Abstract The JUpiter Icy Moons Explorer (JUICE) is a European Space Agency (ESA) mission that will launch in 2022 and arrive in the Jovian system in 2029 to investigate Jupiter's icy satellites. The mission will perform flybys of the icy moons Europa, Callisto and Ganymede before being inserted into a 280-day orbit around Ganymede: 150 days in Elliptical Orbit (GEO) followed by 130 days Circular Orbit at 500 km (GCO-500). During the orbital phase, JUICE will investigate the moon's surface, interior and exosphere, carrying out for the first time a complete characterization of an icy satellite. A suite of field and particle instruments will characterize the plasma and magnetic environment around the body. The 3GM experiment on board the spacecraft will exploit the GCO-500 phase to collect accurate Doppler and range measurements to determine the moon's orbit, gravity field and tide, therefore providing crucial information to accurately model its internal structure. The simulations carried out reveal that the moon's gravity field can be determined up to degree and order 40, depending on the magnitude of the gravity spectrum. The Love number k 2 , modelling the gravitational response to eccentricity-driven, time-variable gravity gradient from Jupiter, is determined with an accuracy of σ k 2 ∼ 10 − 4 . The obliquity, φ, and the libration at orbital period, ϕ, can be retrieved with a level of uncertainty of 1 and 2 μ r a d , respectively. Because of the 97 m 2 solar panels and the ensuing large area-to-mass ratio, JUICE will be affected by neutral particle drag. Here, we also assess the potential effect of spacecraft drag due to Ganymede's tenuous exosphere, which ranges between 10 − 17 − 10 − 16 k g / m 3 and generates an average drag of ∼ 4 ⋅ 10 − 12 m / s 2 , in the GCO-500 phase.

中文翻译：

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来自 JUICE 3 GM 实验模拟的木卫三重力、潮汐和旋转状态

摘要 木星冰卫星探测器（JUICE）是欧洲航天局（ESA）的一项任务，将于 2022 年发射，2029 年抵达木星系统，以调查木星的冰卫星。该任务将飞越冰冷的卫星木卫二、卡利斯托和木卫三，然后被插入围绕木卫三的 280 天轨道：150 天在椭圆轨道 (GEO)，然后是 130 天在 500 公里的圆形轨道 (GCO-500)。在轨道阶段，JUICE 将调查月球表面、内部和外层，首次对冰卫星进行完整的表征。一套场和粒子仪器将表征身体周围的等离子体和磁环境。航天器上的 3GM 实验将利用 GCO-500 相位来收集准确的多普勒和距离测量值，以确定月球的轨道、重力场和潮汐，从而为准确模拟其内部结构提供关键信息。进行的模拟表明，月球的重力场可以确定到 40 级和 40 级，这取决于重力谱的大小。Love 数 k 2 模拟了木星对偏心率驱动的时变重力梯度的重力响应，其精度为 σ k 2 ∼ 10 − 4 。可以分别以 1 μ rad 和 2 μ rad 的不确定性水平检索倾角 φ 和轨道周期 φ 的振动。由于 97 m 2 太阳能电池板和随之而来的大面积质量比，JUICE 会受到中性粒子阻力的影响。在这里，我们还评估了由于木卫三稀薄的外逸层造成的航天器阻力的潜在影响，其范围在 10 − 17 − 10 − 16 kg / m 3 之间，并产生 ∼ 4 ⋅ 10 − 12 m / s 2 的平均阻力，在GCO-500 阶段。