THE PLAN FOR SUSTAINABLE SPACE DEVELOPMENT
- a proposal for America’s space program during the current administration -

We really don't know what effect that the Moon's 1/6th gravity has upon a developing fetus or child but it's probably not good. We also don't know how much of a benefit partial artificial gravity would give. The Plan for Sustainable Space Development supports artificial gravity experiments to find out. But there is a matter of timing. Exactly when do we need to know the answer?

For many years, we have done little to find out the artificial gravity prescription. There was a plan to place a centrifuge module on the International Space Station but budgetary cuts nixed that. Now that module sits unused in a Japanese parking lot. But then, crew on the ISS don't really need to know the artificial gravity prescription. Crew rotations typically last four to six months such that any impact of microgravity is acceptable.

But, do we even need to know the artificial gravity prescription before we go to the Moon? Probably not. As discussed in the Extending Crew Stay page of this Plan, we can use biomedical criteria and for those crew who are nearing these criteria, we can return them to Earth in three days. So, any low Earth orbit-based artificial gravity experiments should be very expensive because the UniHab's indoor centrifuge could be used for artificial gravity animal studies without adding much additional cost or delaying the establishment of the base.

REPRODUCTION
In the long term, we need to figure out the artificial gravity prescription for healthy gestation and childhood. And, since in-space pregnancy could happen in the relative near-term (e.g. in an Earth-orbiting hotel) there is some urgency to figuring this out. Also, the four couples of the initial crew should avoid getting pregnant until the animal studies are done. Perhaps the most logical solution would be for the men to undergo reversible vasectomies and both the husbands and wives should have their gametes frozen on Earth as the ultimate method of ensuring that they could retain the option of having healthy children. These young couples could be fairly motivated to complete the animal studies so that they would know what it would take to have a healthy child on the Moon. There is the possibility that a fetus or child would essentially need full gravity 24/7. This is not practical in an indoor centrifuge. If this is the case then, as a practical matter, that type of space settlement involving children would be limited to large, rotating, orbiting settlements with a long enough diameter to allow for full gravity with a rotation speed that could be accommodated to.

ANIMAL STUDIES
A series of animal studies could be conceived of whereby the artificial gravity prescription (AG Rx) for healthy gestation and childhood could be determined starting with a rapidly-producing mammal such as mice. The question that we would be trying to figure out would probably be, "How many hours a day of full artificial gravity is needed"? Determining the AG Rx for healthy gestation would probably take two or three sessions of 25 days each. So, in two and a half months, one could move on to the next animal model (e.g. marmoset). The longer studies would be to determine the AG Rx for healthy childhood. But, one could begin to guess possible childhood AG Rxs for later animal models and so begin those studies even before one has the precise answer. It is difficult to say, but perhaps the AG Rx for healthy gestation and chilhood for a macaque monkey could be established in 5-10 years after the initial crew arrives. So, the very first crew could also be the first crew to attempt an off-Earth pregnancy. Ultimately it would be their choice having been informed by their own experiments.