I I THE PEACEKEEPER POST BOOST VEHICLE FOR I CIVIL SPACE APPLICATIONS Paul G. Phillips, P.E. I Science Applications International Corporation Dr. Stephen J. Hoffman I Science Applications International Corporation James S. Moore I NASA Johnson Space Center Abstract Orbital UV Jovian Observer missions. The con­ I Ownership of several Peacekeeper fourth stages figurations and preliminary performance require­ has been transferred from the USAF to NASA ments of these missions are discussed. for use in the civil space program. The produc­ I tion of Peacekeeper missiles was discontinued This paper concludes that the Peacekeeper PBV although several of the fourth stages known as provides adequate performance for these mis­ I Post Boost Vehicles or PBV's were in production sions and is worthy of further consideration in and in various stages of completion. This paper the Discovery Program or other programs as a examines the potential use of these PBV's for booster stage or a spacecraft bus. The PBV is I small civil space missions, especially Discovery found to be a versatile spacecraft requiring some class missions. technical work but costing far less than an I equivalently capable three-axis stabilized vehicle. Several configurations of the PBV with small in­ terplanetary missions are examined. The deliv­ Introduction I ered configuration of the PB V is described along As the cold war ends, the possibilities of convert­ with modifications necessary to make them flight ing weapons related equipment to use in civil ready. This paper examines the use of the PBV space program become more and more intriguing. I as a booster stage and as a spacecraft bus. The This is especially true for the upper stage of the booster configurations examined include use of Peacekeeper missile. The Air Force will be dis­ I the PB Valone and in combination with solid continuing production of this weapons system rocket motors. The Delta II and Shuttle launch and has in fact already canceled orders for any systems are considered as launch vehicles for more of them. Some of the upper stages known I these combinations. as Post Boost Vehicles or PBV's are currently on the production line and in various stages of com­ I Discovery Mission performance requirements and pletion. Since they will not be needed for de­ compatibility with the PBV is reviewed. Four of fense purposes, ownership of some of the PBV's the missions which appear to be compatible with has been transferred to NASA for use in the civil I the PBV include the MESUR Pathfinder, the space program. The purpose of this paper is to Near Earth Asteroid Rendezvous, the Venus examine the issues and some of the possibilities I Atmosphere Composition Probe, and the Earth- I 1 I of using these PBV's for small civil space mis­ not the same as space booster or spacecraft bus I sions. missions so the PBV will require some adapta­ tion. The number missions is limited in this study to a I representative set of interplanetary missions. By The PBV is a capable spacecraft. Figure I is an examining this set of missions most of the topics illustration of the PBV itself. It uses a pressure­ surrounding use of the PBV will be covered. fed monomethyl-hydrazine and nitrogen-tetroxide I The Discovery Program of small scale, rapid propulsion system. The system includes a sin­ tum-around, cost constrained interplanetary mis­ gle, gimbal ed, 11400 N (2563 lbf) thrust primary I sions offers a number of opportunities for use engine and eight 311 N (70 lbf) thrust attitude with the PBV. The PBV is compatible with the control engines for three-axis control. The Delta II launch vehicle which is a constraint of the structure is robust consisting of an aluminum I Discovery Program. To illustrate more of the is­ isogrid skin with strong interior primary and sec­ sues of integration, this study also focuses on the ondary elements. It is 96 inches in diameter to I use of the Shuttle for launch purposes. At the match its launch vehicle and is approximately 43 time of this writing, it appears the Shuttle may be inches in its axial direction. These dimensions a available due to possible down-scaling of its leave a significant amount of interior space avail­ I commitment to Space Station Freedom missions. able. Well over 100 of these stages have been The study, then, of the PBV use in civil space built and 18 have been successfully flight tested. I programs will be limited, for this exercise, to the PBV with Discovery missions and will concen­ trate on the Shuttle as a launch vehicle. I The primary options for use of a PBV for I Discovery missions include booster type mis­ sions and spacecraft bus missions. For some missions the best use of the PBV is as a three­ I axis-stabilized stage for injection of the primary spacecraft into its interplanetary trajectory. In I some cases, the mission is such that the PBV can be used as an actual supporting spacecraft bus. This later option involves the use of the PBV as Figure 1 - Peacekeeper Post Boost Vehicle I the primary spacecraft for the mission. The basic PBV is delivered without its Guidance, Navigation and Control system and power sys­ I The Post Boost Vehicle tem, and does not include a thermal control or a The PBV is an integrated, bipropeUant stage de­ communication system. The power or avionics signed to deliver multiple warheads onto highly I subsystem hardware would be clearly inappro­ accurate trajectories. Its design mission is about priate for most civil space applications and may 30 minutes in duration and begins after an ex­ not have been declassified. The PBV never had tended idle period in a missile silo. The entire I communications or thermal control systems be­ missile system is designed to launch into and cause its mission did not require them. The PBV through a hostile environment. This mission is I 2 I I I is structurally robust but does not have launch vehicle or payload mating accommodations. The PBV Performance modifications necessary for adaptation of the Figure 2 shows the performance capabilities of I PBV to civil space missions include design de­ the PBV in various configurations. Shuttle con­ velopment and integration of avionics, power and figurations include the PBV by itself and a light­ thermal system as required along with structural ened version of the PBV with extra propellant. I adaptation to launch vehicles and payloads. This lightened version is assumed to have struc­ ture removed and tanks added such that the dry I The NASA Johnson Space Center owns 12 mass remains constant and the mass of propellant PBV's in various stages of completion. is doubled. Performance figures for the PBV Rocketdyne, the manufacturer, has 4 stages with alone and with extra propellant are shown in solid I all components available and requiring only final lines. As will be shown later, these capabilities assembly. There 6 units for which the compo­ are inadequate for any of the Discovery missions. I nents are nearly complete and piece-parts and raw materials are available on the remaining 2. Cost The PBV capacity as a booster can be enhanced estimates for bringing the PBV's to flight ready by the addition of a solid rocket motor. In these I status including the NASA added subsystems cases the combination of solid rocket and PBV is such as avionics are in the neighborhood of $ 5 a two-stage upper stage with primary control by I million for each PBV. The availability and esti­ the PBV. The performance ofthe PBV launched mated cost of the PBV make it a good candidate in Shuttle with a Morton Thiokol Star 48b and a for a number of applications. Star ·63f are also shown with solid lines and, I relative to the single stage PBV configurations, PBV Use in Civil Launch Systems have correspondingly increased capability. I A PBV is currently planned for the low-earth­ orbit, Liquid Plume Generator (LPG) mission, an The shaded lines in Figure 2 illustrate the perfor­ SDIO mission launched from the Shuttle. mance of the PBV with the Delta IT launch sys­ I Consequently, avionics, power, and thermal tem. The first line indicates PBV performance control subsystems for a non-Peacekeeper appli­ without the standard Star 48b Delta third stage I cation have been designed. In addition, the and is strikingly close to that of the Shuttle Star structural adaptations and safety reviews have 48b line. The second line, which is to the right been completed for PB V integration into the represents PBV performance with the Delta IT and I Shuttle. No required safety modifications have its third stage. This line indicates that a PBV been identified. The choice of launch vehicle will with a Star 48 can provide better performance on make little difference in the work required to a Delta than when launched from Shuttle. This I make the PBV flight ready. So, while the PBV difference is due to the fact that the Delta can will require some adaptation for civil space mis­ place the PBV directly on its injection trajectory I sions, much of the work has already been ac­ without the need to circularize as with Shuttle. complished. I I I 3 I 1000 I 2000 BOO ....'iii' ~ !i 1500 t I ! ! 600 :I :I ! 1000 ! .... .... 400 8 8 I >. E 500 : 200 I 0 0 0 1000 2000 3000 4000 5000 6000 7000 Delta V (melerslllec) I I I I I I I ! I I I I I 0 2 4 6 B 10 12 14 16 1B 20 22 -A- DelIa + PaV Delta V (thousand feet/sec) ......