| 英文摘要: | This is a short-term (less than one-year) effort to complete the construction, functional testing, and instrument calibration of a CubeSat with the capability to measure electric fields in the upper atmosphere. The DIME (Double-probe Instrumentation for Measuring Electric-fields) CubeSat concept builds on and further develops the NSF-funded Dynamic Ionosphere CubeSat Experiment (DICE) project aimed at measuring major space weather disturbances in the upper atmosphere. DICE was one of the first NSF CubeSat missions to be selected and flown. The DICE project consisted of two CubeSats weighing less than 2.2 kg each. They were launched into a low Earth orbit in October 2011 and collected data in space for two years. Each DICE satellite carried a suite of three scientific instruments. However, only two of them functioned successfully in space. Due to difficulties accurately controlling the spin of the spacecraft on orbit it was not possible to deploy the long wire booms that made up the electric field instruments. Thus, the DICE spacecraft could not provide measurements of the electric field. Fulfilling the need for continuous global measurements of this critical parameter in upper atmosphere dynamics remains a key goal and challenge for aeronomy and space weather research. The goal of the DIME project is to continue the development of an innovative approach to space-based measurement of the electric field. Leveraging the successes and lessons learned from the DICE mission DIME is envisioned as the next generation low cost, highly capable ionospheric sensor-sat observatory. New developments include improvements in the spin stabilization and control of the CubeSat, as well as improvements to the DICE electric field deployment mechanism. The DIME development so far has been funded under the Air Force SBIR program but falls short of delivering a fully equipped satellite that is ready to be launched and provide scientific data. Support for the purchase of the remaining parts and completion of the full flight assembly of the DIME CubeSat, and also for the completion of the satellite functional testing and calibration, while the present workforce and expertise is in place is the subject of this RAPID award. Delivery of a fully launch-ready DIME CubeSat, will enlist support from the Air Force for the launch and operation on orbit of the satellite. A newly graduated engineer, who worked as a student on the DICE project, in collaboration with a postdoctoral researcher, who with this project is offered a unique experimental research opportunity, will carry out most of the work under this effort. The project also continues to foster valuable collaboration between industry, academia, and government, involving ASTRA (a small business), the Air Force Research Laboratory, and Utah State University.
There are three fundamental drivers of global ionosphere-thermosphere (IT) behavior: solar UV/EUV radiation, high latitude forcing from solar wind-magnetosphere interaction and coupling to the ionosphere and thermosphere, and forcing by waves and tides from the lower atmosphere. While the principles of IT behavior are generally accepted, a complete understanding of the fully coupled ionosphere-thermosphere-magnetosphere system requires extensive measurements of environmental parameters that are not currently available. What are needed are simultaneous multipoint measurements of the electric field in the ionosphere. Focus here is on the high latitude forcing. While E-field measurements have been available from NSF-funded ground-based radars and the DMSP satellites, there is insufficient data to enable a comprehensive specification of the key high latitude potential pattern, electric fields, and their variability in space and time. The DIME sensor-sat has a unique potential to be a pathfinder that will pave the way for low-cost, very capable, next generation space weather CubeSat platforms from which to observe the system-driving electric field and other parameters in the Earth?s ionosphere. Future constellations of DIME platforms could provide networked, global measurements of the electric field. The DIME design additionally includes instrumentation to provide complementary magnetic field and plasma parameter measurements. In this way, DIME constitutes a key step in enabling large-return Geospace science missions using CubeSat technologies, targeting outstanding unanswered system-science and space weather questions. |