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Flight Times to the Heliopause Using a Combination of Solar and Radioisotope Electric Propulsion

Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang and Schartner, Karl-Heinz (2011) Flight Times to the Heliopause Using a Combination of Solar and Radioisotope Electric Propulsion. 32. IEPC 2011, 11.-15. Sep. 2011, Wiesbaden, Deutschland.

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Abstract

We investigate the interplanetary ight of a low-thrust space probe to the heliopause, located at a distance of about 200AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of ballistic and electrically propelled ight legs, we have investigated whether the set ight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the �rst stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol, using Arti�cial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks' parameter set. Based on a parameter space study, in which the number of thrust units, the unit's speci�c impulse, and the relative size of the solar power generator were varied, we have chosen one con�guration as reference. The transfer time of this reference con�guration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all ight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher- provided hyperbolic excess energy up to 49 km^2/s^2. The resulting minimal ight time for the reference con�guration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is exible enough to allow a launch every year. The inclusion of a y-by at Jupiter �nally resulted in a ight time of 23.8 years, which is below the set transfer-time limit. However, compared to the 27.5-year transfer, this mission design has a signi�cantly reduced launch window and mission exibility if the escape direction is restricted to the heliosphere's "nose".

Item URL in elib:https://elib.dlr.de/70898/
Document Type:Conference or Workshop Item (Speech, Paper)
Title:Flight Times to the Heliopause Using a Combination of Solar and Radioisotope Electric Propulsion
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Ohndorf, Andreasandreas.ohndorf (at) dlr.deUNSPECIFIED
Dachwald, Bernddachwald (at) fh-aachen.deUNSPECIFIED
Seboldt, Wolfgangwolfgang.seboldt (at) dlr.deUNSPECIFIED
Schartner, Karl-Heinzkarl-hein.schartner (at) exp1.physik.uni-giessen.deUNSPECIFIED
Date:September 2011
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:low-thrust trajectory optimization, heliosphere, ion propulsion
Event Title:32. IEPC 2011
Event Location:Wiesbaden, Deutschland
Event Type:international Conference
Event Dates:11.-15. Sep. 2011
Organizer:Electric Rocket Propulsion Society
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Vorhaben Exploration des Sonnensystems
Location: Oberpfaffenhofen
Institutes and Institutions:Space Operations and Astronaut Training > GSOC-German Space Operations Center
Deposited By: Ohndorf, Andreas
Deposited On:18 Oct 2011 12:01
Last Modified:31 Jul 2019 19:32

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