What's new

The Space Medicine Thread | News & Discussion

Galactic Penguin SST

Aug 10, 2017
Hong Kong
Korea, Democratic Peoples Republic Of
The Space Medicine Thread

Need to create a separate dedicated thread, as 80 years of informations are accumulating.


New Insights on Health Effects of Long-Duration Space Flight

2020-November-28 11:03

TEHRAN (FNA)- The historic NASA Twins Study investigated identical twin astronauts Scott and Mark Kelly and provided new information on the health effects of spending time in space.

Colorado State University Professor Susan Bailey was one of more than 80 scientists across 12 universities who conducted research on the textbook experiment; Mark remained on Earth while Scott orbited high above for nearly one year. The massive effort was coordinated by NASA's Human Research Program.

Bailey has continued her NASA research and now joins more than 200 investigators from dozens of academic, government, aerospace and industry groups to publish a package of 30 scientific papers in five Cell Press journals on Nov. 25.

Jared Luxton, who recently received his doctoral degree in cell and molecular biology at CSU, is the first author of two of the studies. He is now a data scientist with the United States Department of Agriculture in Fort Collins.

The research -- including an over-arching paper that covers what the investigators have learned about the fundamental features of space flight -- represents the largest set of space biology and astronaut health effects data ever produced.

For Bailey, it is also a milestone marking many years of working with NASA, which included her lead role on basic radiation studies and the honor of being selected as an investigator for the Twins Study and concurrent research projects involving astronauts. During this time, several graduate students in her lab earned doctoral degrees under her mentorship.

"We now have a foundation to build on -- things we know to look for in future astronauts, including telomere length changes and DNA damage responses," Bailey said. "Going forward, our goal is to get a better idea of underlying mechanisms, of what's going on during long-duration space flight in the human body and how it varies between people. Not everybody responds the same way. That was one of the good things about having the larger cohort of astronauts in these studies."

Studying the ends of chromosomes, with implications for aging

Bailey is an expert on telomeres and radiation-induced DNA damage, areas of research that were of keen interest around the world when the Twins Study was published. In that study, she and her team found that Scott's telomeres in his white blood cells got longer while in space, and subsequently returned to near normal length after he was back on Earth.

Telomeres are protective "caps" on the ends of chromosomes that shorten as a person ages. Large changes in telomere length could mean a person is at risk for accelerated aging or the diseases that come along with getting older, cardiovascular disease and cancer for example.

In the latest research, Bailey, Luxton, Senior Research Associate Lynn Taylor and team studied a group of 10 unrelated astronauts, including CSU alum Dr. Kjell Lindgren, comparing the results with findings from the Kelly twins. The researchers did not have access to in-flight blood and other samples for all of the crewmembers, but Bailey said they did have blood samples before and after space flight for everyone.

The investigations involved astronauts who spent approximately six months on the International Space Station in low-Earth orbit, which is protected from some space radiation. Despite the protection, scientists found evidence of DNA damage that could be warning signs of potential health effects.

New discovery of oxidative stress

Among the new findings, the research team found that chronic oxidative stress during spaceflight contributed to the telomere elongation they observed. They also found that astronauts in general had shorter telomeres after spaceflight than they did before. The team also observed individual differences in responses.

To gain more insight on these findings, Bailey's team also studied twin mountain climbers who scaled Mt. Everest, an extreme environment on Earth. The non-climbing twins remained at lower altitude, including in Boulder, Colorado. Remarkably, the team found similar evidence of oxidative stress and changes in telomere length in the climbers.

Christopher Mason, associate professor at Weill Cornell Medicine and a co-author with Bailey, performed gene expression analyses on the Mt. Everest climbers. He found evidence of a telomerase-independent, recombination-based pathway of telomere length maintenance known to result in longer telomeres.

Bailey said that when chronic oxidative stress occurs, it damages telomeres.

"Normal blood cells are dying and trying to survive," she said. "They're adapting to their new environment. Some cells will activate an alternative pathway to keep their telomeres going. It's similar to what happens with some tumors. Some of the cells emerge from that process. That's what we think we're seeing during spaceflight as well."

Luxton said the mechanism described above -- known as alternative lengthening of telomeres, or ALT -- was an unexpected finding.

"You usually see that in cancer or in developing embryos," he said.

Take care of your telomeres

Similar to conclusions from the Twins Study, Bailey said the new findings have implications for future space travelers establishing a base on the Moon or traveling to Mars, or even as a space tourist. Long-duration exploration missions will involve increased time and distance outside of the protection of the Earth.

Although longer telomeres in space might seem like a good thing, perhaps even a "fountain of youth," the scientist said she suspects a somewhat different ending to the story.

"Extended lifespan, or immortality, of cells that have suffered space radiation-induced DNA damage, such as chromosomal inversions, is a recipe for increased cancer risk," she said.

Bailey said she and the team observed increased frequencies of inversions in all crewmembers, during and after spaceflight.

"Telomeres really are reflective of our lifestyles -- whether on or off the planet," said Bailey. "Our choices do make a difference in how quickly or how well we are aging. It's important to take care of your telomeres."



Galactic Penguin SST

Aug 10, 2017
Hong Kong
Korea, Democratic Peoples Republic Of
Microgravity and Vision Impairments in Astronauts

Authors: Seedhouse, Erik 2015

Recent missions on board the International Space Station have revealed previously unreported physiological consequences of long duration space flight, particularly in eyesight, and in this Brief Dr. Seedhouse reviews the existing theories on what causes this degeneration and how long it will last.

Notably, 60% of long-duration crews have reported subjective degradation in vision, a clear indication that further study is necessary before astronauts embark on even longer-term space missions.

Decreased near-visual acuity was reported in 46% of ISS/Mir crewmembers, resulting in a change of up to 2 dioptres in their refractive correction. It is possible that ophthalmic changes have been present since the first days of spaceflight, but had been attributed to other causes; this approach to the issue as well as other hypotheses are all presented in full to give a broad foundation of the existing knowledge on the topic. The changes have occurred at various times during a mission with varying degrees of visual degradation. Some cases resolved on return to Earth, but several crewmembers have not regained pre-flight visual acuity, indicating the damage may be permanent.

One explanation of the syndrome has been attributed to hyperopic shift due to aging, but onboard analysis techniques, including visual acuity assessments, retinal imagery, and ultrasound examination of the eye, has led to the acceptance of a wider syndrome.

In addition to vision changes, studies have reported flattening of the globe, swelling of the optic disc (papilledema), choroidal folds in the retina, swelling of the optic nerve sheath, and visual field defects. It is widely hypothesized that this spectrum of symptoms may be explained by an elevation of intracranial pressure (ICP).

Establishing the provenance of this medical problem, monitoring its occurrence and resolving the symptoms for future long term space missions is a key challenge for space medicine.

With this book, readers have an entry point for understanding the full scope of the problem and its possible origins.


Microgravity-induced ocular changes in astronauts: a sight odyssey

Alteracées oculares causadas pela microgravidade em astronautas: uma odisseia visual


Submitted for publication: May 30, 2016 Accepted for publication: May 31, 2016

More than a new motivating force to the space race, the arrival of the American astronaut Scott Kelly from almost a year travel to the International Space Station promises a scientific milestone in the study of the long-term effects of the human body outside the Earth’s atmosphere”.

In addition to all the space-related data collected during the trip, the astronaut and his twin brother, Mark Kelly - non participating to this mission, will be extensively compared.

This study is analyzing laboratory samples from both, including assessments of the musculoskeletal, and immune system, genetic analysis and ocular evaluations, in order to increment knowledge related to microgravity effects on the human body.

The results will be crucial for the Journey to Mars program (in 2030's) outlined in the bipartisan United State National Space Policy and National Aeronautics and Space Administration (NASA) Authorization Act issued in 2010.:omghaha:

Microgravity is defined as a very small gravity condition in which objects appear to be weightless. Given the difficulties and cost of space travel, parabolic flight tests (producing transient periods of microgravity) and the head-down bed-rest studies (simulating the pressure effects of microgravity) has been used to examine several systemic and ocular changes.

In addition to space radiation-induced cataract, the effects of microgravity on the eyes are considered the most impactful health problems for the success of long-term space travels.

Still, a minimal comparison can be obtained by the experiences on high-altitude climbing, which have also shown harmful consequences to the retina, optic nerve, and cornea (mainly related to corneal refractive surgeries).

As an analogy to the importance of vision-threatening environmental scenarios, the book “Into thin air”’authored
by Jon Krakauer quotes high-altitude-related blurred vision resulting in a Mount Everest tragedy as the critical limitation to an adventurer.

The first ocular findings in space flights were related to the blurring of vision, described in the 60's and later were associated with the Visual Impairment and Intracranial Pressure (VIIP) syndrome.

The findings outlined in this syndrome could be explained by modifications in the fluid shift pattern resulting from altered pressures in several liquid compartments of the body, especially the intraocular pressure (IOP), the intracranial pressure (ICP) and the blood pressure.

Thus, the neuroretinal-cerebrospinal fluid interface (including lamina cribrosa) could be affected by microgravity, due to the local “cul-de-sac” anatomy of the optic nerve head and the relative increased ICP transmitted to the eye by the subarachnoid space.

As consequence, the optic nerve sheath distension, optic disc edema, vascular changes in the choroid and retina (eg., folds choroidal, thickening of the retinal fiber layer, cotton wool spots), “flattening” of the eyeball and a hyperopic shift have been described in several astronauts.

Still, a moderate acute IOP increase in the first moments in microgravity (probably due to congestion in the episcleral veins), followed by a steady IOP decrease were observed during longer periods under microgravity and in the post-flight evaluations.

On the other hand, these ocular changes displayed in microgravity conditions, and potentially related to increased ICP, could not be directly compared with similar terrestrial disorders, such as idiopathic intracranial hypertension, because some astronauts participating in long-term space flights have not reported any visual symptoms or showed any change in their ocular examinations.

Hence, the understanding of the mechanisms responsible for the changes related to the VIIP syndrome is in the midst of a not completed scientific odyssey.

Besides all the interests in comparing the results of the Kelly twins under different gravity, nutrition, and radiation conditions, their genetic similarities can bring new discernment to current poorly explained findings.

In fact, a recent study showed that genetic background (1-carbon pathways polymorphism genes), combined with lower levels of B-vitamin (B6, folate, and riboflavin), and potentially the before-flight androgen status would be related to some VIIP-related ocular changes”.

Despite the limitations, this study highlighted the involvement of individual factors not directly associated with the internal spacecraft environment in the development of ocular changes.

But it is not just about the trip. Even with the use of spacesuits by the astronauts, Mars also presents 38% of Earth's gravity, and several other vision threats related to its thin, and dusty atmosphere.



Galactic Penguin SST

Aug 10, 2017
Hong Kong
Korea, Democratic Peoples Republic Of
Don't worry Musk is a Martian - he is powered by radiation . :coffee:

The link provided is once again a smoke screen, thus further discrediting the whole lunar and Mars manned spaceflights!

One single example only, as I have no time to waste on these kind of paper:

The ideal path for Apollo would’ve been through the north or south magnetic poles because that is where there are no belts. However, that would also have meant burning a lot of fuel to get into the lunar orbital plane.


Then only 8 paragraphs later, we see an illustration that shows precisely that incoming charged solar wind particles are literally channeled in these polar regions (thus the aurora phenemenon) like in a vaccum cleaner, and therefore reaching deadlier than ever rate of concentration and gaining speed (energy) as well:

https://archive.vn/udr2w/13ca4f8fe69e7e1a6baab4b3b98bac8bae34c8f7.png ; https://archive.vn/udr2w/6f874bb654518bfd7eef7ff0f8170376b3fe6f88/scr.png ; http://web.archive.org/web/20201210...ads/2019/06/08204355/Earths-magnetosheath.png
1. Incoming charged solar wing particles are literally channeled in these polar regions.

But this is not the only contradiction.

This figure shows the path of Apollo 11 through the belts as published by N.A.S.A.:omghaha:

https://archive.vn/EY5rp/bf9c63086c5755a42eb848ecccdd8b6e9be98849.gif ; https://archive.vn/EY5rp/f939b5ee19a4e4336304a0180b46a9a3319d3e1f/scr.png ; http://web.archive.org/web/20201210...ds/2019/06/08203442/Apollo-11_flight-path.gif
2. Fig. 4: This figure shows only the final leg of the path through the belts. Red marks indicate the time in 10-minute intervals of the Apollo 11 flight. The first red dot near Earth is the point of TLI. Photo: Apollo 11’s Translunar Trajectory

In a dedicated spaceflight forum, the moderator himself has posted an improved colored image of the Van Allen Belt also from the very same NASA (!) and not the meaningless all-grey one used in the article (itself from the official Apollo era):

https://archive.vn/ywzSV/0c991fa4d814e3de6195d11dc7d420545a7ea426.jpg ; https://archive.vn/ywzSV/3008f8fc8c7276aba4a913f4c6a036eb41ee420e/scr.png ; http://web.archive.org/web/20201210.../images/content/730041main_20130228-mona2.jpg ; http://web.archive.org/web/20201210...oire-et-passage-dans-la-ceinture-de-van-allen ; https://archive.vn/so5Co
3. Impossible to even escape the deadly zones as they form a closed loop!

Impossible to even escape the deadly zones as they form a closed loop! Thus sealing the fate for the interplanetary manned spaceflight!

You can fool your own people but not all the people in the world and certainly not the educated ones.

NASA Is working on a force field prototype should be ready for the MARS mission
Nice try, but force field are only effective against charged particle.

Absolutely useless against neutral particle such as neutral hydrogen atoms, that is coupled with the solar-wind plasma, high energy neutron, gamma rays, and of course all the secondary highly penetrating particles such as mesons...

12 May 2015

When Joseph Dwyer’s aeroplane took a wrong turn into a thundercloud, the mistake paid off: the atmospheric physicist flew not only through a frightening storm but also into an unexpected — and mysterious — haze of antimatter.

Although powerful storms have been known to produce positrons — the antimatter versions of electrons — the antimatter observed by Dwyer and his team cannot be explained by any known processes, they say. “This was so strange that we sat on this observation for several years,” says Dwyer, who is at the University of New Hampshire in Durham.

A key feature of antimatter is that when a particle of it makes contact with its ordinary-matter counterpart, both are instantly transformed into other particles in a process known as annihilation. This makes antimatter exceedingly rare. However, it has long been known that positrons are produced by the decay of radioactive atoms and by astrophysical phenomena, such as cosmic rays plunging into the atmosphere from outer space. In the past decade, research by Dwyer and others has shown that storms also produce positrons, as well as highly energetic photons, or γ-rays.


Look no further, antimatter is the product of decay following particle showers.

But while inside the earth atmosphere the level is comparatively very low, due to the protective layers of the magnetosphere, in interplanetary space, neutral particle from cosmic sources and from the sun would penetrate any so-called force field, directly inside the spacecraft, to produce antimater that would annihilate ordinary matter, including the astronauts!

https://archive.vn/NKMD4/5d573c5c6c9b3bf72bff9cb6716dc85c31a9ece5.png ; https://archive.vn/NKMD4/9d530d0538ce675593ab09fa47fde86c1d40d15d/scr.png ; http://web.archive.org/web/20201213045502/https://i.imgur.com/gPQz2GT.png
4. The real colonizer of the Moon, Mars and beyond!



Galactic Penguin SST

Aug 10, 2017
Hong Kong
Korea, Democratic Peoples Republic Of
Can a man survive in interplanetary space travel without the protection of the powerful magnetic field of the earth?

Here what could instantly fry not only humans but the sensitive electronics of spacecrafts: worst-case coronal mass ejection (CME) from the Sun.

Expect showers of particles including anti-matter that appear inside the vessel after hitting the outer layers of the spacecraft!

Being hit by solar particles accelerated at the speed of Mach 8'750, obviously humans can not venture outside of the Van Allen Belts, and not even LEO during the worse CMEs.

What if … A Perfect CME Hit Earth?

January 21, 2021

Jan. 21, 2021: You’ve heard of a “perfect storm.” But what about a perfect solar storm? A new study just published in the research journal Space Weather considers what might happen if a worst-case coronal mass ejection (CME) hit Earth. Spoiler alert: You might need a backup generator.

For years, researchers have been wondering, what’s the worst the sun could do? In 2014, Bruce Tsurutani (JPL) and Gurbax Lakhina (Indian Institute of Geomagnetism) introduced the “Perfect CME.” It would be fast, leaving the sun around 3,000 km/s, and aimed directly at Earth. Moreover, it would follow another CME, which would clear the path in front of it, allowing the storm cloud to hit Earth with maximum force.

None of this is fantasy. The Solar and Heliospheric Observatory (SOHO) has observed CMEs leaving the sun at speeds up to 3,000 km/s. And there are many documented cases of one CME clearing the way for another. Perfect CMEs are real.

Using simple calculations, Tsurutani and Lakhina showed that a Perfect CME would reach Earth in only 12 hours, allowing emergency managers little time to prepare, and slam into our magnetosphere at 45 times the local speed of sound. In response to such a shock, there would be a geomagnetic storm perhaps twice as strong as the Carrington Event of 1859. Power grids, GPS and other high-tech services could experience significant outages.

Sounds bad? Turns out it could be worse.

In 2020, a team of researchers led by physicist Dan Welling of the University of Texas at Arlington took a fresh look at Tsurutani and Lakhina’s Perfect CME. Space weather modeling has come a long way in the intervening 6 years, so they were able to come to new conclusions.

“We used a coupled magnetohydrodynamic(MHD)-ring current-ionosphere computer model,” says Welling. “MHD results contain far more complexity and, hopefully, better reflect the real-world system.”

The team found that geomagnetic disturbances in response to a Perfect CME could be 10 times stronger than Tsurutani and Lakhina calculated, particularly at latitudes above 45 to 50 degrees. “[Our results] exceed values observed during many past extreme events, including the March 1989 storm that brought down the Hydro-Quebec power grid in eastern Canada; the May 1921 railroad storm; and the Carrington Event itself,” says Welling.

A key result of the new study is how the CME would distort and compress Earth’s magnetosphere. The strike would push the magnetopause down until it is only 2 Earth-radii above our planet’s surface. Satellites in Earth orbit would suddenly find themselves exposed to a hail of energetic charged particles, potentially short-circuiting sensitive electronics. A “superfountain” of oxygen ions rising up from the top of Earth’s atmosphere might literally drag satellites down, hastening their demise. (Note: Welling’s group stopped short of modelling the superfountain.)

For specialists, Table 1 from Welling et al’s paper compares their simulation of a Perfect CME impact (highlighted in yellow) to past extreme events:

You don’t have to understand all the numbers to get the gist of it. A Perfect CME strike would dwarf many previous storms.

Now for the good news: Perfect CMEs are rare.

Angelos Vourlidas of Johns Hopkins University has studied the statistics of CMEs. He notes that SOHO has captured only two CMEs with velocities greater than 3,000 km/s since the start of operations in 1996. “This means we expect roughly one CME ejected at speeds above 3000 km/s per solar cycle,” he says. Speed isn’t the only factor, however. To be “perfect,” a 3000 km/s CME would need to follow another CME, clearing its path, and both CMEs must be aimed directly at Earth.

It all adds up to something that doesn’t happen every day. But one day, it will happen. As Welling et al conclude in their paper, “Further exploring and preparing for such extreme activity is important to mitigate space-weather related catastrophes.”




Users Who Are Viewing This Thread (Total: 1, Members: 0, Guests: 1)

Top Bottom