Recent mission and system studies conducted for the European Space Agency have involved the design of transfers targeting Earth-trailing or Earth-leading heliocentric operational orbits, in a 1:1 resonance with Earth.
Airbus is currently leading two such studies on behalf of the European Space Agency: the Lagrange (Space Weather) mission targeting the Sun-Earth L5 Lagrange Point, and the LISA (Laser Interferometer Space Antenna) constellation of three satellites, selected as the third large-class mission of ESA’s Cosmic Vision Programme, and whose operational configuration consists in a heliocentric triangular cartwheel formation.
As no spacecraft has ever flown to these destinations, the presentation will focus on the mission analysis techniques that have been used to address this very special class of interplanetary missions, characterised by some unique features and challenges.
In particular, the available injection and transfer strategies will be reviewed and thoroughly traded against the mission objectives and constraints: these include classical direct ascent strategies, but also low-energy escape options via the Sun-Earth L1 or L2 points, as well as advanced strategies involving Earth and/or Lunar Gravity Assists. The benefits and challenges of transfers augmented with Solar Electric Propulsion will be highlighted. A special attention will also be brought to the implications of the selected Launch Vehicle, in particular if characterised by a limited range of available declinations (DLA), the resulting seasonal variation of the transfer problem and the impact of the launch windows definition. Finally, orbital perturbations on station and disposal strategies will be addressed.
While the presentation will focus on the astrodynamics techniques for the relatively generic problem of flying a spacecraft into heliocentric space, the application to the Lagrange and LISA missions will be presented as study cases.
Presentation of special techniques for mission design towards Earth trailing or leading heliocentric orbits at 1au.