An oasis in a desert

The limits of living

How far is it possible to live sustainably with no input from the outside world? Scientists are putting that to the test in three different extreme situations.

An Antarctic research base with a surplus of solar-generated hot water, a laboratory where a rat lives off algae and the algae lives off the rat, and a cockpit where the pilot eats, rests and relieves himself for five days non-stop – these are three of the modern-day frontiers in a push to find the limits of living. Each in different ways shows how engineering ingenuity, scientific knowledge and human willpower are being put to work to answer the question of how we could live, how much we really consume, and how far you can push the vision of sustainability. Humans have limits, so does technology, and our planet. Finding the sweet spot is the challenge.

Algae, rats and astronauts

In a space research lab at the Universitat Autonoma de Barcelona, a rat is breathing gases from algae, and the algae are breathing gases from the rat. For several weeks the two have been happily co-existing, in an experiment run by Christophe Lasseur from the European Space Agency.

“It’s not what we would call a ‘bioequilibrium’,” he stresses. “The reactor is controlled by a computer, and depending on the activity of the rat, we control the environment of the algae to follow the consumption of the rat.” So if the animal needs a bit more oxygen, the microscopic plants can wind up their production and keep the little rodent breathing happily.

The goal is to do the same for humans, in a project called MELiSSA. Its ultimate aim is to develop artificial ecosystems that could feed regenerative life support systems for long-term manned space missions to the Moon and Mars.

For the moment, they’re still working on keeping the rat alive, before they start on humans. The animal is currently fed with water and food from outside the loop, because the main goal is to test the oxygen loop. It wouldn’t make sense to develop a system to make food for rodents, when humans have quite different dietary needs. So Lasseur is working to build a food loop based on two processes: “One with algae, to produce the protein, and the other one is based on plants like potatoes, tomatoes, lettuce, durum wheat, and beet”.

Lasseur has the determined air of a man who masters his subject, and won’t stray from his course until he has built the most sustainable human space habitat possible. So what is the baseline of human needs, what do we need to survive every day? The answer is 5kg. It’s the absolute, non-negotiable minimum, Lasseur declares. The breakdown, he explains, is “three kilos of water, one kilo of oxygen, one kilo of food”.

Of course, even the hardiest of astronauts needs a little more water in order to have a wash and feel comfortable, so Lasseur quotes around 20 to 25kg of water per day for long-term missions.

Right now, the International Space Station is the test-bed for sustainability in space, where up to 80 per cent of the water on board is recycled. The head of ESA’s astronaut corps, Frank De Winne, jokes that “on the space station, we can basically say that the coffee that we drank yesterday is the same coffee that we drink today, and we also drink the coffee of our crewmates.”

They don’t just drink each other’s recycled urine, but also each other’s recycled air and sweat, as the ISS ventilation system allows the collection of condensate, the water exhaled by the astronauts.

Where water recycling is nothing new on planet Earth, it’s definitely a tough ask in space, as microgravity hinders the most mundane of recycling processes, such as filtering and condensing liquids.

Foods are even more complicated, because the scientists would need to “mathematically model biological processes in plants to the level of spacecraft engineering,” says Lasseur. Even with centuries of botanical research behind us, we don’t understand plants as well as we do rockets.

“Systems will always consume some energy, and produce some waste,” says Lasseur. So a closed-loop spacecraft setting off through space with a finite supply of mass and energy and 100 per cent recycling efficiency is nothing more than a sci-fi pipe dream, and will remain as such.

Nonetheless, Lasseur is optimistic that it’s possible to create a system that will recycle 80 per cent of waste mass back into oxygen, food and water.

In hot water at the South Pole

They’re throwing away hot water in East Antarctica. Actually, they’re using it to melt snow, to make more water, which isn’t really essential but nice to have. This is the cutting edge of sustainable living at the high-tech Princess Elisabeth research station in one of the most extreme environments on planet Earth, and it turns out to be pretty comfy.

“We take the snow from -10 to 60 degrees Celsius at absolutely no cost,” boasts Nighat Johnson-Amin as she shares the secrets of life at this Belgian base in the Antarctic. The key is a solar thermal system that heats the water in the summer months when the station is occupied.

“In the beginning shower time was limited,” she admits, but nowadays the scientists, engineers and support staff at the station are encouraged to use the hot water as they wish.

They don’t just have bucketfuls of warm water, but also a surplus of electricity from the wind turbines and more hot air than a global climate summit. “It’s much warmer than we expected inside the building. Everything generates heat,” says Johnson-Amin. The station does not use what most of us would recognise as a heating system; instead it captures the heat of the machines and people inside. Combined with an air and water-tight nine-layer outer shell, the air inside stays at room temperature, while outside it varies between -5 and -50°C.

The popularity of the location and the unusually pleasant environment of the station have meant one of the few headaches the management has encountered is that it’s often fully booked. Designed for 16 people, Princess Elisabeth often accommodates 48, which can lead to a few frictions as visitors run up against the reality of living in one of the world’s most sustainable buildings.

The rub comes in the form of the Hal-like computer at the physical and metaphorical core of the building, which uses 10,000 sensors to controls things like access to Wi-Fi, and power to the kitchen. Three times a day the cook draws down the power, and the laptop recharging has to be put on hold.

“The station is taking decisions for you. In the beginning some are a bit upset when they can’t be on FaceTime and Wi-Fi all the time. When you’re cut off from that, there’s a resistance. But you are in Antarctica, you can’t be that spoilt,” laughs Johnson-Amin.

Waste is another sustainability issue tackled head-on. Water is recycled into the washing machines and toilets, while a bioreactor plant means that after a combined 3,000 person-days of occupation, the season ends with a residue of 40kg of unrecyclable sludge that has to be flown back to civilisation for disposal.

Like many successful frontier colonies, there are dreams of expansion. “We didn’t imagine we’d have so many people. It’s difficult to grow,” says Johnson-Amin, who envisages a prefabricated ‘plug-and-play’ system of accommodation that could be clicked into the building. “Still,” she says wistfully, “that’s humans for you! We’re never happy”.

Living in the clouds

“He took far too much food with him,” admits Solar Impulse flight director Raymond Clerc. On the first day of André Borschberg’s record-breaking flight across the Pacific this summer, he ate exactly one banana, one apple, two cereal bars and a piece of cheese. Not much if you’re trying to fly across an empty ocean in a solar-powered plane. On day two it was pretty much the same, and then on day three he pushed the boat out and had a decent meal of dried meat and potatoes followed by some chocolate. On average he drank an impressive four litres of water per day, and didn’t touch a drop of coffee.

The Solar Impulse project is a curious test of the limits of sustainable technology and the limits of human beings, to see how far you can push the dream of round-the-clock flight, fuelled only by the sun. Those limits are defined by two things, according to Clerc. “The first one is weight. You need to take oxygen, water and food, and that adds up to about 15 kilos per day, which is a significant amount in a plane that weighs just 2,400 kilos,” he says. “The second one is the pilot. I think the pilot could fly for 10 days, but no more.”

Borschberg himself would seem to agree, as he tweeted during the flight: “It’s delicate to maintain a balance between my energy and the energy of the aircraft.”

Although the team had slightly over-catered for Borschberg’s meagre appetite, they had him follow a very strict menu of sleep throughout the crossing, which lasted five days and five nights. He used the same sleep cycle regime as solo round-the-world sailors, napping for 20 minutes at a time, a system that provides enough rest to keep going for another five hours, but prevents his body from entering true deep sleep. He notched up 12 of these power naps on the first night, building up a good base of rest that meant he was able to stay awake much more the following few nights. There were no snoozes in the daytime though: Solar Impulse flies high by day to charge its batteries from the sun, so Borschberg had to keep a careful eye on the flow of air from his oxygen mask.

A good chunk of the 62-year-old’s energy was spent on getting dressed and undressed, as the Swiss engineers discounted the idea of heating the plane’s cabin, and instead bought him a pile of high-tech mountaineering clothing in order to face temperatures of -20°C at a peak altitude of 8500m, and +35°C down near the ocean surface at the end of the wings’ charging cycle.

In fact, heat management is one of the big learning curves of the project. While André donned and doffed his thermals, the aircraft’s batteries had been over-protected from the cold, and ended up being battered by the heat. Fixing that means the next leg of the round-the-world solar flight is postponed until spring 2016.

The next flight can’t come soon enough for Borschberg. “He had to do some stretching before he came out the plane in Hawaii,” confides Clerc, “but I think in the end he was sad it was all over”.

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