Solar Orbiter: The next ESA mission to the Sun

Paper number

IAC-08.A3.6.3

Author

Dr. Mark Ayre, EADS Astrium Ltd., United Kingdom

Year

2008

Abstract

Solar Orbiter has been studied within the framework of the ESA Solar Physics Planning Group, with the objective of taking exploration of the Sun to the next level. The mission concept has been the subject of several years of industrial study, is an established part of the ESA science programme, and is now undergoing detailed definition.

This paper describes the scientific objectives, critical drivers, and design of Solar Orbiter. The main technical driver is the punishing thermal flux that the spacecraft will experience, peaking at 20 solar constants. The challenges involved in designing for this environment are described, including focused technology development activities, most importantly of a heatshield able to protect the spacecraft platform and sensitive elements. In addition to the considerable technical challenges involved, an important driver of the mission is cost minimisation, and consequently the design emphasis is on extensive technology reuse – primarily from the BepiColombo mission, which has comparable thermal design drivers, but also from the Mars Express and Venus Express missions. Reuse of programmatic elements and experience from previous missions shall serve to further restrict the cost.

The baseline Solar Orbiter mission scenario is for a 2015 dedicated direct-injection on-board an Atlas launch vehicle. A series of Earth and Venus gravity assist manoeuvres is used during the mission, not only to facilitate the transfer, but also to allow gradual increases in the inclination of the operational orbit in order to access high solar latitudes. During the operational phase, Solar Orbiter will conduct science observations within the broader context of the HELEX concept, whereby Solar Orbiter will synergistically interact with the NASA Sentinels mission in order to significantly improve the total science return. Apart from the heatshield and associated elements, much of the design of the Solar Orbiter spacecraft is based around technology reuse: A Mars Express derived structure; a monopropellant propulsion system, with thrusters position and orientation largely derived from Mars Express; and telecommunications, data handling, attitude/orbit control, power and thermal subsystems all containing varying levels of BepiColombo-derived technologies and design approaches.

The Solar Orbiter mission is a highly innovative, high science-return mission to an extremely hostile environment. As such it is the perfect opportunity to build upon the considerable experience of Europe in frontier science missions, whilst constraining costs through pragmatic reuse of extant technologies and programmatic lessons learnt from the past. The mission design described in this paper demonstrates this approach.

Abstract document

IAC-08.A3.6.3.pdf

Manuscript document

IAC-08.A3.6.3.PDF (🔒 authorized access only).

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