Within the movie The Martian, astronaut Mark Watney (performed by Matt Damon) survives being stranded on the Crimson Planet by farming potatoes in Martian dust fertilized with feces.
Future Mars astronauts might develop crops in dust to keep away from solely counting on resupply missions, and to develop a higher quantity and number of meals than with hydroponics alone (SN: 11/4/11). However new lab experiments recommend that rising meals on the Crimson Planet will likely be much more difficult than simply planting crops with poop (SN: 9/22/15).
Researchers planted lettuce and the weed Arabidopsis thaliana in three sorts of faux Mars dust. Two had been constructed from supplies mined in Hawaii or the Mojave Desert that seem like dust on Mars. To imitate the make-up of the Martian floor much more intently, the third was constructed from scratch utilizing volcanic rock, clays, salts and different chemical elements that NASA’s Curiosity rover has seen on the Crimson Planet (SN: 1/31/19). Whereas each lettuce and A. thaliana survived within the Marslike pure soils, neither could grow in the synthetic dirt, researchers report within the upcoming Jan. 15 Icarus.
“It’s not stunning in any respect that as you get [dirt] that’s increasingly correct, nearer to Mars, that it will get tougher and tougher for crops to develop in it,” says planetary scientist Kevin Cannon of the Colorado College of Mines in Golden, Colo., who helped make the artificial Mars dust however wasn’t concerned within the new examine.
Soil on Earth is stuffed with microbes and different natural matter that helps crops develop, however Mars dust is mainly crushed rock. The brand new end result “tells you that if you wish to develop crops on Mars utilizing soil, you’re going to must put in quite a lot of work to rework that materials into one thing that crops can develop in,” Cannon says.
Biochemist Andrew Palmer and colleagues on the Florida Institute of Expertise in Melbourne planted lettuce and A. thaliana seeds in imitation Mars dust beneath managed lighting and temperature indoors, simply as astronauts would on Mars. The crops had been cultivated at 22° Celsius and about 70 % humidity.
Seeds of each species germinated and grew in dust mined from Hawaii or the Mojave Desert, so long as the crops had been fertilized with a cocktail of nitrogen, potassium, calcium and different vitamins. No seeds of both species might germinate within the artificial dust, so “we’d develop up crops beneath hydroponic-like circumstances, after which we’d switch them” to the synthetic dust, Palmer says. However even when given fertilizer, these seedlings died inside every week of transplanting.
Palmer’s staff suspected that the issue with the artificial Mars dust was its excessive pH, which was about 9.5. The 2 pure soils had pH ranges round 7. When the researchers handled the artificial dust with sulfuric acid to decrease the pH to 7.2, transplanted seedlings survived an additional week however in the end died.
The staff additionally ran up in opposition to one other downside: The unique artificial dust recipe didn’t embrace calcium perchlorate, a poisonous salt that current observations recommend make as much as about 2 % of the Martian floor. When Palmer’s staff added it at concentrations just like these seen on Mars, neither lettuce nor A. thaliana grew in any respect within the dust.
“The perchlorate is a significant downside” for Martian farming, says Edward Guinan, an astrobiologist at Villanova College in Pennsylvania who was not concerned within the work. However calcium perchlorate could not must be a showstopper. “There are micro organism on Earth that take pleasure in perchlorates as a meals,” Guinan says. Because the microbes eat the salt, they provide off oxygen. If these micro organism had been taken from Earth to Mars to munch on perchlorates in Martian dust, Guinan imagines that the organisms couldn’t solely do away with a poisonous element of the dust, however maybe additionally assist produce breathable oxygen for astronauts.
What’s extra, the precise therapy required to make Martian dust farmable could range, relying on the place astronauts make their homestead. “It in all probability relies upon the place you land, what the geology and chemistry of the soil goes to be,” Guinan says.
To discover how that selection may have an effect on future agricultural practices, geochemist Laura Fackrell of the College of Georgia in Athens and colleagues blended up 5 new forms of fake Mars dust. The recipes for these fake Martian materials, additionally reported within the Jan. 15 Icarus, are based mostly on observations of Mars’ floor from the Curiosity, Spirit and Alternative rovers, in addition to NASA’s Mars World Surveyor spacecraft and Mars Reconnaissance Orbiter.
Every new synthetic Mars dust represents a mixture of supplies that could possibly be discovered or made on the Crimson Planet. One is designed to signify the typical composition throughout Mars, just like the artificial materials created by Cannon’s staff. The opposite 4 varieties have barely totally different makeups, akin to dust that’s significantly wealthy in carbonates or sulfates. This assortment “expands the palette of what we have now out there” as test-beds for agricultural experiments, Fackrell says.
She’s now utilizing her inventory to run preliminary plant progress experiments. Thus far, a legume referred to as moth bean, which has related dietary content material to a soybean however is extra drought resistant, has grown the very best. “However they’re not essentially tremendous wholesome,” Fackrell says. Future experiments might discover what nutrient cocktails assist crops survive within the numerous pretend Martian terrains. However this a lot is obvious, Fackrell says: “It’s not fairly as straightforward because it appears to be like in The Martian.”