On the radiation environment during consecutive balloon flights over New
Mexico and Antarctica
Abstract
Remarkably, we know more about the radiation environment onboard the
International Space Station than we do about radiation values at
altitudes between 30-40 km in the middle stratosphere. Within this work,
we provide data about the radiation dose measured during two consecutive
balloon flights flown within a 4-month timeframe over New Mexico and
Antarctica Data were measured with the M-42 radiation detector. On each
flight, the M-42 was installed as part of a larger research payload:
MARSBOx (New Mexico, 23 September 2019); and E-MIST (Antarctica, 15
December 2019-12 January 2020). The temporal proximity of the flights
provided similar prevailing space weather conditions and solar activity
(minimal during each mission). Against that common backdrop, the main
differences between flights, including mission duration and geomagnetic
shielding could be readily compared. Near identical space weather
conditions provided a window of opportunity for studying the influence
of altitude and geomagnetic shielding on dose and fluence rate of
galactic cosmic radiation under maximum intensity conditions. Herein, we
report relevant count- and dose rates for the missions, alongside Geant4
Monte Carlo calculations; this included crossings of the Regener maximum
during the ascent and descent flights over New Mexico and the absence of
a distinct maximum in dose rates at zero geomagnetic shielding for the
polar flight. While dose rates in silicon at float altitudes (≈35 km-39
km) were a maximum of 2.5 +/- 0.4 microGy/h over New Mexico, we reached
values of up to 8.4 +/- 0.3 microGy/h over Antarctica, thereby
approaching dose rates similar to the surface of Mars.