This is the first in two-​​part series from exotic weapons guru David Hambling.
Theres a sim­ple tech­nol­ogy that could trans­form civil avi­a­tion, slash­ing fuel con­sump­tion, reduc­ing green­house emis­sions and cut­ting noise. The prob­lem is, nobody knows about it yet. It’s a mil­i­tary secret.
The way tech­nol­ogy migrates from clas­si­fied weapons pro­grams to every­day life is the theme of my book, Weapons Grade. (Did I men­tion it was out in paper­back this week?) We wouldnt have jet air­craft, com­put­ers or satel­lite com­mu­ni­ca­tions with­out such pro­grams. But when they stay secret, the pub­lic ben­e­fit is lost. What would have hap­pened to the elec­tron­ics indus­try if the tran­sis­tor had not been declas­si­fied in 1949?
Plasma aero­dy­nam­ics offers tan­ta­liz­ing promises of improv­ing air­craft per­for­mance. By pro­duc­ing a thin layer of charged par­ti­cles around an air­craft you can change the behav­ior of the bound­ary layer, sig­nif­i­cantly reduc­ing fric­tion. The charged layer also absorbs radar, improv­ing stealth.
When my col­league Justin Mullins wrote about the sub­ject for New Scientist mag­a­zine back in 2000, it seemed to be an obscure Russian tech­nol­ogy dat­ing from the late 70s which the US was just begin­ning to exam­ine. But it offered real ben­e­fits, with a poten­tial drag reduc­tion of up to 30%.

A cut in drag of 1 per cent means you can increase an airliner’s pay­load by about 10 per cent, or it could sim­ply fly far­ther or faster, Mullins pointed out, Just imag­ine the effect this could have on cash-​​strapped airlines.

The Russians seemed to be years ahead, even mar­ket­ing a plasma stealth add-​​on device said to reduce radar returns by a fac­tor of a hun­dred.
He con­cludes by won­der­ing if the tech­nol­ogy can actu­ally work in practice.

Either the new labs are a huge waste of time and money, or the American mil­i­tary knows some­thing we don’t.

As it turns out, they cer­tainly do.
A lot of infor­ma­tion on stealth dis­ap­peared from the pub­lic domain decades ago when the whole sub­ject turned black. Which was why I was sur­prised to find the orig­i­nal patent for plasma stealth still intact.
Patent 3,127,608 is called “Object Camouflage Method And Apparatus,” and “relates to a method of mak­ing air­craft or other objects invis­i­ble to radar.” The inven­tor, one Arnold L. Eldredge, describes the the­o­ret­i­cal basis of plasma stealth accu­rately.
The most sur­pris­ing thing is the date. The patent was filed on August 6th, 1956. The tech­nol­ogy has been around for fifty years.
But the big prob­lem is with his appa­ra­tus Eldredge uses an elec­tron gun, which would be way too big to carry on an air­craft. In fact, thats a prob­lem with this whole plasma idea. Apparatus to gen­er­ate the mil­lions of volts needed is big, bulky and imprac­ti­cal; even these days the Russians are talk­ing 100 Kg and tens of kilo­watts.
But there is a way — check out Patent 4,030,098 (1962) Method and means for reduc­ing reflec­tions of elec­tro­mag­netic waves assigned to the Secretary of the Army and the rather sim­i­lar Patent 3,713,157 (1964) belong­ing to North American Aviation, later absorbed by Boeing Energy Absorption by a Radioisotope Produced Plasma
Both of these use the same basic con­cept: a coat­ing of radioac­tive mate­r­ial pro­duc­ing a flux of either Alpha of Beta par­ti­cles ion­ize the air, pro­duc­ing the desired layer of plasma. Its a clever solu­tion. Radioactive paint weighs vir­tu­ally noth­ing, does not require any power input and can be dirt cheap. One of the sug­gested emit­ters is Strontium-​​90, which is pro­duced in abun­dance as a waste prod­uct by nuclear reac­tors.
Its also quite safe. With a thin pro­tec­tive coat­ing to pre­vent it from flak­ing off, the soft radi­a­tion (unlike dan­ger­ous Gamma radi­a­tion) is not a haz­ard to pilot or main­te­nance per­son­nel. This type of mate­r­ial is only dan­ger­ous if inhaled or ingested.
I checked out the idea with some peo­ple who know about these things — Martin Streetly, Editor of Jane’s Radar & Electronic Warfare Systems and Professor Igor Alexeff, for­mer President of the IEEE Nuclear and Plasma Sciences Society and an author­ity on plasma tech­nol­ogy.
Both con­firmed that the idea, though exotic, was sound enough in the­ory. Interestingly, nei­ther had come across the idea before. And both observed one obvi­ous dis­ad­van­tage from the point of view of stealth. The radi­a­tion lev­els involved 10 Curies per square cen­time­ter would give the plane a vis­i­ble glow at night, mak­ing it a bea­con to enemy air defenses.
Did this prob­lem mean that the whole idea was shelved — or were radioac­tive stealth coat­ings taken fur­ther?
Well be look­ing at some sur­pris­ing answers in part two…
– David Hambling