Astronauts may one day dine on salad grown in asteroid soil.
Romaine lettuce, red pepper and pink radishes all grew in mixtures of peat moss and artificial asteroid soilresearchers reported in July Planetary Science Journal.
Scientists have previously grown crops in lunar dirt (SN: 05/23/22). But the new study focuses on “carbonaceous chondrite meteorites, which are known to be rich in volatile sources — especially water,” says astroecologist Sherry Fieber-Beyer of the University of North Dakota in Grand Forks. These meteorites and their parent asteroids are also rich in nitrogen, potassium and phosphorus – key agricultural nutrients. Pulverizing these types of asteroids, perhaps as part of space mining efforts, could potentially provide a ready supply of agricultural material into space.
Fieber-Beyer purchased a material that mimics the composition of space rocks and gave it to his student Steven Russell. “I said, ‘Okay, grow me some plants.
Russell, now an astrobiologist at the University of Wisconsin-Madison, chose a type of radish, lettuce and chili pepper—all of which grew aboard the International Space Station. He, Fieber-Beyer, and their colleague Kathryn Yurkonis, also of the University of North Dakota, compared how plants grew in artificial asteroid soil alone, in peat moss alone, and in various mixtures of the two.
Peat moss keeps the soil loose and improves water retention. Plants grew in all peat moss mixtures. However, artificial asteroid soil itself compacts and cannot hold water, so plants cannot grow.
Fieber-Beyer will then try to grow hairy ficus seeds in this artificial asteroid dirt, let the plants decay, and then mix the dead plant matter throughout the soil. This, she says, can ensure that the soil doesn’t compact. The seeds also weigh much less than peat moss, making them easier to carry into space to aid in future farming attempts.