By Daniel Dunaief
It’s the ultimate road trip into the unknown. Space travel holds out the possibility of exploring strange new worlds, boldly going where no one has gone before (to borrow from a popular TV show).
While the excitement of such long-distance journeys inspires people, the National Aeronautics and Space Administration, among other agencies, is funding scientific efforts to ensure that anyone donning a spacesuit and jetting away from the blue planet is prepared for all the challenges to mind and body that await.
Rachel Caston, recently completed her doctorate, which included work at Stony Brook University in the laboratory of Bruce Demple for a project that explored the genetic damage lunar soil simulants have on human lung cells and on mouse brain cells.
Geologist Harrison Schmitt, who was the Apollo 17 lunar module pilot, shared symptoms he described as “lunar hay fever,” which included the types of annoyances people with allergies have to deal with during the spring: sore throat, sneezing and watery eyes.
Using simulated lunar soil because actual soil from the moon is too scarce, Caston found that several different types of soil killed the cell or damaged the cell’s genes, or DNA for both human lung and mouse brain cells.
While there has been considerable research that explores the inflammation response to soil, “there wasn’t any research previously done that I know of [that connected] lunar soil and DNA damage,” said Caston, who was the lead author on research published recently in the American Geophysical Union’s journal GeoHealth.
The moon’s soil becomes electrostatic due to radiation from the sun. Astronauts who walked on the moon, or did various explorations including digging into its surface, brought back some of that dust when it stuck to their space suits.
Caston sought to understand what causes damage to the DNA.
Going into the study, Demple, a professor of pharmacological sciences at SBU, suggested that they expected that the materials most capable of generating free radicals would also be the ones that exerted the greatest damage to the cells and their DNA. While free radicals may play a role, the action of dust simulants is more complex than that created by a single driving force.
Caston looked at the effect of five different types of simulants, which each represented a different aspect of lunar soil. One of the samples came from soil developed to test the ability of rovers to maneuver. Another one came from a lava flow in Colorado.
Demple said that the materials they used lacked space weather, which he suggested was an important feature of lunar soil. The surface of the moon is exposed constantly to solar wind, ultraviolet light and micrometeorites. The researchers mimicked the effect of micrometeorites by crushing the samples to smaller particle sizes, which increased their toxicity.
In future experiments, the researchers plan to work with colleagues at the Department of Geosciences at SBU, including co-author Joel Hurowitz and other researchers at Brookhaven National Laboratory to mimic solar wind by exposing dust samples to high-energy atoms, which are the main component of solar wind. The scientists expect the treatment would cause the simulants to become more reactive, which they hope to test through experiments.
Caston credits Hurowitz , an assistant professor in the Department of Geosciences, with providing specific samples.
The samples are commonly used simulants for lunar rocks that mimic the chemical and mineral properties of the lunar highlands and the dark mare, Hurowitz explained.
“This has been a really fruitful collaboration between geology and medical science, and we’ll continue working together,” Hurowitz wrote in an email. They plan to look at similar simulants from asteroids and Mars in the future.
NASA has considered engineering solutions to minimize or eliminate astronaut’s exposure to dust. It might be difficult to eliminate all exposure for workers and explorers living some day on the moon for an extended period of time.
“The adherence of the dust to the space suits was a real problem, I think,” suggested Demple, adding that the next steps in this research will involve checking the role of the inflammatory response in the cytotoxicity, testing the effects of space weathering on toxicity and applying to NASA for actual samples of lunar regolith brought back by Apollo astronauts.
It took about two years of preliminary work to develop the methods to get consistency in their results, Demple said, and then another year of conducting research.
In addition to her work on lunar soil, Caston has studied DNA repair pathways in mitochondria. She used her expertise in that area for the DNA damage results they recently reported.
Caston, who is working as a postdoctoral researcher in Demple’s lab, is looking for a longer-term research opportunity either on Long Island or in Michigan, the two places where she’s lived for much of her life.
Caston lives in Smithtown with her husband Robert Caston, a software developer for Northrop Grumman. She earned her bachelor’s degree as well as her doctorate from Stony Brook University.
Her interest in science in general and genetics in particular took root at an early age, when she went with her father Kenneth Salatka, who worked at Parke Davis, a company Pfizer eventually bought.
On April 23, 1997, she convinced her friend and her identical twin sister to attend a “fun with genetics” event.
Two of the people at her father’s company were using centrifuges to isolate DNA out of blood. “That was the coolest thing I ever saw,” she said. “I wanted to be a geneticist from that point on.”
Her sister Madeline, who now sells insurance for Allstate, and her friend weren’t similarly impressed.
As for the work she did on lunar soil, Caston said she enjoys discussing the work with other people. “I like that I’m doing a project for NASA,” she said. “I’ve learned quite a bit about space travel.”