Researchers are planning to bring samples back from the Martian moon Phobos in about a decade, but they may get more than they bargained for.
Researchers analyzed calculate how much Martian material was on Phobos' surface, and found that there was quite a bit, a Brown University news release. A mission set to launch in the year 2020 hopes to bring back samples of the Mars-moon cocktail.
The study concluded that dust, rock, and soil particles had blown off of Mars during large projectile impact events and landed on Phobos. The small moon is believed to have been gathering these emissions for millions of years.
"The mission is scheduled to be flown early in the next decade, so the question is not academic," James Head, professor of geological sciences and an author on the study, said. "This work shows that samples from Mars can indeed be found in the soil of Phobos, and how their concentration might change with depth. That will be critical in the design of the drills other equipment."
The Russian mission will be the countries second attempt at bringing back samples from Phobos after a past mission failed in 2011.
The researchers looked at a model based on our own moon to determine how much dust would transfer over during these impacts.
"When an impactor hits Mars, only a certain [proportion] of ejecta will have enough velocity to reach the altitude of Phobos, and Phobos' orbital path intersects only a certain proportion of that," Ken Ramsley, a visiting researcher in Brown's planetary geosciences group, said. "So we can crunch those numbers and find out what proportion of material on the surface of Phobos comes from Mars."
The researchers determined there is about 250 parts per million of Mars material on Phobos.
"Only recently -- in the last several 100 million years or so -- has Phobos orbited so close to Mars," Ramsley said. "In the distant past it orbited much higher up. So that's why you're going to see probably 10 to 100 times higher concentration in the upper regolith as opposed to deeper down."
The team hopes to learn more about Phobos' origin and whether its core contains water.
"Phobos has really low density," Head said. "Is that low density due to ice in its interior or is it due to Phobos being completely fragmented, like a loose rubble pile? We don't know."
