Analyses of Remote Sensing Mission Scenarios with Electric Propulsion
- Paper number
IAC-05-C1.7.02
- Author
Ms. Stefania Cornara, DEIMOS Space S.L., Spain
- Coauthor
Mr. Fabrizio Pirondini, DEIMOS Space S.L., Spain
- Coauthor
Mr. Augusto Caramagno, DEIMOS Space, Spain
- Coauthor
Mr. Michael E. Price, Qinetiq, United Kingdom
- Coauthor
Mr. Jose Gonzalez del Amo, European Space Agency (ESA)/ESTEC, The Netherlands
- Coauthor
Mr. Bernardo Carnicero Domínguez, European Space Agency (ESA)/ESTEC, The Netherlands
- Year
2005
- Abstract
The increasing number of European Earth Observation programmes and missions has brought to the fore the need for an assessment of innovative concepts to cope with the requirements and the implementation of Remote Sensing (RS) mission scenarios. To address this emerging need, the “Study on RS Spacecraft with Electric Propulsion (EP)” has been carried out in the frame of an ESA contract with the primary aim to identify RS missions that would significantly benefit from the exploitation of the now maturing EP technology, and to quantify those benefits in terms of system improvements (i.e. mass, power) or innovative payload operation concepts. The study is intended to outline a complete set of requirements imposed on EP systems by RS missions and to identify the possible EP systems capable to fulfil these mission requirements. A thorough mission-level trade-off approach has been applied to perform an exhaustive analysis of the possible RS mission/EP system combinations in order to determine which RS missions clearly benefit from the use of EP or are enabled by EP. Mission scenarios instead of specific missions have been evaluated and general requirements for RS mission classes have been obtained, accounting for the close relationship between payload, S/C configuration and power subsystem, and EP system in the overall S/C design process. This study deals with a wide spectrum of RS mission scenarios, including Optical, LIDAR, Gravity and SAR payloads, and encompassing also formation-flying configurations for SAR Interferometry and gravity missions. In every scenario EP plays a key role to allow lowering the orbit altitude (down to 300 km or less) for RS missions, using the high fuel efficiency of an EP system to compensate for continuous severe aerodynamic drag and counteract the rapid decay of the orbit with a low propellant mass consumption compared to chemical systems. Lower altitude can bring tangible advantages leading to improved instrument performance (ground resolution and signal-to-noise ratio) for fixed instrument design, or allowing a reduction in instrument mass, dimensions and power demand for fixed instrument performance requirements. In addition, longer mission duration, potentially enabled by EP at low altitudes, can dramatically improve the quality/quantity of data. EP is also expected to provide improvements in terms of thrust controllability, specific impulse, throttability and power-to-thrust ratio in order to fulfil the tight requirements imposed on the propulsion system by complex orbital configurations, such as formation-flying systems. Finally, EP emerges as a fundamental enabling technology to provide the continuous drag-free attitude and orbit control capacity, as well as thrust throttability and vector stability, so as to meet the payload operational constraints at the very low orbit altitudes required by RS Gravity Missions. The mission scenario analyses have been performed using the RS Mission Performance Model, a SW tool developed by DEIMOS Space to carry out a parametric study based on relevant design drivers (covering mission, spacecraft and payload parameters) and output figures of merits (such as mass and power). The core functional capabilities embedded in this tool allow modelling the relevant components of a RS mission scenario with EP (mission definition, AOCS, payload, S/C configuration, EP system, power subsystem, etc.), as well as their interactions. The Performance Model computes parametric curves of mass and power, and sizes the main spacecraft subsystems for a given input scenario defined in terms of orbit altitude range and propulsion system capability range (specific impulse, thrust and power-to-thrust ratio). Numerical tools have been applied to refine the assessment and the design solutions generated by the parametric analyses. The results obtained generally confirm the expected benefits of EP application in terms of mass and power savings at lower altitudes, and draw meaningful guidelines for further mission and spacecraft design refinements. This paper presents a comprehensive overview of the analyses of RS mission scenarios with EP supported by a parametric study and by numerical simulations. The main effort has been devoted to define a general approach to the analysis, so as to allow the characterization of a wide range of possible RS mission requirements and design solutions. The application of the concepts and the methodologies emerging from the study focuses primarily on the evaluation of on-going and future European Earth Observation missions.
- Abstract document
- Manuscript document
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