Spending time in space for a prolonged period has drastic health effects on the human body. Astronauts that have returned from the International Space Station must work hard to rebuild muscles that they lost from being in a weightless environment for so long. They also face effects such as loss of bone density and a reduction of aerobic capacity.
Astronauts on the International Space Station try to combat this by spending time every day exercising, but they can only do so much. If we ever want to reach a point where humans live for prolonged periods in space, we will need some form of artificial gravity to make the living accommodations as Earth-like as possible.
We've likely all seen science fiction movies with space ships or stations using massive spinning disks to create artificial gravity through centrifugal forces, but for the most part, this is not practical.
Researchers around the world are trying to solve the problem of artificial gravity so that when we do start colonizing space in the future, we have all of the underlying tech worked out.
Bringing artificial gravity into reality
A team from the University of Colorado, Boulder, has developed a rather interesting technology that might help solve the problem at hand.
Rather than making the entire space station a gravity-rich environment, the researchers have come up with the idea of creating smaller pods that "activate" gravity for space travelers, a few hours at a time. This means that the astronauts would essentially experience gravity in the same sense as a spa treatment, for a few hours a day, to keep their bodies acclimated.
Approaching the problem like this solves a lot of the logistical problems which constrain the development of artificial gravity ships designed around centrifugal forces. Mainly, that the ships have to spin and be roughly circular in shape.
The centrifugal approach was based on the understanding that if you spin an object fast enough, the centrifugal forces acting upon it can equal the acceleration due to gravity, about 9.81 m/s^2 at sea level. The bigger problem is that when you create artificial gravity this way, it tends to make people sick.
What does the artificial gravity device look like?
The Colorado team has essentially created a spinning table-like device that provides a platform for the astronaut's feet to press against - simulating a floor. By placing their head along the rotational axis of the device, astronauts can minimize any feelings of dizziness that might come from the disorientating movement.
Dizziness occurs when the nerves in our ears send signals to our brain that are counter to the signals sent by our visual senses. Before we get too far into the details of how the artificial gravity device works, take a look at the short video below to see a practical demonstration.
The user of the device lies down on one side of a bed-like device, with a counterweight on the other side to balance out the rotation. You can start to see why a device of this size would allow future space ship designers to have a little bit more freedom in the design process. Rather than having to go with a spinning ring design, they can go with more fluid designs and allow for weightless rooms to maintain human fitness while in zero gravity.
The device is essentially a human-sized centrifuge. The angular acceleration generated by the spinning of the device pushes the users' feet against the platform.
The user remains perfectly oriented if they maintain their head in a position that faces forward. However, if the user tilts their head in any sort of direction, they would immediately experience vertigo and dizziness.
However, the students believe that this dizziness side effect is something they can solve
Solving the dizziness problem that comes with artificial gravity
The researchers laid out a series of studies and tests to determine whether they could help their bodies build up a tolerance to the sensation of the device.
If you think about it, the premise is fairly similar to what fighter jet pilots go through in training. They sit in devices that spin them around and exert massive g-forces, in order to train their brains to properly interpret and work through the signals that their body is receiving.
The research team took a group of people and worked through personalized training plans on the device, where they slowly raised each person's spinning speed. After about 10 sessions, the group reported that they could spin at the rotational speed needed for artificial gravity and not feel any side effects. This testing is showing early signs of success.
"As far as we can tell, essentially anyone can adapt to this stimulus," said Torin Clark, aerospace engineer and lead researcher on the project.
At the end of the day, the project provides one answer to the question of how to create artificial gravity in space.
The future looks bright for artificial gravity in space.