Collaborative Research: CubeSat--Composition Variations in the Exosphere, Thermosphere, and Topside Ionosphere (EXOCUBE)

该项目是为了执行名为ExoCube的3U立方体卫星任务，在全球范围内测量高层大气中所有重要的中性和电离物种的密度。该项目将提供25年多来首次现场全球中性密度数据，包括首次使用质谱仪技术直接测量氢密度。ExoCube的一个重要科学目标是为高层大气的物理模型提供观测约束。此外，这些测量将用于测试和验证新开发的实验技术，以从雷达和光学观测中获得中性和电离成分和密度。ExoCube的测量还将用于几项直接的科学调查。需要解决的具体科学问题包括：1)静止和风暴时期外太空中氢和质子的半球间传输，以及2)中性大气驱动因素对磁暴的响应特征。四种中性和离子物种(O、He、H、N2、O+、He+、H+和NO+)的数据由一套两台静态能量角分析仪收集，其中一台用于中性(NSEAA)，另一台用于离子(ISEAA)。该仪器是NASA和海军研究实验室最近合作开发的一种新设计。第三种仪器，法拉第杯，用于校准，将离子密度的不确定度降低到大约正负3%。卫星将以两种模式收集数据。在“巡逻模式”下，测量将大致按经度进行，而在“协调实验模式”下，测量将与地面雷达和光学测量相结合，每10度进行一次。卫星将以大于或等于45度的倾角发射进入近地轨道，经过三个当前的雷达站和至少六个光学大气站点。ExoCube项目是科学解决方案公司(SSI)、加州理工州立大学(Cal Poly)和威斯康星大学(UW)的合作项目。参与这一努力的还有NASA戈达德太空飞行中心和SRI国际公司。此外，该项目还与现有的NSF雷达设施和光学站点协调，以便在卫星生命周期内进行有针对性的实验。ExoCube数据集具有广泛的实用价值，使人们期待已久的高层大气的各种物理和半经验成分模型得到改进，并对提供成分数据的雷达和光学测量技术进行了验证。因此，该项目将为进一步开展大规模和多样化的大气学和空间气象科学调查奠定基础。特别是，可靠的外层氢分布知识是现实地模拟总电子含量的关键要求，而总电子含量目前是一个非常优先的空间气象目标。该项目对教育的影响非同寻常。卫星总线和操作系统是由加州大学保利分校的20-40名学生在实验室中设计和建造的，有效载荷集成也由加州大学保利分校的学生进行。威斯康星大学的学生参与仪器校准和测试，以及数据完整性的初步评估。数据格式化和归档也是由学生主导的。

This project is for a 3U CubeSat mission named EXOCUBE to measure the densities of all significant neutral and ionized species in the upper atmosphere on a global scale. The project will provide the first in-situ global neutral density data in more than 25 years, including the first direct measurements of Hydrogen densities using the mass spectrometer technique. An important science objective for EXOCUBE is to provide observational constraints for physical models of the upper atmosphere. Additionally, the measurements will be used to test and validate newly developed experimental techniques to obtain neutral and ionized composition and densities from radar and optical observations. The EXOCUBE measurements will also be used for several immediate science investigations. Specific science questions to be addressed include: 1) the inter-hemispheric transport of Hydrogen and protons in the quiescent and storm-time exosphere, and 2) characterization of neutral atmospheric drivers in response to magnetic storms. Data for each of four neutral and ion species (O, He, H, N2, O+, He+, H+, and NO+) are gathered by a set of two Static Energy Angle Analyzers, one for Neutrals (NSEAA) and one for Ions (ISEAA), respectively. The instrument is a new design that has been developed recently through a collaboration between NASA and the Naval Research Laboratory. A third instrument, a Faraday cup, is included for calibration, reducing ion density uncertainties to approximately plus or minus 3%. The satellite will collect data in two modes. In 'patrol mode' the measurements will be made approximately every degree of longitude and in 'coordinated experimental mode' the measurements will be made every tenth of a longitude degree in conjunction with ground based radar and optical measurements. The satellite is to be launched into low Earth orbit with an inclination of greater than or equal to 45 degrees, passing over three current radar sites, and at least six optical Aeronomy sites. The EXOCUBE project is a collaboration between Scientific Solutions Inc. (SSI), California Polytechnic State University (Cal Poly), and The University of Wisconsin (UW). Also partnering in the effort are NASA Goddard Space Flight Center, and SRI International. In addition, the project coordinates with existing NSF radar facilities and optical sites for targeted experiments during the satellite lifetime. The EXOCUBE dataset has broad utility, leading to long-awaited improvements in a wide range of physical and semi-empirical composition models for the upper atmosphere and to verification of radar and optical measurement techniques providing composition data. As such, the project will provide the foundation for a very large and diverse set of further aeronomy and space weather science investigations. Particularly, reliable knowledge of exospheric Hydrogen distribution is a crucial requirement for realistically modeling Total Electron Content, which is currently a very high priority space weather objective. Educational impacts of the project are extraordinary. The satellite bus and operating systems are designed and built by 20-40 students in the laboratories at Cal Poly, and payload integration is also performed by students at Cal Poly. Students at the University of Wisconsin are involved with instrument calibration and testing and with initial assessment of data integrity. Data formatting and archiving are also student led.