GravSim

GravSim, Will compression waves from vibration simulate gravity in a micro-gravity environment and stop or slow down bone-density loss?

Full body Vibration (FBV) has already been used terrestially after astronauts return to earth to help improve bone and muscle recovery from their stay in micro-gravity.

There has since been several studies to test the usefulness of FBV on bone density such as

• Bone and Mineral Evaluation and Analysis - NASA

• NASA Good Vibrations (equinehealthcentre.com)

• Safety and severity of accelerations delivered from whole body vibration exercise devices to standing adults - PMC (nih.gov)

But safety is also a concern as too much full body vibration or hand-arm vibration is not good and can damage your body

• Human vibration (Human Vibration (br056) (bksv.com))

Full body vibration is measured by acceleration. The is the acceleration of the body experiences to return to the center point of a oscilation. The plan is to used compression waves delivered by modules. These waves that can be visualized below, The peak of the wave (amplitude) is the maximum compression and the lowest point is maximum expansion. When the body is moving between those states that is the acceleration experienced by the body.

This acceleration is routinely described as a fraction of earths gravity (g). The article: Safety and severity of accelerations delivered from whole body vibration exercise devices to standing adults - PMC (nih.gov) describes that a safe full body vibration limit is acceleration of 1/3 g for 8 hrs.

Full body Vibration has 3 aspects that could be useful to astronauts in micro-gravity

• The acceleration the body experiences

• The compression and expansion on the body where is no force otherwise

• The muscles responding to vibration to stabilize the body
  

These 3 aspects could help with the bone density loss of 1% - 2 % per month in microgravity. While it is important to note that too much vibration could result in nerve, and musculoskeletal issues and keeping the amount of vibration in the safe and healthy range and not too much.

Testing is needed to investigate the validity of the full body vibration method in an extended micro-gravity environment