## 5 Conclusions  
We propose a novel concept for the implementation of the classical test of general relativity related to light bending around the Sun, which may allow for discrimination among competing theories of gravitation at the \(10^{-7}\) level or better. The key technology of an external occulter in formation flying, generating an artificial long-lasting eclipse, shall be demonstrated by the forthcoming ESA mission PROBA3. The measurement concept, also thanks to the circular symmetry enforced into the design, is robust with respect to rejection and/or calibration of instrumental and external disturbances, including uncertainty on the position and parallax of observed sources. The main instrument is a small telescope (0.3 m diameter) with an annular field of view at \(\sim\)\(0^{\circ}\).7 from the Sun, performing high-precision astrometry on comparably bright stars \(G\leq 16\) mag. By simulating the real sky distribution of observable stars down to \(G=16\) mag, we figure out that the proposed GLADE setup, over a mission lifetime of three years, will be able to achieve a relative precision of light deflection of \(\sim\)\(5\times 10^{-8}\). A moderate increase in the instrument size by a factor of three may provide a performance improvement of one order of magnitude.  
Conceptualization, M.G. and A.V.; methodology, M.G., A.R. and F.L.; software, A.V. and M.G.; validation, M.G., A.V. and A.G.B.; formal analysis, A.V. and A.G.B.; investigation, M.G., A.R. and D.B.; resources, M.G. and A.R.; data curation, A.V., F.L. and M.G.; writing--original draft preparation, M.G., A.V. and A.G.B.; writing--review and editing, D.B., F.L. and A.R.; visualization, M.G. and D.B.; supervision, M.G.; project administration, A.R.; funding acquisition, M.G. and A.R. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Agenzia Spaziale Italiana (ASI) through contract 2018-24-HH.0 and its Addendum 2018-24-HH.1-2022 to the Italian Istituto Nazionale di Astrofisica (INAF).  
Astrophysical data for the performance simulation are derived from the publicly available Gaia catalog (DR3). Optical design data of the telescope will be detailed in a forthcoming paper. Intermediate and final results of our simulation will be made available (within reason) upon request.  
We gratefully acknowledge the contribution of [PERSON] to the development of the idea of a modern rendition of the 1919 Eddington, Dyson and Davidson eclipse experiment. Many other scientists helped our understanding of the scientific and practical issues involved and eventually to the currently proposed solution.  
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.  
The following abbreviations are used in this manuscript:  
Association de Satellites Pour I'Imagerie et l'Interferometrie de la Couronne Solaire  
Complementary metal-oxide semiconductor  
Data Release 3  
Folding mirror  
Focal plane  
Galaxe  
Gravitational Light-bending Astrometry Dual-satellite Experiment  
GR General relativity  
M1 Primary mirror  
M2 Secondary mirror  
M3 Tertiary mirror  
PPN Parametrized post-Newtonian  
PPN Parametrized post-post-Newtonian  
PROBA3 Project for On-Board Autonomy-3