Earth-to-Orbit Rocket Propulsion

The Earth-to-orbit (ETO) phase of access to space is and always will be the first and most critical phase of all space missions. This first phase of all space missions has unique characteristics that have driven space launcher propulsion requirements for more than half a century. For example, the need to overcome the force of the Earth s gravity in combination with high levels of atmospheric drag to achieve the initial orbital velocity; i.e., Earth parking orbit or =9 km/s, will always require high thrust- to-weight (TN) propulsion systems. These are necessary with a T/W ratio greater than one during the ascent phase. The only type of propulsion system that can achieve these high T/W ratios are those that convert thermal energy to kinetic energy. There are only two basic sources of onboard thermal energy: chemical combustion-based systems or nuclear thermal-based systems (fission, fusion, or antimatter). The likelihood of advanced open-cycle, nuclear thermal propulsion being developed for flight readiness or becoming environmentally acceptable during the next century is extremely low. This realization establishes that chemical propulsion for ET0 launchers will be the technology of choice for at least the next century, just as it has been for the last half century of rocket flight into space. The world s space transportation propulsion requirements have evolved through several phases over the history of the space program, as has been necessitated by missions and systems development, technological capabilities available, and the growth and evolution of the utilization of space for economic, security, and science benefit. Current projections for the continuing evolution of requirements and concepts may show how future space transportation system needs could be addressed. The evolution and projections will be described in detail in this manuscript

Overview of the In-Space Propulsion (ISP-1) Project

The intent of this publication is to provide an overview of the progress of the ISP1 project over the 2011-2012 period. In the frame of the European FP7 Collaborative Project, Focused Research Project Theme 7, the In-Space Propulsion (ISP-1) project GA# 218849 was initiated in 2009 with the objective of improving the knowledge and the techniques which are necessary for future space missions relying on cryogenic propulsion. The ISP-1 program is structured into five main work packages which deal with various technological issues associated to the development of a Low Thrust Cryogenic Propulsion system. It concentrates on liquid oxygen, liquid hydrogen, and liquid methane propellants. The subject addressed by the work packages are the LOX-methane combustion, the hydrogen embrittlement, the material compatibility and tribology in liquid oxygen, the energy management of low thrust propulsion system, and the development of electrically driven cryogenic turbopumps. The scientific and technological goals assigned to each work package can be summarized as: - LOX/CH4 Combustion studies and test focused on low thrust LOX/CH4 space propulsion with an emphasis on low pressure liquid injection - Compatibility and tribology analysis and tests addressing both technological aspects (Foil bearings in cryogenic conditions , material for bearing retainer, graphite against a hard surface for dynamic seals) and more fundamental aspects (feasibility of CH4 tribological tests, theoretical analysis of local contact conditions) of tribology. - Hydrogen embrittlement studies and tests with the objective of testing new materials in a High pressure and medium range temperature environment - Heat Accumulators studies and tests, focused on energy management techniques, with testing of a low temperature accumulator - The Propellant Electric Pumps design and tests, to be concluded by the testing of a demonstrator pump in LN2 The work packages of project ISP1 rely on a combination of analysis and test, of theoretical activities which can serve as a basis for PhD theses or more application oriented activities such as the design and testing of a demonstrator pump or a demonstrator accumulator. These work packages are focused on technologies which are considered as the critical points of future cryogenic space propulsion systems. By increasing the technological readiness level of these technologies, these activities pave the way for the development of future propulsion systems and constitute an asset with respect to possible future international cooperation.JRC.F.4-Nuclear Reactor Integrity Assessment and Knowledge Managemen