THOR · Towards Higher Levels of Autonomy and Robustness in Space Operations through Uncertainty Management and Quantification
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2021-11-01 → 2024-04-30
- EU contribution
- €204,416
- Participants
- 2
- Scheme
- MSCA-IF
Lines connect the coordinator with its partners.
Results in brief
Towards Higher Levels of Autonomy and Robustness in Space Operations through Uncertainty Management and Quantification
The THOR project has explored gravity field modeling and the gravimetry problem around asteroids. These celestial bodies have irregular shapes and heterogeneous density distributions that create a very complex gravity field. It is well-known that satellite orbits in these gravity fields can divert into escape or collision trajectories. In astrodynamics, gravity field modeling beyond the point mass is usually done with the spherical harmonics series expansion. However, spherical harmonics are not a valid approximation within the celestial body's circumscribing sphere, which is relatively large for elongated asteroids. There are several alternatives to spherical harmonics, such as polyhedron, mascon, and various neural network approaches. The THOR project mainly focuses on the discretized mascon approach and its fusion with physics-informed neural networks. Additionally, it also offers perspectives on how to determine the asteroid gravity field while on orbit (namely gravimetry). From a societal perspective, THOR is mainly involved in advancing deep space exploration. In particular, it focuses on asteroids, which are of great scientific interest since they are remnants of the early Solar System period. Moreover, certain types of asteroids contain valuable resources such as water, metals, and minerals. These resources could be mined and utilised in space exploration endeavours, potentially enabling long-duration space missions through resource utilisation. The THOR project contributes to these areas by developing methods to characterize gravity around asteroids while in flight. Asteroid details are hardly observable by Earth-based sensors; thus, they have to be characterised in situ. THOR project objectives can be succinctly resumed in: I. How can we solve the asteroid gravimetry problem using on-board optical navigation measurements?. II. How can we fuse physics-founded gravity models with neural network models?.
Data: CORDIS, © European Union
Project objective
The overarching goal of the THOR research project is to augment space operations autonomy and robustness through uncertainty management and quantification. This involves a bottom up process where novel uncertainty estimation and propagation techniques will be employed to be subsequently embedded within a stochastic robust controller. The main outcome will be a robust non-linear non-gaussian integrated guidance, navigation and control strategy with both model-based and exogenous disturbance estimation. Since both uncertainty sources are quantified, a more reliable and efficient space operation management and planning will be obtained. The THOR scenario relates to asteroid exploration which is one of the most challenging and uncertain space operations nowadays. This is due to the limited asteroid data known prior to the arrival if the body is visited for the first time. Two mission phases can be clearly distinguished: on-orbit data collection where most of the uncertainty will be removed by estimation; then, an entry descent and landing critical phase where the stochastic robust controller will use the previous uncertainty knowledge, is envisioned. The THOR project methodology and results are expected to advance current state-of-the-art in autonomous spacecraft guidance, navigation and control, thus enabling more advanced space exploration mission concepts with a higher scientific return, without loss of generality.
Original text from CORDIS.
Participants
- UNIVERSIDAD DE SEVILLA · SevillaCoordinatorSpain
- REGENTS OF THE UNIVERSITY OF COLORADO · Boulder CoUnited States
Links
Data: CORDIS, © European Union