Dec 272009
 

He came by briefly yesterday. Crappy photo taken through barely-open door… open it further than that, and he takes off like a shot.

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 Posted by at 5:08 pm
Dec 272009
 

Almost certainly the second most badass interceptor missile ever built, the SPRINT missile was one of the most bland looking. A cone 27 feet long and 4.4 feet in diameter, the SPRINT was nearly featureless except for four small control fins about halfway up. But what it lacked in aesthetics it more than made up for in performance:

1: Acceleration exceeded 100 G’s. This would turn a hypothetical passenger into paste.

2: Maximum speed was in excess of Mach 10, reached in about 5 seconds

3: As a result of the high speed at low altitude, drag and aerothermal heating were immense. The ablative nosecone got hotter than the core burning region of the rocket motors.

4: The warhead was a nuclear bomb. More specifically, an “enhanced radiation” (i.e. “neutron”) bomb of low kiloton yield.

The SPRINT missile was the second in a three-tier anti-missile system known as “Safeguard.” The first tier was the Spartan missile… itself impressive, in that it packed a two megaton nuke and was able to reach incoming targets up to 450 miles away, and 350 miles in altitude (it could be used to take out satellites). Spartan would be used to try to take out incoming missiles while still at some distance. But SPRINT would be used for those warheads that made it past Spartan… intercept altitudes from between 1500 and 30,000 meters. At these altitudes, the detonation of the SPRINTs own warhead would cause damage to soft targets on the ground; thus SPRINT was to be used to defend hardened targets such as ICBM silos.

The neutron bomb warhead would destroy incoming warheads not with blast, but with neutron flux. This would not only damage electronics, causign the warheads to either prematurely detonate, or not detonate at all… the neutron flux would do the fissile materials of the warheads themselves no good, causing the warheads to melt down or burst (though not detonate).

In order to get the high accelerations required for SPRINT, early research on the solid rockets led to some interesting concepts. A former co-worker of mine was involved in the early development in the early 1960’s. One of the more interesting motors tested used propellant that was not so much cast as it was *built.* Normal “composite” solid rockets use propellants such as ammonium perchlorate (an oxidiser that’s a powder something like fine salt, and something like fine flour), aluminum powder (the fuel) and a liquid rubber binder. Mix these all up in something like a giant cake mixer, throw in a catalyst that will cause the rubber to solidify, and pour into the rocket motor. Composite propellants are simple, cheap, reliable and fairly safe, but the burn rate – and thus maximum thrust – can be somewhat limited. “Double base” propellants are generally sportier. Nitrocellulose (AKA “guncotton” to all you Baltimore Gun Club fans) is mixed with nitroglycerine (yes, THAT nitroglycerine), which dissolves the nitrocellulose, and forms a gel; other chemicals cause the mixture to set up as a solid. Adding metals such as aluminum to the mix can increase performance. Double base propellants perform well and can have good, high burn rates. They can also decide to detonate just to be spiteful.

The early SPRINT motor that was described to me was a nitrocellulose/nitroglycerine motor with a difference. Rather than mixing the components and then pouring into the motor, the nitrocellulose powder was sifted into the motor a thin layer at a time. (The motor, conical in shape, was upside down, forming a “cup,” with a metal mandrel in the core. The powder would thus form a layer that would bond to the conical motor walls, and when the mandrel was withdrawn, leave a large void volume in the center.) Then an early industrial robot would reach down into the motor case and carefully place zirconium “staples” onto the powder. These staples were described as looking like regular office staples, except one of the “arms” was bent up 90 degrees so that the staple covered all three X-Y-Z axes. Once the staples were in place, more powder would be added, then more staples, then more powders, etc. When the motor was properly filled with powder and staples, nitroglycerine would be carefully poured in; it would infiltrate the powder and turn it all to gel while leaving the staples in place. The gel would set up solid and the mandrel would be removed from the motor.

The end result was that the zirconium staples would not only burn as fuel, adding performance, being metal they would conduct heat into the propellant. The result of that was that burn rate would be greatly increased, and thus thrust. Apparently it worked great… when it worked. Sometimes it went kerflooey. One motor registered 50,000 psi internal pressure just before it turned into a fiberglass-confetti fireball. Additionally, propellant casting was slow and expensive.

In the end, simpler propellants were used (though the details remain fuzzy). Ammonium perchlorate was added to the propellant powder (presumably nitrocellulose plus other additives), and a solvent was them poured in to cause the mix to set up and bond to the walls. Only a small amount of aluminum powder was added… too much metal in the propellant caused the smoke trail to ionize and disrupt communications with the ground-based controls.

The SPRINT missiles were kept and launched from silos. Due to the need to get the hell out of Dodge in a hurry, normal silo systems were not used. Instead, the cover door over the silo was blow off with explosives; an explosive-actuated piston was used to punch the missile out. Within 1.2 seconds the first stage would burn out; the second stage shortly thereafter.

SPRINT, and the Safeguard system, were operational for only a few short months in late 1975/early 1976, defending the Minuteman missile silos at Grand Forks Air Force Base in North Dakota.

There was a third planned, but not-operational, tier in the defense system: the HiBEX missile. Now *that* was a badass rocket…

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An early SPRINT test missile.

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SPRINT missiles immediately after launch

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SPRINT compared with the LoAD (Low Altitude Defense), a later design to protect MX missiles… similar to HiBEX

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SPRINT missile, cutaway view

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SPRINT launch station

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SPRINT videos:

http://www.youtube.com/watch?v=YZZV464z9g8

 http://www.youtube.com/watch?v=LsnkmpJhzlo  This one features a slo-mo of the launch. Notice that the first stage gets torn to flinders immediately after separation. Also behold as the second stage goes so fast that the whole outer shell begins to glow incandescently.

http://www.youtube.com/watch?v=5vq4mWyYl2Y

 Posted by at 4:23 pm
Dec 262009
 

Here’s a missile I’ve not seen too much on… the early/mid-1950’s “Cannon Ball” developed by Johns Hopkins for the Navy and the Army. Some aspects of its design are suprisingly modern-looking, while some are creakingly antiquated. It was a spherical anti-armor missile (apparently also adapted for anti-submarine use) with an impressively large shapred charge warhead. The solid propellant seems to have been wrapped around the central cylindrical core formed by the warhead, and contained within the spherical shell. A single propulsion nozzle was located off-axis; three sets of control jets (attitude control thrusters) were located equidistant around the perimeter.

It was controlled remotely via radio. Sadly, the control system seems to have been a nightmare… there were *two* pilots, one controlling pitch, the other yaw. They guided it by watching the smoke trail its rocket left behind.

The basic design is very similar to modern hit-to-kill anti-missile systems. Simply replace the warhead with an optical sensor and some computers, and you’ll be pretty much there.

<> A bit more on Cannonball is here.

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 Posted by at 10:56 pm
Dec 262009
 

Frost:

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<>More frost: dsc_8812.jpg<>

<>Snow/frost covered tree: dsc_8834.jpg

Mountains through the haze, looking west: dsc_8866.jpg

Cuttler reservoir, frozen. The little flower-lookin’ things are frost on the ice. dsc_8911.jpg

Mountains through the haze, looking east: dsc_8923.jpg

Raptor in a tree: dsc_8930.jpg

Frozen tree (spot the raptor): dsc_8944.jpg

Raptor against the mountains: dsc_8947.jpg

Moonrise: dsc_8969.jpg

Moonrise: dsc_9050.jpg

 Posted by at 6:09 pm
Dec 262009
 

Normally, listening to NPR is an excercise in building up ones tolerance to boredom and idiocy. Take, for example, the interview I heard a part of today with someone who wrote a book on the concept of “happiness…” it was bland if forgettable up until the point where he started to go leftwingnut and expressed shock and dismay that after 9-11, the American people got angry and wanted vengeance. Well… duh, Spanky.

However, on rare occasions NPR can be damned funny. “Car Talk,” of course, and “Wait Wait Don’t Tell Me.”  And today they actually had me laughing out loud at two stories, one read by David Sedaris, the other by Julia Sweeney. Listen to them here: A Very Special Sedaris Christmas

The Sedaris bit is a theater reviewer tearing apart several Christmas plays… being staged by children. The Sweeney bit is the annual Christmas newsletter from a family in a state of collapse. The theater critique starts at about 7:00, Sweeney’s bit follows at 15:00. Sweeney’s storyincludes what is perhaps the best name for a baby EVAR.

 Posted by at 5:10 pm
Dec 252009
 

<>But… I thought they all loved us now that Obama has saved the world from Chimpy McBushitler?

<>http://www.msnbc.msn.com/id/34592031

A Nigerian man tried to light a powder aboard a commercial jetliner before it landed Friday in Detroit in what senior U.S. officials called an attempted act of terrorism.

Flight 253 with 278 passengers and 11 crew members aboard was 20 minutes from the airport when passengers heard popping noises, witnesses said. Passengers saw the attempted attack, and at least one of them jumped on the man and subdued him, airline officials and passengers said.

The man had “some kind of incendiary device he tried to ignite” in a bag strapped to his body, U.S. officials told NBC News.

 

Let’s hope that by “subdued” they meant “beat the crap out of.”

Fortunately, the best punishment for this jackhole it right at hand…

 Posted by at 11:18 pm
Dec 252009
 

Neato!

Scientists restore eye sight by stem cell treatment

 In yet another medical achievement, British scientists have restored eyesight of a partially blind person using pioneering stem cell treatment.

Eye surgeons at the North East England Stem Cell Institute (NESCI), has almost completely restored the vision of Russell Turnbull who was blinded in one eye by a chemical attack.

Huzzah. But in order to bring this back to politics, consider this line:

his sight has been almost fully restored thanks to the new technique in which doctors regrown the outside membrane of his cornea from stem cells taken from his healthy eye.

Note that this was *not* done with embyonic stem cells… but with his *own.* While the embyronic stem cell arguement seems to have faded from the scene (pretty much the moment Bush was out of office, and it was no longer a useful political arguement for the Left), it’s important to note that just about all (maybe just “all”) of the actual practical advances in stem cells have come from using the patients *own* cells, not embryonic. And there’re good reasons for this…  not least being that anythign grown from your own cells is *you,* while anythign grown from embyros is *someone* *else,* meanign you’ll live the rest of your life with your immune system attacking and rejecting it.

 Posted by at 4:47 pm
Dec 252009
 

A Boeing graphic from 1978 showing several different approaches to the idea of using shockwaves from one part of an aircraft to increase lift and/or cancel out other shockwaves and decrease drag. Notice the “Busemann Biplane” in lower left… silly as it may look, a straight-winged biplane can have surprisingly low supersonic drag due to favorable shock interactions. The big problem is that such configurations are usually pretty sensitive to flight conditions… if they are optimised for, say, Mach 4.5 and 80,000 feet, if you fly at 80,000 feet and Mach 4.2, your range might drop by half.

The flat top wing/body is seriously old (as is the Busemann Biplane), having been generated at the NACA in the late 1950s.

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 Posted by at 2:52 pm