When Indian astronaut Shubhanshu Shukla looks out the window of the International Space Station (ISS), he sees Earth floating peacefully below. But inside the station, life is far from ordinary, especially when it comes to something as basic as using the toilet or dealing with waste.

On Earth, drinking water comes from rivers, lakes, or taps. In space, water is one of the rarest resources. Since astronauts can’t carry unlimited water from Earth, the ISS uses a high-tech system called the Water Recovery System (WRS) to recycle every possible drop.

This includes urine, sweat, and even moisture from the breath. These fluids go through layers of filters, chemical treatments, and purification stages to make them 100% safe to drink. NASA even claims this water is sometimes cleaner than what people drink on Earth.

Even though the ISS recycles liquids, human poop is not reused, at least not yet.

Instead, solid waste is sealed in plastic bags and placed in special containers inside the station. These bags are stored in a designated waste area until a cargo spaceship arrives.

Every few months, a supply vehicle brings fresh items to the ISS. When it leaves, it takes back all the trash, including poop and other waste. These loaded cargo ships are then sent back to Earth’s atmosphere, where they burn up completely, leaving no trace behind.

Life in space can be rough on the body. In the first few days, astronauts often experience space motion sickness, also called space adaptation syndrome. Symptoms include nausea, headaches, tiredness, and even vomiting.

To deal with this, astronauts carry special "space sickness bags", also known as barf bags. These are designed for zero gravity and are lined with absorbent material to prevent leaks. Once used, they are sealed and stored with other waste to be destroyed during re-entry.

NASA isn’t giving up on the idea of recycling solid waste. In fact, the agency is encouraging new ideas from around the world.

Through a global contest called the Lunar Loo Challenge, NASA is inviting engineers, scientists, and startups to design toilets for space missions that can turn feces, urine, and vomit into something useful, like water, energy, or even fertilizer.

The prize? A whopping $3 million (around Rs 25–26 crore).

The goal is to create sustainable systems for future missions to the Moon or Mars, where resupplying from Earth won’t be possible, and recycling will be the only way to survive.

From drinking purified sweat to burning poop in space, life aboard the ISS is anything but ordinary. But thanks to science, and a bit of innovation, astronauts like Shubhanshu Shukla are keeping things running smoothly, one recycled drop at a time.

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