While floating through space on the International Space Station, astronauts have a lot of time on their hands. Rather than hanging around all day and doing nothing, they fill their days conducting research on the ISS, some which seem like they could be inspired by a cartoon mad scientist. However, while some of their projects have the distinction of being futuristically bizarre, many also have far-reaching medical implications.
It's inevitable that at some point the first baby born in space is going to manifest. But before astronauts can mate in the ISS they have find to out how space radiation affects mammalian reproduction. It would be irresponsible (and probably illegal?) to force astronauts to sleep with each other in space until we understand exactly what impact that will have so, in the meantime, we're just making our researchers bring freeze-dried mouse sperm to the ISS which is held for a period of up to one or two years.
Just a bunch of highly-trained space scientists hanging out with a jug of mouse sperm. Looking at it. After the sperm stays on board for its cycle it's brought back to Earth where it will then be looked over my different highly-trained space scientists who will use it to fertilize mouse eggs that have never left Earth.
As weird as this may sound, it's a necessary test in order to find out if humans can sustain life on a long-term mission. So far there has been considerable DNA breakdown in the sperm after nine months on the ISS, but researchers are hoping to improve on those numbers. Also? We might finally learn what space mouse babies look like.
In April 2018, Elon Musk's SpaceX sent a “proof of concept” machine to the International Space Station called RemoveDEBRIS that's meant to help astronauts get rid of a lot of the junk that's floating through space. (Hey, Elon; don't forget there's still an entire island of garbage here on Earth.) Before the experimental spacecraft will get to the job of hoovering up the more than 500,000 pieces of debris that are in space, a series of tests will have to be performed on the module, but it is projected to be ready by summer 2018.
RemoveDEBRIS will be the largest satellite ever released from the ISS once it has been launched, and after it finishes its mission, the machine won't become the space trash that it so thoroughly hates, but instead will gracefully fall to Earth and burn up in the atmosphere.
In 2017, tissue from a human lung was brought to the ISS so researchers aboard the space station could attempt to grow a fully functioning copy of the organ. If they manage to grow an actual lung, scientists will be able to study the effects of space travel on human lungs in real time. This study won't just show astronauts what's happening inside their bodies; it also has far reaching implications in the realm of regenerative medicine.
Joan Nichols, an associate director for research at the University of Texas Medical Branch who is helming the Earth based portion of the study said that the experiment will be used to
...test strategies for growing new lung tissue, and will assist Earth-based efforts to develop complex bioengineered tissue that can be used to repair damaged organs or reduce organ rejection in the future.
Some experiments that happen in space are all about utilizing the specifics of space to develop something new (like the previously mentioned lung project which hopes to harness the microgravity of space to help generate new cells). But a lot of the experiments are born out of a sense of "Hey, let's just do this one weird thing in space and see what happens." This is in the second category.
What's the scariest thing an astronaut could do while on the ISS? Outside of jumping out of an air lock, playing with fire is a close second. Researchers on the ISS have been studying the differences between flames on Earth and in space; because of the lack of a gravitational pull, flames take on the form of a fire ball rather than the flame stretching to the sky.
The fireballs don't just look different; they're also extinguished differently. After setting droplets of heptane on fire in a specialized chamber, the fires went out almost immediately, but the heptane continued to burn via something that NASA refers to as a "cool flame" (didn't really break the bank on that name, Scientists). These cool flames burn at around 400 degrees Fahrenheit, and they're rarely found on Earth. If they ever did occur in your home, they would likely only burn for a second or two; however, on the International Space Station a cool flame can burn for up to a minute.
Astronaut-scientists claim that playing with fire like this could lead to advances in fuel efficiency. But, ya know, worst case scenario they get to play with fire and yell "cool" a lot.