Space Habitation and Life Support Commons^™

Dynamic Modeling Of The Earth's Trapped Proton Environment, Xiaojing Xu, Steve R. Blattnig, Francis F. Badavi, Martha S. Clowdsley, Edward J. Semones

Physics Faculty Publications

Context: Reliable prediction of space radiation exposure is critical for safeguarding spacecraft systems and ensuring astronaut health during missions. Accurate radiation risk assessment for space mission requires advanced models of the Earth’s trapped proton environment. These models must reflect temporal variations driven by geomagnetic field evolution and solar cycle modulation. Existing static models, such as AP8 and IRENE-AP9, are not designed to fully capture these evolving conditions. Aims: This paper presents a dynamic modeling method for the prediction of trapped proton fluxes, which incorporate time-dependent variations due to geomagnetic field evolution and solar cycle fluctuations. Methods: The …

Reduced Set-Shifting Processing Speed In Male Rats Following Low Dose (10 Cgy) Proton Exposure, Hui Ho Vanessa Chang, Gyutae Kim, Kyu-Sung Kim, Richard A. Britten

Center for Integrative Neuroscience and Inflammatory Diseases (CINID) Faculty Publications

Space radiation (SR) exposure poses significant biomedical risks, including effects on the central nervous system (CNS). These risks are particularly relevant to cognitive function during long-duration space missions. One critical cognitive skill is decision-making, which requires attentional set-shifting (ATSET)—the ability to quickly assess problems, evaluate options, and select the best actions. Previous studies have shown that exposure to However, the impact of low LET (< 1 keV/μm) protons, which significantly contribute to the total radiation flux astronauts encounter within spacecraft, on ATSET performance is unknown. To address this gap, we evaluated the effects of cranial irradiation with 10 cGy of 100 MeV/n protons (LET = 0.732 keV/μm) on ATSET performance in male Sprague-Dawley rats. We also investigated whether concurrent exposure to variable gravity (hypergravity step-up, step down, purported to have the same effect as exposure to microgravity (another major spaceflight stressor) exacerbated SR-induced cognitive deficits. Our findings indicate that proton exposure alone significantly impaired ATSET performance, as evidenced by decreased processing speed while performing compound discrimination reversal and extra-dimensional shifting. Notably, no additive or synergistic effects were observed when hypergravity was combined with proton exposure. The impact that low-dose proton exposure has on CNS functionality, particularly in reducing processing speed during complex tasks, warrant further investigation. If similar cognitive deficits were to occur in astronauts exposed to galactic cosmic rays, mission success and safety could be significantly compromised.

Sex-Dependent Changes In Risk-Taking Predisposition Of Rats Following Space Radiation Exposure, Elliot Smits, Faith E. Reid, Ella N. Tamgue, Paola Alvarado Arriaga, Charles Nguyen, Richard A. Britten

Department Radiation Oncology & Biophysics Faculty Publications

The Artemis missions will establish a sustainable human presence on the Moon, serving as a crucial steppingstone for future Mars exploration. Astronauts on these ambitious missions will have to successfully complete complex tasks, which will frequently involve rapid and effective decision making under unfamiliar or high-pressure conditions. Exposure to low doses of space radiation (SR) can impair key executive functions critical to decision making. This study examined the effects of exposure to 10 cGy of Galactic Cosmic Ray simulated radiation (GCRsim) on decision-making performance in male and female rats with a naturally low predisposition for risk-taking (RTP) prior to exposure. …

A Two-Hit Model Of Executive Dysfunction: Simulated Galactic Cosmic Radiation Primes Latent Deficits Revealed By Sleep Fragmentation, Richard A. Britten, Ella N. Tamgue, Paola Arriaga Alvarado, Arriyam S. Fesshaye, Larry D. Sanford

Department Radiation Oncology & Biophysics Faculty Publications

Future Artemis-class missions to Mars will expose astronauts to prolonged space radiation (SR), sleep disruption, and operational demands requiring greater autonomy, placing decision making and executive function at heightened risk. Both SR and sleep fragmentation (SF) independently impair cognition, yet their combined effects remain poorly understood. Using the Associative Recognition Memory and Interference (ARMIT) task, we assessed cognitive performance in male rats exposed to 10 cGy of Galactic Cosmic Ray simulation (GCRsim), SF, or both. Under well-rested conditions, GCRsim-exposed rats exhibited overt deficits in the C.1.2 stage, performing at chance when reinforcement contingencies shifted, consistent with impaired cognitive flexibility. In …

Different Spectrum Of Space Radiation Induced Cognitive Impairments In Radiation-Naïve And Adapted Rats, Richard A. Britten, Arriyam S. Fesshaye, Alyssa Tidmore, Ella N. Tamgue, Paola A. Alvarado-Arriaga

Center for Integrative Neuroscience and Inflammatory Diseases (CINID) Faculty Publications

NASA's decision to resume manned deep space mission, first to the Moon and then Mars, necessitated a detailed assessment of the potential health effects that astronauts may experience on long-duration missions. Multiple studies suggest that there may be significant space radiation (SR)-induced impairment of neurocognitive processes, including advanced executive functions. However, given the multitude of SR-induced changes in the CNS, it is possible that completely different SR-induced sequelae will be induced in previously exposed individuals. Thus, current risk estimates are likely to be pertinent only for the early stages of a deep space mission, and even then only for astronauts …

Exposure To Low (10 Cgy) Doses Of ⁴He Ions Leads To An Apparent Increase In Risk Taking Propensity In Female Rats, Nina Li, Simran Phuyal, Elliot Smits, Faith E. Reid, Ella N. Tamgue, Paola Alvarado Arriaga, Richard A. Britten

Department of Medicine Faculty Publications

The planned missions to the Moon and Mars will present more significant health challenges to astronauts compared to low earth orbit missions. During deep space missions, astronauts will be constantly exposed to Space radiation (SR). Multiple rodent studies suggest that < 25 cGy of SR impairs performance in executive functions, which play a key role in advanced cognitive processes, but also regulate response inhibition and impulse control. There is the possibility that SR exposure may exacerbate aberrant behaviors evoked by psychological stress related to exposure to isolated and confined (ICE) hostile environment or independently induce additional aberrant behaviors. This study has determined that female Wistar rats exposed to 10 cGy of 250 MeV/n He had an increased risk taking propensity (RTP)\compared to shams. The increased RTP of the He-exposed rats was associated with significantly increased reaction times during the trials, suggesting a SR-induced loss of processing speed. The response times of the He-exposed rats were even further reduced in trials that immediately followed a loss, raising the possibility that conflict and interference avoidance may be impaired after SR exposure. Whether these findings occur following other types of SR exposure, and/or in male rats remains to be determined.

Modeling And Simulation Of Electromagnetic Fields To Maintain Bone Density During Prolonged Low Gravity Exposure, Austin Tapp, Michael Francis, Michel A. Audette

Electrical & Computer Engineering Faculty Publications

Astronauts in a long term, low-gravity environments experience bone density loss at 10 times the rate of those diagnosed with osteoporosis. One treatment effective at maintaining bone density in osteoporotic individuals is electromagnetic field (EMF) therapy. Tools that induce EMFs are becoming increasingly prevalent, but to amplify osteogenesis and encourage superior bone density retention for astronauts, ideal EMF therapy parameters must be determined on patient-specific bases. Therefore, this study explores simulation environments that elucidate highly favorable EMF factors. Pulsed electromagnetic field and combined magnetic field generating devices are variably introduced near partient-specific, finite element (FE) models of the femur, spine, …

Mechanisms Of T Helper Cell Modulation In A Simulated Space Radiation Environment, Asma Rizvi

Loma Linda University Electronic Theses, Dissertations & Projects

Exposure to solar particle events (SPEs) poses the most serious threat to astronaut health. Due to this radiation environment, exploration of the solar system beyond Earth’s orbit entails many risks for the crew on these deep space missions. Depression or dysfunction of the immune system is a major concern due to its high radio-sensitivity; potential consequences include overwhelming infection, development of cancer, fibrosis, and poor wound healing. Astronauts are also exposed to low dose/low dose rate (LDR) radiation. A three month stay at the international space station exposes them to ~ 0.05 Gy of radiation.

C57BL/6 mice received LDR gamma-radiation …