Cochrane Corey J, Murphy Neil, Raymond Carol A, Biersteker John B, Dang Katherine, Jia Xianzhe, Korth Haje, Narvaez Pablo, Ream Jodie B, Weiss Benjamin P
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA.
Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA USA.
Space Sci Rev. 2023;219(4):34. doi: 10.1007/s11214-023-00974-y. Epub 2023 May 26.
The goal of NASA's Europa Clipper Mission is to investigate the habitability of the subsurface ocean within the Jovian moon Europa using a suite of ten investigations. The Europa Clipper Magnetometer (ECM) and Plasma Instrument for Magnetic Sounding (PIMS) investigations will be used in unison to characterize the thickness and electrical conductivity of Europa's subsurface ocean and the thickness of the ice shell by sensing the induced magnetic field, driven by the strong time-varying magnetic field of the Jovian environment. However, these measurements will be obscured by the magnetic field originating from the Europa Clipper spacecraft. In this work, a magnetic field model of the Europa Clipper spacecraft is presented, characterized with over 260 individual magnetic sources comprising various ferromagnetic and soft-magnetic materials, compensation magnets, solenoids, and dynamic electrical currents flowing within the spacecraft. This model is used to evaluate the magnetic field at arbitrary points around the spacecraft, notably at the locations of the three fluxgate magnetometer sensors and four Faraday cups which make up ECM and PIMS, respectively. The model is also used to evaluate the magnetic field uncertainty at these locations via a Monte Carlo approach. Furthermore, both linear and non-linear gradiometry fitting methods are presented to demonstrate the ability to reliably disentangle the spacecraft field from the ambient using an array of three fluxgate magnetometer sensors mounted along an 8.5-meter (m) long boom. The method is also shown to be useful for optimizing the locations of the magnetometer sensors along the boom. Finally, we illustrate how the model can be used to visualize the magnetic field lines of the spacecraft, thus providing very insightful information for each investigation.
The online version contains supplementary material available at 10.1007/s11214-023-00974-y.
美国国家航空航天局(NASA)的木卫二快船任务的目标是使用十项探测手段来研究木星卫星木卫二地下海洋的宜居性。木卫二快船磁力计(ECM)和用于磁探测的等离子体仪器(PIMS)探测将协同使用,通过感应由木星环境中强烈的时变磁场驱动产生的感应磁场,来表征木卫二地下海洋的厚度和电导率以及冰壳的厚度。然而,这些测量会被来自木卫二快船航天器的磁场所干扰。在这项工作中,提出了木卫二快船航天器的磁场模型,该模型由260多个单独的磁源组成,包括各种铁磁和软磁材料、补偿磁体、螺线管以及航天器内流动的动态电流。该模型用于评估航天器周围任意点的磁场,特别是在分别构成ECM和PIMS的三个磁通门磁力计传感器和四个法拉第杯的位置处。该模型还通过蒙特卡罗方法用于评估这些位置处的磁场不确定性。此外,还提出了线性和非线性梯度测量拟合方法,以展示使用沿8.5米长吊杆安装的三个磁通门磁力计传感器阵列可靠地将航天器磁场与周围环境磁场区分开的能力。该方法还被证明对于优化吊杆上磁力计传感器的位置很有用。最后,我们说明了该模型如何用于可视化航天器的磁力线,从而为每项探测提供非常有见地的信息。
在线版本包含可在10.1007/s11214-023-00974-y获取的补充材料。