DYNA SOAR I'S ATLAS ED CENTAUR B BOOSTER Article by Dave Stern, August 2004 E-mail: psidavid@yahoo.com Voice: 425-271-2480 NEWS page----back to Sharkit home page --- e-mail renaud -- Introduction. -- Spaceflight fans and especially those intently focused upon America's first boost-glider, the Dyna Soar series, are aware of Internet describing this fascinating vehicle. Unfortunately, the majority of these sites suffer inaccuracies in that the authors have not thoroughly researched the important early aspects of the overall DS program. There were actually two BAC (Boeing Airplane Company) Dyna Soar gliders: the initial winner--BAC's Model 814-1050-1 Dyna Soar I that progressively developed into, the late BAC Model 844-2050 boost-glider. -- Both vehicles, while bearing external similarities, are two distinctly different boost-gliders. This leaves open the story of the competition winner, the Dyna Soar I, that generated a continuous and heavy research effort leading to the popular and well known-glider displayed on the Internet as the "not so finalized" Boeing Model 844-2050 series. -- In addition, most Dyna Soar Internet sites imply that only one booster was chosen for the glider, the Martin Titan series ICBM, modified. This implication is patently false, and the early booster studies were anything but vague; in fact, engineering files were generated on Boeing's choice of one particular two-stage booster. While scant attention was paid to rocket boosters for late 1950s boost-glider projects, Boeing engineers offered the USAF various choices. Among their major offerings were BAC's clustered solid-fuel Minuteman ICBM, their Model 825 Start booster, the 1958 Boeing "Early Bird" or "Hi Fli," a three-stage booster configuration, and a flyback winged booster that carried an early DS-I glider piggyback style. -- A forthcoming in-depth story concerning the initial Dyna Soar I designed to be coupled with the Atlas ED Centaur B will hopefully be presented in QUEST, The Spaceflight History Magazine during 2004. The article will present previously unpublished information (including highly tantalizing unpublished photographs and little known drawings) excerpted from a book manuscript currently in progress, concerning the intriguing and fascinating "nuts and bolts" history of the Boeing Dyna Soar gliders. -- ------------- -- Long before Sputnik induced shock and fear into the psyche of the Western nations upon reaching low earth orbit, the USAF and selected aircraft companies held the advantage of a six-year start in ongoing classified studies of robotic and manned, winged, rocket-launched satelloid vehicles. Such vehicles were progressively identified by their short acronyms of BoMi (Bomber Missile cum System 118P), RoBo (Rocket Bomber), HYWARDS, Hi Fi Recce, IBV (Intercontinental Ballistic Vehicle), and the least known series of ICGMs (Intercontinental Glide Missile), Boeing's in-house robotic and piloted kissing cousins to their Dyna Soar I Model 814-1040 and later series of boost-gliders. -- Bell Aircraft Company led the way in faster" studies of a manned winged vehicle initially propelled into a low earth orbit by huge rocket boosters or manned recoverable "motherships." Variously known as hypersonic glide vehicles, rocket gliders, boost-gliders, orbital gliders, and space-air vehicles, they did not fly so much as they moved hypersonically on the sheer momentum imparted by their successive propulsion rockets; they entered a skip-glide or flat-glide pattern culminating in a shallow plunge through the atmosphere, where they glide-landed onto a runway. -- Studies focused upon boost-glider design and advanced technology necessary to build them so they could survive atmospheric reentry without roasting the pilot and destroying the glider. Most boosters appearing in various artists' drawings were projections, because no concerted effort was expended to purpose-build a powerful booster for these vehicles. -- In 1957, when USAF Captain William C. Walter was ordered to combine all boost-glider projects into the Abbreviated Development Plan for a single boost-glider to be built and tested, attention was given to rocket boosters. Upcoming IRBM and ICBM rockets were studied with the object of applying them to thrust a boost glide-vehicle into low earth orbit, or provide enough momentum, as with the ICGM, to glide extremely long distances in suborbital fashion. The Dyna Soar Project was the culmination of all the 1950s boost-glider projects. The USAF narrowed down the Dyna Soar (Hypersonic Strategic Weapon System 464L) competitors to Martin-Bell-BAC (Boeing Airplane Company). -- Competitors were bound under USAF regulations to create their boost-glider within the framework of the "weapon system" concept. The major contractor, i.e., Boeing, would provide all related equipment (including integration of the DS glider to Titan boosters provided by the Martin team), skills, and personnel required to test and operate the weapon system. -- Although the Dyna Soar was later redesignated SS (Support System) and even RS-620A (Reconnaissance System), the weapon system philosophy still applied, the prime contractor was responsible for the overall Titan/Dyna Soar and support systems. -- Martin-Bell chose a modified and yet untried WS-107A-2 or SM-68 Titan ICBM, while Boeing engineers opted for the initially troublesome Convair Astronautics WS-107A-1 or SM-65 Atlas. But BAC management and engineers also created an in-house rocket booster composed of surplus clustered ex-Army solid-fuel battlefield Corporal rockets. Known as the BAC Model 825 START (Space Transport and Re-Entry Tests), it would boost-test vehicles to high speeds and altitudes. Boeing's newly designed Model 423 or LGM-30 (WS-133A) Minuteman solid-fuel, quick-reaction ICBM was also studied as a multi-clustered, multi-stage Dyna Soar I booster, but proved too complex. These were the most promising and realistic boosters proposed in the late 1950s. By April 1959, when the USAF/NASA Source Selection Board visited Boeing's secret DC (Development Center) for Boeing's DS I presentation, Strategic Air Command crews were receiving their first operational Atlas D ICBMs. -- BAC's DC mockup engineers apparently received Convair plans for an Atlas first-stage booster they identified as ED, and a second-stage unit called Centaur B (letter designations Boeing engineers assigned to it), and proceeded to build a full-scale wood and mixed materials mockup! The Convair hydrogen-burning Centaur program was directed by former Pennemunde V-2 engineer, Kraftt A. Ehricke. Boeing engineers initially chose the Atlas Centaur combination for its availability, simplicity, efficiency, and Atlas's increasing reliability, plus the possibility of easily engineering certain modifications for boost-glider work. -- From late 1958 to mid-1959, all efforts were focused upon the BAC Model 1047-1 and its successor, the Model 814-1050-1, to stay within strictly defined weight limits of 7,800 pounds empty and 10,000 pounds maximum, allowing the Atlas ED Centaur B to thrust the DS-I glider to orbital speeds of 26,250 fps. Launch weights were calculated at 320,370 pounds. The Atlas ED would burn 170,315 pounds of LOX and 76,030 pounds of RP-1. They estimated that Centaur B would burn 6,670 pounds of SF-1 and 33,330 pounds of LOX at a specific impulse of 412 seconds. -- However, to achieve the performance specifications necessary to launch a piloted boost-glider, the Atlas ED Centaur B had to undergo specific engineering design mdifications. The Atlas engine's gimbal angles were increased to stabilize the booster, while the DS-I's wings and tip fins worked to force the overall booster into a different flight path. -- To accommodate the Model 814-1047-1 and its updated replacement, the Model 814-1050-1, thicker skin gages would provide the necessary booster fuselage stiffness, while the Atlas's ICBM half-stage feature was totally eliminated. Atlas fuel tank capacity and helium pressures were increased, thus generating increased power to 172,000 pounds of thrust. -- Centaur B's fuel tank was increased to 110 inches and, with higher pressures, would generate 20,000 plus-pounds, with growth to 30,000 pounds. BAC engineers also designed a Centaur-to-glider space switch, or interstage unit. The modified "beast" would successfully launch a glider weighing between 7,000 and 9,800 pounds to orbital altitudes of 300,000 feet at 26,200 fps. The DS-I glider could then be operated at various velocity and altitude combinations by means of engine cut-off procedures. -- The booster and glider combination could then perform a spectrum of unmanned glider tests, glider capsule breakaway tests, and finally, robotic and piloted suborbital and orbital flights, including "twice-around" piloted flights. A recently acquired drawing displayed yet another booster, either preceding the Atlas ED Centaur B or an update of it, with stabilizing fins, designated the Convair Astro IV. -- In early 1960, the USAF AMC/ASC (Air Material Command and Aeronautical Systems Command) offices sent a hand-carried termination letter to BAC. Boeing's Dyna Soar management and engineers were ordered to immediately terminate Atlas ED Centaur B studies plus "any growth versions thereof" and to relinquish all accumulated Atlas Centaur design and engineering data, sending it as a contract item to the Dyna Soar Project Office and AFBMD/BMC offices. Atlas ED Centaur B was effectively eliminated as an early and readily available booster; it simply faded from everybody's mind, while BAC focused upon refining the original DS-I glider and integrating it with Martin's Titan booster system. -- This is but a fraction of the fascinating and still fragmented history of the BAC Dyna Soar boost-glider program. *** SPECIFICATIONS CHART Atlas ED Centaur B booster. Launch Weight with 7,800 pound BAC Dyna Soar Glider, 318,369 pounds. Atlas Engines: Two NAA Rocketdyne Engines. Sea Level Thrust, 172,000 pounds each. Center Sustainer Engine. Sea level Thrust, 57,000 pounds. Two Vernier Engines. Sea Level Thrust, 1,000 pounds each. Centaur B. Two Pratt & Whitney Engines. Thrust, 15,000 pounds each. Overall length with BAC 1050-1 Dyna Soar I glider, 138 feet, 6 inches.