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SUMMARY:ELECTRO: a SW tool for the ELECtric propulsion TRajectory Optimiza
tion
DTSTART;VALUE=DATE-TIME:20181109T100000Z
DTEND;VALUE=DATE-TIME:20181109T103000Z
DTSTAMP;VALUE=DATE-TIME:20220528T104133Z
UID:indico-contribution-3875@indico.esa.int
DESCRIPTION:Speakers: Juan C. Bastante (OHB System AG)\nELECTRO: a SW tool
for the ELECtric propulsion TRajectory Optimization\n\nLow-thrust orbit t
ransfers are becoming increasingly attractive thanks to the mass savings t
hey offer and the maturity of electric propulsion technology. For this rea
son\, there is an interest in developing fast\, but still reliable traject
ory optimisation methods that can be applied in the preliminary phase of t
he design of a mission. The tool presented is based on the averaging of th
e equations of motion written in equinoctial elements over true longitude.
The calculus of variations is used to identify the optimal control law. I
n particular\, the indirect optimisation method used here is based on a se
quential gradient-restoration algorithm. Perturbations such as zonal gravi
ty harmonics are included as well as shadowing effects\, which need to be
modelled because electric propulsion is normally switched off during eclip
ses. For the eclipse detection algorithm\, an analytical formulation for t
he extreme points of the eclipse is mandatory\, since the entry to and exi
t from the eclipse set up the limits of integration for the averaging. Fur
ther\, low-thrust trajectories require a continuous variation of the thrus
t direction and this has to be compatible with the capabilities of the att
itude control system of the satellite. This constraint can be formulated i
n terms of maximum angular rate for the satellite axes\, maximum angular m
omentum and/or maximum torque. A discussion on how to cope with these cons
traints in the optimisation method will be presented. The capabilities of
the developed tool are illustrated with examples of transfers to Geostatio
nary Earth orbit (GEO).\n\nKeywords: trajectory optimization\, low-thrust\
, electric propulsion\, indirect methods\n\nhttps://indico.esa.int/event/2
24/contributions/3875/
LOCATION: 103 and 105 combined
URL:https://indico.esa.int/event/224/contributions/3875/
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