Table 1. Summary of exploration mission exposures.

Exploration Mission	Mission Duration	Dose (mGy)	Gray Equivalent (mGy-Eq)a	Dose Equivalent (mSv)b
ISS in LEO	6 months	30–60	–	50–100
ISS in LEO	1 year	60–120	–	100–200
Sortie to Gateway (free space)	30 days	20	35	55
Lunar Surface Mission (2 weeks on surface)	42 days	25	45	70
Sustained Lunar Operations	1 year	100–120	180–220	300–400
Deep-Space Habitat	1 year	175–220	300–400	500–650
Mars Mission	650 to 920 days	300–450	550–800	870–1,200

^aConversion of dose to gray equivalent uses RBE values recommended by NCRP No. 132 [25]

^bBoth NASA-defined quality factors [26] and ICRP 60 quality factors [11] considered in range of estimates.

Abbreviations: ICRP, International Commission on Radiological Protection; ISS, International Space Station; LEO, low Earth orbit; NCRP, National Council on Radiation Protection; RBE, relative biological effectiveness