Agriculture is the oldest and, at the same time, the most important job on the planet. And in the 21st century it will become one of the most promising future in space. It all started in 1977, when a young researcher at the Chinese Academy of Agricultural Sciences, Jiang Xingcun, wondered how space flight could affect plant growth . It was obvious that exposure to cosmic radiation and other factors would produce mutations in their DNA, and that’s what he found: 12% of the seeds he sent into space on satellites had some kind of mutation. Since then and until 2006, China has been continuously sending seeds of more than 400 species of plants into space, with which they have obtained giant eggplants or cucumbers half a meter long and almost 10 kg in weight. In 2006, the Chinese space agency took a qualitative leap and sent more than 2,000 types of seeds, a total of 215 kg of plants and fungi, into space on its Shijian-8 satellite. What the Space Seeds Research Center was looking for was to locate, among the mutations produced, those that were useful in the short term for agriculture.
Island-3: the first proposal
Xingcun was not the only one to think of the agricultural potential of the space. In the United States, a physics professor at Princeton University, Gerald K. O’Neill, published in that same year of 1977 a book destined to become a reference for the future. titledThe High Frontier,O’Neill establishedhow to build, with the technology then accessible, true stations-colonies in space. The largest of all was baptized with the name of Island-3, and theoretically it was designed to house a population of 10 million people. To maintain such a space city, agricultural areas had to be implemented, which would be far from the habitable module since, obviously, plants do not need luxuries beyond a good ration of sunlight, air, water and food. According to O’Neill’s calculations,feeding 10 million mouths required an area of 650 square kilometers, more or less one and a half times the surface of Andorra. In the 1970s, before the appearance of biotechnology, O’Neill advocated intensive agriculture based on multiple planting – mixing fast-growing plants such as corn with slow-growing ones such as potatoes – and double planting : In the first weeks after sowing, the growth of the seedling does not depend on sunlight or nutrients, since all it needs is heat and humidity. In this way, one growth cycle can be superimposed on another. If the maize reaches maturity at 100 days, the next crop can be planted 20 days before harvest. Thusfour harvests a year are obtained in a climatologically controlled environment, which means -all according to O’Neill- that 21 hectares could support 53 people without problems. Furthermore, plants do not need as much air as we do to live: an atmosphere equivalent to that found over the city of Cuzco, at an altitude of 3,400 m, is sufficient. And the diseases that devastate the crops? This would be one of the main problems to combat. Fortunately,the way to kill pests is relatively simple: First, all the water is drained from the contaminated area, which is transferred to a sterilization tank. And to make sure that the environment is free of any microbe, we just have to open the gate to the outside…
Obviously one thing is to make calculations on paper and quite another to do the real world. Proof of this is that from 1971, when the Soviets launched the first space station in history, until 2015, the food of its occupants has been limited to dehydrated and freeze-dried foods that are delivered with cargo resupply missions. And taking into account the cost of sending things to space, almost 20,000 euros per kilo, it is really expensive to send a package of freeze-dried spaghetti to low Earth orbit. No wonder space agencies are looking for ways to grow vegetables in space . Something that in recent years has borne its (rare) fruits: in August 2015 astronauts aboard the International Space Station (ISS) were able to enjoy fresh lettuce grown on the station.
This achievement was the culmination of a program that began in 2010 near Flagstaff, Arizona. There the Desert Research and Technology Studies -or Dessert RATS as they like to call themselves, in clear allusion to General Montgomery’s troops who fought in North Africa during World War II- carried out the preliminary phases of VEGGIE, the NASA project to develop a greenhouse in which to grow plants in microgravity . This system of vegetable production not only makes it possible to study the influence of gravity (or its absence) on plant growth, but also has two added benefits: astronauts can enjoy fresh food on the space station (essentially lettuce) and provides a means for crews to relax. Nothing is better for the tension accumulated on the ISS than the diligent cultivation of the land… in space.
Over the years, VEGGIE has been increasing its volume -the first one only measured 50 cm-, which has made it possible to grow larger and larger plants. The research does not stop and in 2017 Seedling Growth-3 was launched, the third in a series of joint scientific missions of NASA and ESA that aims to achieve a reliable method to grow plants in microgravity. On this occasion the main researcher is the Spaniard Francisco José Medina, from the CSIC Biological Research Center in Madrid. All the research is carried out in a module of the International Space Station dedicated exclusively to space agriculture, the European Modular Cultivation System. On the other hand in Germany, there is Daniel Schubert, an engineer at the German Aerospace Center (DLR), who is growing vegetables in a laboratory with ultraviolet light and, most curiously, with recycled urine as fertilizer . And he’s found that altering the mix of red, blue, and ultraviolet light makes vegetables tastier. “The more ultraviolet, the better the flavor,” says Schubert.
The real challenge for space greenhouses is finding the most suitable plant varieties. The ideal plant must meet three basic characteristics : short stems to save space, few non-edible parts and resistance to lack of light and the inevitable pests. Research is directed towards wheat, rice, lettuce, potatoes… To do this, scientists have at hand a tool that O’Neill never even dreamed of: biotechnology. Identifying the genes that make a plant withstand extreme living conditions and then transplanting them into the chosen varieties turns out to be of paramount importance. Now, all this effort is focused on something with much more packaging. Considering that by 2030 NASA intends to put a human foot on Mars, all eyes of space farmers are on the trip to our beloved red planet.
“White Paper. The Space Agriculture Endeavour”. Open Agriculture. 1 (1): 70–73. 26 May 2016. doi:10.1515/opag-2016-0011
Wheeler, R. (2010) “Plants for human life support in space: from Myers to Mars”. Gravitational and Space Biology. 23: 25–36