BepiColombo ESA/JAXA mission is currently in its 7 year cruise phase towards Mercury. The Mercury orbiter radioscience experiment (MORE), one of the 16 experiments of the mission, will start its scientific investigation during the superior solar conjunction (SSC) in March 2021 with a test of general relativity (GR). Other solar conjunctions will follow during the cruise phase, providing several opportunities to improve the results of the first experiment. MORE radio tracking system allows to establish precise ranging and Doppler measurements almost at all solar elongation angles (up to 7–8 solar radii), thus providing an accurate measurement of the relativistic time delay and frequency shift experienced by a radio signal during an SSC. The final objective of the experiment is to place new limits to the accuracy of the GR as a theory of gravity in the weak-field limit. As in all gravity experiments, non-gravitational accelerations acting on the spacecraft are a major concern. Because of the proximity to the Sun, the spacecraft will undergo severe solar radiation pressure acceleration, and the effect of the random fluctuations of the solar irradiance may become a significant source of spacecraft buffeting. In this paper we address the problem of a realistic estimate of the outcome of the SSC experiments of BepiColombo, by including in the dynamical model the effects of random variations in the solar irradiance. We propose a numerical method to mitigate the impact of the variable solar radiation pressure on the outcome of the experiment. Our simulations show that, with different assumptions on the solar activity and observation coverage, the accuracy attainable in the estimation of γ lays in the range [6–13] 10⁻⁶.

BepiColombo ESA / JAXA任务目前正处于向水星航行的7年巡航阶段。水星轨道无线电科学实验（MORE）是该飞行任务的16个实验之一，将于2021年3月在优越太阳结（SSC）期间开始其科学调查，并进行广义相对论（GR）测试。在巡航阶段还将进行其他太阳活动，这将为改善第一个实验的结果提供若干机会。更多的无线电跟踪系统几乎可以在所有太阳延伸角（高达7​​–8个太阳半径）上建立精确的测距和多普勒测量，从而提供SSC期间无线电信号所经历的相对论时延和频移的精确测量。实验的最终目标是为GR的精度设置新的极限，作为重力理论在弱场极限中。与所有重力实验一样，作用在航天器上的非重力加速度也是一个主要问题。由于靠近太阳，航天器将经受剧烈的太阳辐射压力加速，并且太阳辐照度的随机波动的影响可能成为航天器抖振的重要来源。在本文中，我们通过在动力学模型中包括太阳辐照度随机变化的影响，来解决对BepiColombo SSC实验结果进行现实估计的问题。我们提出了一种数值方法来减轻可变太阳辐射压力对实验结果的影响。我们的模拟表明，γ在[6-13] 10 ^-6的范围内。