Advanced Space Propulsion for the 21st Century
2003; American Institute of Aeronautics and Astronautics; Volume: 19; Issue: 6 Linguagem: Inglês
10.2514/2.6948
ISSN1533-3876
Autores Tópico(s)Planetary Science and Exploration
ResumoHE overriding goal of advanced space propulsion is to reduce the costs of doing space missions, and to enable totally new types of missions that basically could not be performed (even at essentially unlimited cost) with existing technology. For example, with Earth-launch costs on the order of $10,000 per kilogram (comparable to the current cost of gold!) of delivered payload, one important application of advanced propulsion is to reduce thecostofaccessto space(andtransportation oncein space), both in the initial Earth-launch vehicle and then in the in-space vehicles, by reducing the total mass (most of which is propellant) that must be launched from Earth. This can be achieved by either developing more efe cient, higher-performance (i.e., higher specie c impulse Isp/ propulsion technologies, or by reducing the propellant requirements by reducing dry mass, mission velocity 1V, and so on. (Note however that launch cost is strongly driven by launch frequency; 1 thus, some advanced propulsion concepts attempt to both improve performance and increase launch rate.) A second goal of advanced propulsion is the ability to perform previously “ impossible” missions. An example of an impossible mission is attempting an interstellar mission using chemical propulsion. No matter how large the rocket, no matter how many stages it has, you simply cannot achieve the speeds (typically at least 10%of the speed of light) required for a practical interstellar mission using a chemical propulsion system. More generally, it is not practical to performaspace mission wherethe mission 1V isgreater than afew (e.g., two to three) times the propulsion system’ s exhaust velocity Vexhaust or, equivalently, Isp. Ultimately,theperformanceofanyrocketislimitedbytheRocket
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