NOTE: End date changed to 03/31/2029 per L. Juliette/JSC (Ed., 5/3/22).

In summary, this international project will monitor changes in brain structure and function up to 3-years post-flight to determine 1) whether they persist in some astronauts, 2) if so, for how long, and 3) whether there are any long-term health consequences. It will thus deliver critical insights into the time course of brain changes and their functional relevance observed in astronauts after ISS missions lasting 6-months and longer. Synergies between the projects will be used to provide NASA and DLR/ESA with insights that go beyond the specific aims of the individual projects.

Ed. Note (2/29/24): This project has been combined with the work of three other Principal Investigators (PIs) who responded to the same solicitation with independent proposals. The protocols and aims from all four PIs have been integrated into a revised proposal that was delivered to NASA Human Health Countermeasures (HHC) and Human Factors and Behavioral Performance (HFBP) Element Scientists in January 2022. For information on the four related investigations, see:

• The Long-Term Consequences of Spaceflight on Brain and Eye Health (PI: Bershad). • Long-Term Brain Structural and Functional Consequences of Spaceflight (PI: Basner). • Investigating Long-term Structural and Functional Changes in the Eye and Brain After Spaceflight (PI: Macias). • Recovery Timeline of Spaceflight-Induced Central Nervous System Changes (PI: Seidler).

The “LTH Call Back” retrospective arm will focus on investigating the structural and functional changes in the eye, brain, and cognition in astronauts who previously participated in long-duration missions, calling them back at least 5 years after their previous flights to determine changes that may endure long after return from spaceflight. Major accomplishments during this reporting period for this sub-study include:

• The protocol was approved by the Institutional Review Board (IRB) in August 2023.

• ROI submitted the Feasibility Assessment to the HHC and HFBP Elements and the sub-study was approved for Select for Ground in September 2023.

Ongoing work with ROI for “LTH Call Back” includes:

• The development of a testing schedule for participants.

• ROI submitted the NASA Lifetime Surveillance of Astronaut Health (LSAH) data share request and is awaiting the completion of a Feasibility Assessment by LSAH prior to moving forward with their recruitment effort.

• The development of a list of potential crewmembers who meet the recruitment criteria for this sub-study.

• The development of an Informed Consent Briefing.

• The completion of the MRI facility contract, which is in progress.

The “LTH Flight” component is prospective and will investigate the development and recovery of structural and functional changes in the eye, brain, and cognition in astronauts participating in standard or extended duration missions and will follow them out 5 years postflight. Major accomplishments for the Flight Study during this reporting period include:

• The protocol was approved by the IRB in October 2023.

• Inputs to the ROI Feasibility Assessment.

Ongoing work with ROI for “LTH Flight” includes:

• Providing testing constraints to ROI so they can begin developing testing schedules for participants.

NOTE: End date changed to 03/31/2029 per L. Juliette/JSC (Ed., 5/3/22).

In summary, this international project will monitor changes in brain structure and function up to 3-years post-flight to determine 1) whether they persist in some astronauts, 2) if so, for how long, and 3) whether there are any long-term health consequences. It will thus deliver critical insights into the time course of brain changes and their functional relevance observed in astronauts after ISS missions lasting 6-months and longer. Synergies between the projects will be used to provide NASA and DLR/ESA with insights that go beyond the specific aims of the individual projects.

In summary, this international project will monitor changes in brain structure and function up to 3-years post-flight to determine 1) whether they persist in some astronauts, 2) if so, for how long, and 3) whether there are any long-term health consequences. It will thus deliver critical insights into the time course of brain changes and their functional relevance observed in astronauts after ISS missions lasting 6-months and longer. Synergies between the projects will be used to provide NASA and DLR/ESA with insights that go beyond the specific aims of the individual projects.

[Ed. Note, Sept 2021: HRP Gap numbers listed above are not current. For the current list of HRP Gaps, see updates at the Human Research Roadmap: https://humanresearchroadmap.nasa.gov/ ].