Bryan Versteeg for Explore Mars
Artist's impression of ExoLance probes being launched from a skycrane-like lander hovering over the Martian surface.
To find life on Mars, some scientists believe you might want to look underground for microbes that may be hiding from the harsh radiation that bathes the red planet’s surface. Various NASA rovers have scraped away a few inches at a time, but the real paydirt may lie a meter or two below the surface.
That’s too deep for existing instruments, so a team of space enthusiasts has launched a more ambitious idea: dropping arrow-like probes from the Martian atmosphere to pierce the soil like bunker-busting bug catchers.
The “ExoLance” project aims to drop ground-penetrating devices, each of which would carry a small chemical sampling test to find signs of life.
“One of the benefits of doing this mission is that there is less engineering,” said Chris Carberry, executive director of Explore Mars, a non-profit space advocacy group pushing the idea. “With penetrators we can engineer them to get what we want, and send it back to an orbiter. We can theoretically check out more than one site at a time. We could drop five or six, which increases the chances of finding something.”
Each penetrator would have a tail section sticking above the surface with an antennae sending data back to the lander, while a second section would detach and burrow into the ground in search of life.
Explore Mars is launching a crowd-funding effort this month, as well as announcing a corporate and academic partner at a July 31 event at American University in Washington, DC.
The goal is to begin engineering and testing of the small, lightweight “arrows” in the Mojave Desert, which has some of the same soil and rock characteristics as Mars, explained Carberry.
“We want to show that we can get to the proper depth, that it would survive the force of the impact and that we could have a science payload on this that could communicate back,” he said. “We might also be proven wrong.”
Schematic of one of the ground-penetrating devices as conceptualized by the ExoLance project.Bryan Versteeg for Explore Mars
Carberry says the idea is to piggyback off a future Mars mission.
“Most landers have ballast that they get rid of. The ExoLance would not be terribly expensive and won’t have a lot of mass to it.”
The idea is intriguing, according to one scientist, but still has a few things to work out. For one, making sure the device doesn’t crash on impact, says Chris Carr, a research scientist at the Massachusetts Institute of Technology’s Department of Earth and Planetary Sciences who works on ways to detect life on other planets.
“The (NASA) Mars program has been pretty risk-averse,” Carr said, “and so it is worth looking at higher risk alternatives. Ultimately when you want to decide do you want to spend the money you are going to make a decision about likelihood for success. There are some hurdles to ExoLance, but it seems like a reasonable concept to explore at this stage of the game.”
Carr noted that NASA tried to do something similar back in 1999 during the “Deep Space 2” mission to Mars, but the penetrators failed to establish radio contact after hitting the Martian surface. NASA wasn't able to determine whether the batteries, radio or the device itself failed on impact.
Despite the odds of failure, another mission like ExoLance might be worth it, Carr said. That’s because the subsurface is a good place for microbes to thrives, especially in regions where there may be patches of frozen water.
“It’s definitely the most promising place at the moment,” Carr said about the subsurface. “If there is life on Mars, it’s possible that it only has a habitable environment periodically when there is melting going on. One benefit is if you have a bunch these (penetrating devices), you don’t need them all to survive.”