TY  - CHAP
A1  - Gehler, M.
A1  - Ober-Blöbaum, S.
A1  - Dachwald, Bernd
T1  - Application of discrete mechanics and optimal control to spacecraft in non-keplerian motion around small solar system bodies
T2  - Procceedings of the 60th International Astronautical Congress
N2  - Prolonged operations close to small solar system bodies require a sophisticated control logic to minimize propellant mass and maximize operational efficiency. A control logic based on Discrete Mechanics and Optimal Control (DMOC) is proposed and applied to both conventionally propelled and solar sail spacecraft operating at an arbitrarily shaped asteroid in the class of Itokawa. As an example, stand-off inertial hovering is considered, recently identified as a challenging part of the Marco Polo mission. The approach is easily extended to stand-off orbits. We show that DMOC is applicable to spacecraft control at small objects, in particular with regard to the fact that the changes in gravity are exploited by the algorithm to optimally control the spacecraft position. Furthermore, we provide some remarks on promising developments.
KW  - Spacecraft
Y1  - 2009
SN  - 978-161567908-9
N1  - 60th International Astronautical Congress 2009, IAC 2009; Daejeon; South Korea; 12 October 2009 through 16 October 2009
SP  - 1360
EP  - 1371
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Schulte, Jonas
A1  - Schwager, Christian
A1  - Noureldin, Kareem
A1  - May, Martin
A1  - Teixeira Boura, Cristiano José
A1  - Herrmann, Ulf
T1  - Gradient controlled startup procedure of a molten-salt power-to-heat energy storage plant based on dynamic process simulation
T2  - SolarPACES: Solar Power & Chemical Energy Systems
N2  - The integration of high temperature thermal energy storages into existing conventional power plants can help to reduce the CO2 emissions of those plants and lead to lower capital expenditures for building energy storage systems, due to the use of synergy effects [1]. One possibility to implement that, is a molten salt storage system with a powerful power-to-heat unit. This paper presents two possible control concepts for the startup of the charging system of such a facility. The procedures are implemented in a detailed dynamic process model. The performance and safety regarding the film temperatures at heat transmitting surfaces are investigated in the process simulations. To improve the accuracy in predicting the film temperatures, CFD simulations of the electrical heater are carried out and the results are merged with the dynamic model. The results show that both investigated control concepts are safe regarding the temperature limits. The gradient controlled startup performed better than the temperature-controlled startup. Nevertheless, there are several uncertainties that need to be investigated further.
KW  - Power plants
KW  - Energy storage
KW  - Associated liquids
Y1  - 2023
SN  - 978-0-7354-4623-6
U6  - https://doi.org/10.1063/5.0148741
SN  - 1551-7616 (online)
SN  - 0094-243X (print)
N1  - SolarPACES: SOLAR POWER & CHEMICAL ENERGY SYSTEMS: 27th International Conference on Concentrating Solar Power and Chemical Energy Systems, 27 September–1 October 2021, Online
IS  - 2815 / 1
PB  - AIP conference proceedings / American Institute of Physics
CY  - Melville, NY
ER  -