Polaris Dawn experiments support space exploration

The Polaris Dawn, the pioneering mission of the three Polaris missions to space, conducted from September 10–15, 2024, unveiled the initial findings of the nearly 40 science research experiments. These experiments, executed by a crew of four before, during, and after their spaceflight, have brought significant insights into various aspects of space exploration and human health.

A closer look to some results

The mission was a testament to global collaboration, with Jared Isaacman, Kidd Poteet, Sarah Gillis, and Anna Menon conducting a series of experiments sponsored by universities and centers worldwide. These experiments, spanning human physiology, molecular biology, radiation, plant growth, and operational technologies, were designed to explore the effects of long-duration human spaceflight and their implications for human health on Earth.

Here, we will look at those relating to human physiology, which provide fascinating insights about the human body. These also answer some of our questions about space exploration and how we would adapt to living in space.

Bone loss

The first one is the experiment designed by the University of Calgary. Using high-resolution imaging to study the bones (https://ucalgary.ca/news/floating-space-might-be-fun-tbone-study-shows-its-hard-earthly-bodies), they found bone loss in astronauts' lower legs after just five days in space.

Earlier studies also revealed that the longer the space flight, the longer it takes to recover the bone mass upon return to Earth. In some cases, there is only a partial recovery. This study highlights the rapid bone loss in microgravity, answering my question about the importance of traveling to Mars in the shortest amount of time, short enough for space travelers to walk by themselves upon arrival.

Anemia can be common for space travelers

The anemia study, conducted by the Ottawa Hospital Research Institute (OHRI) (with Université Paris-Est Créteil Val de Marne), is an extension to previous studies (https://www.nasa.gov/missions/station/scientists-find-increased-red-blood-cell-destruction-during-spaceflight/) conducted at the International Space Station (ISS) in 2022.

In these studies, researchers found that in space, the human body destroys 54 percent more red blood cells (RBC) than on Earth, and that this process continues for the entire duration of the astronaut's mission. This RBC damage eventually causes anemia; hence, the success of future space missions necessitates a solution to this problem. One reason behind the RBC's destruction is radiation; the other is the microgravity environment.

Researchers believed that the body compensated for the fluid shift in microgravity by reducing the plasma volume, leading to anemia. These findings underscore the importance of developing effective countermeasures for anemia in space, such as increased exercise or dietary supplements, to ensure the health and safety of astronauts on long-duration missions. Interestingly, the same teams have observed an increase in anemia in patients subjected to prolonged bed rest, suggesting that exercise could be a potential solution to mitigate this problem. This finding brings a ray of hope for future space missions and the health of astronauts.

Monitoring diabetic astronauts

SpaceX used this flight to continue assessing the efficacy of their Continuous Glucose Monitoring (CGM), which could be used to provide care for future diabetic astronauts. Studying the device on space missions also helps improve the devices for use here on Earth.

Kidney stones might affect space explorers

A related study called The Stone Risk study (https://home.dartmouth.edu/news/2024/09/preventing-bone-loss-caused-zero-gravity) by the Geisel School of Medicine at Dartmouth demonstrated how morning urine calcium measurements could track kidney stone and bone loss risk, allowing personalized countermeasures for space travelers.

Why is this important? Bone mass loss does not need an explanation. Kidney stones, on the other hand, are a concern for space travel because they can cause severe pain, urinary obstruction, and infections, potentially jeopardizing mission success or astronaut health.

Unfortunately, kidney stones could be common in space due to several factors. Bone mass loss in microgravity releases calcium into the bloodstream and urine, forming calcium oxalate or calcium phosphate stones. Lower fluid intake and fluid loss in space lead to reduced urine volume and high concentrations of stone-forming minerals. Changes in the urine pH, citrate levels, and oxalate excretions increase the supersaturation of stone-forming salts.

NASA has explored countermeasures to this problem. Besides hydration, possible solutions include supplements like Potassium Citrate to raise the urine's pH. Potassium-Magnesium Citrate supplements could lower calcium oxalate crystal formation. Biophosphonates, used here on Earth to help with osteoporosis, could also help reduce bone loss and lower urinary calcium excretion. These potential solutions highlight the importance of proactive health management in space missions and the need for further research and development in this area.

Supporting medical diagnosis in space

NASA had two interesting studies. The first one, the Tempus Pro study, demonstrated vital signs collection and medical simulation. In this mission, the crew tested real-time diagnostic capabilities via Starlink. It also ensured crew safety during the high-risk commercial spacewalk.

ESA used this device previously to monitor the astronaut's post-flight health. Its use during the Polaris Dawn mission revealed its complexity, which can be an issue for use in space. The crew noted that this device's number of cords and complex interface posed challenges during flight.

Motion sickness in space

The second of NASA's studies, "The Motion Sickness Countermeasures,” has been in the annals of NASA for quite some time. It is quite common for space traveler, affecting 60-80% of astronauts during their first few days in microgravity. It arises from the struggle of the brain to interpret conflicting signals from the inner ear, eyes, and body.

NASA collected crew feedback on effective motion sickness mitigation strategies. This data is another datapoint in the long-term research NASA is conducting in this area to inform future mission protocols. Applying this countermeasure is definitely a must for someone like me.

If you want to find about all the experiments and a summary of the results, visit the Polaris Dawn pages.

References:

• https://www.esa.int/Applications/Connectivity_and_Secure_Communications/Highlights/Tempus_Pro

• https://www.nasa.gov/reference/tempus-pro/

• https://polarisprogram.com/polaris-dawn-crew-meets-with-principal-investigators-of-science-and-research-experiments-to-discuss-initial-findings/

• https://engineering.dartmouth.edu/news/polaris-dawn-project-aims-to-prevent-bone-loss-in-space#

• https://www.space.com/astronaut-bone-loss-jumping-exercise-study