World Record Flights of Beam-Riding Rocket Lightcraft: Demonstration of "Disruptive" Propulsion Technology

AIAA 2001-3798 World Record Flights of Beam-Riding Rocket Lightcraft: Demonstration of "Disruptive" Propulsion Technology

Leik N. Myrabo Llghtcraft Technologies, Incorporated Bennington 0520T V , 1

37th AIAA/ASME/SAE/ASEE Joint Propulsion Conference 8-11 July 2001 Salt Lake CityT U ,

For permission to copy or to republish, contact the copyright owner named on the first page. AIAA-helr Fo d copyright, writ AIAo et A Permissions Department, 1801 Alexander Bell Drive, Suite 500, Reston 20191-4344, ,VA . (c)2001 American Institute of Aeronautics & Astronautics or Published with Permission of Author(s) and/or Author(s)' Sponsoring Organization.

AIAA 01-3798

WORLD RECORD FLIGHTS OF BEAM-RIDING ROCKET LIGHTCRAFT: DEMONSTRATIO "DISRUPTIVEF NO " PROPULSION TECHNOLOGY

Leik N. Myrabo* Lightcraft Technologies, Incorporated Bennington, VT 05201

Abstract unmanne d mannean d d aerospacecraft designed O Octoben2 r 2000 12.2-ca , m diameter, to ride "Highways of Light." Simply expressed, 50.6-gram laser-boosted rocket Lightcraft flew to I believeLT s that only beamed energy propulsion altitudw ne a e recor f 71-metero d s (233-ftt a ) holds the promise of radically reducing the cost White Sands Missile Range (WSMRw Ne n i ) of space acces nexe th 100y tsb n i 5-1X 0 years, Mexico. The PLVTS 10-kW pulsed carbon and ultimately by 1000X within 15-25 years. dioxide laser, locateHige th hn do Energ y Laser The establishment of an energy beam highway to Systems Test Facility (HELSTF) powered the space will simultaneously increas reliabilite eth y record flightwhicf o other x o wels si h a ,tw s a sl- and safet f manneo y d suborbita d orbitaan l l reached 48.4-m (159-ft) and 56-m (184-ft). flight incrediblo t s y high levels t leasa , t equao t l These were the first outdoor vertical, spin- airline operations today, or better. stabilized flights of laser Lightcraft to be performed with assigned launch windows Highways of Light secured from NORAD, wit e cooperatiohth f no This vision of the future depends upon WSMR range control - to avoid illuminating significant investments into an energy-beaming LEO satellites and/or low flying aircraft. Besides infrastructure (lase d microwavean r ) that large nearly doublin e previougth s altitude recorf o d number f inexpensivo s e Lightcraf n rideca t . 39 meters (128-ft) set on 9 July '99, the Model Today's expendable, and partially-reuseable #200 Lightcraft simultaneously demonstratee dth launch systems with their on-board power plants longest laser-powered free-flight, and the greatest cae considereb n d "infrastructure poor,n i " 'air time' (i.e., launch-to-landing/recovery). comparison e near-terth r Fo m. nano-satellite Wit a hmodes t investmen f undeo t a millior n launch application (i.e., 1-10 kg payloads), the dollars a strin, f ever-increasino g g Lightcraft technology and affordability of 1-10 megawatt- altitude records have bee t ove pasne se th r t four class commercial power-beaming lasers is year - sincs firse eth t Apri3 fligh2 n lo t 1997. certainly close at hand. In contrast, the several This embryonic, propulsion concept embodies hundred-megawatt to one billion watt energy- "disruptive technology" that promiseo t s beamers of the future, needed for manned radically transform our ideas about global flight Lightcraft (e.g., payload f 100-100so a 0 e kg)ar , transportation and space launch systems, over the a stretc f o t h bi today e musW o .tt learw nho nex years5 t2 1o 5t . build these powerful laser and/or microwave sources, economically. At present, they are only INTRODUCTION within financial reac f nationaho l governments, and perhaps some very large multi-national Lightcraft Technologies, Inc. (LTI) is corporations. launching a revolution in low-cost space access, However, once fully mature "Highways promotinf beameo e us de energgth y transmitted of Light" are eventually in place, the global from remote power-plants o propet , l vehicles transport system will be unbelievably aroun e plane5 minutes4 th d n i tn suborbita o l inexpensiv rideo t s .u safd Laser ean efo r and/or trajectories, or right into orbit - without staging. microwave source hundredn so f orbitinso g solar LTI intends to develop and manufacture such power stations, linked in a space power "grid," will transmit completely "green" energy for Earth's flight transportation needs (Refs. 1-3). * AIAA Senior Member A large flee f smalo t l Lightcraft (e.g.3 , Copyrigh 200 © tL.N y 1b . Myrabo. Publishee th y db American Institut Aeronauticf eo Astronauticsd san , Inc., passengers)2 1 o t , flying sub-orbital trajectories with permission. might eventually replace conventional jumbojets and high speed civil transports. Lightcraft could

give highly personalized service, that woule db structural weigh r Lightcraftfo t s opposea , o t d hard to beat - 'called' to a local neighborhood more conventional flight platforms - in both 'Lightport' like we call for a cab today. Such suborbita orbitad an l l launch applications. Ultra- vehicles could transport passengers half way energetic flight trajectories are altogether feasible around the globe in 45 minutes, at hypersonic with Lightcraft technology. speeds, where most of the flight is outside the atmosphere. Competitive Energetic Sources? This is the ambitious LTI company Three other "on-board" super energetic vision o ultimatelT : y enable affordable orbital, sources have been proposed for future trans- and suborbital flights around the planet, for a atmospheric aerospacecraft: a) nuclear fission, space-faring society. b) fusion (once someone figures out how to do it), and c) antimatter. However these energetic LTI Company Overview sources produce high levels of ionizing radiation, Lightcraft Technologies was and will likely requir metri0 10 radiation ea cto n incorporate e solth er purposdfo f developineo g shield for manned operations. The potential for beamed energy propulsion into a commercial catastrophic accidents with these source eves si r reality I defineLT . Lightcrafa s flighy an ts a t present, and clearly, a tank of antimatter is a platform, airborne vehicle, or spacecraft virtual bomb waitin o offg . o t g Althougn a h designed for propulsion by a beam of light - be it existing technology, nuclear rockets would spew microwav r lasere authoeo DeaTh d . an r n Ing, fission products into the atmosphere, trailing an were the first to coin the word "Lightcraft" in exhaust clou radioactivf do y e "falloutwa e th l al " their 1985 boo Futuree kTh of Flight (Ref) 4 . orbit o exactlt t No . y "green" propulsion. Lightcraft Technologies, Inc. is an emerging technology based business, developing Lightcraft Engines & Power Plants innovative advanced flight propulsion powerd an o distincTw t categorie f o Beames d application f o long-ters m significancr fo e Energy Propulsion (BEP) technologn i e ar y industry and society. Presently, LTI is forming evidence for Lightcraft engines: 1) simple laser- strategic partnerships withe th other n i s thermal or microwave thermal engines, and, 2) energy/utility, transportation d aerospacan , e more complex laser-electric r o microwave, - industrie o acceleratt s e applicatioth e f suco n h electric engines e 'BEP-thermaTh . r engines innovative technologies in the first five years of must only absor e beameth b d electromagnetic the 21st Century s seekini I LT g. discourse with power directly into the working propellant. other like-minded entrepreneurs, financiers, Clearly e morth , e sophisticated 'BEP-electric' marketers, and institutions with vision - to engines must first conver e captureth t d beam identif people yth wilo elwh likely plaroley yke s power into electricity, before the in this technological drama as it unfolds over the magnetohydrodynamie Th . it c e engineus n ca s nexyear w decadesd fe t san . latter categor f "BEP-electricyo " engines holds the greatest promise for evolving hyper-energetic "DISRUPTIVE" TECHNOLOGY manned Lightcraft in the next 15-20 years. Most beamed-energy propulsion systems will likely Air and space transportation systems exploi atmosphere th t r momentuefo m exchange undergo remarkable transformations when o improvt e engine efficiency radically beyond massive quantitie f o "weightlesss " that of today's chemical rockets. The matrix of electromagnetic power can be beamed directly to feasible engine/optics/vehicle configurations i s vehicla flightn ei . This qualifie s "disruptivea s " near infinita pulo f t e t of l(e.g. bu e Ref , se ,5) . technology at its best. Principally, the craft Lightcrafnew t design successfully will require becomes unburdened from havin e o lift gth t the close integration of widely different energy source for its propulsion system. engineering disciplines. Lightcraft engine design Compared e witlimiteth h d energeticf o s is a formidable exercise in interdisciplinary chemical fuels (i.e., kilojoule kilogramr spe ) used design. by today's turbomachines and rockets, beamed t whaBu t abou e difficultth t f o y 100-folo t - energ10 pacn da yca increasn ki n ei designing the requisite power-beaming the same "fuel" tank. Such has been the goal of technology, taking for example, high power HEDM (high energy density materials) research lasers eass i t understano yI t ? commerciay dwh l for the past decade, but thus far, none have ground-base r space-baseo d d lasers woule b d appeared. Beamed-energy translates into striking designed around completely different reduction e propellanth n i s t fuel fractiod an n engineering design requirements than that of

military directed-energy weapons e latteTh r. satellites should cost no more than the price of a (i.e., laser weapons) face severe restrictions upon new automobile. -And to accelerate them into the overall package dimensions, arrangement of orbit will cost no more than a few hundred components, and total mass. Military missions dollars worth of electricity to run the megawatt driv e desig a th compace o t nd powerfuan t l closed-cycle electric laser. variety of open-cycle chemical laser, and short run times (typically -100 seconds or less, as limited by the allowable weight for Launch Laser Design consumables). In sharp contrast, the engineering High power electric infrared laser design constraints for a commercial power- technology in the USA was pushed rapidly into beaming laser (or microwave) power plant are: maturity throughout the 1970's, benefiting in part high reliability, affordable cost, easy fro "Stae mth r Wars" program 1980y B . , SDFs maintenance lond an ,g service lifetime (e.g.- 10 , attentio shifted nha shorteo dt r wavelength lasers, years or more). As such, cost is the major driver, even though Russia continue improvo t d e their second only to reliability. own CO2 lasers. Today infrared electric laser technolog s i sufficiently y developee b o t d MICROSATELLITE LAUNCHER seriously considered for commercial laser launch applications of small payloads. Pulsed, electric A realistic five-year objective for LTI is discharge carbon dioxide lasers exhibit electric- o launct e firsth h t kilogram-class commercial to-laser conversion (i.e., "wall plug") efficiencies micro-satellite wit a hmegawat t ground-based of 20% to 30%, with very good operational infrared electric laser. Note thatraditionae th t l reliability. They employ benign gases sucs ha figure-of-merit invoke r lasedfo r propulsio- 1 s ni d Nan 2, , COwhic He e 2normall,ar h - re y r megawatpe f kpayloaO o g f laseLE o t o t rd circulated in closed-cycle flow systems. On the power. Even sooner, suborbital e flightth o t s rare occasion that a leak occurs anywhere, there edg f spaco e e (i.e., "sounding rocket' type dangerouso n e ar , noxious gase worro st y about. trajectories) may present interesting commercial As mentioned abovelonD o ag gDO , opportunities for 100 gram payloads and a 100 abandoned megawatt-class infrared electric laser kilowatt-class laser ) spaca : e radiation hardness technology in favor of more energetic, short- testin f o smallt g criticabu , l electronic wavelength alternatives - specifically designed component f futuro s e large satellites) b d an , for military weapon systems. Such systems had short term zero-G testing. e smallb o t , compacs lightweigha d an t s a t possible -to stuff into a large jet transport, or Potential Applications space pase platformth t r 15-2Fo .0 yearse th , I envisionLT a hos sf innovativo t e militar s showha y n little real interesn i t applications for a microsatellite laser launch resurrecting its high-power infrared laser services enterprise, including hig) a : h resolution technology - largely because of the low lethality imagin d mappinan g g (Earth resources (i.e., inferior target "coupling"), and necessity of inventories, real estate mapping, statlocad ean l large transmitter apertures. Neither feature tax parcels); b) global positioning system; c) presents a problem for the commercial laser astronomical telescope using the 1-meter launch application, because therdesir) o 1 n : s ei e diameter Lightcraft rear optic (amateud an r damago t targee eth t (i.e. Lightcraft)e th , , and) 2 , professional use); c) secure communications and criticao lasee n th s rgroune ha staylth d n so dan relay platform (cellular phones); e) delivering dimensional or weight restrictions. Note that lightweight replacement electronic components very large 10-meter diameter telescopesa , (small, but urgently needed payloads) to the necessary ingredien r infrarefo t d laser launch, International Space Station; and ) thread , t have been built for as little as $10-$ 11 million ~ detectio trackind nan g (military). using hexagonal segmented optic technology By exploiting the economies of large (e.g., university astronomical observatories). scale mass-production, kilogram-class micro-

Table 1 Lightcraft Vertical Free-Flight Records

Altitude Date Lightcraft Miscellaneous Details (feet) Model # 1.0 23 Apr. '97 early #100 Non-spinning; truncated optic; conical forebody & shroud. 6.5 26 Aug. '97 early #150 First gyro-stabilized flight, inside lab; flat-plate forebody. 14. 1 Oct. '97 early #150 Inside lab; flat-plate forebody. 50. 5 Nov. '97 #200 First outdoor record flight. 73. 4 Dec.' 97 #200 Last record fligh 14.7-ca y b t m Lightcraft 91. 18 Apr. '98 #200-3/4 First record flight by an 1 1-cm Lightcraft. 99. 22 Apr. '98 #200-3/4 Last airbreathing engine record flight. 127. Jul9 y '99 #200-3/4SAR First ablative rocket record flight; 23rd WSMR test. 233. 2 Oct. '99 #200-5/6SAR LTI flights sponsored by non-government grant.

LASER LIGHTCRAFT FLIGHT HISTORY last WSMR test for which the author functioned as Principal Investigator of the USAF/NASA Perhaps the simplest 'yardstick' for (i.e., government-sponsored) Laser Lightcraft measuring the progress of laser Lightcraft Program. technolog sequence th s yi altitudf eo e recordt sse LTI's record flight Octobe2 n o s r 1999 (sey ealonwa Table th g, startin 1) e g wite th h were sponsored under a non-government grant first 1-foot vertical free-fligh Apri3 2 n lo t 1997. (see details below). This was the author's 24th e informatioTh n containe Tabls n beedi ha n1 e laser propulsion test at WSMR. quite thoroughly disclosed in numerous television documentaries, newspapers and Origin of Laser Lightcraft Concept magazines produced ovee pasx yearsth rsi t . e autho Th s personallha r y evolvee th d Additional details have been revealed in several curren d mosan t t successful #200-series technical papers (e.g. e Refsse , . e 6-16)Th . Lightcraft engine over a 4-year period involving design of the author's best-flying, spin-stabilized, 23 laser propulsion tests at WSMR - starting beam-riding Lightcraft is revealed in Refs. 10,13, fro s originamhi l desig nLightcrafe studth r yfo t &15. Designated Model #200, it has claimed all Technology Demonstrator (LTD). D ThiLT s the altitude records of 50-ft and beyond, concept s (sedevelopewa e ) Reft 17 a d. accomplished through a sequence of subtle Rensselear Polytechnic Institute (RPI n 198i ) 9 improvements in the design of the Lightcraft, under e contracLawrencth o t t e Livermore laser, telescope, launcher and launch procedures. National Laboratory and the (now defunct) The Model #200 engine contours were Strategic Defense Initiative Organization, for the designed to provide an autonomous, 'beam- Laser Propulsion Progra e SDIOth e f mTh o . riding' function that causes the exhaust flow to studs carriewa y d wite participatioth h f o n automatically vector in flight -thereby pulling the numerou I graduatRP s d undergraduatan e e vehicle back inte e lasecenteth oth rf o rbea m students e full-sizeTh . 0 kilogram10 d , 1.4-m during flight. This critical "beam-riding" feature diameter LTD spacecraft was designed for the is the principal ingredient made all these record- micro-satellite sensor & communications roles ~ breaking flights feasible in the first place. The to be boosted into low Earth orbit by a powerful, 99-ft flight on 22 August 1998 was the last 100-MW ground-based e laserinitialTh . , altitude record to be demonstrated with an atmospheric portio laser-propellee th f no d flight airbreathing, pulsed detonation engine (PDE) employed an airbreathing PDE engine mode, which has a propellant specific impulse of followe rockea y db t mode (using onboard liquid infinit - becausy o propellann e s carriei t - on d hydrogen )r becam ai whe e thio nth eto n (about board. The 9 July 1999 record flights were the Mach 5 and 30-km altitude).

firs o emplot t n ablativa y e rocket propellant. Bue laseth t r LightcrafI t worRP t a k

d The 127-ft record flight occurred at the 23 anr d really began several years before the LTD study

(e.g., see Refs. 18-19). All told, the author has Lightcraft Technology Demonstration (LTD) collaborated with nearly one thousand RPI Program remain un-acknowledged in Ref. 13 students ove decade th r e from 198 o 19955t n i , (i.e., quite 'conspicuous by absence'), C.W. developing beamed-energy propulsion Larso Refn i inventio.e refed 1th 4 di e o t r th s na technology. This RPI research was funded under "Myrabo Laser Lightcraft "MLL.r "o " However, mostly NASA and USAF research contracts mose inth t recent AFRL paper (see Ref. 16)o n , totaling just over $1M ultimateld an , y evolved mention is made of the author's contributions to laser Lightcraft technology to a critical threshold 'launching ProgramD LT e th '. Note Refs& 3 1 . level where success with building real engines 16 are "officially released" publications of the was eminent. This is fairly complicated AFRL Propulsion Directorate, Edwards AFB, propulsion technology t i too d klarga an , e team CA. of creative young mind movo st t forwardei e Th . In summary, it took a combined author couldn't possibly credit e claith d l man al , USAF/NASA investment of just under $1M over owes a great deal to his RPI student e four-yeath r perio o advanct d e Lightcrafth e t collaborators. Without this preparatione th , technology program. Half of this was personally prospect e r subsequenth succesfo s n i s t solicited (and secured) from the NASA Marshall "hardware" phase (funded under the Space Flight Center o grot , t wi int a joino t USAF/NASA Laser Lightcraft Program) would program. Note also that only 10% of the $1M have been slim indeed. wa CentraI s spenRP r tfo l Machine Shop services anpurchase dth e (through RPI f essentiao ) l test Transformation into Hardware equipment/ instrumentatio r thafo n t 4-year The design and construction of the first period. Lightcraft engin d tesan et equipment begat a n RPI in 1995 with a $45K contract from the Transition to Solid Ablative Rockets Phillips Laboratory (commonly known as the The LTD's airbreathing engine mode Rocket Lab) at Edwards AFB. One year later, the had a predicted theoretical impulse Coupling author was invited to join the Rocket Lab in what Coefficient (CC) performanc 0 newton58 f o e s becam a 3-ye r IPA Fellowship (i.e., sabbatical (thrust r megawat)pe t (laser power launce th t a )h from RPI, from 1 Sept. '96 through 31 Aug. 499) altitude of 3-km, but required a laser pulse width transforo t - s 198LightcrafD mhi 9LT t concept of 0.3 microseconds. This pulse width is 50 to into hardware reality. 100 times shorter than the 18 to 30 ^sec pulses Throughout those 4 years of available fro s e PLVTu m th 8 1 Se th laser t A . collaboration with the Rocket Lab (which later pulse width, the #200-3/4 airbreathing engine merged into AFRL), the author effectively served had experimentally demonstrated (in the as principal investigator for this Laser Lightcraft laboratory a pea) k performanc f 0 onlo e 16 y program. To be entirely factual, the author N/MW, which is a factor of 3.6X less than that personally designed every piece of Lightcraft test predicted for the LTD. Since PLVTS cannot be hardware, flightweigh d laboratoran t y engines, converted to such short pulse widths, other test stands, launch stands d auxiliaran , y solution improvino st thruse gth t performancf eo equipment during this 4-year period authoe Th . r e #200-3/th e identifiedb 4 o t engin d .ha e also supervised the fabrication of this equipment Furthermore, attempts at powered flight times I CentraRP e lth b y Machine Shopd an , longer than 4 seconds with this aluminum engine wrote/conceived all but two of the 23 WSMR were abruptly terminated - when the "absorption test plans formeA . I Ph.DRP r . student (Don chamber" (i.e.e shroudth , ) melte d caman d e Messitt) of the author, assembled the computer- apart. based data acquisition and schlieren photography To circumvent both problems (i.e., for systems; several other RPI undergraduate and the short term), the author adapted the #200- graduate students were also- 4 involve e th n i d series Lightcraft engine to use solid ablative activityD yearR& . rocket propellants that absorbed the infrared e autho Th s unquestionablha r y created energy volumetrically (i.e., in depth). This all the laser Lightcraft hardware emerging during solution came out of conversations with Dennis this 4-year perio t AFRL drecognizea s i d an , s da Reilly and Claude Phipps; both scientists had the sole invento a recen n o rt USAF patent experimentalld ha y confirmed that laser impulse application covering this invention. The enhancements were indeed available from such applicatio submittes n wa Paten S U o dt t Officn o e solids. Reilly suggested t Delrini indee d an d, 27 April 2001. Although the author's substantial worked very well. The ablative rocket approach contributions to what now is called the AFRL revealed a dramatic increase in thrust for the

basic model #200-series Lightcraft engine (i.e., Post flight inspection of the two rocket linke PLVTS)o dt e expensth t a ,f havin eo o gt Lightcaft and their rear reflectors (i.e., thin carry propellant (see belo r morwfo e details). aluminum mirrors) revealed that the first engine Otherwise e 99-ftth , . record Augus2 fligh2 f o t t flyo t , showe signo dn f stressso . Howevere th , 1998 might stil standinge b l today. second engine' heaviee s optith n c(o r Lightcraft) had indeed sustained visible thermo-mechanical July '99 Flight 127-fo st t damage; it was somewhat warped, but still in As mentioned earlier, this was the 23rd one piece. Neither rear optic appearee b o t d and last WSMR laser propulsion test (under the contaminated (i.e., e ablatecoatedth y b d) USAF/NASA Laser Lightcraft Program), thae th t propellant; no obvious evidence of such author effectively served in the capacity of condensation could be found on the mirrored principal investigator e followinTh . g provides surfaces. Also, whe flighto ntw e videos th f o s more details on this 9 July 1999 test, the were carefully reviewed, no indication of essential f whico s h were disclose Refsn i d 3 1 . particulate-induced air breakdown could be and 14. observed in the beam transmission path. consecutivo Intw e launche Jul9 n yo s 1999, lasting -3.5 seconds each differeno tw , t Advantages of SAR-Lightcraft laser-propelled ablative rockets climbed rapidly e earlieth r r Fo airbreathing-engine altitudtn oa f 128-feo t (39-m impacted )an - 4 da versions, peak air plasma temperatures can reach ft x 8-ft plywood "beam-stop" suspended by a 20,000- o 30,000-KKt time5 ,o t whics 3 s i h crane. These Lightcraf beam-stoe th t hi t p witha hotter tha e sun'nth s surface. Hence timen ru , s velocity sufficient to crush in their aluminum with the 11-cm bare aluminum engines are noses e spin-stabilizedTh . , beam-riding rocket severely limited to about 100 laser pulses, or less design was a logical derivative of an earlier tha nsecond4 f operationso , befor chambee eth r airbreathing engine design that establishee th d walls melted and blew apart. This of course former free-flight altitude record of 99-ft on 22 abruptly ende flighte dsharth n I . p contraste th , August 1998. The new Lightcraft were aluminum shroud on both ablative rocket flights designated model #200-3/4SAR r whicfo ,e th h survived well, sustaining minimal damage. This 'SAR' stand solir sfo d ablative rocket. suggests that the craft could have flown well These 127-ft record flights (as usual) beyond the 127-ft plywood beam stop. Note too Mexick w Whit e placth Ne n n eei o Sands that the PLVTS infrared laser was set up to Missile Range (WSMR) at the High Energy deliver 18-us joul0 45 , e pulse t repetitiosa n rate Laser Systems Test Facility (HELSTF) - using of 26 to 28 pulses per second. the 10-kW pulsed infrared laser called PLVTS. Not only does the ablative propellant This US Army laser is operated by the increase vehicle gyroscopic stability (i.e., Directorate for Applied Test, Training and throug propes hit r placement reducd an ) e engine Simulation (DATTS). The historic videos of the temperatures, but it also more than doubles the record 127-ft flights were include Nationaa n di l thrust available from PLVTS. Whereas the pure Geographic Television production (Explorer- airbreathing engine version developed only 0.36- Series) entitled "The Ques r Spacefo t "- whic h Ib (1.6 newtons f time-averageo ) d thruste th , was first aireJul6 n ydo 2000. ablative rocket gives better than 0.81-lbs (3.6 N) The two record-breaking rocket - on the same 10 kilowatts of laser power. At the Lightcraft were made at RPI from 6061-T6 s 1pulsu 8 e width e #200-3/th , 4 airbreathing aluminu diametea mo t f 11-co r m (4.3 inches), engine has experimentally demonstrated (in the d launcanha d h masse 9 grams2 f 26.o d s 3an . laboratory peaa ) k impulse Coupling Coefficient The second rocket to be flown carried slightly (CC) performance of only 160 to 170 N/MW. In more ablative propellant aloft than the first. An contrast, the #200-3/4 SAR engine has exhibited especially important design featur thif eo s engine 360 N/MW at low pulse energy of -95 Joules, at wa o pac t se iner th k t ablato a plac n i re that which energ e airbreathinth y g engine develops would increase Lightcraft stability, rather than only 80 N/MW. This was the principal ingredient reducwrappiny B . eit plastie gth c propellana n i t that enabled rocket-propelled Lightcraft to easily thin band abou e thrusth t t chamber's perimeter, exceed the previous year's 99-ft record. gyroscopic stability was indeed improved - at Finally, by packing this ring of ablative least until the propellant was all ablated. The solid propellant intannulae oth r focal regiof no rapidly evaporating plastic probably reduced the the rear concentrating optic, the Lightcraft's engine's operating temperature, thereby propulsion system may also be transformed into a extending engine life. kin f rocket-basedo d , combined-cycle (RBCC)

engin t leasa e- t withi dense nth e atmosphert ea subsonic speeds. Under these conditionsn a auxiliary airbreathing process, wherein the local ambient air is expelled ahead of the hypervelocity ablating rocket exhaust, might augmen engine'e th t s thrust.

LTI RECORD FLIGHTS TO 233-FT

Early in the morning of 2 October 2000 on the High Energy Systems Test Facility (HELSTF), Lightcraft Technologies, Inc. (LTI) set a new altitude record of 233 feet (71 meters) inc8 4. hfos it (12.r diamete) 2cm r laser boosted Figure 1: Lightcraft and Launcher (WSMR, rocke a flight n i ~t lasting 12.7 seconds. Oct2 . '00) Although most of the 8:35 am flight was spent hoverin t 230ga + Lightcrafe ft.th , t sustaineo dn All three Lightcraft wer improven a e d real damage will d againy an ,fl . Besides settinga version of the basic model #200-5/6SAR new altitude record e crafth , t simultaneously configuration. Tabl 3 givee e initiath s l gross demonstrated the longest ever laser-powered liftoff mass for the vehicles, and the flight Run free-flight, and the greatest 'air time' (i.e., #'s for each. The ablative rocket propellant ring launch-to-landing/ recovery). The #200-series added 4.12 grams to the initial launch mass, and Lightcraft employed a plastic ablative propellant t replace, no s wa d t i with "fresh propellant" and were spin-stabilize t leasa o dt 10,000 RPM between flights. Note that Lightcraft #1 was just prio launcho rt . flown thrice, and accumulated 71.6-ft + 159-ft + LTI launched a total of seven vertical 184-ft - for a total of 415 feet of altitude in the spin-stabilized, free-flights (see Table 2 below) process, with quite a lot of propellant still between the hours of 8:30 am and 11:30 am, with remaining. Clearly, with the proper telescope three Lightcraft weighing about 1.8 ounces (i.e., arrangement PLVTS could have boosted this 50-51 grams). Two lesser flights reached 159 ft #200-series craf 500-fto t t , which indeew no s di and 184 ft (Runs #4 & #6), as shown below in the objective for the next LTI flight test. Tabl. e2

Table 2 Lightcraft Flight Details (2 October '00)

Flight Theodalite Maximum Altitude Time to Max Tim 23-o et m Time to 46-m (Run #) (degrees) (meter / sfeet ) Altitude (sec) (sec) (sec) 1 30 21.8-m (71.6-ft) 3.5 2 62 71.1-m (233-ft) 12.73 2.57 5.17 3 14 9.4-m (30.9-ft) 4 52 48.4-m (159-ft) 5.16 2.03 4.8 5 18 12.3-m (40.3-ft) 6 56 56.0-m (184-ft) 5.57 1.6 4.5 7 22 15.3-m (50.1 -ft)

Table3 Lightcraft Gross Liftoff Mass (Recorded Before First Flight)

Lightcraft Launch Mass Diameter Flight #'s Accumulated Altitude (vehicle #) (grams) (cm) (meter sfeet/ )

#1 49.02 12.2 Runs 1,46 & , 124-m (415-ft.) #2 50.62 12.2 Run 2 71-m (233-ft.) #3 51.05 12.2 Runs 3, 5, & 7 37-m (121-ft.)

Laser Problems from NORAD . flighft Octn .3 o t , Wit23 2 . e hth The record flights were (as usual) LTI attained its objective of nearly doubling the performed with the 10 kW pulsed carbon dioxide previous altitude record of 128 ft. - set on July 9, laser named "PLVTS" by the Directorate for 1999 (wit #200-serieh1a m 1c s Lightcraft) under Applied Training, Test and Simulation prior joint USAF/NASA funding. (DATTS) beae Th .m profillaunce s i th d t ea hpa given below in Figure 2. Even though the laser Post-Flight Inspection was suffering from a grounding or arcing e majoOn r concern with longer problem in the sustainer that caused it to run Lightcraft flights was that ablating rocket erratically e time-averagth , e beam powes wa r propellant might contaminate either: a) the still adequat o propet e e craf th o recort l t d engine's rear paraboli lasee th rc ) b optic r o , altitudes. (This laser proble identifies mwa d dan beam's atmospheric propagation path. In the followine fixeth n di g day.) Note that vehicle #3 former, vaporized propellant that condensed san did not fly well, but it might be blamed on reae stickth r o opticst , could eventually 'darken' unlucky timing with a rough-running laser. brightle th y polished aluminum surface, reducing s reflectivityit . Thiy caus e thima sth en metal reflector to overheat and warp, especially in the forward portion of the optic where high over- pressure e createar s d from reflecting laser- induced detonations (e.g., see Refs. 10 & 15). However, these fears were unfounded. Post flight inspectio e threth f eo n Lightcraft's rear reflectors revealed no signs of either mechanical stress or contamination. Also when the videos of the seven flights were carefully reviewed, no indication of particulate- induced air breakdown could be observed. No attempt was made to measure laser transmission losses through the rocket's plume.

Computer-Based Motion Analysis The results from a detailed computer- based motion analysis study of Flights #2, #4, Figure 2: PLVTS beam profile at launch pad and #6 are plotted in Figures 3 through 8. Note thae camerth t a use o fildt m these flightss wa , NORAD Clearance positioned wite DATTth h S "manlifter" base These were the first ever vertical, free- centered in the video frame, to indicate an flight tests to be performed without a 4-ft X 8-ft altitude of 75 feet from the launch pad. Hence plywood "beam-stop," suspended by a crane - to e maximuth m altitude recorde e camerth y b da intercept stray laser energy that sometimes 'spills' 0 feetwa15 s. Fortunately, theodalite readings aroun e vehiclth d n flighte i LTe Th I . flights were take identifo nt maximue th y m altitudf eo were carrie t wit cooperatioe dou h th NORAf no D each flightotheo Tw r. cameras were employed and WSMR range contro avoio t l irradiatioe dth n o recort d additional flight footage a vertica: l of bot Eartw hlo h orbital satelliteflyinw lo gd san "look-up" camera positioned roughly 1-foot from aircraft. Twelve launch "windows" varying from the launch pad, and a mobile hand held 2.5 o 41.26t 5 minute n lengti s h were secured camcorder.

For Run #2 in Figs. 3 and 4, the reached the 140-ft point in 3.5 seconds, which Lightcraft accelerated ove firssecondse o rth tw t , wa5 second1. s s quicke0 1. r d #2than an ,n Ru thereafter maintaining a quasi-constant velocity second faste . Notr#4 thaFigurn n ei nRu , thae8 t nexe secondsft/se5 7 oth 2 f3. tr cfo . Mose th f to Ru attaine6 n# dmaximua m velocit ft/se9 4 f yco 12.73 second flighs spenwa t t hovering above peaa o t k y altitudwa e o f n18th eo e 4 th feet f I . 200 feet, before setting the new World's altitude PLVTS laser had not been suffering that morning record (at least for laser Lightcraft) of 233 feet. from an electrical grounding problem, no doubt ; not#4 n e stortele 6 Ru Figure th r ld yfo an s5 all peak velocities would have bee thin i s range, that this craft reached a top velocity of 35 ft/sec higherr o . peaa o t 6 k # y altitud n feet9 wa Ru 15 e o. nf th e o

180

160

140

120

100

Time (sec)

Fig : Altitud.3 Tim. eFlighvs r efo t2

O °

Time (sec)

Fig : Averag.4 e Velocit . Tim yFlighvs r efo t2

160

140

120

_ 100

-, 80

5 5 4. 4 5 3. 3 5 2. 2 5 1. 1 5 0. 0 Time (sec)

Fig : Altitud5 . . Time vs Fligh r efo t4

5 5 4. 4 5 3. 3 5 2. 2 5 1. 1 5 0. Time (sec)

Fig. 6: Average Velocity vs. Time for Flight 4

160 -, «••••* ^ ^ . - -

•» «• «• 120 H •

«• 80

60 .••* .••.••^

20 ..-"'"

01 234567 Time (sec)

Fig. 7: Altitude vs. Time for Flight 6

.•••** * .. .•.•>" *• ** ^ • / - . 35

^P •X* *»

t ~ " • -

*§ I20 15

0 ------r ———————————————————————————————————————— --- 01234567 Time (sec)

Fig. 8: Average Velocity vs. Time for Flight 6

FINDS Sponsorship record, again—to attair o . n ft altitude 0 50 f o s Th 2 Octobee r 2000 record-breaking beyond within the foreseeable future. Note that Lightcraft flight t WSMa s R were sponsorey db ten more doublings in altitude are necessary to e th Foundatio r fo Internationan l Non- reach the edge of space (e.g., 256-kft, or 78-km). governmental Developmen Spacf o t e (FINDS)a , non-profit organization dedicate o promotint d g THE NEXT STEPS? low cost acces spaceo st . With FINDS funding, laser launch technology has been decidedly e feasibilitTh f o ambitiouy s flight exclusive th move f o t edou real governmentf mo - demonstrations for laser Lightcraft to extreme sponsored research inte commerciaoth l launch altitudes (e.g., 10 to 30 kilometers) in the near arena. Lightcraft Technologies attributes it s future, depends upon three key steps: 1) scaling successful flights to proprietary improvements in the launch laser power to at least 100-150 the design of both the launch stand, and the kilowatts ) linkin2 ; g thimete4 s1. lasea r o t r #200-series Lightcrafs it t t itselfse w . no LTs Iha telescope; and finally, 3) scaling the #200-series sights squarely upon doubling its current altitude Lightcraft design to diameter of 23-cm or more.

Scaling Lightcraft Technology Launch Laser Technology e JulTh y 199 d Octobe9an r 2000 Several high power lasers of "Star WSMR tests have conclusively proven that the Wars" vintage have been "mothballedt a " requisite Lightcraft engine technology for flights HELSTF ove pase th r t decade: e.g., DRIVER, 'extremo t e altitudes s certainli ' y clos t handa e . MALIBAR d mosan , t recently, CORA. Also, What remain done scalo t b engine s o ei th et s e store n Tesi da formidablt s i Cel 2 l e pulsed siz 23-co et r larger mreasonabl(o a r fo ) e near- electric power supply from the EMRLD excimer term objective of 10-km to 30-km altitudes. laser. This power suppl s sufficienyi drivo t t ea Note that two 23-cm Lightcraft have been megawatt-class CO2 laser. Several mammoth constructe t a RPd I undee th author'r s cylindrical pressure vessel alse sar o availabln eo supervision, prio Septembeo t r r 1999 firse Th .t site, for potential use in laser gas 'blow-down' 23-cm complete Lightcraft was designed and experiments (a customary process in shaking out built as a rotating wind tunnel model as the a new prototype 'laser head.' central focu graduata f o s e student thesis project In short, HELST larga s Feha stockpile by Andrew Panetta (supervised by the author). of high power laser part handn o s , sufficieno t t The rotating model was run in RPFs 4-ft X 6-ft construct (or restore and/or upgrade) a 100-150 subsonic wind tunnel obtaio t , aerodynamie nth c kW pulsed CO2 electric laser. The laser upgrade performance data desired for future flight project has been estimated to cost nearly $ 2.5 simulations (see Ref. 9) . million and take 2 years to complete. Clearly, to e seconTh d 23-cm diameter Lightcraft be useful the new laser must also be linked with a designes engin fabricatee wa b I r o et fo dRP t a d large telescope (i.e. transmittere th , orden i ) o t r laboratory experiments with and without ablative project a collimated beam to high altitudes. propellants e engin Th finalls . ewa y tested with Anticipating this need, NASA Marshall Space solid ablative insert Tesn si t t HELSTCela 3 l F Flight Cente s alreadha r y transporte a surplud s on 9-11 July 1999, with PLVTSe Th . 1.4 meter telescope to HELSTF in 1999, taken performance data revealed coupling coefficients from a remote outpost in Australia. The a0 newtons 46 hig s r megawatha pe s t (N/MW) telescope must rolstil w convertee eb ne l s it r dfo using laser pulse energies up to 667 joules with a as high power laser transmitter. 30-usec pulse duration. Further increases in CC Note that this new 100-kW or 150-kW performance beyon N/M0 d50 W would seemo t CO2 laser could later serve as the master- be feasible - with substantially higher laser pulse oscillator for a 1 or 2 megawatt power amplifier. energies. Fully developed e 23-cth , m laser This megawatt launch lase bees ha rn estimateo dt propulsion engine could conceivably produca e cost about $25M and take 3 years to construct. thrust of at least 100 newtons (22.5 pounds) with Hence e 150-kth , W syste s significanha m t a 150-kW infrared laser that deliversy sa , growth potential - leading directly to a 1-kg perhaps, 10 kJ pulses @ 150 Hz. For a projected micro-satellite launch t lasero leasA tw t. 23-cm Lightcraft vehicle empty weight (i.e.o n , megawatt-class CO2 electric lasers have been propellant or payload) of just 1.5 newtons (5.3 built during the 1970's in this country. These ounces), thrust/ weight ratio woul nearle db . y67 were the open-cycle "Thumper" laser, and very This scal f Lightcrafo e t could certainly enable much smaller "flight-weight" systeme builth r fo t flights to the edge of space, but the discussion is Airborne Laser Laboratory, both constructed by academic until a 10X more powerful CO2 electric the AVCO Everett Research Laboratory. discharge lase builts ri . Capitalizin thin go s mature CO2 electric laser technology shoula straight-forwar e b d d SO WHAT IS LTI UP TO? engineering enterprise expensivNo . e cutting- edge "Star Wars" expenditurD R& - s neededi e , LT s i pursuinI e developmenth g f o t since that technology investment was made over beamed energy propulsion technology on two two decades ago in the USA. Constructing a simultaneous fronts ) a creatin: g substantially megawatt CO2 electric laser could indeea e b d improved Lightcraft engin vehicld ean e concepts, conservative undertaking, with well-defined ) anb encouragind e restoratioth g n and/or risks, incorporating the most up-to-date upgrades of infrared launch lasers at HELSTF. electronic control systems. Note thaoriginae th t l Clearly, withou t leasa t a 10-folt d upgradn i e planhalf-megawata r sfo t CO electric laser still beam power beyond the present 10-kilowatt

exis majoa t a t r aerospace compan2 USAe th n yi . carbon dioxide laser at WSMR, everyone's ability to set future Lightcraft altitude records

will be severely curtailed. One thousand feet diameter, payload mass, and propellant fraction besmighe th t e thab t t PLVT. do n Sca against altitude objectives indeedd An . , altitude As mentioned above, LTI receivea d is the most accurate measure of progress in grant last year from a non-profit organization beamed energy propulsion technology. -But intereste promotinn di cosw glo t acces spaceo st . without serious investment in more powerful Under this s developini grant I LT , familga f o y launch lasers exercise th , futiles ei . HenceI LT , new laser propulsion engine geometries, is committed to promoting the growth in launch integrated with vehicle concepts e thaar t laser powe t WSMa r R- immediatel 0 15 o t y specifically tailore laser dfo r launch applications. kilowatts, then to one megawatt in the near These innovative prototype engines will sooe nb future. fabricate e laboratord testeth an dn i d y with available pulsed CO2 lasers. Once compatible SUMMARY launch stand e constructedar s , theslasew ne er Lightcraft designs will then be flight-tested We are facing a revolution in advanced outdoors. propulsion and power technology - for future LTI is seeking sponsors to explore flight transportation systems. This technology major refinement f thio s s revolutionary kinf do can certainl labelee yb s d"disruptive,a t i d "an laser propulsion engine vehicled brino t an , d gan , will ultimately touch each and every one of us the system to a much higher performance level within the next 15 to 25 years. In this future era, thabees nha n demonstrate dateo dt . Additional subsonic jumbojets and high-speed civil fund e e constructioneedear th s r fo d f theso n e transports will be as obsolete as the first Wright new Lightcraft prototypes, to protect intellectual Flyer biplane r spacou ; e shuttles will have been property obtaio t d nan , engine performance data retired to the Space museums. What is this - from both in the laboratory and from outdoor revolution answere ?Th : "Highway Light.f so " flight-testing. Investors hav opportunite eth o yt (www.lightcrafttechnologies.com) e grounth t a d n i floord promott an ge , a e revolutionary "disruptive" launch technology that ACKNOWLEDGEMENTS will ultimately reduce payload delivery costs to unheard of levels. Chemical rockets will not be The author gratefully acknowledges the abl competo et nanosar efo microsad an t t clasf so important contributions to this project by the RPI payloads, once laser launch technology becomes Central Machine Shop; Stephen Squires, Chris commercially available. Beairsto and Mike Thurston of DATTS; Ron Accomplishing the laser-launch of Grimes for recording the peak altitudes for the 2 microsatellites objective is simply a matter of October 2000 Lightcraft flights FINDd an ; r Sfo will, and finances. The scientific knowledge and sponsorin I tests additionn LT I .e gth authoe th , r engineering expertis pulo et s alreadli thif of s y would like to thank the AFRL and NASA here: e.g. hige ,th h power infrared electric lasers, Marshall Space Flight opportunitCentee th r rfo y high power laser optics, ceramic matrix guido t e their Laser Lightcraft Program through composite materials, lightweight electronics, the firs WSM3 2 t R tests from 1995-1999. sophisticated guidanc controd ean l systemsd an , the e laselikeTh r. launch system has, among REFERENCES others e notablon , e asset e mosth :t expensive part of the launcher (i.e., the laser and telescope), 1. L. N. Myrabo, "Solar-Powered Global Air always remain e grounds nevei th d n o ran s , Transportation," Paper 78-698, subjected to the risks of launch. Produced in AIAA/DGLR 13th International Electric large quantities, microsat Lightcraft shoule b d Propulsion Conference Diegon , Sa , CA , almost expendable, certainly reusable, and 25-27 April 1978. probably recoverable from any failed flight. After minor refurbishment, they coule b d launched again (and again - )unti l successfully 2. L.N. Myrabo, "A Concept for Light- Powered Flight," AIAA/SAE/ASME delivered into orbit. th Lightcraft engine and vehicle 18 Joint Propulsion Conference, development goals must certainly be anchored to, Cleveland , 21-2OH , 3 June 1982. and interwoven with, their high power lasers. Anyone can put together an ambitious schedule . WaltonD . L Myrabo . . 3 d ListG ,an ,, for growing laser Lightcraft technology ovee th r "Economic Analysia Beam f o s- next five years or more - mapping vehicle Powered, Personalized Global

Aerospace Transport System," 11. D.G. Messitt, L.N. Myrabo F.Bd an , . Mead Rensselaer Polytechnic Institute, Jr., "Laser Initiated Blast Wavr fo e December 1989 (unpublished). Launch Vehicle Propulsion," AIAA 2000-3848, 36th AIAA Joint Propulsion 4. L. Myrabo and D. Ing, The Future of Flight, Conference, 16-19 July 2000, Baen Books, Distributed by Simon & Huntsville, AL. Schuster, 1985. 12. D.G. Messitt, L.N. Myrabo, and F.B. Mead 5. L.N. Myrabo, "Advanced Beamed-Energy Jr., "Laser Initiated Blast Wave for and Field Propulsion Concepts," BDM Launch Vehicle Propulsion," AIAA Corp. publication BDM/W-83-225-TR, 2000-3848, 36th AIAA Joint Propulsion Final Report for the California Institute Conference, 16-19 July 2000, of Technology and Jet Propulsion Huntsville, AL. Laboratory under NASA Contract NAS7-100, Task Orde . RE-156No r , 1983y dateMa .1 d3 13. F.B. Mead Jr., S. Squires, C. Bearisto, and M. Thurston, "Flights of a Laser- Powered Lightcraft During Laser Beam 6. L.N. Myrabo, D.G. Messitt, and F.B. Mead Hand-off Experiments," AIAA 2000- Jr., "Groun Flighd dan t Test Lasea f so r 4384, 36th AIAA Joint Propulsion Propelled Vehicle," AIAA Paper No. Conferenc d Exhibitan e , 16-19 July 98-1001, 36th AIAA Aerospace 2000, Huntsville. AL , Sciences Meeting & Exhibit, Reno, NV, 12-15 Jan. 1998. . C.W14 . Larso F.Bd an n . Mead Jr., "Energy Conversion in Laser Propulsion," AIAA . 7 F.B. Mead Jr., L.N. Myrab d D.Gan o . 2001-0646, 39th AIAA Aerospace Messitt, "Right Experiments and Sciences Meeting & Exhibit, 8-11 Evolutionary Developmen a Lase f o tr January 2001, Reno, NV. Propelled, Transatmospheric Vehicle," Space technolog & Applicationy s 15. T.-S. Wang, Y.-S. Chen, J. Liu, L.N. International Forum (STAIF-98), Myrabo F.Bd an , . Mead Jr., "Advanced Albuquerque, NM, 25-29 Jan. 1998. Performance Modeling of Experimental Laser Lightcrafts," AIAA 2001-0648, 8. F.B. Mead Jr., L.N. Myrabo and D.G. 39th AIAA Aerospace Sciences Meeting Messitt, "Fligh Ground an t d Testa f o s & Exhibit, 8-11 January 2001, Reno, Laser-Boosted Vehicle," AIAA Paper NV. No. 98-3735, 34th AIAA Joint Propulsion Conference & Exhibit, 16. F.B. Mead Jr., "Laser-Powered, Vertical Cleveland , 13-1OH , 5 July 1998. Flight Experiments at the High Energy Laser System Test Facility," AIAA 9. A.D. Panetta, H.T. Nagamatsu, L.N. 2001-3661, 36th AIAA Joint Propulsion Myrabo, M.A.S. Minucci, and F.B. Conference and Exhibit, 8-11 July Mead, Jr., "Low Speed Wind Tunnel 2001, Salt Lake City, UT. Testin Lasea f go r Propelled Vehicle," Paper #1999-01-5577, 1999 World 17. L.N. Myrabo, et.al., "Lightcraft Technology Aviation Conference 19-21 October Demonstrator," Final Technical Report, 1999, San Francisco, CA prepared under Contract No. 2073803 for Lawrence Livermore National 10. T.-S. Wang, Y.-S.Cheng, J. Liu, L.N. Laboratore SDIth Od an yLase r Myrabo, and F.B. Mead Jr., Propulsion Program, dated 30 June Modeling of an "Performance 1989. Experimental Laser Propelled Lightcraft," AIAA 2000-2347, 31st . L.N18 . Myrabo, et.al., "Apollo Lightcraft AIAA Plasmadynamics and Lasers Project," Final Report, preparee th r dfo Conference, 19-22 June 2000, Denver, NASA/USRA Advanced Design CO. Program, Annual Summer

Conference, Washington, D.C., 17-19 June 1987.

19. L.N. Myrabo, et.al, "Apollo Lightcraft Project, Final Report, preparee th r dfo NASA/USRA Advanced Design Program, 4th Annual Summer Conference, Kennedy SFC, FL, 13-17 June 1988.

15 American Institute of Aeronautics and Astronautics