Collaborative Research: CubeSat: Ionosphere Thermosphere Scanning Photometer for Ion-Neutral Studies (IT-SPINS)

该项目旨在设计、开发、建造、操作和分析名为“用于离子中性研究的电离层-热层扫描光度计”（IT-SPINS）的航天器立方体卫星任务的结果。 电离层影响民用和军用通信、导航和监视系统等现代技术。 因此，可靠的通信和导航通常需要针对电离层造成的影响校正信号。为此，必须充分理解电离层的特性并对其进行建模，例如其相对于磁层扰动、一天中的时间、一年中的季节和太阳周期变化的变化。 IT-SPINS 的基本测量是对氧离子与电离层上部电子重组产生的紫外夜光辐射进行高灵敏度视线观测。 IT-SPINS 将以每分钟两圈的速度围绕轨道法线旋转，每转将获得 60 次辐射测量值。 然后，将多次旋转的观测结果合并到层析成像反演算法中，以生成排放的二维高度/轨道图像。 通过这种方式，IT-SPINS 将提供第一套明确的、地理范围广泛的夜侧电离层氧离子分布测量结果。 具体来说，IT-SPINS 将提供有关所谓的顶部过渡区域（从大约 500 公里到 1000 公里高度）的离子梯度结构的重要信息，该区域的等离子体条件发生从氧离子主导到氢离子主导的转变。先前对 TTR 的研究主要在世界各地的少数几个地点使用大型非相干散射雷达。因此，目前还没有对 TTR 对纬度、当地时间以及太阳和地磁活动的依赖性进行彻底的气候学研究。缺乏对 TTR 变化性和整个 TTR 中氧离子分布的详细形态的基本了解，是目前我们准确建模和预测电离层变化能力的一个关键限制。 除了基本的空间天气目标之外，IT-SPINS 项目还高度重视大学本科阶段科学、技术、工程和数学 (STEM) 教育的实验学习。本科生将参与项目各个方面的负责工作。 这为学生提供了难得而宝贵的学习和实践项目管理的机会；系统工程；工程设计、开发和测试；在教师和专业人员的指导下，通过基于项目的第一手学习来掌握飞行操作和数据分析技能。此外，通过与蒙大拿州太空资助联盟 (MSGC) 的合作，该项目将让 MSGC 附属部落学院的传统弱势学生在轨道阶段参与 IT-SPINS 运营活动。 IT-SPINS 可以在各种可用轨道倾角（40 度）和高度（500-700 公里）上取得令人信服的科学成果。这个高度范围使我们能够最佳地观察上方的 TTR 和下方的等离子体结构，同时确保 25 年脱轨标准。设计以下主要和次要科学目标以及派生的科学问题，以便无论卫星轨道如何，IT-SPINS 都可以解决其中的一部分。该任务的主要科学目标是研究 TTR 和 O 高度剖面的变化。 将解决以下三个问题： 1） O 主导的电离层物理与 H 、 He 主导的等离子体层物理之间的边界高度和厚度如何随磁性 L 壳层、磁经度、当地时间和地磁活动而变化？ 2) 地球空间数值模型对观测到的 TTR 和 O 高度剖面变化的预测效果如何？ 3）O和中性氢之间的电荷交换对TTR有何重要性？ 对赤道等离子体气泡和极帽斑块的中尺度结构进行成像是该任务的次要科学目标。次要科学目标的赤道部分可以通过中倾角和高倾角轨道来解决，而极地斑块部分只能通过高倾角轨道（~70度或更高）来解决。

This project is to design, develop, construct, operate and analyze the results of a spacecraft CubeSat mission named "Ionospheric-Thermospheric Scanning Photometer for Ion-Neutral Studies" (IT-SPINS). The ionosphere affects modern technologies such as civilian and military communications and navigation and surveillance systems. Reliable communication and navigation, therefore, often requires correction of the signals for effects imposed by the ionosphere. To do that the properties of the ionosphere, such as its variability with respect to magnetospheric disturbance, time of day, season of the year, and solar cycle variability must be well understood and modeled. The fundamental measurements of IT-SPINS are high-sensitivity line-of-sight observations of Ultra Violet nightglow radiance produced by the recombination of Oxygen ions with electrons in the upper ionosphere. IT-SPINS will rotate at two rotations per minute about the orbit normal and will acquire 60 radiance measurements per revolution. Observations from several rotations will then be combined in a tomographic inversion algorithm to produce two-dimensional altitude/in-track images of the emissions. In this way, IT-SPINS will provide the first-ever set of unambiguous, geographically-extended measurements of the Oxygen ion distributions within the nightside ionosphere. Specifically, IT-SPINS will provide crucial information on the ion gradient structures in the, so-called, Topside Transition Region, from approximately 500km to 1000km altitude, where a transition takes place in the plasma conditions from being dominated by Oxygen ions to being dominated by Hydrogen ions. Prior studies of the TTR have primarily used large incoherent scatter radars at only a few locations around the World. Consequently, a thorough climatological study of the TTR's dependence on latitude, local time, and solar and geomagnetic activity does not exist at present. Lacking fundamental understanding of the variability of the TTR and the detailed morphology of Oxygen ion distributions throughout the TTR is a critical limitation currently in our ability to accurately model and predict ionospheric variability. Beyond fundamental space weather objectives, the IT-SPINS project places a significant priority on experimental learning in Science, Technology, Engineering and Mathematics (STEM) education at the university undergraduate level. Undergraduate students will participate in responsible roles on all aspects of the project. This provides the students with rare and valuable opportunities to learn and practice project management; systems engineering; engineering design, development and testing; and flight operations and data analysis skills through first-hand, project-based learning while being mentored by faculty and professional staff. In addition, through affiliation with the statewide Montana Space Grant Consortium(MSGC), the project will engage traditionally disadvantaged students at MSGC affiliated Tribal Colleges with IT-SPINS operational activities during the orbital phase. IT-SPINS can achieve compelling science results over a wide range of available orbit inclinations (40 degrees) and altitudes (500-700 km). This altitude range puts us at optimal viewing of the TTR above, and plasma structures below the satellite while ensuring a 25-year de-orbit criteria. The following primary and secondary science objectives and derived science questions are designed so that a subset of them can be addressed by IT-SPINS regardless of the satellite orbit it will be given. The primary science objective for the mission is to study the variability of the TTR and O+ altitude profiles. The following three questions will be addressed: 1) How does the altitude and thickness of the boundary between O+ dominated ionospheric physics and H+, He+ dominated plasmasphere physics vary as a function of magnetic L-shell, magnetic longitude, local time and geomagnetic activity? 2) How well do Geospace numerical models predict the observed variability of the TTR and O+ altitude profiles? 3) What is the importance of the charge exchange between O+ and neutral hydrogen to the TTR? Imaging the mesoscale structuring of equatorial plasma bubbles and polar cap patches constitutes a secondary science objective for the mission. The equatorial part of the secondary science objective can be addressed by both mid- and high inclination orbits, whereas the polar patch part can only be addressed for high inclination orbits(~70 degrees or higher).