A Negative Pressure Suit for Astronauts in Low Gravity Conditions
The lack of gravity in space takes a heavy toll on the human body, but a new negative pressure suit could help
Not a holiday
Space is not a nice place for life that evolved on a planetary surface. We need gravity and we are shielded from excessive cosmic radiation by the atmosphere. Most of space, though, is full of radiation and the strong pull of gravity is quite dissipated, unless you’re close to — or on — a massive heavenly body.
And yes, there are some organisms that can cope with at least a brief sojourn in space, but enduring is not exactly thriving. Carbon-based, DNA-encoded life simply isn’t fit for space. So, when we choose to take a leap into the great star-studded unknown, we need plenty of protection. Even with all the physical barriers, drugs, and exercise regimes, long retreats into space — even low earth orbit, which isn’t exactly deep space — are not beneficial for our health.
In a previous post, we discussed how the high radiation/low gravity environment negatively affects the risk for cancer, unbalances our immune system, causes our bones and muscles to atrophy, and might cause neurological problems.
Plenty of shielding can help with the radiation issue, but that still leaves the lack of gravity to deal with. Our bones, muscles, and circulatory system all need gravity to function properly.
Unfortunately, our current technology for building spaceships and -stations does not include means to generate sufficient gravity. We can’t artificially make it, the ships/stations are nowhere near large enough to spin around for providing a gravity-mimicking centrifugal force, and maintaining a constant acceleration to ‘push’ on our bodies sufficiently is energetically far too expensive.
There is another way to fake the effect of gravity in some respects: lower body negative pressure (LBNP). As the term suggests, this involves lowering the ambient pressure surrounding the lower half of the body, drawing away blood from the head (blood and fluid retention in the head is a major problem in low gravity environments). This makes the heart and circulatory system work harder. The heart is a muscle, so it needs to ‘train’ to keep doing what it does appropriately.
But applying LBNP usually requires bulky chambers. In spaceships, space is at a premium (pun one), so big chambers are not exactly the most economically feasible option.
Now, however, scientists present an LBNP suit that can be worn during daily activities in the spaceship/-station. Basically, it comes down to vacuum pants. They call it the mobile gravity suit.
The negative pressure is generated by its own portable vacuum system, ensuring full mobility, and user-control. Additionally, the gravity suit’s endoskeleton is equipped with its own pressure/thermal control system and three safety features. Due to the gravity suit’s biomechanical design, the flexible exoskeletal membrane axially contracts under negative pressure. This mechanical and dynamic characteristic may provide an additional force that the static LBNP chamber does not generate.
In fact, the suit generated slightly more ground reactive force than a standard LBNP chamber. Since ground reactive force is an important component of the gravity load we experience on earth, this is a good thing. The suit is also energetically more efficient than an entire chamber.
Now, the sample size was small. At the moment, there’s only one size of the suit and, in this case, one size does not fit all (pun two). Quite the opposite, a good fit is essential here. For example, if the ‘joints’ in the suit do not align with the joints in the user’s limbs, this will obstruct the person’s knee mobility and put pressure where it shouldn’t be. This is a minor quibble, however, as it can be prevented by biometric measurements of astronauts or space tourists for a custom-made suit.
The somewhat utopian conclusion:
With the gravity suit, astronauts will be able to float freely around the space station while adhering to their every day tasks. However, this device is not just relevant for astronauts. Once space travel becomes commercialized, this device may ensure the health of future civilian space travelers. It is important to develop effective devices, like the mobile gravity suit, that simulate the very conditions our bodies on Earth depend on. This innovation may be pivotal for the journey to Mars.
Want to explore space? Get your pants here.