RadioAstron as a target and as an instrument: Enhancing the Space VLBI mission’s scientific output

¹ Joint Institute for VLBI in Europe, PO Box 2, 7990 AA Dwingeloo, The Netherlands
e-mail: duev@jive.nl
² Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetsky av. 13, 119991 Moscow, Russia
³ Keldysh Institute for Applied Mathematics, Russian Academy of Sciences, Miusskaya sq. 4, 125047 Moscow, Russia
⁴ Metsähovi Radio Observatory, Aalto University, 02540 Kylmälä, Finland
⁵ Department of Astrodynamics and Space Missions, Delft University of Technology, 2629 HS Delft, The Netherlands
⁶ Shanghai Astronomical Observatory, 80 Nandan Road, 200030 Shanghai, PR China

Received: 7 September 2014
Accepted: 26 October 2014

Abstract

Context. The accuracy of orbit determination has a strong impact on the scientific output of the Space VLBI mission RadioAstron.

Aims. The aim of this work is to improve the RadioAstron orbit reconstruction by means of sophisticated dynamical modelling of its motion in combination with multi-station Doppler tracking of the RadioAstron spacecraft.

Methods. The improved orbital solution is demonstrated using Doppler measurements of the RadioAstron downlink signal and by correlating VLBI observations made by RadioAstron with ground-based telescopes using the enhanced orbit determination data.

Results. Orbit determination accuracy has been significantly improved from ~600 m in 3D position and ~2 cm/s in 3D velocity to several tens of metres and mm/s, respectively.