] Dawn picks up our interview from where we left off in part one, discussing the Human Research Program for Civilian Spaceflight. She goes on to mention that Chris Mason at Cornell University has a biobank of 1,500 samples across 22 astronauts and seven missions, and that these samples will lead to deeper insights on the effects of spaceflight on humans. Dawn switches gears to ask Michael about the cognitive and physical challenges of spaceflight over long duration missions.

] Following up on the cognitive challenges of long duration spaceflight, Ken mentions that the hippocampus, the primary memory center of the brain, has a relatively low radiation threshold compared to other tissues in the brain. Ken asks Michael to touch on the vulnerability of specialized brain tissues to radiation, particularly in the context of a long duration spaceflight to Mars.

] Ken mentions that it is understood that the APOE4/4 genotype is associated with impaired cognitive performance under certain circumstances and an elevated risk of dementia. While it is currently unknown whether APOE4/4 has any correlation of increased risk associated with cognitive impact resultant from environmental exposure due to spaceflight, Ken highlights the concern with sending APOE4/4-positive astronauts on long duration spaceflights without knowing the risks.

] Ken notes the worsened cognitive impacts resultant from medical radiation, and while therapeutic radiation is different than radiation experienced by astronauts, these results give some indication of the effects astronauts might experience.

] Dawn mentions that we recently had planetary scientist and director of NASA’s Haughton-Mars project, Pascal Lee, on the podcast, who explained his view that since there are so many engineering and biological challenges with going to Mars, we should take a more measured approach to a Mars mission, perhaps even beginning with a roundtrip to Mars rather than landing on our first visit. Dawn asks Michael what his thoughts are on this approach.

] Ken shifts the discussion to the subject of one of Mars’ moons, Phobos, and its potential role in a Mars mission.

] Dawn pivots to talk about Michael’s Book “Building a Space-Faring Civilization: Advancing the Renaissance of Science, Medicine and Human Performance in Civilian Spaceflight.” Dawn asks Michael to talk about the chapter concerning the question of space radiation from the standpoint of precision medicine.

] Dawn asks Michael to talk about the lack of appreciation people have for the fact that a Mars mission would be the most dangerous thing we’ve ever done.

] Ken mentions that Michael has worked with a lot of organizations, including Space X, which has a program, the Space X Mars Colonization Program, dedicated to the establishment of a permanent colony on Mars. Space X’s founder Elon Musk recently made a statement to his employees that in 20 years he anticipates having a million people colonizing Mars. Ken asks Michael to elaborate on the difficulties entailed with not just a sortie mission to Mars but attempting to establish a permanent presence there.

] Ken notes the effect that lofty ideas about colonizing Mars have on people is a lack of appreciation for the tremendous difficulty of the task before us. Ken notes that when we do make it to Mars, the appreciation for the monumental accomplishment that it will be could be seen as inadequate by a public fed ideas about colonizing Mars in the next 20 years.

] Dawn notes that one of the most underappreciated, yet critical, components of long duration spaceflight is the psychology of team dynamics. Considering the isolation and close quarters environment of a spacecraft, how teams interact and how they will mediate conflict is an important problem to consider.

] Dawn shifts gears to talk about Michael’s co-editor for his book, Dr. Marianne Legato, an emeritus professor of clinical medicine and Columbia University, and a practicing internal medicine specialist in New York City known for her sex-specific medicine and research. Dawn asks Michael how he and Marianne met.

] Dawn asks Michael, with respect to his and Marianne’s work on sex and gender differences, how the challenges that men and women face in spaceflight differ.

] Dawn comments on Michael’s fascinating career and asks him if it is what he envisioned for himself when he was in college.

] Ken wraps up our interview by asking Michael what advice he has for students and young researchers just starting their careers.