Annonce

2years post-doc position Machine Learning and nanosats to probe small bodies interior

22 December 2023

Catégorie : Post-doctorant

Post-doc position a Paris observatory (https://www.dim-origines.fr)

available: asap 2years

contact: daniel.hestroffer@obspm.fr

BIRDY: nanosatellites for probing the internal strucutre of small bodies The study of asteroids is fundamental both for our understanding of the formation of the Solar System, or the supply of water and origin of life on a planet, and for the characterisation of near-Earth impacts. Knowledge of the structure of small bodies (from a few meters to several hundreds of km) is an important element. Indeed the mass, the density, and the internal structure of the small bodies are as many key factors to understand their formation, and diversity, and tracing the origins of planetary systems in general. Moreover, making the link between the internal structure of small bodies and their external shape is the next big challenge in the field. Nanosatellites or cubesats offer a new opportunity to perform gravity field determinations that we are developing with the BIRDY project. In particular, we want to study the radio-science technique, considering and exploiting all the possibilities offered by inter-satellites links (ISL) radio links between one or more nanosatellites.

Three research axis will be covered with this post-doc work:
-develop precise orbit determination process to probe the gravity field through ISL (radio/optical). Derive an optimisation analysis for the measurements and nanosatellites configuration, assess the need for complementary ground-based measurements. Validate the approach with our RF-test bench deployed at CENSUS.
-develop a gravity-and-tomography global inversion algorithm, using artificial neural networks, to derive the internal structure of small bodies. This will be done by combining complementary radio-science (gravity) and LFR radar (tomography) observations.
-model granular systems using SSDEM numerical simulations, to provide a link between the external morphology of a body with it's modelled interior.

The work will be performed at Paris observatory within IMCCE and CENSUS space centre. The methodology will be applied to several targets of interest, and in particular to the HERA mission from ESA.

References

Izzo & Gomez 2022 Commun. Eng. 1, 48 https://doi.org/10.1038/s44172-022-00050-3 Hestroffer et al. 2019, AARv 27, 6 https://doi.org/10.1007/s00159-019-0117-5