There’s no question that the radiation on Europa is lethal. The surface receives about 14,000 rads in an hour. That’s 14 times the dose that is fatal to 100 percent of people exposed. This radiation, lack of atmosphere, and the minus 260-degree temperature make Europa an unlikely future tourist stop.
Yet Europa is near the top of the list for places likely to host alien life. How can life exist in this harsh environment? In a word: Water. Though Europa is about 90 percent the size of our Moon, it may host an ocean containing more water than all of Earth’s oceans combined.
Europa Clipper sits on the moon’s icy surface with Jupiter in the sky and its sample arm extended. Launch is planned as one of the first uses of the Space Launch System as early as Spring 2022. [Reference]
Water is not only essential for life, it is an excellent shield for radiation. Just four inches of ice can reduce Europa’s surface dose to the level of a CT scan (about one rad). However, a long-term stay, like getting a CT scan every hour, could still be deadly if cells are damaged faster than they can be repaired or replaced. One hundred hours at this dose level would kill 5 percent of people within six weeks of exposure, and the rest would have an increased risk of cancer.
So future human visitors to Europa will want to send robots ahead to dig under or drill through the surface for protection from radiation. Besides, under the icy shield of the surface is also the place to find alien life.
Dim sunlight (Jupiter is five times the distance of Earth from the sun) would not penetrate far through the thick surface ice. But life doesn’t actually need sunlight, as scientists discovered back in 1977 when they observed giant tube worms living off of hydrogen sulfide bubbling out of volcanic vents in the sunless depths of the Pacific Ocean. Similar hydrothermal vents may exist at the base of Europa’s ocean, constantly heated by the tidal tug-of-war as Europa passes between Jupiter and its Mars-sized moon, Ganymede. The tidal forces also create dramatic upheavals on the surface that may be dangerous to visitors but offer exciting possibilities for research.
As a writer, I couldn’t resist setting a story on Europa. How might people get there and stay there safely? What kind of bacteria and viruses might co-evolve there? How might human activity, requiring energy and releasing waste, impact them? Since any existing life would not likely survive transport to Earth for study, what equipment and skills would scientists need to unlock the mysteries of alien life and distinguish it from manmade contamination? What kind of people would be motivated enough to devote years of their lives and risk getting cancer to explore this distant world? Would a young scientist with terminal cancer perhaps find a way to go so her final days might count for something?
If you’re curious to see how I answered these questions, I invite you to read, Europa’s Survivors, first published in the March/April 2017 issue of Analog Science Fiction magazine, and now included in my collection of previously published stories called, Fly Me to the Moon and other stories which is available in print or eBook form.
Writing about Space
Thursday January 25 at 2 AM CST to Tuesday, January 30 at 2 AM CST: Fly Me to the Moon and other stories (including Europa’s Survivors) is FREE on Kindle (regular price $2.99). Print copies are $9.99. Receive a 10 percent discount on print copies: enter this 8-digit code: 488RKZ5V on CreateSpace.
My new book, coauthored with Buzz Aldrin, To the Moon and Back: My Apollo 11 Adventure, a pop-up book from National Geographic, is due out in September. The first printing is likely to sell out, so you might want to preorder now from Amazon.
Speaking about Space
Whether you’re looking for a role model for female students, a scientist to run a STEM workshop, or a speaker with some unique stories, please consider an author visit. I offer programs appropriate for school-aged children up through senior citizens, as well as science workshops for students and teachers. See my list of programs and prices on the Author Visits tab of my website. Book a fall visit before July to lock in current fees.
February 12-15, 2018. I’ll be in Atlanta, participating as a member of the National Assessment of Educational Progress (the Nation’s Report Card) panel for 4th grade writing.