Coordinating the movement of goods on Earth, even with its consistent gravity and regular supply of oxygen, is difficult enough. But what happens when you need to get supplies to and from the International Space Station -- and beyond?
Here in the safety of the Earth’s atmosphere, it’s easy to take for granted the most basic life-sustaining elements -- clean drinking water and breathable air, for example. But in space, the natural processes that make our existence possible obviously do not exist, and there are therefore a limited number of ways to ensure our astronauts survive and thrive: either deliver all the necessary supplies in a single (and incredibly expensive) trip, or mechanically replicate those natural processes to create a sustainable environment in space.
For the International Space Station (ISS), a combination of the two methods is necessary. Launching and delivering a single pound of supplies into Low Earth Orbit (where the ISS resides) costs $6,000, explains SupplyChain247; delivering a single gallon of water (or 8.3 pounds of liquid) to the moon? $690,000. To meet the basic needs of the ISS astronauts without these prohibitively expensive rocket deliveries, NASA explains, scientists and engineers had to develop systems that recycle water and air from the natural by-products of human metabolism.
While these incredibly complex systems reduce the need for constant deliveries from Earth, they by no means eliminate them entirely. Not only do basic supplies need to be restocked, but the new instruments and technologies powering the groundbreaking research taking place at the ISS (not to mention new crew members, maintenance materials, and tools) also need to be delivered.