Author: Maritza Tsabitah
Editor: Afreen Hossain
Abstract
The data obtained from the Apollo Lunar Astronauts highlights a concerning long-term risk: radiation-induced cardiovascular disease (RICVD) resulting from exposure to galactic cosmic rays (GCR). To ensure the success of future Moon-Mars missions, the development of an effective protection shield is imperative. This study aims to assess the effectiveness of a pumpkin configuration as a shield against GCR, considering its impact on the cardiovascular system, mortality rate data from the Apollo Lunar Astronauts, and insights from previous studies on magnetic shielding. The findings suggest that the pumpkin configuration holds promise in shielding against GCR, but further refinement of the concept and innovative advancements are needed for swift code implementation. This study advocates for considering the pumpkin configuration as an alternative, aligning it with NHS training and the recent Orion Protection Plan, HERA, which can efficiently detect and categorize space radiation.
Introduction
In 2022, the Artemis Program heralded the continuation of the Moon to Mars expedition and extended its policy for International Space Station (ISS) operation. This signifies the onset of exploration beyond Low Earth Orbit (LEO) in the foreseeable future. However, ensuring the health of astronauts remains a primary concern for the success of these missions, particularly given the challenges posed by space radiation. The primary sources of space radiation include Solar Particle Events (SPE) and Galactic Cosmic Rays (GCR). While various active shielding methods can insulate against SPE, the formidable challenge lies in shielding against GCR, primarily due to the presence of high-energy ions (HZE) that have the potential to damage physiological functions, notably the cardiovascular system. During a Mars mission, astronauts may be exposed to approximately 1Sv of GCR, resulting in a potential 5% increase in cardiovascular damage.
The impacts of GCR
Galactic cosmic rays (GCR) harbor the potential to instigate severe pathologies, encompassing fatal conditions like cancer, cardiovascular disease, and organ inflammation. A retrospective analysis of the mortality data of 20 deceased US astronauts spanning from 1959 to 1991 underscores the gravity of cardiovascular implications, attributing 10% of deaths to cardiovascular disease and 5% to cancer. This investigation illuminates the vulnerability of the human cardiovascular system to the deleterious effects of space radiation. In a meticulous examination, patients exposed to radiation were compared with those diagnosed with radiation-induced cardiovascular disease (RICVD), specifically through chest X-ray and gamma radiation. The outcomes are unmistakable, with RICVD demonstrating an alarming radiation dose of 500Gy, significantly surpassing the range of chest X-rays (0.1 - 120 Gy) and gamma radiation (more than 3Gy) . The composite elements of GCR, prominently featuring hydrogen (H), iron (Fe), helium (He), and silicon (Si), impart a spectrum of detrimental impacts on the cardiovascular system. These repercussions encompass endothelial dysfunction in the aortic wall, identified as the primary instigator of RICVD, myocardial damage due to apoptosis, perpetuation of a chronic inflammatory state, upregulation of oxidative enzymes, and DNA double-strand destruction. Notably, astronauts in low earth orbit (LEO) may find reprieve from radiation exposure owing to the protective influence of the magnetosphere. However, those venturing beyond this protective shield face heightened susceptibility. Data extrapolated from the Apollo Lunar astronauts accentuates this risk, revealing a cardiovascular mortality rate 4-5 times higher than their LEO counterparts. As the adage goes, anticipation becomes paramount in navigating the intricate interplay between space exploration and cardiovascular well-being.
Experiment with shielding: pumpkin configuration
Numerous initiatives have been undertaken to explore Active Shielding Methods (ASM) to counter the formidable energy of Galactic Cosmic Rays (GCR). Diverging from the effectiveness observed in Solar Particle Events (SPE), GCR proves resistant to preventive measures involving Electrostatic Fields (EF) and Plasma Shielding (PS), primarily due to their focus on protons rather than High-Energy Ions (HZE). Intriguingly, past research has unveiled a promising avenue in the utilization of Superconducting Materials (SM) within the unique framework of the Pumpkin Configuration (PC). High-temperature superconductors, such as Niobium-Titanium (NbTi) and Niobium-Tin (NbSn), have emerged as the most efficient options per unit mass for Active Shielding against Space Radiation (ASR). Leveraging the Lorentz Force (LF), these materials induce particle motion perpendicular to the Magnetic Field (MF), thereby altering the trajectories of charged particles. Recent advancements in the study of the Pumpkin Configuration (PC) have notably propelled the transition of Magnetic Shielding Concepts (MSC) from theoretical constructs to practical applications in Spacecraft Design (SD).
Result
The pumpkin configuration refers to a multiple toroid magnet system in which each toroid is built with three racetrack coils and has a lower construction mass than a typical toroidal structure. Furthermore, its magnet can defend a 1083m volume (5m diameter by 5.5m long), reducing the dose of free space by 45%, and it weighs 54. This could reduce the GCR and allow for adequate dosages to be absorbed. However, it would not be able to totally protect the astronauts from the GCR because there are no recognized radiation limitations for the mission and the long-term physical impact has not been well examined. This approach has the potential to limit the exposure, but it has yet to be thoroughly researched and improved. Another reason that would make implementation difficult is the large number of codes required to model the heavy ions and licensing issues.
Alternatives
Nonetheless, there are techniques to safeguard the astronauts' cardiovascular health in preparation for the near-term trip. NASA collaborated with Orion to develop the Orion Radiation Protection Plan, which includes the Hybrid Electronic Radiation (HERA) operation process. HERA is designed to advise crew members if they need to seek shelter in the radiation case and to characterise the sort of shielding they encounter. Non-Technical Skill (NTS) training has also been proven to reduce RICVD by 18% in 1-year death rates. The compatibility of the NTS training in leadership, teamwork, situation awareness, and surgical skills will result in better mission, safety, and health results for the crews.
Conclusion
The space mission beyond the LEO is limited by GCR which contains HZE as a leading cause of radiation-induced cardiovascular disease among the Apollo Lunar astronauts. Many people have devised a solution to protect astronauts by employing a magnetic shield with a pumpkin configuration of superconducting materials and the Lorentz force. The concept, however, has not been thoroughly tested and developed. It also requires a large number of codes to be deployed for HZE. As an alternative to the neartime mission, the collaboration between NASA and Orion in establishing the Orion Radiation Protection Plan would be an effective way to reduce the risk of RICVD. The NTS training also has shown positive outcomes to ensure mission success with safe and healthy astronauts, which could be a fundamental requirement for the Moon-Mars astronauts.
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