Exposure to microgravity has been shown to weaken astronauts’ immune systems and increase the activity if harmful microorganisms. The news from space medicine is not all bad, however. New research suggests that thyroid cancer cells enter a less aggressive state under the influence of microgravity. By understanding the genetic and cellular changes that occur in space, scientists may be able to develop new cancer treatments for use on Earth.

“Differential Gene Expression Profile and Altered Cytokine Secretion of Thyroid Cancer Cells in Space” was published in the February issue of The Journal of the Federation of American Societies for Experimental Biology.

Daniela Gabriele Grimm, MD, from the Department of Biomedicine at Aarhus University in Denmark, said, “Research in space or under simulated microgravity using ground-based facilities helps us in many ways to understand the complex processes of life and this study is the first step toward the understanding of the mechanisms of cancer growth inhibition in microgravity. Ultimately, we hope to find new cellular targets, leading to the development of new anti-cancer drugs which might help to treat those tumors that prove to be non-responsive to the currently employed agents.”

Grimm and colleagues from Denmark and Germany used the Science in Microgravity Box facility aboard the Chinese Shenzhou-8, which was launched on October 31, 2011. Cell feeding was performed automatically on day 5 of the mission and automated cell fixation was conducted on day 10. An onboard centrifuge was used for inflight control cultures.

On the ground, additional cells were tested using a random-positioning machine, which aims to simulate microgravity by rotating a sample around two axes.

Cells were studied for gene expression and secretion profiles, using modern molecular biological techniques such as whole genome microarrays and multi-analyte profiling. Results suggest that the expression of genes that indicate high malignancy were down-regulated in microgravity.

“We are just at the beginning of a new field of medicine that studies the effects of microgravity on cell and molecular pathology,” said Gerald Weissmann, MD, editor-in-chief of The FASEB Journal. “Space flight affects our bodies, both for good and bad. We’ve known that microgravity can cause some microorganisms to become more virulent and that prolonged microgravity has negative effects on the human body. Now, we learn that it’s not all bad news. What we learn from cells in space should help us understand and treat malignant tumors on the ground.”

Soyuz TMA-08M suffered a failure during its descent over Kazakhstan on September 11. The capsule’s altitude sensors, which determine timing for retrorocket firing, failed. Fortunately, the rescue crew was able to radio audio cues to the flight crew.

NASA has downplayed the problem, saying “the crew was in no danger.”

“What I can tell you is that the crew doesn’t fly the Soyuz,” Navias said. “They’re passive. This thing about flying blind has to do with their situational awareness of altimeter data based on what appears to have been a sensor issue that prevented them from seeing data onboard.”

Because the astronauts were unable to follow their altitude from readings in the cockpit, recovery crews on the ground kept them updated with information being relayed to them from Russian Mission Control.

NASA spokesman Rob Navias told Space.com,
“The crew doesn’t fly the Soyuz. They’re passive. This thing about flying blind has to do with their situational awareness of altimeter data based on what appears to have been a sensor issue that prevented them from seeing data onboard…. the Soyuz performed as it was expected to.”

This is not the first time NASA has downplayed problems with the Soyuz capsule and launcher. NASA seems willing to trust the Russian Space Agency despite multiple problems, while insisting on super-strict Human Rating Standards for US companies such as Boeing and SpaceX.

Peggy Whitson, the former head of the NASA Astronaut Office, believes NASA’s radiation standards are too restrictive and discriminate against female astronauts.

Whitson expressed her views at a workshop on Ethics Principles and Guidelines for Health Standards for Long-Duration and Exploration-Class Spaceflights, conducted by the National Academy of Science’s Institute of Medicine. The story was reported by Space.com.

NASA limits astronauts’ lifetime radiation exposure to keep the probability of radiation-induced cancer death below 3%. The limit for NASA astronauts is higher than the limit for terrestrial radiation workers. Women are more susceptible to certain forms of cancer, however, so the limit for female astronauts is lower than the limit for male astronauts. A female astronaut can fly only 45-50% as many missions as a male astronauts, Whitson said.

Many of NASA’s astronauts are already limited by their lifetime radiation exposure. According to Col. Robert Behnken, who replaced Whitson as head of the Astronaut Office, only three of NASA’s 50 astronauts were eligible for the recent one-year mission to ISS, because of radiation limits. A mission to Mars is probably impossible within current radiation limits.

Questions for NASA

Three questions come to mind:

First, is NASA calculating the radiation risk correctly? At present, no one has good data on the biological effects of long-term low-level radiation exposure. Instead, the risks are inferred from data on the effects of short-term, high-level radiation exposure (collected from events such as Hiroshima and Nagasaki). This data is applied to low-level radiation using an extrapolation model known Linear No Threshold (LNT).

The LNT model assumes that a given dose of radiation will have the same effect regardless of the dose rate. It is a highly conservative model, which assumes the body has no way to recover from the effects of gradual, low-level radiation exposure over time. It ignores the usual principles of toxicology and much of what we know about the biological repair mechanisms. There is no scientific evidence to prove the LNT model is correct, but the government has adopted it out of an abundance of caution (the “precautionary principle”).

The LNT model has been criticized many times in the past, but environmentalists and anti-nuclear activists have resisted any attempted change. In space, however, the precautionary principle may cost NASA the chance to go to Mars.

Second, does the 3% fatality limit makes sense? The Shuttle had about a 2% fatal accident rate on each flight, as does Soyuz. Future launch systems may do better, but right now, an astronaut who flies multiple missions has a just of death that is significantly greater than 3%.

Third, is the male-female dichotomy really the best way to classify radiation risks? There’s no doubt that cancer risks differ between men and women, but gender is only one of many variables that affect cancer risks. With the development of modern genomics, we’re reaching the point where it’s possible to determine risks on a personal level based on individual genetic markers. This is part of an emerging field known as personalized medicine, which treats people as individuals rather than broad statistical groups. Inspiration Mars is looking at personalized medicine to help select crew members for its proposed Mars flyby mission. Is NASA doing the same?

These are questions which NASA needs to answer as it plans for future exploration activities.

Following Felix Baumgartner’s record-setting skydive, Space Safety Magazine has published an article on how to survive supersonic freefall. The article is generally accurate, but unfortunately, it does perpetuate one of the myths about aerospace physiology:

At 18,900-19,350 meters, the point known as “Armstrong’s Line,” the pressure experienced is enough to make fluids within the body boil at 37 °C, the temperature of the human body.

This is not correct. Fluids in an open container will indeed boil at that temperature, above the Armstrong Line. The human body is not a closed container, however. It is enclosed by an elastic integument (skin), which prevents bodily fluids from boiling. Blood is additionally enclosed within the blood vessels. Saliva in the mouth will boil above the Armstrong line, but blood in the veins, arteries, and capillaries will not. Death from vacuum exposure will occur within minutes, but the cause of death will be hypoxia – lack of oxygen – not boiling blood.

Proof of this fact comes from laboratory experiments with animals and also from NASA astronauts who have suffered rips in their pressure suits during EVA, resulting in parts of their body being exposed to hard vacuum. The result was some local swelling and discomfort, but no boiling blood, just as physics predicts.

Safe, affordable pressure suits are a critical, enabling technology for commercial spaceflight. Cost reductions are especially important for suborbital spaceflight, where the ticket prices will be about an order of magnitude lower.

Some progress has been made in this area. Orbital Outfitters and the David Clark Company have produced prototype suits for suborbital spaceflight. A new company, Final Frontier Design, recently unveiled its prototype and even held a successful Kickstarter campaign.

This progress, while promising, is not sufficient. David Clark has a great of experience building pressure suits for NASA and the military, dating all the way back to the Bell X-1, but has never delivered a commercial spacesuit. (The company does have a great deal of experience delivering commercial products in other areas, however, especially its highly successful aviation headsets.) The other companies are startups, with a strong commercial orientation, but have not yet delivered a suit that’s actually flown in space.

A healthy industry needs to have multiplier suppliers for critical components like spacesuits. A single source would lead to monopoly pricing and leave the industry vulnerable to single-point failures due to a natural disaster, product recall, or business failure. Two suppliers are better, but a single failure would still put the industry right back in a monopoly situation. For the long-term health of the industry, at least three viable suppliers are preferable.

Right now, most impartial observers would put the number of proven suppliers at about one and a half.

One way to address this problem is a prize for low-cost spacesuit development.

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Yesterday, we reported on Astrobotics and Carnegie Mellon University working to develop robots for proving lava caves on the Moon and Mars.

We look forward to the day when astronauts go cave exploring on other worlds. The European Space Agency already has a program that’s training astronauts in cave exploration in preparation for the isolation and close confines of the International Space Station. CAVES (Cooperative Adventure for Valuing and Exercising human behaviour and performance Skills) trains astronauts to work safely and effectively using crew procedures.

Six astronauts will spend a week learning cave safety and exploration procedures on the Italian island of Sardinia. Then, on September 7, they will venture underground for a six-day mission in a Sardinian cave. Just as on ISS, the astronauts will have a busy research schedule. In this case, looking for new life forms in the largely unexplored caves.

[youtube=http://www.youtube.com/watch?v=T44jdLESa5w&w=700]

Will Watson, executive director of the Space Frontier Foundation, made some over-the-top statements about the Space Shuttle on a blog at the Forbes website.

It’s important to note that this is a “contributor” blog. That means the author does not work for Forbes. She is an amateur blogger. Thus, she has no obligation to fact-check Watson’s statements or present contrary views. If she had, the errors would have been obvious.

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A team of researchers using Magnetic Resonance Imaging has found that most astronauts exhibit optical abnormalities after long-duration spaceflights.

An online article in the journal Radiology reports on a study of 27 astronauts who spent an average of 108 days on a Space Shuttle or International Space Station mission. Eight of the 27 astronauts also undertook a second mission lasting an average of 39 days. The study was headed by Dr. Larry Kramer, professor of diagnostic and interventional imaging at the University of Texas Medical School at Houston. (Press release here.)

The MRI study found that 33% of astronauts with more than 30 days of cumulative microgravity exposure showed expansion of the cerebral-spinal fluid space around the optic nerve. 22% shows flattening of the rear of the eyeball. 15% showed bulging of the optic nerve and 11% showed changes in the pituitary gland and its connection to the brain.

These changes are similar to symptoms seen in cases of intracranial hypertension (increased blood pressure). The authors hypothesize that the changes may be due to microgravity-induced intracranial hypertension. (Microgravity is known to cause fluid shifts from the lower extremities toward the upper body and head.)

This is not the first time optical abnormalities have been noted. A paper published in the October 2011 issue of Ophthalmology reported similar results. Dr. Robert Gibson, one of the authors of the Ophthalmology paper, said “We think it is intracranial pressure related, but we’re not sure; it could also be due to an increase in pressure along the optic nerve itself or some kind of localized change to the back of the eyeball.”

NASA is concerned about vision changes which have been reported by astronauts returning from long-duration missions. A post-flight survey of 300 Shuttle and ISS astronauts showed that 60% of ISS astronauts reported a decline in far and near visual acuity. Only 29% of Shuttle astronauts (who experienced shorter missions) reported such a decline.

How serious these changes will be is still unknown. Such changes are unlikely to be a problem for suborbital spaceflights due to their very short duration, but could become a limiting factor for interplanetary flights and other long-duration missions unless countermeasures such as artificial gravity are employed.