I agree with much that is in their letter, especially:

"In FY05, NASA's independent Office of Biological and Physical Research (OBPR) had expenditures totaling $925 million. Since then, the Life and Microgravity Science budget has been decimated and control of these long-term research programs were turned over to a development Program (ESMD) with management by the operational Center in-charge of Constellation (JSC). Thus, the Advanced Capabilities Program has been dominated by operationally-relevant short-term interests in direct support of near-term Orion and Ares development with the abandonment of nearly all of the fundamental and longer-term applied research necessary for extended human exploration. This decision was taken despite the fact that human health and performance issues may present the primary risk to mission success for extended human exploration beyond LEO."

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The critical path and critical issue is human reaction to lower gravities and finding methods to mitigate negative health consequences. Ramping up MANNED space vehicles at this time is premature. We need to have robots build our bases/colonies and that is the capability that should be ramped up (we do need large cargo transport capability).

Mars is a better long term colonization target, but does not provide any help in building up near earth infrastructure. The moon and asteroids are the only likely help for that (unless we can make a breakthrough in dramatically lowering launch costs from earth). The distance to Mars to me implies trips there should be one way and should not be undertaken until all the necessary infrastructure to survive is in place.

Understanding and emplacing off world robotic bases is obviously much cheaper on the moon. First we need to survey, plan, and design. In the case of the moon, we must find if there is accessible water there or not. That will dramatically affect all potential plans.

We should not make any steadfast decisions until we narrow down some of these huge unknowns (human health effects of lower gravity, and accesibility of water on the moon). Since that is true, every effort should be made to shine some light in those areas as soon as possible. Those variable are in the time limited critical path.

I would rather take 30 years to bootstrap up a viable colony presence than 20 years to send some short term expeditions that will just be costly publicity stunt.

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The ISS and Shuttle have fitted the white elephant moniker to a tee. The white elephant was a protected creature that had to be cared for at great expense by decree of the sultan. So, the sultan could give a white elephant to his enemies, bankrupting them in the process. The 200 billion spent with very little return on our manned space in the last 20 years, has been a NASA white elephant. One of the few issues for which ISS could be useful is health issues of gravity. And yet, we have not made provision to do any research except on microgravity. To not have centrifuges that enable Mars, and Lunar gravity research at least for animal studies is a mind boggling oversight which has slowed long term plans 20 years. We could already have answers to these critical questions and yet they remain to be researched. It has been the critical path for 20 years and it is still the critical path. Let's make sure we get started on this.

NASA needs a steady budget, but more importantly to have the obvious priorities laid out, that quit protecting white elephants and capture vision rather than jobs programs.