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Any mission to Jupiter and its moons must contend with the gas giant’s overwhelming radiation. Only a judicious orbital pattern and onboard protective measures can keep a spacecraft safe. Even then, the powerful radiation dictates a mission’s lifespan.

However, researchers may have found a way to approach at least one of Jupiter’s moons without confronting that radiation.

When NASA launched its Juno mission to Jupiter in 2011, it knew it was sending its spacecraft into an extreme radiation environment. Jupiter’s radiation is generated by its magnetic field, which is 30,000 times stronger than Earth’s. The magnetic field captures charged particles from Jupiter’s environment and accelerates them to create its powerful radiation belts.

Juno follows an elliptical polar orbit around Jupiter, dipping into the hazardous radiation for periods of time and then leaving it behind. Juno’s most sensitive electronics are inside a titanium vault designed to resist the radiation for as long as possible.

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Astronomers are intensely interested in the Jovian system because three of its Galilean moons—Europa, Ganymede, and Callisto—appear to have warm oceans buried under layers of ice. This poses the question of habitability, but the first order of business is to confirm that these oceans are actually there.

ESA’s JUICE (Jupiter Icy Moons Explorer) is en route to Jupiter, and NASA’s Europa Clipper will launch in a few weeks. (The Europa Clipper will overtake JUICE and reach Jupiter first.) Both missions will visit Europa and attempt to determine if its subsurface ocean is real. Both must contend with the intense radiation near Jupiter.

NASA’s Juno mission has created a radiation map of the Jupiter region and found a potential low-radiation route to Europa. How will it affect these and future missions?

“This is the first detailed radiation map of the region at these higher energies, which is a major step in understanding how Jupiter’s radiation environment works.”

Scott Bolton, Principal Investigator, Juno mission

NASA’s Juno spacecraft and the people on the mission team get credit for finding the low-radiation route to Europa. Juno used its two low-light cameras used in deep space navigation to map the radiation environment near the icy moon. The result is the first complete 3D radiation map of the Jupiter system.

“On Juno we try to innovate new ways to use our sensors to learn about nature and have used many of our science instruments in ways they were not designed for,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio.

The instruments responsible are the Advanced Stellar Compass (ASC) and the Stellar Reference Unit (SRU). The ASC was designed and built in Denmark, and the SRU is from Italy. Most spacecraft have these types of instruments to help them navigate.

The ASC is actually four cameras on the spacecraft’s magnetometer boom. They orient the spacecraft in space and are also part of the magnetometer’s mission to measure Jupiter’s magnetic field in detail. The SRU helps Juno determine its attitude relative to a horizontal plane. It also serves as an in situ particle detector in Juno’s Radiation Monitoring Investigation.

Together, they’ve been used to create the radiation map.

“This is the first detailed radiation map of the region at these higher energies, which is a major step in understanding how Jupiter’s radiation environment works. That we’ve been able to create the first detailed map of the region is a big deal, because we don’t carry an instrument designed to look for radiation. The map will help planning observations for the next generation of missions to the Jovian system,” says Scott Bolton.

Juno’s elliptical polar orbit means that as the spacecraft approaches the planet, a different part of the surface is directly underneath. While its job isn’t to image Jupiter’s surface, the ASC takes advantage of this. Since Juno has traversed the entire region around Jupiter, so has the ASC.

“Every quarter-second the ASC takes an image of the stars,” said Juno scientist John Leif Jørgensen, professor at the Technical University of Denmark. “Very energetic electrons that penetrate its shielding leave a telltale signature in our images that looks like the trail of a firefly. The instrument is programmed to count the number of these fireflies, giving us an accurate calculation of the amount of radiation,” said Jørgensen.

Advanced Stellar Compass data revealed two important things. There is more very high-energy radiation relative to lower-energy radiation near Europa’s orbit than scientists thought. There is also more high-energy radiation on the moon’s leading orbital edge than on the trailing edge. This is because most electrons in Jupiter’s magnetosphere overtake Europa from behind due to Jupiter’s magnetic field rotation. But the high-energy electrons end up drifting backward, pummeling Europa’s leading edge with high-energy radiation. Interactions with Europa’s surface deplete them.

The Stellar Reference Unit also contributed to a new understanding of how Jupiter’s radiation affects Europa. It has been used as a low-light camera, which is its intended purpose, and as a radiation detector.

An upcoming paper based on these observations will present a complete radiation map of Jupiter and its environment. Earlier this year, the same authors published a paper titled “Europa’s Influence on the Jovian Energetic Electron Environment as Observed by Juno’s Micro Advanced Stellar Compass.” The lead author is Matija Herceg, a Senior Researcher in the Department of Space Research and Technology at the Technical University of Denmark.

“As most of the energetic electrons, drifting retrograde, will encounter Europa and impact its downstream side before they can reach the upstream side, Europa will stop the energetic electron drift shells and will be mostly free from hard radiation on the upstream side,” the authors wrote in their paper.

This graphic shows Europa orbiting Jupiter, with Juno’s looping orbits shown in red. The yellow graph shows the radiation flux measurement during one of Juno’s orbits. High-energy particles end up slamming into Europa’s leading orbital edge while the wake is somewhat protected. The lower-radiation plasma wake is shown in green. Image Credit: Herceg et al. 2024.

Juno is on an extended mission now, and more orbits should capture more data on the radiation.

The question is, can this low-radiation environment be used in future missions to avoid radiation exposure? It’s possible, but more work needs to be done.

“The results from the upcoming Juno orbits, during its mission extension, might result in populating the Juno plasma wake with additional crossing observations,” Herceg and his co-authors write. “As the first in situ compilation of energetic electron flux observations of both upstream and plasma wake sides of Europa, the presented data set gives us estimates of the thickness and electron density distribution in the vicinity of Europa. The results from this paper could contribute to dedicated studies aimed at preparation for the upcoming NASA mission Europa Clipper and ESA’s Juice mission.”

One of those dedicated studies, by the same authors as Herceg et al., will present the complete 3D radiation map of Jupiter. However, it’s currently under peer review. Will that research lead to a low-radiation pathway to studying Europa, the most prized target in our search for life elsewhere in the Solar System?

Stay tuned.

The post Is There a Low-Radiation Path To Europa? appeared first on Universe Today.

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The post The Biopolitics of Quackademic Medicine in Iran first appeared on Science-Based Medicine.

Human bodies are sacks of fluids supported by skeletons. The entire human organism has evolved over billions of years on Earth in harmony with the planet’s specific gravity. But when astronauts spend too much time on the ISS in a microgravity environment, the organism responds, the fluids shift, and problems can occur.

One of those problems is with vision, and scientists are working to understand how it happens and what they can do about it.

We’re talking about Spaceflight-Associated Neuro-Ocular Syndrome (SANS). NASA says that 70% of astronauts who spend time on the International Space Station (ISS) experience at least mild SANS. Sometimes, the effect is minor and often temporary. Other times, it’s more severe and can cause long-term vision problems, including partial loss of vision.

Researchers have been dealing with microgravity and its effects on vision for a while. “Spaceflight Associated Neuro-ocular Syndrome (SANS), previously known as Visual Impairment Intracranial Pressure (VIIP), is a major risk associated with long-duration spaceflight,” wrote the authors of a 2020 paper. “During prolonged missions, optic disk edema, posterior globe flattening, decreased near vision, and hyperopic shifts are hallmarks of SANS. This risk stems from the lack of gravity, which causes a headward shift of blood and other body fluids.”

Now, a group of physicians are working with Polaris Dawn to understand the problem.

Polaris Dawn is a private spaceflight initiative operated by SpaceX. It will send four private astronauts on a highly elliptical Earth orbit that will take them 1,400 kilometres (870 mi) away from Earth. This is the furthest any human being has been from Earth since the Apollo missions.

Matt Lyon, MD, from the Medical College of Georgia (MCG) at Augusta University, is leading a team that is working with Polaris Dawn to study SANS.

“The changes start happening on day one,” said Lyon, who also is the J. Harold Harrison M.D. Distinguished Chair in Telehealth. “We are not entirely sure what causes these issues with vision, but we suspect it has to do with a shift in cerebrospinal fluid in the optic nerve sheath. On Earth, gravity pushes that fluid down and it drains out, but in space, it floats up and presses against the optic nerve and retina.”

Lyon and his colleagues are focusing on the optic nerve sheath. The optic nerve is a conduit that carries visual information from the eyes to the brain. Inside the sheath, the nerve is protected by cerebrospinal fluid. The cerebrospinal fluid (CSF) carries toxins away from the eye.

A simple schematic of the optic nerve and the sheath with cerebrospinal fluid. Image Credit: Netteland et al. 2023.

Here on Earth, MCG patented the use of ultrasound to image the optic nerve and its sheath and rapidly visualize damage associated with pressure and fluid changes in the sheath. Now, Lyon and his team are putting a portable ultrasound machine in the hands of the four Polaris Dawn astronauts and training them on how to use it.

But first they’re screening the four astronauts to try to determine which people are more susceptible to SANS. They think that people who suffered concussions or mild traumatic brain injuries (TBIs) in the past are likely more susceptible to SANS.

“We discovered that when the cerebral spinal pressure goes up with mild traumatic brain injuries (TBIs), there is resulting damage to the sheath that is likely lifelong,” he explained. “We think that when astronauts who have experienced concussions or mild TBIs go into space and experience the low-gravity fluid shifts, the sheath dilates from the increase in volume. It is like a tire — a normal tire remains its normal shape as it is filled with air, and the shape doesn’t change. When it’s damaged, like bulges on the side of a tire, the fluid fills the bulges up and the sheath expands. This can cause pressure on the nerve and retina. A damaged sheath is less of a problem on Earth, but in space, the excess fluid has nowhere to go.”

It’s critical that the private Polaris Dawn astronauts image the changes to their optical nerves and sheaths in real-time. Real-time data will help researchers understand if vision changes due to SANS are caused by the sheer volume of fluid, the increased pressure from the fluid, or interactions between the two.

The video below shows how ultrasound is used to scan the eye, including the optical nerve (0:40).

Go to the 0:40 second mark to see the eye being scanned.

“If it’s just volume, we suspect the cerebrospinal fluid goes up, fills this floppy bag and gets stuck. It’s almost like not flushing your toilets. You’re creating this toxic environment, because the cerebral spinal fluid (CSF) is what carries toxins away from your eyes and nerves, and instead the toxins sit against the optic nerve, killing it,” Lyon said. “But it could be that combined with the increased pressure that comes with increased CSF, which would be like getting intermittent hypertension in your eye.”

The solution to SANS could be a Lower Body Negative Pressure (LBNP) device. These are large, bulky devices that counteract the headward shift of fluids in microgravity by creating ground reaction forces (GRFs). They’re typically airtight chambers that astronauts spend time in. Unfortunately, LBNPs require astronauts to be static while using them. NASA tested them during the International Microgravity Laboratory on Space Shuttle Mission STS-65.

This image showed payload commander Richard Hieb wearing and testing the LBNP on Shuttle mission STS 65 in 1994. By creating lower pressure in the bottom of the body, blood and fluids are prevented from accumulating in the upper body in microgravity. Image Credit: NASA.

Researchers at the University of California’s Department of Orthopaedic Surgery and Department of Bioengineering are developing a mobile version of an LBNP.

“Our new mobile gravity suit is relatively small, untethered, and flexible in order to improve mobility in space. We hypothesized that this novel mobile gravity suit generates greater ground reaction forces than a standard LBNP chamber,” wrote the authors of the 2020 paper.

This image shows a mobile LBNP suit under development. Image Credit: Ashari and Hargens, 2020.

Mobile Lower Body Negative Pressure suits are still under development, and scientists need more data. Polaris Dawn can help provide the needed data.

The ultrasound images of the optical nerve are part of a broader research effort that will be conducted during Polaris Dawn. The Medical College of Georgia is one of 23 institutions that the mission is working with. The data that Polaris Dawn returns should help lead to a solution for SANS.

The post How Can Astronauts Avoid Vision Loss from Spaceflight? appeared first on Universe Today.

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