Our ability to travel beyond our own atmosphere has barely existed for half a century, but the human impulse to explore the cosmos is much older. It’s amazing, then, that the idea of hurtling through the empty void of space has become routine enough that we’re now taking home comforts like tea into space.
Astronauts can drink tea in space! Flavored drinks such as tea, coffee and lemonade are freeze-dried on Earth and stored in vacuum-sealed pouches. These are then rehydrated in orbit through the use of a low-pressure hose, so astronauts can enjoy their favorite drinks hundreds of miles from home.
But the story of how astronauts came to drink tea in space goes beyond a simple explanation. Read on to find out about the lengths to which people will go to enjoy a hot brew, even in zero gravity.
Do astronauts drink tea in space?
Astronauts have been drinking tea in space for decades, which shows that scientists really must consider it brain fuel! Memorably, in 2003, astronaut Don Petitt performed an experiment onboard the International Space Station (ISS) in which he showed off a unique way to drink tea in space: he used chopsticks.
You read that right – in video footage, Petitt is able to pick up a sphere of tea with chopsticks and pop it into his mouth. Now that’s what we call bubble tea.
This is possible in space due to the lack of gravity. Liquids exhibit surface tension, which is to say that water (for example) will naturally bind together rather than separate. Consider skipping a stone across a lake: the stone is able to bounce off the surface of the water rather than immediately sinking if thrown at the right angle and with enough velocity. It eventually sinks, however, because the force of gravity ultimately exceeds the resistant surface tension of the water.
In space, however, it’s the other way around: surface tension usually triumphs over gravity, which gets weaker the further you travel from a large mass (such as Earth). This means that tea and other liquids bind together into small balls in microgravity settings, allowing them to be manipulated by chopsticks. Says Petitt: “It’s easy.” In fact, the article highlighting Petitt’s experiment suggests that we might see a day in which guests have a low-gravity afternoon tea in space as a luxurious venture. Given that commercial space travel is becoming more and more possible with each passing year, these comments made all the way back in 2003 might yet come true.
NASA has said that understanding the behavior of fluids in space is hugely important in our efforts to explore the cosmos. For example, while it’s possible to resupply the ISS through docking procedures, this is complex and costly – and it would become even more challenging the further away from Earth we travel. It would be more efficient, therefore, to transport only raw materials that could then be used in manufacture in low-gravity environments. Given that fuel, plastic components and a multitude of other useful manufacturing elements are used in liquid form, our understanding of how fluids can be manipulated in space is critical – or, at least, that’s what the astronauts must say when they take a break to have a cuppa!
Naturally, drinking tea by way of chopstick is far from the norm in space. Instead, as with other drinks, a powdered tea mix is created on Earth, freeze-dried and placed in a vacuum-sealed pouch. This means that the tea is present in its most concentrated, smallest and lightest form – all hugely important considerations on missions that are measured with mind-boggling precision. These pouches are then rehydrated in orbit and consumed through a straw. It hardly sounds like the ideal tea-drinking experience, but it must be better than going without.
A key detail is that tea, for the longest time, was unable to be heated, meaning the rehydrated pouches were served cold. In 2016, however, Chinese scientists reported a new breakthrough in the drinking of tea in space – a watershed moment that allowed astronauts to enjoy tea just as it should be: hot. (Just don’t tell the people who love cold brew tea!)
In contrast to the futuristic – or, depending on your perspective, primitive – look of the metallic pouch-and-straw combo, the team at the Chinese space program created a special tea cream that enables astronauts to drink the tea hot and from a teacup. At that point, what does Earth have left to offer?
The tea they drink is a Pu’erh tea, cultivated in Yunnan province. China Daily reports that Zhang Guanghui, president of the Gongrunxiang Tea Industry Corporation, declared that drinking tea in space is a turning point for what China Daily calls the “floundering Pu’er tea industry.” Pu’erh tea has recently been engulfed in fraud scandals, with phony tea being sold as a vintage product at extortionate prices. Said Zhang, “For us, astronauts’ drinking tea in space means our biotechnology applied to the tea industry has had some achievements.” So when you think of industries that contribute to the advancement of space exploration, make sure you now include tea on that list.
How do astronauts drink tea in space?
The brewing process for tea is different than on Earth! Plus, tastebuds are affected the further you are away from Earth. If you’re planning on a trip to space anytime soon (and, who knows, you might be!) you’d do well to keep the following things in mind to get your perfect cup of tea.
Astronauts drink tea in space by boiling the water to 60° Celsius (140°F); they then completely dissolve a tea mixture into it. However, because the normal laws of convection do not apply in space, orbital stations must also use heat pipes with partial vacuums to distribute the heat evenly.
You might not have realised it, but gravity is integral to the boiling process. After all, it’s gravity that ensures that cold liquid falls to the bottom of a mixture, and that the warmer liquid – energised by heat – can rise to the top. This drag effect on the cooler liquid is far less prominent in microgravity environments, meaning that the same liquid would be heated constantly; that is to say, the liquid closest to the heat would grow incredibly hot, while the liquid just above it would remain cold.
On the International Space Station, this is mitigated with the use of ‘heat pipes,’ partial vacuums that move cold and warm liquids around in a similar fashion to the natural effect of gravity.
Astronauts must also be careful not to raise the heat of liquid above 60° Celsius for safety reasons. This causes issues with tea, which typically brews at 100° Celsius! That’s why special teas must be mixed that can dissolve completely in this hot (but less hot than usual) water.
Why must they dissolve entirely? Well, it’s to do with bacteria. In low-gravity environments, it’s much easier for bacteria to spread – after all, these living organisms must expend energy to move in much the same way as humans; similarly, much as humans expend less energy to move in weightless environments, so does bacteria. Any food waste could cause bacteria to spread very quickly, so everything must be entirely consumed – or be large enough to jettison – to create a safe space for eating.
How do astronauts get drinking water in space?
Rather than taking enormous canisters of tea and coffee into space, it makes sense to take powder – which can be compressed into smaller spaces – which is then rehydrated in orbit. But… where does the rehydrating water come from?
Drinking water is obtained from the recycled urine and sweat of astronauts. It might not sound pleasant, but urine is sterile and it can be purified into drinking water with heat. There’s very little room to store water in rockets and space stations, meaning reusing water as much as possible is key.
You might have argued with a friend about what kind of water makes for the best tea (which usually comes down to a divide between soft and hard water), but this fact makes such disagreements look petty. Surely we can all agree that any water is better than the urine that came out of your spacefaring colleague – or out of you – only that morning, even if it has been properly purified.
Not only that, but the water recovery system onboard the ISS also plays a crucial part in its oxygen generation. As we all know, water is chemically composed of hydrogen and oxygen (H2O), which means that the oxygen can be separated out and recycled. Yep, they’re all breathing toilet water up there – the astronaut life isn’t as glamorous as it’s made out to be!
Can astronauts drink alcohol in space?
Tea and coffee (or their powdered, rehydrated equivalents) are popular beverages aboard the ISS, but what about those astronauts who’d prefer something a little stronger? Unfortunately for them, there’s no such luck.
Astronauts cannot drink alcohol in space. Since it functions as a depressant, which numbs the senses and aids relaxation, alcohol is not permitted to be consumed during space missions. This is because astronauts are required to be alert at every moment due to the life and death nature of their role.
That said, there is one astronaut who consumed alcohol during a critically important mission, and at an incredibly important moment. As the Apollo 11 lunar module touched down on the surface of the Moon – carrying the first human beings to set foot on our closest celestial neighbor – Buzz Aldrin took Holy Communion.