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TitleHighly elliptical orbits for Arctic observations: assessment of ionizing radiation
AuthorTrichtchenko, L D; Nikitina, L V; Trishchenko, A P; Garand, L
SourceAdvances in Space Research vol. 54, issue 11, 2014 p. 2398-2414, (Open Access)
Alt SeriesEarth Sciences Sector, Contribution Series 20140185
PublisherElsevier BV
Mediapaper; on-line; digital
File formatpdf
SubjectsHealth and Safety; remote sensing; Arctic; space environments; highly elliptical orbit; Earth radiation belts; total ionizing dose
Illustrationsgraphs; plots
ProgramNorthern Canada Geohazards Project, Public Safety Geoscience
AbstractThe ionizing radiation environment was analyzed for a variety of potential Highly Elliptical Orbits (HEO) with orbital periods ranging from 6 to 24 hours suitable to continuously monitor the Arctic region. Several models available from the ESA's Space Environment Information
System (SPENVIS) online tool were employed, including the new-generation AE9/AP9 model for trapped radiation. Results showed that the total ionizing doze (TID) has a well-pronounced local minimum for 14-hr orbit, which is nearly identical to the overall minimum observed for the
longest period (24hr). The thickness of slab aluminum shielding required to keep the annual TID below 10, 5 and 3.33 krad (i.e. 150, 75 and 50krad for 15 years of mission duration) for a 14-hr orbit is 2.1, 2.7 and 3.1 mm respectively. The 16-hr orbit requires a supplement of 0.5 mm to achieve the same results, while the 24-hr orbit requires less shielding by 0.2 to 0.3 mm.
Comparison between AE8/AP8 and AE9/AP9 models was conducted for all selected orbits. Results demonstrated that the differences were ranging from -70% to +170% depending on orbit geometry.
The vulnerability to the single event effect (SEE) has been compared for all orbits by modelling the Linear Energy Transfer for long-term conditions and for the 5 min ?worst case scenario. The analysis showed no preference among orbits with periods longer than 15-hr, and in
order to keep the 14-hr orbit at the same level, the shielding should be increased by ~ 33% or approximately by 1 mm. To keep the Single Event Upset (SEU) rate produced by the ?worst case event at the same order of magnitude as for the ?statistical long-term case, the thickness of aluminum should be as high as 22 mm. The overall conclusion from space environment point of view is that all HEO orbits with period equal or longer than 14 hours can be regarded as good candidates for operational missions. Therefore, the selection should be based on other criteria,for example, uniformity of spatial coverage for meteorological imaging or the configuration of the ground network for data reception.
Summary(Plain Language Summary, not published)
Space Weather refers to the dynamic conditions on the Sun and in the space environment, in particular in the near-Earth environment, that can affect critical infrastructure. NRCan operates the Canadian Space Weather Forecast Centre and conducts research into space weather effects on satellites, GNSS positioning, radio communication, power systems, pipelines to help canadian Industry understand and mitigate the effects of space weather. In the presented paper, the ionizing radiation environment was analyzed for Highly Elliptical Orbits (HEO) with orbital periods from 6 to 24 hours suitable to continuously monitor the Arctic. Local minimum of total ionizing doze for 14-hr and 15-hr orbits was discovered.