# If colonists burrowed far enough under the ice on Ganymede or Europa, would the ice provide adequate protection for them from Jupiter's radiation?

This is a hypothetical question I'm asking as a SF writer, and the time setting would be approximately 2,250 AD.

• Welcome to the site @MikeAckerman. Often world building questions are closed but this is a good science based one and I suspect you'll get good answers. – GdD Feb 15 '18 at 10:04
• Thank you for asking this! I had wondered this myself but never thought to post the question. I've heard so much about Jupiter's ferocious radiation environment that I always envisioned the answer would be "miles" or "you can't." I'm pleasantly stunned by PearsonArtPhoto's elegant answer. – Kengineer Feb 15 '18 at 17:15
• What a great question !!!! – Fattie Feb 15 '18 at 21:31
• For those inclined, paper 2601 from the 47th Lunar and Planetary Science Conference (2016) titled Ionizing Radiation on the Surface of Europa: Implications for the Search for Evidence of Life addresses this question using a Monte-Carlo simulation of realistic fluxes of the various components – uhoh Feb 16 '18 at 11:24
• Does Ganymede's magnetic field (only moon which has one) not protect it against Jupiter's radiation? – johnM Jan 2 '20 at 0:28

Yes, it absolutely would! The radiation on Europa is about 5.4 Sv (540 rem) of radiation per day. Looking at this guide, and assuming you want to meet OSHA standards of 5 rem per year, you would need to only allow 1 part in 40,000 of the base radiation to make it through. The website linked indicates you want a mass of about 375 pounds/square foot to only allow 1 part in 1000. The chart says 72 inches of water. Ice isn't quite as dense, so a bit more ice. Let's say 2 m of ice will do. The factor is roughly $31^{\text{thickness}(m)}$, so to get the 40,000 value, you need about 3.1m. I would say leave an extra meter or two just to have a large buffer.