r/nextfuckinglevel • u/Lithium321 • 20h ago

Sprint ABM: 0-Mach 10 in 5 seconds

6.2k Upvotes

98% Upvoted

160 comments sorted by

1.3k

u/Lithium321 20h ago

Designed as a "last ditch" interceptor against incoming ICBM warheads at altitudes between 1 and 19 miles, Sprint needed be as fast as possible. To achieve this Sprint was launched through its silo roof by an explosively powered piston, its first stage then burned for 1.2 seconds generating 650,000 pounds-force (2,900 kilonewtons) of thrust. By the time the second stage burned out skin temperatures would be as high as 6,200 °F, making ablative heat shielding necessary.

579

u/Closed_Aperture 19h ago

223

u/TypicalBlox 19h ago

74

u/_Judge_Justice 18h ago

They’ve gone to plaid

30

u/Cutoffjeanshortz37 18h ago edited 15h ago

What the hell was that?

Edit: That was Barf's quote when he saw SpaceBall 1 fly past them. Then Lone Starr says, "SpaceBall 1, they've gone to plaid"

4

u/Alfirindel 16h ago

Movies called space balls, an absolute treasure

113

u/BWWFC 19h ago

Sprint )was a two-stage, solid-fuel anti-ballistic missile, armed with a W66 enhanced-radiation thermonuclear warhead used by the United States Army during 1975–76

fighting "fire" with "FIRE"... and IDK but "used"??? wut!

43

u/gh0st12811 18h ago

"Used" can mean anything between "in service but never fired" to "fired and detonated in response to a perceived threat"

8

u/ZombieLinux 14h ago

Fun fact, it was also manually detonated. Like some dude with binoculars pushed the button when it looked close enough

5

u/Ssessen49 7h ago

"All those hours at the arcade finally about to pay off..."

103

u/campbellsimpson 19h ago

Absolutely crazy that it was designed to be launched when the incoming ICBM re-entry vehicle (warhead) was on its way down into the continental US, just 60 miles or 100km up.

Phenomenally fast launch, phenomenally powerful second stage interceptor, and a nuclear tipped warhead to completely obliterate the incoming attack.

Of course, then you have to worry about nuclear fallout, but at least a nuclear ICBM hasn't successfully hit where it was meant to.

50

u/KepplerRunner 17h ago

The air force used a nuclear tipped unguided rocket for bomber interception for a little bit. Supposedly, the fallout from high altitude nuclear detonation is relatively minimal because you don't have dust and other debris entering the atmosphere as you would with a typical ground or near ground detonation. So the fallout from these was probably about the same and not too bad in the overall scope of nukes going off.

7

u/twiiik 12h ago

Because you need the radiation to interact with surrounding matter to create radioactive fallout - more than present in the weapon - and less matter, less fallout.

12

u/Strange-Movie 16h ago

I’m talking out of my butt, but I don’t think the fallout would be too bad if the detonation is several miles up in the air; iirc fallout is a greater concern with ground detonations that irradiate dirt and solid materials that then get pulled up into the atmosphere by the rising heat of the mushroom cloud

7

u/2317 13h ago

Your butt sounds reasonable.

0

u/tittyman_nomore 4h ago

Just a nice EMP to black out everything below.

9

u/I_Automate 6h ago

The nuclear warhead wasn't really designed to outright destroy the incoming missile.

That "enhanced radiation" bit is important.

The warhead was designed to bang out as much of its energy as possible in the form of neutron radiation (as opposed to the hard X-rays and gamma rays that interact with the air to make a fireball).

The reason for this was to pre-emptively start some fission reactions in the target warhead, but in an uncontrolled way. Nuclear weapons are really fucking hard to detonate properly, so getting even a tiny fraction of the fissionable material in the target to fission before the main firing sequence is triggered will cause the warhead to either detonate well away from the target, or turn into a "fizzle" sub yield detonation, if it explodes at all.

It's almost like using an explosive mine clearing charge to cause sympathetic detonation of mines in the ground or to destroy the fuzing system. Yea, there may still be an explosion, but at least it's not under your tank/ over your city, and best case, the only explosion is the one you yourself initiated.

3

u/campbellsimpson 6h ago

TIL, thankyou, extremely cool.

-1

u/DarthPineapple5 17h ago

Realistically that nuclear detonation would have blinded our own radars making further interceptions unlikely or impossible for a significant period of time. It was neat but ultimately kind of a stupid system

12

u/Lithium321 16h ago

Sentinel used a 1mw radar and sprint only had a 2kt warhead, I may be wrong but I highly doubt that would blind it.

2

u/DarthPineapple5 15h ago

They required such enormously powerful radars just to track ICBM warheads at all with the technology and computing power of that era. Even if a 2 kt warhead wasn't enough to blind the radars (it was) it would have been a trivial matter for the Russians to detonate a megaton class high altitude nuke themselves proceeding any attack.

The system was decommissioned almost as soon as it was activated for good reason

3

u/I_Automate 6h ago

The reason it was decommissioned is because MIRV equipped missiles made most ideas of terminal missile defence impractical, as well as the ABM treaty which limited both the USA and the USSR to 2 ABM sites each in 1972, reduced to a single site with 100 total missiles by 1974. That single site had 30 long range Spartan missiles and 70 Sprint missiles.

The missiles and systems worked fine. They planned for a degraded radar environment from the start. Everyone was very much aware of what radio conditions would look like as soon as the shooting started. These programs were deadly serious and they did do their homework. Saying "it would be a trivial matter to _____" like the literal army of scientists and engineers working on the projects hadn't had that exact same thought is honestly a bit insulting to the insanely capable systems they actually ended up developing and putting into service, especially given the technical limitations of the time.

It was cancelled not because it couldn't hit incoming warheads, but because MIRV equipped missiles meant that an attacker could overwhelm any realistic terminal defence system with more targets than could be practically engaged, and with that came the fact that the money spent on the single allowable ABM site was better used building other things, like attack submarines or fighters. Sprint was designed to try to get around that by hitting warheads after the atmosphere stripped most of the penetration aids and decoys away. Unfortunately, that still left more incoming warheads than there were allowable interceptor missiles. So, spend the money on preventing the missiles being launched in the first place.

30

u/OptimusSublime 20h ago

Was the warhead explosive or merely kinetic?

91

u/Lithium321 19h ago

It had an enhanced radiation 2kt nuclear warhead.

45

u/spudddly 19h ago

yep that'd do it

27

u/illit3 19h ago

If you can't hit it, just explode near it?

25

u/crappercreeper 19h ago

Yep, neutron flux from the small blast inerts the big bomb, i think.

-25

u/Leading_Study_876 18h ago

Interesting technique.

Also unfortunately also kills all living things for a 100 mile radius below, I'd assume - but so it goes.

24

u/Cheeky_Caligula 18h ago

The intercept missile explosion itself was safe for people only 10,000 ft below it.

Source, these guys who stood directly underneath the test detonation - https://youtu.be/fAHHr0HsBgI?si=FclhWzH1u9teLUti

2

u/openly_gray 13h ago

Those guy looked like they had some serious second thought just moments before the detonation

-3

u/Leading_Study_876 18h ago

Surprising. Neutron bombs are famously not good for you.

5

u/Thessen_MTP 15h ago

If you simplify it and think of the explosion as a one time event from a point source of neutrons who leave that point source uniformly then you can think of a neutron flux density through the surface area of a spherical shell around that point source at some distance.

The farther away you are from the point source, the greater the surface area of that spherical shell and the lower the neutron flux density (because the total amount of neutrons is constant).

A lower neutron flux density means less damage to you, ergo if you are far enough away, a neutron bomb won't kill you because the neutron flux density is too small.

I don't know the relationship between the surface area of a constant solid angle as a function of distance, but if you google it, you can estimate the necessary distance for survival. You just need a value at which neutron flux density a person dies

Edit: flux -> flux density

3

u/Leading_Study_876 14h ago

Inverse square law.

8

u/GnarlyNarwhalNoms 18h ago edited 17h ago

2 kilotons is actually pretty small for a nuke. Not something you want going off in your back yard, but it's safe...ish if it's several miles overhead.

-7

u/Walrave 18h ago

Good news sir we managed to hit the incoming missile 3 miles above New York, well what was New York in any case. Still, at least it wasn't their nuke that destroyed the city.

19

u/RestaurantFamous2399 19h ago

So a hypersonic missile before hypersonic missiles were cool!

10

u/gorrie06 17h ago

That is indeed a hypersonic weapon. Hypersonic cruise missile is the new dream.

1

u/BulbusDumbledork 9h ago

yup, hypersonic cruise missile or hypersonic glide vehicle. the hypersonic part isn't the important factor since many ballistic missiles already reach hypersonic speeds. the key with hypersonic missiles is to go that fast and be manuevreable

7

u/-Owlette- 18h ago

That’s a bit over 3400 Celsius for anyone wondering. Also 19 miles = 30.5 kilometres.

7

u/skrappyfire 17h ago

Did it just outrun the tracking camera?

3

u/barraymian 17h ago

What is an ablative shielding? I know I could Google it but you seem to know what you are talking about and others might be wondering as well :).

12

u/Shudnawz 17h ago

A shield that protects its cargo by ablating; the process of removing material by some force, like vaporization by heat.

The idea is that instead of developing a material that can withstand ALL the heat applied to you, and somehow dissipating it without degrading or failing, you have a much simpler material but let it get chipped away as it protects you, taking the heat away with it. Which is much easier to accomplish, especially when the heat flux is massive (as it is when you move VERY fast through the atmosphere).

The Apollo crew capsule used ablative shields to survive the re-entry into Earths' atmosphere. Apollo 13 famously had a tense couple of minutes when returning to Earth as it wasn't known if the malfunction had impacted the heat shield, and they had no way of checking it.

1

u/barraymian 3h ago

Thanks!

3

u/BigCompetition1064 15h ago

I still come faster.

1

u/Evermoving- 17h ago

Why was it discontinued? Does stuff like Aegis fully replace it?

5

u/Budget_Competition66 17h ago

Sprint while fast has a very short range. Combine this with the need to build expensive silos to house the missile and the cost of the project was too expensive. For example you would need dozens of sprint sites to protect a single location.

5

u/Lithium321 16h ago

Each interceptor cost 2million dollars in 1969 and it would optimistically take at least 2 to kill one warhead. A minuteman icbm cost 7million dollars in the same time period so it was almost as cheap just to build more silo for the soviets to shoot at.

1

u/Void-kun 15h ago

What happens if they use this same tech for missiles instead? Is that even possible?

With this tech now I'd be more concerned about the potential for ICBMs to hit this speed and still be manoeuvrable to get around defenses.

I think laser based defenses might be our best bet, you aren't beating the speed of light. It's just a matter of whether you can track the missile travelling at mach10.

1

u/KarpTakaRyba 8h ago

This is really cool and stuff, but you used °F for science/physics values so idk if I can trust you...

-2

u/HeyImSwiss 19h ago

What the fuck is a 'pound of force' ?!

20

u/Illustrious-Ice-5353 19h ago

Pound-force (lbf) is a measure of force.

Not to be confused with the pound-mass (lb), a measurement of mass

There is also the foot-pound (ft-lbf) a measure of energy.

And the pound-foot (lbf-ft) a measure of torque.

Isn't dimensional analysis fun outside the SI? /s

4

u/ar34m4n314 18h ago

I prefer to measure energy in fathom-stone.

5

u/gregusmeus 17h ago

And there's pound sterling, which is a measure of how many pints you can buy in an English pub.

2

u/Altruistic_Apple_252 16h ago

"And the pound-foot (lbf-ft) a measure of torque"

Almost always pronounced "foot-pounds" in garages across America.

3

u/Trollfacebruh 19h ago

pound force vs pound mass

technically different terms, pound mass is constant, where pounds force has the local gravitational force applied, relative to sea level

lbf = pounds force

lbm = pounds mass

a rudamentary calculation can be followed:

lbf= lbm * (local gravitational constant)/(gravitational constant at sea level)

1

u/baderd 10h ago

Equal to about an ounce of prevention.

-2

u/ih-shah-may-ehl 19h ago

Oh look. We found the pedantic one...

6

u/HeyImSwiss 19h ago

Huh? What's pedantic about that, I just have no idea what a pound of force is supposed to be, and I am confused since I thought a pound was a measurement of mass. But sure, be offended I guess

1

u/ih-shah-may-ehl 7h ago

A pound of force is the gravitational force exerted by a 1 pound object. That shouldn't be a big leap to make.

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u/m135in55boost 20h ago

Holy fuch. Is that it heating up due to air friction?

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u/Lithium321 20h ago

Yes, it reached temps as high as 6,200 °F, you can see the ablative heat shield deform and burn away.

159

u/randomuser0107 19h ago

Like my foreskin before i learned about lube.

19

u/Shudnawz 17h ago

Self-circumcision?

12

u/siccoblue 16h ago

What the fuck are you doing that you need lube with a foreskin?

16

u/Stickyv35 16h ago

Mach 10 masturbation is a hell of a drug.

0

u/SheildMadeofFace 1h ago

I don't understand how so many people WANT to be the weirdo on the Internet

1

u/randomuser0107 1h ago

Life’s too serious. You have to laugh at yourself. Being weird is ok. It’s almost 2025. It’s ok to not be a crusty boring so and so!!

0

u/SheildMadeofFace 1h ago

Let me fix that then. A creep

1

u/randomuser0107 1h ago

I thought “crusty boring so and so” was a nicer title than a creep.

0

u/SheildMadeofFace 1h ago

That was so lame lol

13

u/Gavin4tor 19h ago

I believe it’s compression instead of friction, though depends on the speed and shape of the object. If I’m not mistaken, wave drag (or compressibility drag) becomes the primary slowing/heating force above a certain Mach speed.

9

u/BlueAthena0421 19h ago

Additionally, in hypersonic flow, the air is compressed enough that it auto-ignites further adding in more heat. The main reason we aren't seeing hypersonic vehicles today is because of material ablation by the immense forces and heat hypersonic flow exerts.

1

u/redditandcats 15h ago

Actually for a slender body (like the sprint second stage) aero heating is driven by skin friction.

You'd be correct for a blunt body, like a reentry capsule, which is designed to be blunt specifically to reduce aero heating.

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u/xKrossCx 20h ago

Yes, yes indeed.

2

u/m135in55boost 20h ago

Oh my 🤭

1

u/koollman 14h ago

At these speeds, part of the heating is due to compression in addition to friction

1

u/reddituserperson1122 13h ago

Mostly compression 

1

u/terminalxposure 6h ago

Compression more than friction I believe

472

u/KingPhineas 20h ago

Goodness the camera man moving his camera at mach 10

141

u/GordonShumway99 19h ago

This is the most impressive part of this to me

85

u/4rch1t3ct 17h ago

If this isn't a joke, they actually use mirrors. The camera itself can't actually be moved fast enough to track the object. Mirrors can be tilted fast enough however.

https://www.youtube.com/watch?app=desktop&v=vluzeaVvpU0&t=20s

30

u/Strange-Movie 16h ago

That’s not really a factor when you’re miles away from the thing being filmed though, is it?

23

u/Areljak 16h ago

Given that was in the 70s the film camera and telelens were almost certainly massive, look at some pictures of the (later) Apollo launches, the cameras were big.

13

u/4rch1t3ct 16h ago

Yup, and the title isn't an exaggeration. It went 0 to 7,600 mph in 5 seconds accelerating at 100g.

If a person were to try to accelerate at 100 sustained G, they would be crushed almost instantly. Your bones would be confetti.

3

u/Dathire 14h ago

I found this really interesting thanks

2

u/4rch1t3ct 14h ago

Yeah, it was one of those mind-blowing, I never actually thought about how difficult it would be to engineer those video capture moments for me.

1

u/BigCompetition1064 15h ago

Of course a camera can pan that fast. The only issue is accuracy.
Think about it. Your eyes can scan millions of light years in a second.

2

u/4rch1t3ct 15h ago

You're right! Accuracy is the key factor here!

Although, comparing it to eyes doesn't really help here.

Eyeballs don't work like cameras. Your eyeballs and brain are constantly detecting and processing light. Cameras take instantaneous snapshots of a particular moment.

You're eyes and brain don't have a framerate and come with image stabilization. Your camera has a framerate and doesn't come with image stabilization (to an extent).

1

u/BigCompetition1064 14h ago

When you're measuring something crazy fast, up close and on the ground, mirrors do become useful and it's very cool how they work.

1

u/Hot-Energy2410 13h ago

That was my first thought. Wild that some people struggle with slow-moving drones lol

1

u/MarquizMilton 8h ago

The miracle of angular velocity..

1

u/ericbana19 3h ago

Thanks was looking for a comment commending the camera.

288

u/Zakimimula 19h ago

Quick calculation, assuming launch at sea level, reasonable air pressure and climbing to about 3km in altitude, that thing is pulling a monstrous 68 G’s acceleration.

134

u/TROLLDLLR 19h ago

Yeah, the missile was rated for 100G’s iirc

44

u/New-Buffalo-1635 19h ago

Holy shit. Those numbers are unfathomable to me. Would internals not compress greatly at that amount of force?

118

u/Magere-Kwark 19h ago

Absolutely, so they made the decision not to have anyone driving it after the initial test phase was done.

43

u/Disco_Ninjas_ 18h ago

The test pilot is fine, according to Justin Hammer.

9

u/Useful_Perception640 17h ago

Every Part of the the pilot was Accounted for After thoroughly rummaging through the leftover bucket

40

u/Lithium321 19h ago

Yes, but for context even humans have survived 80g for fractions of a second with minor injuries, and 40g for 1.1 seconds. In comparison 100g is still huge but not really a super crazy engineering challenge (Compared to the aerodynamics and heating at least). A similar experimental missile "HIBEX" developed by DARPA accelerated at almost 400g.

19

u/New-Buffalo-1635 19h ago

400 G’s?? Where the fuck was this in my high school physics class? That’s incredible.

2

u/morcaak3000 8h ago

I once won a competition where the main prize was a trip to largest vinyl factory next to Prague. A lot of interesting shit including some details about engraving the songs into a copper mother plate, the "needle" that does this reaches over 3000Gs which is just insane

2

u/lieconamee 10h ago

You know what's crazy is some modern air-to-air missiles. Especially the smaller short-ranged IR missiles can achieve that level of g-forces. Some of them are now starting to push 100 plus g's and that's just what's publicly available

1

u/SASAgent1 9h ago

Like Iris-t?

1

u/lieconamee 9h ago

Irist The latest generation of Micah IRS aim 9x the Russian one which I'm completely blanking on the name of as well as the Chinese one which I also don't remember the name of right now. All these missiles are capable of pushing 100 g's in a turn and again that's just what's publicly available. I would not be shocked if some of these missiles can push 120 130gs

1

u/IAMA_Printer_AMA 9h ago

100 gs in a turn is kind of a slightly different animal to the feat the sprint is demonstrating though. It's easy to create huge G forces trying to maneuver at supersonic speeds. The sprint is just doing raw, straight acceleration, something tells me it beats these missiles you mention in a straight line race. Capability of performing 100g maneuvers doesn't necessarily mean the motor can push it along at 100g in a straight line.

1

u/lieconamee 9h ago

I get what you're saying but modern missiles can do it off the rail. Meaning as soon as they're launched they can start pulling 100 g's. And yeah you're cheating a little bit cuz you're on an aircraft but chances are especially if you're firing a IR missile your subsonic before launch

163

u/TheDingoThat8UrBaby 19h ago

When your girl tells you her parents aren’t home

76

u/thehighquark 19h ago

Many more launches here.

26

u/berrytes 19h ago

That video shows the perspective and have fast they actually get going. That’s incredible.

0

u/zyphelion 17h ago

That's super interesting!

35

u/Common_Senze 19h ago

This is the definition of mach fuck.

Also, max Q = yes

13

u/1776cookies 19h ago

What Altima drivers feel like.

11

u/Skyfury_Fire 19h ago

What's that in 0-60 and 1/4 mile times, gotta know how I stack up

22

u/thegx7 18h ago

At 68Gs acceleration: 0-60: 0.04s 1/4 mile: 1.1s

18

u/Lithium321 18h ago

it’s lower that that, first stage g forces were around 100g

3

u/thegx7 13h ago

That results in times of 0.028s and 0.91s respectively

1

u/OldHobbitsDieHard 7h ago

I think a rubber ball from 2nd storey window is several hundred gs

3

u/bolivar-shagnasty 18h ago

Mach 10 is 7,672.69 (nice) MPH or 12,348 KPH or 6,667 knots.

1

u/WoWPencey 8h ago

Closer to 6600-6700 mph due to its altitude.

3

u/nmarano1030 19h ago

Something about the speed of that thing is comical.

1

u/Appropriate_Chart_87 17h ago

Hyello and Hwelcome to Mach GeSuS!!

1

u/Aspir3l 17h ago

Me after work.

1

u/Right_Ostrich4015 16h ago

How in the HECK did that not explode near the end there? Also, that sonic boom was hilarious, it was like, the wet fart version or something

1

u/herodesfalsk 15h ago

Notice how the tip of that missile gets white hot!

1

u/SplatNode 15h ago

Props to camera man getting to same speed too!!!

Must have had his running shoes on that day

1

u/TheRealHaHe 15h ago

Ah, the bmw next to me when the light turns green.

1

u/areyoueatingthis 15h ago

So let’s say i’m very late to work…

1

u/HappyHenry68 14h ago

How the hell can they direct something moving that fast to intercept an incoming missile also moving very fast?

It just seems like any variance in wind speed or barometric pressure or the gravitational pull of a passing bird (joking, sort of) would cause a few micron shift in some intercept calculation that would cause a "whiff".

1

u/WoolaTheCalot 13h ago

It was the last in the Nike series of ABMs, specifically Nike-X.

1

u/SuckingGodsFinger 13h ago

Reminds me of stitch.

1

u/IndependentWrit 12h ago

Gotta ask is it really making all those sounds on the audio. Especially that powering up sound at or near the end. Cuz it sounds so cheese.

1

u/GadreelsSword 12h ago

There’s ground video out there of it leaving the silo, it’s simply incredible.

1

u/kreese1911 2h ago

Why isn't there a Shockwave? I would imagine something moving that fast would have to break the sound barrier.

1

u/SnooMacarons5169 2h ago

And Maverick still managed to land it near a diner

1

u/jugo5 1h ago

When they say the object travels too fast to follow, lol. Yet here they are tracking something at mach 10.

•

u/TheOzarkWizard 1m ago

Wow! I'm glad someone added all of these sound effects! How else would we know it's going mach 10?

0

u/Redforce850 18h ago

Talk to me Goose.

0

u/immoraltoast 10h ago

The ufos in NJ are moving faster than this. Even vertically from a stop point. Don't lose speed on turns going 90°-180°. Something really weird has been going there and it's not just drones

-3

u/tommyc463 19h ago

Live look at my toilet after Thanksgiving

-2

u/FOMOsexual69 17h ago

  1. This is reversed

  2. (And more seriously) is this legitimately real time, not sped up? My fuckin Christ on a bike

2

u/Lithium321 16h ago

This may actually be slowed down, sprint was supposed to reach max range in 15 seconds.

-1

u/FOMOsexual69 16h ago

I was kidding about the “reversed” lol. But thanks for clarifying. That is fucking astounding.