Sir, I appreciate Bill Tomlinson's interest
in our letter (Spaceflight, December 2004, correspondence) but clearly
he missed its major thrust,
i.e. the necessity of attempting to duplicate, as much as possible, Earth (1 g) gravity for a long mission.
In addition, apparently he is unaware of the cardiovascular
complications experienced by two of the Apollo 15 astronauts but particularly
41 year old James Irwin's cardiovascular problems, which could have resulted in a fatality.
This mission of only 12 days was not a piece of cake, as Tomlinson implies regarding the Apollo missions in general. Apollo 15 portends
numerous medical problems for a Mars mission - even without contemplating those which might be experienced from unknown levels of radiation.
On the Moon, Irwin's heart rate rose to a dangerous level of 167 per minute after just two hours on the lunar surface  and he lost consciousness as a result of a brief heart rhythm disturbance, while transferring gear from the lunar to the command module .
Irwin described in his autobiography that he experienced, during
the four minutes of re-entry at 7 G's, so much shortness of breath that he
could not speak and provided an account of classical angina during that period:
"It felt like an elephant was standing on my chest".  Twenty-one
months later, Irwin suffered the first of four heart attacks .
Of course one may provide a reasonable explanation for Irwin's problems, i.e. that he had underlying heart disease and that various predisposing cardiac risk factors were overlooked in the NASA astronaut selection process at that time. But this begs the question, as to why males are selected in the first place for space missions to the Moon or beyond, with the cardiovascular risk six times higher in males in comparison to females in the third and fourth decades . Furthermore the repair process of the lining of the blood vessels is somewhat impaired after about age 30 .
William J. Rowe, MD
1. Apollo 15 mission report, NASA Manned Spacecraft Center, Houston, Texas, 1971 10-1-15 NASAmsc.05161.
2. R.S. Johnson, L.F. Dietlein and C.A. Berry (eds) Biomedical Results of Apollo, Washington DC. NASA 1975: 227-264, 573-579, 581-591, NASA SP-368.
3. J.B. Irwin and W.A. Emerson, To Rule the Night:The Discovery Voyage of Astronaut Jim Irwin, Philadelphia PA, Holman 1973, 72-108.
4. M.S. Seelig, Interrelationships of magnesium and estrogen in cardiovascular and bone disorders, eclampsia, migraine and premenstrual syndrome, J Am Coll Nutr 1993, 12, 442-58.
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