Spartan/Sprint ABM and Derivatives

[KJ_Lesnick]

I'm curious about a couple of things I've read on this particular thread: I've tried to keep my questions concise for brevity purposes

I. Regarding the idea of ABM's being destabilizing
My assumption would be, from what I've read on this topic, that a missile shield is only destabilizing when it is actually capable of repelling nearly all or all ICBM attacks: Am I right or wrong?

II. US Army & ABM Operations
Not that I object to the US Army handling ABM operations: I am curious why it wasn't covered under NORAD's air-defense mission?

III. Nike Improved-Spartan
I have the following questions (provided they aren't classified of course)

....1. The Improved Spartan had a range of around 2,000 miles due to superior acceleration and the ability to shut down it's motor; then re-activate it at a later date: I assume it was guided initially by the MSR, then used it's own IR-seeker for the terminal run to target?
....2. Was the IR-seeker similar to the types used on current air-to-air missiles, or a more sophisticated IR-Electro-Optic system?
....3. The Improved Spartan depended on the knowledge that the enemy fired missiles pretty much from the ground (it sounds like it in the excerpts): Was this provided by Satellites, Over-the-Horizon Radar, or both?
....4. Was the reduced warhead yield solely to give it greater range, or merely because it was unnecessary?

IV. Martin-Marietta Sprint
I have the following questions, provided they aren't classified

....1. Was the Sprint as intended, designed to defend only hardened targets, or population centers as well as hardened targets?
....2. How many g's could the missile pull?

V. Other Last-Ditch ABM-Systems

....1. I've seen pictures of the LoAD system: Does anybody have any information on it?
....2. Was the Boeing HiBEX used as the basis for the later Sprint II
....3. Was the likelihood of MaRV's a serious threat in reality (i.e did the fUSSR develop them) provided it's not classified?

VI. Fire-Control Systems

....1. If the missiles were fired fully automatically: Was there a human being in the loop to consent to the release of the weapons, to manually assign targets, or to self-destruct a missile if necessary?
....2. The computers used for the Sentinel & Safeguard consisted of multiple CPU's (this is from a site called http://www.nuclearabms.info ) which featured programming that allowed auto-reconfigurations on the fly in the event of the failure of a CPU, memory unit, console, as well as the ability to self-correct various errors/glitches: Would this (along with the ability to determine decoys from actual targets) qualify as early artificial intelligence?

 

[Yellow Palace]

I. Regarding the idea of ABM's being destabilizing
My assumption would be, from what I've read on this topic, that a missile shield is only destabilizing when it is actually capable of repelling nearly all or all ICBM attacks: Am I right or wrong?

My personal view is that it's stabilising, not destabilising.

That said, the theory behind the missile shield being destabilising is that if Orangeland is building an ABM system, Greenland's ballistic missiles lose their effectiveness. There's therefore a 'use it or lose it' effect, whereby Greenland has to strike before it loses the capability to overcome Orangeland's defences.

Greenland can spend money to develop ways to penetrate the ABM system, and Orangeland will respond by making the ABM system more capable. The offence:defence spending ratio is argued to be anywhere between 100:1 and 1:100 by proponents of one side or the other.

In the Cold War context, the US would have been less affected by Soviet ABMs than vice versa, since the US bomber force was capable enough to inflict serious damage whilst being immune to ballistic missile defences. The Soviets were much more dependent on ballistic missiles.

II. US Army & ABM Operations
Not that I object to the US Army handling ABM operations: I am curious why it wasn't covered under NORAD's air-defense mission?

It was. The North American Air Defense Command is, and was, a joint command including elements of the US and Canadian air forces, the US Army's Air Defense Command, and US Navy units at times.

 

[Rickshaw]

I'm curious about a couple of things I've read on this particular thread: I've tried to keep my questions concise for brevity purposes

I. Regarding the idea of ABM's being destabilizing
My assumption would be, from what I've read on this topic, that a missile shield is only destabilizing when it is actually capable of repelling nearly all or all ICBM attacks: Am I right or wrong?

Wrong. Anything that potentially prevents destruction of the ABM owner's own assets means that it will either be safe from a first strike or second, retaliatory strike. An ABM defence doesn't have to be 100% effective, in fact it doesn't have to be effective at all, however it has to be perceived as effective. Once the perception is planted and grows, the perceivers will act upon the assumption that it is effective. So, the first use imperative will grow, on both sides of a strategic balance. The owners, to destroy the potential threat that the other sides' ICBMs represent and the opponents' to ensure that while the ABM system is still being built and not yet operational, so as to prevent it from rendering it's ICBM forces obsolete.

This happened with the SDI "Star Wars" system. The US hyped it, with lots of pretty animations and drawings showing how it would destroy the nasty, incoming Soviet missiles and RVs. The Soviets fearful that their missiles would be rendered obsolete were forced to try and build their own (or more ICBMs to swamp SDI). No SDI system was built but the fear was sufficient to see the Soviets try and build the means of either matching or defeating it. The real danger was if the hawks had managed to gain power, that they would have seriously contemplated a first strike, rather than see their missiles rendered obsolete the moment the system was operational.

Remember, the Cold War was as much as about perceptions of capabilities as it was about the real capabilities themselves. Both sides often acted on faulty, flawed intel. In the US there was the "Bomber Gap", the "Missile Gap" and the "Window of Opportunity" which were used for domestic political gains. In the fUSSR there were similar scares about US capabilities, which led up the Able Archer '83 scare. The fUSSR was no more monolithic than the US and there were debates within the Politburo as to who or what should be believed, just as there were in the US. Hawks versus Doves, etc. Cold War Warriors who saw a capitalist under their beds, just as those in the US saw Communists under theirs.

 

[KJ_Lesnick]

Wrong. Anything that potentially prevents destruction of the ABM owner's own assets means that it will either be safe from a first strike or second, retaliatory strike. An ABM defence doesn't have to be 100% effective

Of course not -- even losing half your population is better than losing them all.

in fact it doesn't have to be effective at all

A bluff, it works so long as your opponent believes it.

So, the first use imperative will grow, on both sides of a strategic balance. The owners, to destroy the potential threat that the other sides' ICBMs represent and the opponents' to ensure that while the ABM system is still being built and not yet operational, so as to prevent it from rendering it's ICBM forces obsolete.

If what I read is correct: What you described sounds exactly like the definition of destabilizing

 

[Richard N]

A picture of the upper half of a Nike Zeus A from "Rockets of the Armed Forces" by Erik Bergaust, 1966. Comparing it to the size of the man in the sling chair, it is a very large missile.

 

[sferrin]

Interesting footage of Sprint and Spartan. Hadn't seen this clip before.

 

[phil gollin]

.

This might be interesting about the other side ;

http://www.amazon.co.uk/dp/1624103499/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=U0BWZDEY7NLX&coliid=I32BTQ6VJERCRH

.

 

[sferrin]

.

This might be interesting about the other side ;

http://www.amazon.co.uk/dp/1624103499/ref=wl_it_dp_o_pC_nS_ttl?_encoding=UTF8&colid=U0BWZDEY7NLX&coliid=I32BTQ6VJERCRH

.

http://arc.aiaa.org/doi/abs/10.2514/4.103506

 

[RyanC]

According to this:

http://www.dtic.mil/dtic/tr/fulltext/u2/a017242.pdf

---------------------

Development of SPRINT II began in 1972 -- it was to be a cheaper improved performance version with 65% commonality with SPRINT I.

SPRINT II CHANGES: Changes brought about by the Site Defense role of providing low altitude defense of Minuteman sites against an increased ICBM threat included Integrating the missile guidance set and autopilot into an integrated circuit Missile Guidance Set (MGS) which would increase reliability and accuracy at a reduced cost. Advances in semiconductor technology made it possible to combine the SPRINT autopilot and missile guidance set into one integrated assembly capable of performing in the SPRINT II environment.

----------------------

Development began in 1974 of yet another (tm) derivative, called Improved Sprint II Missile Subsystem (ISMS) which would be a "significantly enhanced performance capability SPRINT derivative".

Improved Sprint II Missile Subsystem (ISMS) CHANGES: The ISMS improvement includes a change from the analog MGS to a digital missile controller set (DMCS). The DMCS yields substantial improvements over the SPRINT II MCS in the areas of radiation order limits and reduced trajectory deviations, digital control circuits, improved circumvention scheme, and limited inertial navigation. This later capability is provided through the strap down inertial system using a laser gyro together with the on-board digital computer. The inertial navigation technique provides a large system benefit via a reduction in radar scheduling. Retention of vital system variables such as gains, steering commands, discretes, missile mode logic, and major filter state variables, enables a major reduction of radiation induced trajectory deviations. Restoration of the DHCS to normal operation is achieved more quickly and completely than in SPRINT II because the DMCS digital circuits have faster recovery times than the SPRINT II analog circuits.

Some data on SPRINT was also included. They are:

"The development philosophy for SPRINT was "a tactical missile from a tactical silo with the initial design." Although many changes occurred during the 13 year development, the first flight test missile (launched successfully on November 17, 1965) is not greatly different than the 70 that are being deployed at Grand Forks, North Dakota.

At the end of the Reliability Demonstration series (flown at both WSMR and KMR), the SPRINT subsystem had completed 51 flight tests with no electronic failures. Each missile contains about 9,000 electronic piece parts and the Ground Support equipment contains an additional 5,000 parts for a total of just over 700,000 parts tested with no failures. This highly successful flight test series demonstrated the flight reliability of the SPRINT subsystem."

...

The SPRINT I analog autopilot was the last major assembly to be qualified for tactical use.

-----------------

So basically, looks like:

1.) SPRINT I was analog.

2.) SPRINT II was aimed at cost reductions by making 2 circuit boards into 1, etc; similar to how you have today's PS4 (2013) and PS4 Slim (2016) with some around the edge performance increases.

2.) IMPROVED SPRINT II was to be *the* major change, going to a fully digital guidance system, allowing for a much "harder" missile against radiation, and significantly reducing the workload of the radar/computer combination on the ground, because it could now be commanded to fly a preset course in between guidance commands, as opposed to having to constantly track/guide it.

 

[RyanC]

http://www.dtic.mil/dtic/tr/fulltext/u2/a210006.pdf

Apparently the HEDI KITE test demonstrator in the late 1980s consisted of surplus SPRINT components:

Flight one (KITE 1) will be a basic test of the ability to safely and accurately launch the booster vehicle. The booster vehicle (the first- and second-stage rocket motors from a SPRINT missile) will be launched along a trajectory with an azimuth of 330 degrees (Figure 1-3) from Launch Complex
37.

...

Flight two (KITE 2) will be an experiment in which the HEDI seeker will track an IR
target flare to measure seeker performance. The target flare will be fired from the
vicinity of the Small Missile Range (Figure 1-3) using a 155-mm Howitzer, whereas
the HEDI KITE 2 vehicle (a first- and second-stage SPRINT missile plus the HEDI KV)
will be launched from Launch Complex 37 along the same trajectory as KITE 1

...

Flight three (KITE 3) will be an actual intercept test, featuring a HEDI KV engaging a
surrogate RV (attached to an ARIES booster), which will be launched from Launch
Complex 36, just west of Launch Complex 37 (Figure 1-3). The latter test will
include evaluation of the seeker system, fusing performance, and overall evaluation of
the performance of the conventional warhead. The HEDI KV will be launched from
Launch Complex 37 along the same trajectory as KITE 1

HEDI XTV was to have an improved Kill Vehicle (KV) and a new booster to replace the SPRINT booster used in HEDI KITE tests.

---------------

http://www.astronautix.com/h/hedi.html

KITE was a rail-launched two-stage test vehicle using surplus Sprint ABM motors (Hercules X-265 and a Hercules X-271). A KKV (Kinetic Kill Vehicle) fitted with an infrared seeker, was protected under a shroud during the initial high-speed 200G acceleration through the lower atmosphere.

KITE-1 on 26 January 1990 was followed by the failed KITE-2 on 23 September 1991 and the final KITE-2A on 26 August 1992. The operational HEDI program had been cancelled in 1992, but the KITE flights tested various system components like seeker, guidance and control systems. No actual intercepts were attempted.

 

[A Tentative Fleet Plan]

I have no idea if this should be here, but here is an image of the vertical-silo (as opposed to the horizontal MPS system) Sentry radar.
From here

 

[KJ_Lesnick]

If it's not classified: The piston charge used to launch the missile used an explosive charge, correct? That must have produced some serious acceleration rates. From what I was told, the missile was supersonic by the time it left the silo...

 

[stealthflanker]

I think it's more on the propellant side. rapid burning + high fuel mass ratio can do wonders to acceleration.

 

[Zoo Tycoon]

Sprint was piston ejected, a slower burning composite propellant based on Ammonia perchlorate acting more as a gas generator. Pretty sure it was not supersonic an exit;- needed to be at lower inertia to complete it post silo/pre boost manoeuvre, the heavy piston was arrested by an impact with lead which briefly flowed in a damper thus absorbing the KE.

The Spartan was rail launched and was probably supersonic at silo exit. These sort of acceleration in missile are not unusual;- at launch, the Sea Dart was supersonic when it had travelled approx its own length;- 14ft.

Loads of information about the Sentinel system development on this link.

ABM R & D at Bell Labs: PDF Files

PDF Files for ABM Research and Development at Bell Laboratories: Project History

srmsc.org

 

[sferrin]

Sprint was piston ejected, a slower burning composite propellant based on Ammonia perchlorate acting more as a gas generator. Pretty sure it was not supersonic an exit;- needed to be at lower inertia to complete it post silo/pre boost manoeuvre, the heavy piston was arrested by an impact with lead which briefly flowed in a damper thus absorbing the KE.

The Spartan was rail launched and was probably supersonic at silo exit. These sort of acceleration in missile are not unusual;- at launch, the Sea Dart was supersonic when it had travelled approx its own length;- 14ft.

Loads of information about the Sentinel system development on this link.

ABM R & D at Bell Labs: PDF Files

PDF Files for ABM Research and Development at Bell Laboratories: Project History

srmsc.org

Spartans silo lid was actually welded shut. A shaped-charge had to cut it before pistons pulled it open.

(1:25)

 

[KJ_Lesnick]

Sprint was piston ejected, a slower burning composite propellant based on Ammonia perchlorate acting more as a gas generator.

That can burn pretty hot, from what I remember: The space shuttle used a rubberized mix of ammonium perchlorate and aluminum oxide, and it produced temperatures of around 8000F (4400-4500C). If I recall the overall thrust produced by the boosters was around 3.3 million pounds of thrust and, with a velocity that hot, you'd probably see quite a respectable expansion velocity (I saw some footage of the PEPCON plant getting blown sky high and remember distinct shockwaves seen).

Pretty sure it was not supersonic an exit;- needed to be at lower inertia to complete it post silo/pre boost manoeuvre

If you did a rail-launch, I figure acceleration would be slower (after all you'd have the rocket thrust and drag only; with the piston you have the force of the piston kicking you up to speed before the motor even engages) and, from what I remember -- both engines had about the same overall thrust, ironically.

That said, I do remember seeing the footage of the initial maneuver -- Boy, that was a tight turn!

These sort of acceleration in missile are not unusual;- at launch, the Sea Dart was supersonic when it had travelled approx its own length;- 14ft.

Depending on exact speed, if I were to use 1200-1600 fps as a reference point, that would produce acceleration loads of around 1600-2850 G.

 

[Gator62]

Sprint was piston ejected, a slower burning composite propellant based on Ammonia perchlorate acting more as a gas generator. Pretty sure it was not supersonic an exit;- needed to be at lower inertia to complete it post silo/pre boost manoeuvre, the heavy piston was arrested by an impact with lead which briefly flowed in a damper thus absorbing the KE.

The Spartan was rail launched and was probably supersonic at silo exit. These sort of acceleration in missile are not unusual;- at launch, the Sea Dart was supersonic when it had travelled approx its own length;- 14ft.

Loads of information about the Sentinel system development on this link.

ABM R & D at Bell Labs: PDF Files

PDF Files for ABM Research and Development at Bell Laboratories: Project History

srmsc.org

Spartans silo lid was actually welded shut. A shaped-charge had to cut it before pistons pulled it open.

(1:25)

I’m not sure the missile and exhaust cell cover halves were welded together. My airframe data book shows a tie strip that is bolted to a cover that captures both sides and is cut by redundant Confined Detonating Fuses (CDF).

 

[sferrin]

I’m not sure the missile and exhaust cell cover halves were welded together. My airframe data book shows a tie strip that is bolted to a cover that captures both sides and is cut by redundant Confined Detonating Fuses (CDF).

Sounds more likely.

 

[Grey Havoc]

SPRINT – The Unwanted Blog

 

[NMaude]

The space shuttle used a rubberized mix of ammonium perchlorate and aluminum oxide

Aluminium powder NOT Aluminium Oxide (That was one of the reaction products) as the powder was the fuel.

 

[T. A. Gardner]

Conical ABM missile made quite a stir in the 80's gossip's then quickly faded from vogue. Wish I knew if any ever went into service and what became of them. Seems a few made to to museums I would love to pick one up from a remote desert aerospace boneyard....

Both Sprint and Spartan did go into service for a short time in the 70's. The Stanley R. Mickelsen Safeguard complex in N. Dakota was completed near Nekoma N. Dakota was completed in April 1975, declared operational in October, then shutdown in February 1976.
It had 30 Spartan and 16 Sprint missiles while operational.

This site was primarily to defend the US ICBM launch sites. Studies at the time showed that dozens of sites would be necessary to stop a full on ballistic missile attack and the nuclear weapons necessary to stop it were almost as bad as the nuclear strike would be. The problem at the time was available computer systems simply lacked the necessary speed and volume of calculation necessary to accurately intercept an ICBM except using large nuclear warheads to make up for guidance errors.

This was studied and even known all the way back into the late 40's when the first ABM studies were done. These were projects MX 794 Wizard, and MX 795 Thumper. Wizard was conducted by the University of Michigan and Boeing, while Thumper was done by GE. By 1948, Thumper was cancelled but Wizard continued.

Wizard slowly combined with Boeing's project MX 606 GAPA (Ground to Air Pilotless Aircraft--The USAF attempt to build a SAM) and would evolve into a long-range SAM program as MX 1599 BOMARC. By 1957 Wizard was cancelled in favor of the US Army's Nike Zeus program.

Most of the reason there were two competing programs had to do with the USAF - Army rivalry for control over various programs. One of the fallouts of this was Nike Zeus ended up being incapable of ABM defense due to limited range while the CIM-10 BOMARC being powered by ramjets to get the requisite range couldn't intercept ICBMs either.

 

[Zoo Tycoon]

The Sentinel systems fundamental flaw is often reported as its inability to deal with a combination of MIRV’s, decoys and low trajectory SLBM’s.

As for what happened to the Sprints ? Well a few were modified and fired as part of the Kite Hedi program. Most of the first stage motors produced were used at the Holloman AFB to accelerate various payloads on their sled track. I believe a twin arrangement, fired into a Helium filled poly tunnel was used to set their all time record of Mach 8.6 ....which trashed the track in the process..... a seriously expensive business these mega speeds.

Spartan motors were stored for decades and then destroyed with controlled burns in the early naughties;-

View: https://m.youtube.com/watch?v=uHuTeOY-ca0

 

[NMaude]

As for what happened to the Sprints ? Well a few were modified and fired as part of the Kite Hedi program.

Weren't a few of the Sprint missiles converted to Arrow 1 prototypes for the Israelis back in the 90s?

 

[Zoo Tycoon]

Not heard that one, Arrow seems a little small by comparison although maybe a Sprint second stage only; do you have a reference ?

 

[Firefinder]

This has a wealth of sources and even better has reduct TMs for the Spartan and Sprint systems.

Index of /WW3/WW3_Documents/ABM_Bell

Apperantly the Spartan nuke was expected to be able to proxy kill the income warheads by burn out the electronics and fucking up the warhead itself via its radaition pulse*. If turn that will take care of the Decoys and at the time Mirvs pretty well since they had to get within the Spartan range before splitting up to Mirv and would be close enough that it wasn't consider that big of an issue.

Then the Sprint was apparently to have a fairly large kill radius again thanks to the radiation pulse and being a nuclear explosion in atmosphere basically.

With Decoys being consider none issue since these where area of effect weapons and not point, while the SLBM was also consider still a easy target for the Sprint.


*I have heard of this before with the AIM26 and Genie nuclear A2A weapons. How well does that pan out?

 

[sferrin]

The Sentinel systems fundamental flaw is often reported as its inability to deal with a combination of MIRV’s, decoys and low trajectory SLBM’s.

As for what happened to the Sprints ? Well a few were modified and fired as part of the Kite Hedi program. Most of the first stage motors produced were used at the Holloman AFB to accelerate various payloads on their sled track. I believe a twin arrangement, fired into a Helium filled poly tunnel was used to set their all time record of Mach 8.6 ....which trashed the track in the process..... a seriously expensive business these mega speeds.

Sprint motors were not used. Where did you see that they were?

846 TS Hypersonic Upgrade Program

The Air Force's 846th Test Squadron conducted a world record rocket sled test on the Holloman High Speed Test Track (HHSTT) at 0033 on 30 April 03. The sled obtained a velocity of 9,465 feet per

www.holloman.af.mil

"The sled was propelled by a four-stage sled train. A Super Roadrunner (SRR) rocket motor, developed specifically for the HUP program, powered each of the last two stages. The SRR motor produces 228,000-pounds of thrust for 1.4 seconds and only weighs 1,100 pounds. The maximum acceleration of the sled was 157-g's or 157 times the force exerted by gravity. When the payload impacted the target it had 363 megajoules of energy or the energy of a car impacting a brick wall at 2,020 miles per hour."

 

[Zoo Tycoon]

This has a wealth of sources and even better has reduct TMs for the Spartan and Sprint systems.

Index of /WW3/WW3_Documents/ABM_Bell

Apperantly the Spartan nuke was expected to be able to proxy kill the income warheads by burn out the electronics and fucking up the warhead itself via its radaition pulse*. If turn that will take care of the Decoys and at the time Mirvs pretty well since they had to get within the Spartan range before splitting up to Mirv and would be close enough that it wasn't consider that big of an issue.

Then the Sprint was apparently to have a fairly large kill radius again thanks to the radiation pulse and being a nuclear explosion in atmosphere basically.

With Decoys being consider none issue since these where area of effect weapons and not point, while the SLBM was also consider still a easy target for the Sprint.

Ref National Security Policy 1969-72 Volume XXXIV page 54 minute 16

“Spartan - Kill radius of 20miles (later said to be 12miles for a soft target, 4 miles for a hard target)”

I understand that SLBM’s present a difficult target because its low trajectory reduced reaction time. This combined with the burst black out time, atmospheric refraction from a MIRV attack created a particularly challenging environment.

 

[NMaude]

Not heard that one, Arrow seems a little small by comparison although maybe a Sprint second stage only; do you have a reference ?

I'll have a look however IIRC I remember reading it in an article in either Flight International or Aviation Week and Space Technology back in the 1990s.

 

[AN/AWW-14(V)]

 

[sferrin]

 

[sferrin]

Can't believe I missed this. Been waiting for DECADES to see it. Now we just need HiBex and the external burning Upstage.

 

[aferguson]

i have a couple of questions about the Sprint. I read that the tip of the nose could be deflected slightly to steer the missile in flight. My questions are: when the Sprint was in flight was the steering mechanism covered over by some sort of flexible cover? In many pictures of the Sprint, there is a very obvious gap behind the tip of the nose where steering mechanism is and then the smooth conical shape of the missile continues after the gap, but in launch pictures there is no gap of any kind.

Secondly, why was this steering by the nose tip needed? The 2nd stage had 4 small fins on it, why not just steer the missile with those?

 

[sferrin]

i have a couple of questions about the Sprint. I read that the tip of the nose could be deflected slightly to steer the missile in flight. My questions are: when the Sprint was in flight was the steering mechanism covered over by some sort of flexible cover? In many pictures of the Sprint, there is a very obvious gap behind the tip of the nose where steering mechanism is and then the smooth conical shape of the missile continues after the gap, but in launch pictures there is no gap of any kind.

Secondly, why was this steering by the nose tip needed? The 2nd stage had 4 small fins on it, why not just steer the missile with those?

Never heard that before. Any sources?

 

[aferguson]

I've read about the movable nose tip in several sources online. Here is a picture of a the mechanism on the Sprint in a silo,

https://upload.wikimedia.org/wikipedia/commons/a/a3/Sprint_nose.jpg

The caption for the picture is: "Close up of Sprint anti-ballistic missile nosecone in its silo. The nose would deflect slightly to steer the missile in flight."

 

[sferrin]

That surprises me a bit because Raytheon apparently got a patent for this later.

US6364248B1 - Articulated nose missile control actuation system - Google Patents

A missile nose is tiltable and rotatable relative to a missile body through the action of an actuator system. In an exemplary embodiment, the actuator systems uses two electro-mechanical actuators mounted co-axially and having the output shaft of one actuator fed through the shaft of the other...

patents.google.com

After looking through tons of pictures, that gap, where the umbilicals attach, is missing when it leaves the silo. Looks like the nose cap closes down right after they detach. Wondering if whoever wrote the wiki comment was just guessing.

 

[aferguson]

interesting....so are you saying that the nose on Sprint wasn't used to steer the missile, and the gap is simply there to attach umbilicals prior to launch? I read in more than one source that the nose of Sprint was used to steer the missile but it could be a case of sources copying the same mistake from each other, I suppose. To be honest, when the nose cone is down I don't see how it could tilt, which is why I asked if there was a flexible cover around the tilt mechanism, in my first post.

 

[Zoo Tycoon]

Probably the most comprehensive original source material that describes the Sprint systems makes no reference to nose cone steering;-

https://srmsc.org/pdf/004431p0.pdf

The cross section shows no control actuator in the nose section. While it might have been secret at the time of publication I doubt it;- the nose volume just isn’t big enough.

 

[NMaude]

I haven't checked it yet however the 2nd edition of the late Chuck Hansen's "Swords of Armageddon" CD-ROM should have some information in the section on the Sprint's W66 warhead.

 

[Download]

Super weird to join a forum looking for Sprint/Spartan info and find people discussing something you wrote the very day you join.

I wrote that comment about steerable noses. I don't recall where I heard it and you normally don't cite image comments on Wikimedia Commons. I recall something about how at very high supersonic speeds that fins aren't very useful for steering due to shock waves across the body, which is why ICBM MaRV concepts used steerable noses.

Feel free to snip that out of the image comment if you want.

Now on to why I joined: has anyone seen an image of the W66 warhead? Alex Wellerstein's silhouette is the best I have seen so far. Does anyone know the US Army designation for the warhead section on Sprint? It will be something like XM followed by a number then "atomic warhead section".

 

[NMaude]

has anyone seen an image of the W66 warhead?

To the best of my knowledge no declassified image has been released. The best source of information on the W66 is Chuck Hansen's "Swords of Armageddon, 2nd edition" CD-ROM.