Coordination within the remote sensing payload on the Solar Orbiter mission

¹ Université Paris-Saclay, CNRS, Institut d’Astrophysique Spatiale, 91405 Orsay, France
e-mail: frederic.auchere@ias.u-psud.fr
² National Institute for Astrophysics (INAF), Astrophysical Observatory of Torino, Via Osservatorio 20, 10025 Pino Torinese, Italy
³ RAL Space, STFC Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX, UK
⁴ Naval Research Laboratory, Space Science Division, Washington, DC 20375, USA
⁵ University of Applied Sciences and Arts Northwestern Switzerland, 5210 Windisch, Switzerland
⁶ European Space Agency, ESTEC, PO Box 299, 2200 Noordwijk, The Netherlands
⁷ Centre Spatial de Liège, Université de Liège, Av. du Pré-Aily, 4031 Angleur, Belgium
⁸ Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Göttingen, Germany
⁹ Solar-Terrestrial Centre of Excellence – SIDC, Royal Observatory of Belgium, Ringlaan -3- Av. Circulaire, 1180 Brussels, Belgium
¹⁰ Southwest Research Institute, 1050 Walnut Street, Boulder, CO, USA
¹¹ Solar Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 2077, USA
¹² European Space Agency (ESAC), Camino Bajo del Castillo, Villanueva de la Cañada, 28692 Madrid, Spain
¹³ INAF – Astronomical Observatory of Capodimonte, Naples, Italy
¹⁴ SSL, UC Berkeley, 7 Gauss Way, Berkeley, CA, USA
¹⁵ The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
¹⁶ INAF-Catania Astrophysical Observatory, 95123 Catania, Italy
¹⁷ Space Systems Research Corp, Alexandria, VA, USA
¹⁸ Instituto de Astrofísica de Andalucía (IAA-CSIC), Apdo. de Correos 3004, 18080 Granada, Spain
¹⁹ ADNET Systems, Inc., NASA Goddard Spaceflight Center, Code 671, Greenbelt, MD 20771, USA
²⁰ Dipartimento di Fisica e Astronomia, SASS, Universitá degli Studi di Firenze, Largo E. Fermi 2, 50125 Firenze, Italy
²¹ UCL-Mullard Space Science Laboratory Holmbury St Mary, Dorking, Surrey RH5 6NT, UK
²² Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, 7260 Davos Dorf, Switzerland
²³ ESA/ESOC, Robert-Bosch-Str. 5, 64293 Darmstadt, Germany
²⁴ Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS)/CNRS, Toulouse, France
²⁵ Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029 Blindern, 0315 Oslo, Norway
²⁶ INAF/Osservatorio Astrofisico di Arcetri, Firenze, Italy
²⁷ National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303, USA
²⁸ Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, Russia
²⁹ School of Space Research, Kyung Hee University, Yongin, Gyeonggi-Do 446-701, Republic of Korea
³⁰ School of Physics, Trinity College Dublin, Dublin 2, Ireland
³¹ ASRC Federal Space and Defense, Washington, DC, USA
³² ETH-Zürich, IPA, Hönggerberg campus, Zürich, Switzerland
³³ Heliophysics Division, NASA HQ, Washington, DC 20546, USA

Received: 31 October 2019
Accepted: 22 January 2020

Abstract

Context. To meet the scientific objectives of the mission, the Solar Orbiter spacecraft carries a suite of in-situ (IS) and remote sensing (RS) instruments designed for joint operations with inter-instrument communication capabilities. Indeed, previous missions have shown that the Sun (imaged by the RS instruments) and the heliosphere (mainly sampled by the IS instruments) should be considered as an integrated system rather than separate entities. Many of the advances expected from Solar Orbiter rely on this synergistic approach between IS and RS measurements.

Aims. Many aspects of hardware development, integration, testing, and operations are common to two or more RS instruments. In this paper, we describe the coordination effort initiated from the early mission phases by the Remote Sensing Working Group. We review the scientific goals and challenges, and give an overview of the technical solutions devised to successfully operate these instruments together.

Methods. A major constraint for the RS instruments is the limited telemetry (TM) bandwidth of the Solar Orbiter deep-space mission compared to missions in Earth orbit. Hence, many of the strategies developed to maximise the scientific return from these instruments revolve around the optimisation of TM usage, relying for example on onboard autonomy for data processing, compression, and selection for downlink. The planning process itself has been optimised to alleviate the dynamic nature of the targets, and an inter-instrument communication scheme has been implemented which can be used to autonomously alter the observing modes. We also outline the plans for in-flight cross-calibration, which will be essential to the joint data reduction and analysis.

Results. The RS instrument package on Solar Orbiter will carry out comprehensive measurements from the solar interior to the inner heliosphere. Thanks to the close coordination between the instrument teams and the European Space Agency, several challenges specific to the RS suite were identified and addressed in a timely manner.