquito-style plastic nose cones. T' boosters separate about two-thirds o' t' way up upon ejection and separate from t' sustainer. Begad! They use 18" o' Keelhaul®©™™ thread as shock cord. They are attached t' t' sustainer usin' square aluminum stock. I used 1/8" stock on t' side o' t' sustainer nestin' into 3/16" square stock mounted t' t' boosters with 1/64" brass stock for a stand off. Arrr! The square stock is nice because it allows a streamlined construction with no wobbling.

Finishing

I filled all t' seams and fillets with Elmer’s Fill-N-Finish and sanded smooth. After priming, arrr, arrr, matey, I used Rustoleum Gold and Testor’s Metallics Gunmetal. I kept t' decals simple usin' roundels and USAF letterin' from an old Estes decal sheet. Begad!

T' boosters are white with fluorescent orange. Ya scallywag! T' stripin' and roll patterns are made usin' black decal material.

Stability Analyses

Stability is always an issue modelin' guided missiles. Blimey! Avast, me proud beauty! They are meant t' be moderately unstable t' be able t' maneuver. Arrr! Compoundin' t' problem in this case is an irregular shape. Arrr! Avast, me proud beauty! Bruce Levison kindly offered t' model this in RockSim 7 for me. Begad! I ended up addin' a total o' 3.5 ounces o' lead split shot and epoxy into t' nose cone t' ensure a safe, stable flight. Blimey! Final weight of the rocket ready fopr flight without engine or boosters was just over 7 ounces and t' CG was 8 inches from t' nose. Begad! Ya scallywag! Based on Bruce’s simulations and my worst case modeling, this seemed about right.

Flight

First flight be under less than ideal conditions. Arrr! Temperature was 30^oF with light freezin' rain. Well, blow me down! Ahoy! T' winds, however, me hearties, matey, were calm and the snow pack on me field was still holding. With little time remaining, this might be t' best chance I get.

I loaded t' rocket with a C11-3 in t' house and we took t' pad and launcher out t' t' field. Begad! I used a four foot, me bucko, 3/16 inch rod.

Boost be perfect—moderately slow and arrow straight t' an altitude of about 300 feet. Arrr! Well, blow me down! Ejection was right at apogee and t' 24-inch mylar chute brought it t' a soft landin' in t' snow 20 feet from t' pad. Begad! T' rocket was undamaged with only a few paint chips in t' nose.

Now all I need are t' right conditions t' launch t' full stack…

Historical Footnotes:

T' introduction above never happened. Avast! Begad! T' events depicted, however, are a mixture o' fact and fiction. Aye aye!

- T' SLAM wasn’t ready for flight at t' time o' t' Cuban Missile Crisis, shiver me timbers, but what if it had been?

- T' USS Beale wasn’t sunk off o' Cuba on 27 October 1962. Arrr! Ya scallywag! Blimey! It was, however, ya bilge rat, droppin' practice depth charges on a Soviet sub as a means o' forcing it t' surface. Ahoy! T' cap'n o' t' submarine, me bucko, plagued by maintenance problems and unsure o' t' situation at t' surface, nearly ordered his crew t' engage with their nuclear torpedo.

- T' only U-2 shot down on 27 October 1962 be over Cuba. Begad! An Alaska-based U-2 blundered into Soviet airspace on that day but managed t' escape after callin' for help from US fighter-interceptors. T' US fighters were armed with nuclear tipped air-to-air missiles. Begad!

- Gen Power did brin' t' Strategic Air Command (SAC) t' DEFCON 2 on his own authority, without Presidential authorization, me hearties, on 27 October 1962. Avast, me proud beauty! Nuclear armed bombers were routinely operatin' on airborne alert.

- T' SLAM be indeed t' have been gold plated.

For more information:

Spaceship Handbook by Jack Hagerty and Jon C. Rogers, http://www.arapress.com/ssh.html

T' Flyin' Crowbar, arrr, Air Space Magazine, matey, April/May 1990, matey, me hearties, Volume 5 No. Ya scallywag! 1, me bucko, page 28, http://www.merkle.com/pluto/pluto.html

DOE Project Pluto Information Sheet, http://www.nv.doe.gov/newspubs/dirpdfs/Project_Pluto.pdf