5.23

Astronauts data

Days into mission % Reduction in body mass % Reduction in leg strength % Reduction in cardiac output
10 -2.15% -2.50% -1.50%
20 -4.30% -5.00% -3.00%
30 -6.45% -7.50% -4.50%
40 -8.60% -10.00% -6.00%
50 -10.75% -12.50% -7.50%
60 -12.90% -15.00% -9.00%

Can you think of any problems with this data? On day 60 the astronaut has lost 15 % of their leg strength.

According to this data they would then be at 30% of their original leg strength at day 120. There would be a point when they would have no leg strength at all. Calculate for body mass, leg strength and cardiac output, the point that they each reach zero.

For the astronaut with a body mass of 100 kg, what would their body mass be after 220 days in space if they did not exercise? Does this seem like a sensible calculation?

Can you suggest a better way of expressing loss of body functions over time? Do you think this linear model is sensible?

In the next step you will be answering some questions which ask you to think about how you have approached these self assessment questions and the material in this lesson in general.