The space mission MICROSCOPE dedicated to the test of the equivalence principle (EP) operated from April 25, 2016 until the deactivation of the satellite on October 16, 2018. In this analysis we compare the free-fall accelerations (a _A and a _B) of two test masses in terms of the Eötvös parameter η ( A,B ) = 2 a A − a B a A + a B . No EP violation has been detected for two test masses, made from platinum and titanium alloys, in a sequence of 19 segments lasting from 13 to 198 h down to the limit of the statistical error which is smaller than 10⁻¹⁴ for η(Ti, Pt). Accumulating data from all segments leads to η(Ti, Pt) = [−1.5 ± 2.3 (stat) ± 1.5 (syst)] × 10⁻¹⁵ showing no EP violation at the level of 2.7 × 10⁻¹⁵ if we combine stochastic and systematic errors quadratically. This represents an improvement of almost two orders of magnitude with respect to the previous best such test performed by the Eöt-Wash group. The reliability of this limit has been verified by comparing the free falls of two test masses of the same composition (platinum) leading to a null Eötvös parameter with a statistical uncertainty of 1.1 × 10⁻¹⁵

The MICROSCOPE mission was designed to test the weak equivalence principle (WEP), stating the equality between the inertial and the gravitational masses, with a precision of 10-15 in terms of the Eötvös ratio η. Its experimental test consisted of comparing the accelerations undergone by two collocated test masses of different compositions as they orbited the Earth, by measuring the electrostatic forces required to keep them in equilibrium. This was done with ultrasensitive differential electrostatic accelerometers onboard a drag-free satellite. The mission lasted two and a half years, cumulating five months worth of science free-fall data, two-thirds with a pair of test masses of different compositions - titanium and platinum alloys - and the last third with a reference pair of test masses of the same composition - platinum. We summarize the data analysis, with an emphasis on the characterization of the systematic uncertainties due to thermal instabilities and on the correction of short-lived events which could mimic a WEP violation signal. We found no violation of the WEP, with the Eötvös parameter of the titanium and platinum pair constrained to η(Ti,Pt)=[-1.5±2.3(stat)±1.5(syst)]×10-15 at 1σ in statistical errors.

Efforts to minimise the environmental impact of aviation can be implemented at several levels including electric green taxiing systems, novel propulsion systems, jet fuels, improvements in aircraft efficiency and optimisation of climb profiles. In this paper, we address the optimisation of flight plans in a route network considering operational parameters and weather forecast. We implement an A* based approach to explore all possible sequences of nodes, altitudes with given wind, temperature and pressure forecasts in order to minimise total flown distance, total burnt fuel, CO2 and non-CO2 emissions, the latter being responsible for two-thirds of aviation radiative forcing. We evaluated our approach on both a network of standard routes and through free route areas, and observed that our optimised flight plans are consistent with those that have actually been filed to be flown in similar weather conditions during December 2021.