Countermeasures

What can be done to help you deal with the microgravity environment? With respect to non-living things, every object in the shuttle or space station must be stowed in lockers, strapped down or attached to the wall with Velcro.



Photos courtesy NASA
Everything and everyone in microgravity must be restrained.

For example, when you eat a meal in microgravity, you must be held to the shuttle with footholds, and your food tray is attached to you with a strap. Your food tends to be in forms that are sticky or pasty, like rice or peanut butter, so that it does not float away. If you are at a work station, you use straps and footholds to restrain yourself. Portable equipment, such as a laptop computer, is strapped to either you (as shown above), an equipment rack or the wall of the spacecraft.

As for all of these changes that occur in your body during your stay aboard the International Space Station, what can you do to remain healthy, especially upon your return to Earth? Remember that we have to deal mainly with three changes:

  • Fluid loss
  • Loss of muscle tissue
  • Loss of bone mass

Fluid Loss
One countermeasure to deal with fluid loss is a device called lower body negative pressure (LBNP), which applies a vacuum-cleaner-like suction below your waist to keep fluids down in your legs. This device might be attached to an exercise device, such as a treadmill. You might spend 30 minutes per day in the LBNP to keep your circulatory system in near-Earth condition.


Photo courtesy NASA
Test of LBNP device

Also, just prior to your return to Earth, you can drink large volumes of water or electrolyte solutions to help replace the fluids you've lost. This can prevent you from fainting when you stand up and step out of the shuttle.

Deterioration of Muscles and Bones
NASA and the Russian Space Agency have found that the best way to minimize loss of muscle and bone mass in space is to exercise frequently. This trains your muscles, prevents them from deteriorating and places stress on your bones to produce a sensation similar to weight. You exercise as much as two hours every day on various machines (treadmill, rowing machine, bicycle). You have to be restrained during your exercise, usually by tension-producing straps, such as bungee cords, that hold you to the machine.




Photos courtesy NASA
Exercising in microgravity

Much more research needs to be done to develop countermeasures to the body's changes in microgravity. This research must be conducted both on the ground and in outer space -- aboard the International Space Station -- using both humans and animals. The results of such research will help to improve the health of astronauts and pave the way for long-term space exploration, such as a trip to Mars.

How to Simulate Micro-gravity on Earth

Here are some human and animal models for simulating and studying microgravity on Earth:

  • Head-down tilt - A person lies down on a bed tilted head down about five degrees from horizontal. The tilt reproduces the headward shift of body fluids encountered in microgravity. In addition, weight-bearing bones and muscles will not be used and will deteriorate or atrophy as seen in astronauts in microgravity.
  • Swimming-pool immersion - Place a subject in a warmed swimming pool of water for extended periods of time. The buoyancy of the water will produce the fluid shifts and relieve the weight-bearing bones and muscles as in microgravity.
  • Tail-suspended rats - Rats are suspended head down by their tails in cages for extended periods of time. The tilt reproduces the headward shift of fluids, and inactivity of the hind legs reproduces the deterioration of muscles and bones.
  • KC-135 ''Vomit Comet" - Ride an airplane through a series of up and down (parabolic) flight paths that achieve brief periods (30 seconds each) of microgravity at each peak. NASA uses this technique in astronaut training and has even made it available for student research projects.