title: Letter to the Editor.
authors.affiliation: Space Research and Technologies Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: T P
authors.initials: TP
authors.lastname: Dachev
authors.affiliation: Space Research and Technologies Institute, Bulgarian Academy of Sciences, Sofia, Bulgaria.
authors.forename: N G
authors.initials: NG
authors.lastname: Bankov
authors.affiliation: DLR, Institute of Aerospace Medicine, Cologne, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Horneck
authors.affiliation: FAU, Neue Str. 9, 91096 Möhrendorf, Germany.
authors.forename: D-P
authors.initials: DP
authors.lastname: Häder
mesh_terms: D018480:Astronauts; D003359:Cosmic Radiation; D006801:Humans; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000379:methods*; D012426:Russia; D013026:Space Flight; D018531:Spacecraft