Highly Elliptical Orbits for Arctic observations: Assessment of ionizing radiation

The vulnerability to the Single Event Effect (SEE) was compared for all orbits by modeling the Linear Energy Transfer (LET) for long-term conditions and for the 5 min “worst case” scenario. The analysis showed no preference among orbits with periods longer than 15 h, and in order to keep the 14-h 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 a space environment point of view is that all HEO orbits with periods equal to or longer than 14 h can be regarded as good candidates for operational missions. Therefore, selection of orbit 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.