As humans have ventured out into the great unknown, we’ve had to make some serious technological advancements. Space travel is no exception, if anything, space offers a challenge that dwarfs-flight and sailing. One such challenge is the realization that there isn’t any perceivable gravity in space. The human body (along with various other forms of life) evolved to survive Earth’s environment. As a part of this package, we get a very comfortable gravity field.
Gravity helps with a number of bodily functions. Without it, bodily systems begin to weaken. For example, gravity has an enormous affect on our cardiovascular system. Similarly, it helps regulate our sleeping habits and and our sense of balance. Living in microgravity also causes our muscles and bone density to decay – which is OK if you never want to set foot on another planet, moon, or asteroid again. In addition, there are a number of other physiological and psychological effects that accompany life without gravity. Even with the exercise regiments that astronauts are on to help prevent some of these problems (such as resistance weight training), when humans return from space, it takes them a few weeks to recover from the effects of living in low-gravity environments.
But improvements in exercise and nutrition can only do so much. In reality, these exercises are more like a bandage than an actual fix. If humans ever hope to travel beyond the Earth-Moon system, and certainly into the outer solar system, we really need to come up with a more comprehensive solution to the gravity problem. This is where artificial gravity comes in.
THE CONCEPT: FROM THE GROUND & UP:
The concept of artificial gravity isn’t new – in fact, it’s even within our technological capabilities. It’s one of the first things engineers considered when designing machines to venture out into space (in this case, I’m including low-earth orbit in the ‘space’ category). Their elegant solution was to construct a rotating space-craft/station. This doesn’t ‘create’ gravity, but it simulates it – which is all that really matters in this case. Basically, as the station rotates, it generates centripetal force. Instead of you being ‘pushed’ against the ground (as is the case with Earth), the floor of the station pushes against you. If you imagine the station/craft being shaped like a wheel or hula hoop, the size of that hollow tube and the speed of its rotation can be adjusted to change the strength of gravity.
(as a side note, a useful aspect of having a ‘gravity field’ you can change allows you to train human explorers to operate on planets with a higher gravity than Earth. During the voyage, you slowly ramp up the gravity so when you arrive at a so-called ‘super earth’, you’re already acclimated to the stronger gravity.)
An example of a rotating satiation can be seen on the television show, Babylon 5 (it is pictured below). For those of you familiar with the series, you’ll remember that the space station has several different rotating sections, some of the sections are adjusted to simulate gravity for species from worlds with a weaker or stronger gravitational pull than the one experienced on Earth.
It might interest you to know that, in 1949, the Journal of British Interplanetary Society had an article published by H. E. Ross which proposed a steam-powered rotating space station that would be placed between the Earth and the Moon. That’s right… a steam powered space station.
Then, the Skylab missions of the 1970s came around and scientists learned a very interesting fact – one of the advantages of going to space is the ability to conduct research in microgravity. Because of this, our projects for space stations with artificial gravity were shelved. Now, as we look at venturing further into the solar system, such projects are being reinvestigated.
ENTER THE NAUTILUS-X:
The Nautilus-X (also known as the Multi-Mission Space Exploration Vehicle) comes at an estimated cost of $3.7 billion and is designed to house six people – some other similar designs can house up to 50 people. These stations would be constructed in orbit using inflatable sections and techniques learned from the construction of the International Space Station (ISS). The spacecraft is designed to evolve – meaning it’s versatile in its construction, thus allowing us to add or remove sections as each specific mission requires.
There are plans to test a prototype of this rotating device on the ISS. This project would cost anywhere between $83 million and $143 million and would be the first in-space test of sufficient scale for artificially producing gravity. At the moment, the Nautilus project been put on hold, if not cancelled indefinitely, because of NASA budget cuts.
Even then, that’s not the end of artificial gravity. A cheaper option would be to follow in the steps of the NASA Gemini missions during the 1960s. Here, astronauts connected two spaceships via a tether and spun them around each other. This, in turn, generated some artificial gravity (on a completely unrelated note, I think that type of design would be funny to see flying through space). A second option would be to provide astronauts with a centrifuge-type device to which they would strap themselves into and spin around for a few hours each day, giving themselves little dose of gravity. As an added bonus, as space travel is picked up by private companies, these companies could potentially sink billions or trillions of dollars into research concerning the development of artificial gravity devices for spacecrafts (such as space hotels, or space elevators, even). This seems like a given considering the fact that gravity is key for any entrepreneurial space venture designed to last more than a few hours.
Our pursuit of artificial gravity has been very bipolar. One thing is for sure though, we’ll have to return to the concepts of artificial gravity if we ever hope to leave the gravitational bind of Earth – at least, we’ll have to revisit artificial gravity if we want to stand and walk around on the surface of the next planet we conquer. After all “That’s one small crawl for man, one giant crawl for man-kind” just doesn’t have the same ring to it, does it?)
Want more? Here's another great piece about artificial gravity. Also, you should check out our list: 5 of NASA's Most Ambitious Undertakings.