The entry begins in 1972 with the door of Bios-3 closing. This piece is about the eight years before that, when the Krasnoyarsk group learned, in two smaller systems, what a single-celled alga could do for a sealed human and what it could not. It is short because the published record in English is short: a few paragraphs in the 1997 and 2008 papers, a chart, and the institute’s own summary pages.

Why algae

The arithmetic of a person in a sealed room is simple and unforgiving. Each day the person turns about a kilogram of oxygen into a little more than a kilogram of carbon dioxide and breathes out and sweats off several litres of water, and the room has to take all of that back and return it as air and drink. Plants do exactly this. A photosynthesising cell takes carbon dioxide and water and light and gives back oxygen and sugar, and the question for the first space biologists of the 1950s and 1960s was which plant does it fastest in the smallest space. The answer, everywhere, was Chlorella, a green alga of a few micrometres that doubles itself in hours in a lit tank and never stops. Jack Myers, working for the US Air Force’s school of aviation medicine in the 1950s, had put a mouse under a bell jar with Chlorella to breathe its oxygen, and the mouse, as Gitelson and Lisovsky recalled in 2008, had suffocated. In 1960 and 1961 Yevgeny Shepelev and Gana Meleshko at the Institute of Aerospace Medicine in Moscow had put people into sealed chambers whose air came from algal tanks.

Krasnoyarsk’s contribution was control. The group’s whole method, which Gitelson and Lisovsky in 2008 called “parametric control of biosynthesis”, was to grow a culture continuously, with sensors watching the cells and the medium and a controller adjusting light, nutrients and flow so that the culture sat at its fastest growth rate indefinitely. A culture run that way is a machine: its output is a function of its inputs and can be set. What they found was that a layer of Chlorella spread thin under strong light produced so much oxygen that, in the 2008 paper’s words, “17 liters of the culture spread in a thin layer in the reactor with the light-receiving surface area 8 m² was enough for gas exchange of a human subject whose body mass amounted to 70 kg.”

Bios-1

That was the basis of Bios-1, built in 1964 by the institute’s own dating and 1965 by the 1997 paper’s. It was a sealed cabin of twelve cubic metres joined by air ducts to an algal cultivator of eighteen litres, in which about eight square metres of culture was lit by three xenon lamps of six kilowatts, giving 200 to 300 watts per square metre at the surface. A man sat in the cabin and the algae took the carbon dioxide he gave off and returned oxygen. The 1997 paper is exact about what that amounted to: “The algal system, by removing carbon dioxide and producing oxygen, accounted for approximately 20% of the quantities (mass) of pure air, water, and food required by a single human; that is, the system achieved 20% closure. Food and water had to be taken into the system before a human could be sealed inside.”

The runs lengthened. The 1989 paper, looking back, says that “the experiments, which lasted 6 weeks, proved the algae to be able to fulfill successfully the functions of gas- and water-exchange in the system for man.” A thirty-day run, published in Life Sciences and Space Research in 1968 by Kirensky, Terskov, Gitelson, Lisovsky, Kovrov and Okladnikov, gave the group its first balance chart, which the 2008 paper reprints: carbon dioxide, oxygen and the man’s body weight across thirty days, three lines that hold level. That chart is the ancestor of every balance in the entry.

In 1965, by the institute’s account, the water cycle was closed too, with the man’s used water going to the algae and the condensate coming back; the 1997 paper dates the 80 to 85 percent closure that resulted to 1968. Either way, within four years of starting, the group had a sealed man whose air and most of whose water came from a tank.

What the algae could not do

The food was the wall. Chlorella is, on paper, excellent food: the 1997 paper lists “all essential amino acids, sufficient lipids, and nearly all the essential vitamins”, and the 2008 paper says that 300 to 400 grams of algal biomass a day would cover a person’s amino acids, including the scarce sulphur-containing ones. The trouble was everything else. Algae “contain virtually no carbohydrates”, so the diet would be grossly out of proportion, with 150 to 200 grams of protein and 15 to 20 grams of nucleic acids a day, “excessive pigments, potassium, magnesium, and sulfur”. Processing the cells into anything a person would eat was difficult, and the experience of feeding large amounts of Chlorella to animals and people, the paper says, “has led to nutrient deficiencies and illness”. A 2005 Krasnoyarsk newspaper account puts it more plainly: the algal food tasted strongly of swamp. The 2008 paper concludes that algae could contribute “just 5-10%” of a human diet, “as their biomass mainly contains proteins and nucleic acids, while normal human diet must predominantly contain carbohydrates.”

There was a second problem, which only showed up when the two kinds of plant were put together. In the 1976 Acta Astronautica paper, as the NASA plant physiologist Raymond Wheeler reports it, the group recorded that in a system with algae and higher plants sharing air, cucumbers stopped flowering and their leaves turned yellow, and beet leaves went dark with anthocyanin: “This suggested that there was some unidentified toxic volatile(s) produced by the algae.” The algae were not just failing to feed the crew. They were poisoning the crops that could.

Bios-2

The answer, which the 1997 paper credits to Lisovsky, was to grow what people actually eat. In 1968 the Bios-1 cabin was joined to a chamber of 2.5 by 2.0 by 1.7 metres for higher plants, and the pair was renamed Bios-2. The builders called the plant chamber a phytotron, a word two American botanists had coined in jest in the 1940s to suggest that their field could build something as imposing as a cyclotron, and the Krasnoyarsk group kept it for the rest of the programme. A man could go through a hatch from the cabin into the phytotron to tend the plants and harvest them. In some runs the crop was wheat; in others a set of vegetables, “beetroots, carrots, cucumbers, and dill”. The algae did about three quarters of the air regeneration and the higher plants about a quarter, and “this three-component system demonstrated the feasibility of direct gas exchange between humans and higher plants.” The institute’s own page says that by 1968 the air was 99 percent regenerated, the water 85 percent, and food and nutrients about half, and that dried meat was brought in to balance the diet; the last of those figures, for a chamber the size of a large wardrobe, should be read as the institute’s summary rather than a measurement.

Lisovsky’s finding, which the 2008 paper states as a correction of what everyone had assumed, was that a field of wheat grown as a conveyor, with plants of every age at once, yields “the same amount of biomass and, hence, the same amount of oxygen as the microalgal culture.” It had been “earlier assumed that productivity of the algae was many times higher than that of higher plants.” If that was wrong, there was no reason to keep the tanks. Thirty square metres of lit crops per person, the paper says, could supply the plant part of a diet: “That was the basis for constructing Bios-3.”

So the tanks went into one of the four compartments of the big system, as insurance, and were used for the oxygen in the last four months of the first run in 1973. Then they were taken out, and the compartment became the third phytotron. Everything after that is in the entry.

Sources

• Frank B. Salisbury, Josef I. Gitelson and Genry M. Lisovsky, “Bios-3: Siberian experiments in bioregenerative life support”, BioScience 47 (9), 575–585, October 1997. Shepelev and Meleshko, Bios-1’s dimensions and 20 percent, the 1968 water closure, Bios-2 and the phytotron, the quarter and three-quarters, and the case against algae as food. simoc.space
• Iosef I. Gitelson and Genry M. Lisovsky, “Creation of closed ecological life support systems: results, critical problems and potentials”, Journal of Siberian Federal University, Biology 1 (1), 19–39, 2008. Parametric control, the 17 litres and 8 square metres, the thirty-day chart, the diet arithmetic, and Lisovsky’s finding. elib.sfu-kras.ru
• I. I. Gitelson and colleagues, “Long-term experiments on man’s stay in biological life-support system”, NASA Conference Publication 10040, 1989, pages 61–66. The six-week runs and the reference to the 1968 thirty-day paper. ntrs.nasa.gov
• Raymond M. Wheeler, “Agriculture for space: people and places paving the way”, Open Agriculture 2, 14–32, 2017, reporting the cucumber and beet symptoms from the 1976 Acta Astronautica paper. sciences.ucf.edu
• Institute of Biophysics, “BIOS-3” and “History” pages, for the 1964 and 1965 dates and the 1968 percentages. ibp.ru/science/bios3.php, ibp.ru/history/info01_eng.php
• Zolik Milman, Rossiyskaya Gazeta, 1 July 2005, for the taste of swamp. rg.ru
• L. V. Kirensky, I. A. Terskov, I. I. Gitelson, G. M. Lisovsky, B. G. Kovrov and Yu. N. Okladnikov, “Experimental biological life support system. II. Gas exchange between man and microalgae culture in a 30-day experiment”, Life Sciences and Space Research VI, 37, 1968. Not read; cited as the 1989 paper cites it.