17/12/2015 12:51 GMT | Updated 17/12/2016 05:12 GMT

Father Christmas, The Original Astronaut

On Christmas Day 1965, the crew of NASA's Gemini VI-A mission reported a small satellite travelling in a polar orbit, made up of what appeared to be a red space craft pulled by eight small objects. The punchline of this joke was delivered by a rendition of jingle bells played over the communications on a harmonica, the first instrument played in space.


The festive red satellite has yet to be seen since, but there has been another satellite carrying humans around the Earth for the last 15 Christmases. The International Space Station (ISS) is basically a high-tech flat-share in constant free-fall around the Earth at 17,500 miles per hour. This technological marvel has meant that remarkably at no point during the 21st Century have there not been humans in low-Earth orbit. With the ISS orbiting the Earth once every 92 minutes whilst simultaneously keeping its crew alive in the extreme environment of space, perhaps Father Christmas is simply hitching a ride these days, and for good reason.

If we define extreme environments by how long a person could survive unsupported, then space is the ultimate extreme. Without a plethora of technology and life support, humans would only survive for mere seconds in space. Astronauts on the ISS however, stay in low-Earth orbit for months at a time, thanks to the sophisticated engineering of its design. The station is able to provide air, water and heat whilst also shielding astronauts from the dangers of space radiation.

The ISS is fundamentally engineered to maintain an artificial environment that mimics Earth's to counteract the unforgiving austerity of space. Oxygen is predominantly supplied by the electrolysis of water, a deceptively simple reaction that separates water into breathable oxygen and explosive hydrogen, which is vented externally. This life-giving reaction is powered by the ISS' enormous solar panels and is able to provide around 5.4 kg of Oxygen a day.

Whilst the ISS is a symbol of international co-operation, the Russians and Americans each have individual systems for carrying out the electrolysis, with the Russians using the Elektron system and the Americans relying on their rather unimaginative Oxygen Generation System (OGS). But space is too extreme an environment to omit a plan B or even plan C. The ISS is backed up by pressurised oxygen tanks that are replenished from Earth, as well as providing the option to ignite Solid Fuel Oxygen Generation tanks, which are filled with lithium perchlorate.

There are huge temperature extremes in space to contend with. Whilst in full view of the sun, temperatures outside the ISS can rise to a scorching 120 degrees Celsius. In the shade, the temperature plummets to around -160 degrees. This is due to how heat energy can be transferred in space. Conduction and convection are impossible, as there's nothing to touch in space and no air to move heat around. Radiation is therefore the only form of heat energy available, and it's an all or nothing kind of heat. The ECLSS's Temperature and Humidity Control (THC) system is tasked with maintaining a liveable temperature whilst the station hurtles from sweltering highs to perishing colds.

On board the station astronauts are almost constantly working, whether running experiments, conducting maintenance or trying to keep fit. This is thirsty work, and the ECLSS has an ingenious way of recycling the water that astronauts use. The Russian Zvezda system extracts waste water from wherever it's been produced on the station such as showers and even the water vapour exhaled by the astronauts themselves. Zvezda feeds this water back into Elektra, providing the vital fuel for oxygen.

The American system takes things a step further and is tasked with the rather unenviable task of - you guessed it - rescuing water from the astronauts' urine. The Urine Processor Assembly spins and distills the urine, separating the water and gaseous components. The water then feeds into the Water Processor Assembly, which filters it before cranks up the heat and passing the water through a high-temperature catalytic assembly that makes it safe to drink. This process also removes minerals such as calcium, which astronauts' bodies strip from their bones as they become weaker in microgravity.

Space however, isn't as empty as it seems, but not in a good way. High-energy charged particles erupt from stars and distant galaxies and tear through space at light speed. On Earth, we're shielded from this radiation by the magnetosphere, but astronauts have no such luxury. Instead, the ISS is shielded by aluminium, which alleviates the effects of radiation. Astronauts on board the ISS however still experience more effects of radiation than we do on Earth. This is an issue that space agencies are still investigating and will have to solve if humans are to explore the final frontier and push beyond low-Earth orbit.

With the ISS to take advantage of, Father Christmas has at his disposal a bespoke and truly unique mode of transportation for getting around the planet, custom built to house its crew in relative safety and security. Reindeer are likely to suffer from the adverse effects of space travel just as much as humans, so it would make sense for St Nick to retire his sleigh and hitch a ride on the most technologically advanced, planet-navigating homestead ever created by man or myth.

To find out more about how to survive in space tune into this year's Royal Institution CHRISTMAS LECTURES on BBC Four on Dec 28th