Nov. 28—Newly interpreted data from the Mars Curiosity rover shows that physical barriers reduce radiation levels on the red planet, giving scientists at the Southwest Research Institute insight into what future human exploration on Mars might look like.
The rover's Radiation Assessment Detector, or RAD, is one of 10 instruments on Curiosity and has been making observations on Mars since the rover landed in 2012. The RAD is overseen by a team at SwRI.
Looking at data from 2016, scientists found that the instrument detected a week-long decrease in radiation, said Bent Ehresmann, research scientist and lead author on a new paper detailing the findings.
"We looked at the fuller data and realized nothing really explained what was going on and then realized that, oh yeah, we were driving through this area and the rover was parked right next to a butte," Ehresmann said. "It makes total sense that less radiation will reach the rover."
The instrument measured a 4% decrease in overall radiation and a 7.5% decrease in neutral particle radiation, which includes neutrons that are particularly harmful to human health. Those numbers are high enough to show that the decrease was related to the rover's location in the Murray Buttes region, not just normal changes in background radiation, according to NASA.
It's always been the idea to use Mars' natural resources to protect astronauts, and it makes sense that being surrounded by more material would reduce radiation levels, Ehresmann said. That's particularly important on Mars, which doesn't have the same global magnetic field or atmosphere as Earth to deflect radiation.
"We will send astronauts to Mars, and when we do, protecting them from the environment is part of NASA's responsibility," said Don Hassler, RAD principal investigator and science program director at SwRI.
But before now, the ideas on radiation shielding were theoretical. With data from the RAD, scientists have an anchor point to create models that can show radiation levels through different levels of shielding.
It also raises possibilities like building astronaut shelters in lava tubes, Hassler said. While the rover can't drive into tubes directly to measure radiation — it would lose communication with Earth — Curiosity's RAD has already taken more radiation measurements in other areas of Mars that will further inform SwRI's research into radiation shielding.
In the past two years, the SwRI team has found four more incidences of a similar shielding effect.
"You're not surprised, but it gives you a reminder that radiation on Mars is very diverse and influenced by many different things," Ehresmann said. "You want to get a complete picture of the radiation because all of those aspects are important for later human exploration of Mars."