G020-08
MARVEL Mission Proposal: The Latest Update
Wednesday, 16 December 2020: 04:28
Virtual
Jean-Michel Lemoine1,2, Benoit Meyssignac1,3, Mioara Mandea1, Etienne Samain4,5, Stephane Bourgogne6, Alejandro Blazquez7, Georges Balmino1,8, Lopes Louise1, Joël Michaud1 and MARVEL Mission Team, (1)CNES French National Center for Space Studies, Toulouse Cedex 09, France, (2)GET Géosciences Environnement Toulouse, CNRS, Toulouse, France, (3)LEGOS, Toulouse, France, (4)Géoazur - Université Nice Sophia Antipolis, Valbonne, France, (5)SigmaWorks, Valbonne, France, (6)Stellar Space Studies, Toulouse, France, (7)Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), Toulouse, France, (8)GET Géosciences Environnement Toulouse, Toulouse, France
Abstract:
The GRACE and GRACE-FO missions have demonstrated the importance of continuous gravimetric observations of mass transfers within the Earth system for many fields of earth sciences. A new generation of gravity missions is brewing. In this context, and following the recommendations of the 2019 CNES scientific prospective seminar, a pre-Phase-A study was launched in January 2020 at CNES on the concept of the MARVEL mission. MARVEL proposed to carry out in a single mission the survey of earth mass transfers with increased precision and the determination of the terrestrial reference system, thanks to two constellations of satellites at 500 and 7000 km altitude equipped with "radial" measurement links between the constellations. The results of the first six months of this pre-Phase-A will be presented.
Our work has mainly focused on two axes:
- a closed-loop numerical simulation to assess the scientific performance of a large number of orbital configurations, including radial links but also "Bender" and "Pendulum" configurations;
- a technological study to bring the precision of a laser inter-satellite chronometry link to the micrometric level.
This work has, so far, highlighted:
1 / the poorer performance for the determination of the gravity field of the "radial" type measurements compared to a pendular configuration in which the satellites are at the same altitude, separated by a few hundred km (because the ascending nodes of the moving spacecraft is slightly offset);
2 / the technological possibility of achieving by chronometric laser link, over a few hundred or even a few thousand km, the precision of 1 micrometer in distance and 0.1 micrometer / s in relative velocity, which is necessary for the achievement of the scientific objectives.
The pre-Phase-A MARVEL, taking into account the "Mass Change" studies on the NASA side and "NGGM" on the ESA side, is therefore reoriented towards a "pendulum" type mission, abandoning the objective of determining jointly the terrestrial reference system.
