Posted on by Elizabeth Howell

The Battle Against What Spaceflight Does To Your Health

Expedition 36/37 astronaut Karen Nyberg uses a fundoscope to take still and video images of her eye while in orbit. Credit: NASA

Why do some astronauts come back from the International Space Station needing glasses? Eye problems are one of the largest problems that have cropped up in the last three to four years of space station science, affecting 20% of astronauts. And the astronaut office is taking this problem very seriously, pointed out Scott Smith, who leads the Nutritional Biochemistry Lab at the Johnson Space Center.

It’s one example of how extended stays in flight can alter your health. Despite NASA’s best efforts, bones and muscles weaken and months of rehabilitation are needed after astronauts spend a half-year on the space station. But in recent years, there have been strides in understanding what microgravity does to the human body — and how to fix it.

Take the vision problem, for example. Doctors believed that increased fluid shift in the head increases pressure on the optic nerve, a spot in the back of the eye that affects vision. There are a few things that could affect that:

Expedition 32 astronaut Aki Hoshide with a fistfull of blood samples on the International Space Station in 2012. Credit: NASA
Expedition 32 astronaut Aki Hoshide with a fistfull of blood samples on the International Space Station in 2012. Credit: NASA
  • Exercise. Astronauts are told to allot 2.5 hours for exercise on the International Space Station daily, which translates to about 1.5 hours of activity after setup and transitions are accounted for. Weight lifting compresses muscles and could force more blood into their heads. NASA installed an advanced Resistive Exercise Device on the space station that is more powerful than its predecessor, but perhaps this is also causing the vision problem, Smith said. “It’s ironic that the exercise device we’re excited about for working the muscles and bone, may hurt eyes.”
  • CO2 levels. This gas (which naturally occurs when humans exhale) is “relatively high” on the space station because it takes more power and more supplies to keep the atmosphere cleaner, Smith said. “Increased carbon dioxide exposure will increase blood flow to your head,” he said. If this is found to be the cause, he added, NASA is prepared to make changes to reduce CO2 levels on station.
  • Folate (Vitamin B) problems. Out of the reams of blood and urine data collected since before NASA started looking at this problem, they had been looking at a biochemical (nutrient) pathway in the body that moves carbon units from one compound to another. This is important for synthesizing DNA and making amino acids, and involves several vitamins and nutrients. After scientists started noticing changes in folate (a form of Vitamin B), they probed further and found an interesting thing regarding homocysteine, a type of amino acid at the heart of this one carbon pathway. It turns out those astronauts with vision issues after flight had higher (but not abnormal) levels of homocysteine in their blood before flight, as published here.

“It’s speculating, but we think that genetic differences in this pathway may somehow alter your response to things that affect blood flow into the head,” Smith said.

After finding these essentially “circumstantial” evidence of a genetic predisposition to vision issues, they proposed an experiment to look at genes associated with one carbon metabolism. “To give you an idea of the importance of this problem, we went to every crew member that’s flown to space station, or will fly to space station.  We asked if they would give us a blood sample and look at their genes for one carbon meytabolism,” he said. “We approached 72 astronauts to do that, and 70 of them gave us blood, which is unheard of.”

While NASA tries to nail down what is going on with astronaut vision, the agency has made substantial progress in preserving bone density during flights — for the first time in 50 years of spaceflight, Smith added.

We mentioned the advanced Resistive Exercise Device, an orbital weight-lifting device which was installed and first used during Expedition 18 in 2008 and has been in use on the space station ever since. It’s a large improvement over the previous interim Resistive Exercise Device (iRED), which didn’t provide enough resistance, allowing some astronauts to “max out” on the device and could not further increase weightlifting loads after some weeks or months of use.

“We flew the iRED on station and the bone loss on station looked just like it did on Mir, that is, with no resistive exercise device available,” Smith said. But that changed drastically with ARED, which has twice as much loading capability. Crews ate better, maintained body weight and had better levels of Vitamin D compared to those that went before. Most strikingly, they maintained their bone density at preflight levels, as this paper shows.

While we think of bone as being cement-like and unchanging (at least until you break one!), it’s actually an organ that is always breaking down and reforming. When the breakdown accelerates, such as when you are not putting weight on it in orbit, you lose bone density and are at higher risk for fractures.

Why is unknown, except to say that the bone seems to rely on some sort of “signalling” that indicates loads or weights are being put on it. Conversely, if you are to put more weight on your bones — maybe carrying a backpack with weights on it — your skeleton would gradually get bigger to accommodate the extra weight.

While it’s exciting that the ARED is maintaining bone density, the question is whether the body can sustain two processes happening at a faster rate than before flight: the breakdown and buildup of bone. More study will be needed, Smith said, to pinpoint whether this affects the strength of the bone, which is ultimately more important than just mineral density. Nutrition and exercise may also be optimized, to further allow for better bone preservation.

That’s one of the things scientists are excited to study with the upcoming one-year mission to the International Space Station, when Scott Kelly (NASA) and Mikhail Kornienko (Roscosmos) will be one of a small number of people to do one consecutive calendar year in space. The bone “remodelling” doesn’t level off after six months, but perhaps it will closer to a year.

Smith pointed out the quality of health data has also improved since the long-duration Mir missions of the early to mid 1990s. Specific markers of bone breakdown and formation were just being discovered and implemented during that time, whereas today they’re commonly used in medicine. Between that, and the fact that NASA’s Mir data are from shorter-duration missions, Smith said he’s really looking forward to seeing what the year in space will tell scientists.

This concludes a three-part series on astronaut health. Two days ago:  Why human science is so hard to do in space. Yesterday: How do we make exercises work in Zero G?

Posted on by Elizabeth Howell

How Much Can Titan’s Sunsets Teach Us About Alien Planets?

An illustration of a Titanic lake by Ron Miller. All rights reserved. Used with permission.

Titan — that smoggy, orangy moon circling Saturn — is of great interest to exobiologists because its chemistry could be good for life. It has a thick atmosphere of nitrogen and methane and likely has lakes filled with liquid hydrocarbons, and scientists believe there is enough light filtering down into the atmosphere to drive chemical reactions.

It turns out the moon could also be a good analog to help us understand the atmospheres of exoplanets far beyond our solar system. From looking at sunsets on the moon, scientists led by NASA believe that a thick atmosphere could influence how we perceive a planet from afar.

First, a bit of information about how scientists learn about planet atmospheres in the first place. When a distant planet passes in front of its parent star, the light from the star passes through the atmosphere and gets distorted.

The spectra that telescopes pick up can then tell scientists information about what the atmosphere is made of, what temperature it is, and how it is structured. (This science, it should be noted, is in its very early stages and works best on very large exoplanets that are relatively close to Earth, since the planets are so small and far away.)

“Previously, it was unclear exactly how hazes were affecting observations of transiting exoplanets,” stated Tyler Robinson, a postdoctoral research fellow at NASA’s Ames Research Center who led the research. “So we turned to Titan, a hazy world in our own solar system that has been extensively studied by Cassini.”

Titan's surface is almost completely hidden from view by its thick orange "smog" (NASA/JPL-Caltech/SSI. Composite by J. Major)
Titan’s surface is almost completely hidden from view by its thick orange “smog” (NASA/JPL-Caltech/SSI. Composite by J. Major)

To do this, Robinson’s team used data from the Cassini spacecraft during four solar occultations, or times when Titan passed in front of our own sun from the perspective of the spacecraft. They found out that the moon’s hazy atmosphere makes it difficult to figure out what is in its spectra.

“The observations might be able to glean information only from a planet’s upper atmosphere,” NASA stated. “On Titan, that corresponds to about 90 to 190 miles (150 to 300 kilometers) above the moon’s surface, high above the bulk of its dense and complex atmosphere.”

The haze is even more powerful in the shorter (bluer) wavelengths of light, which contradicts previous studies assuming that all wavelengths of light would have the same distortions. Models of exoplanet atmospheres usually have simplified spectra because hazes are complex to model, requiring a lot of computer power.

Researchers hope to take these observations of Titan and then use them to better inform how exoplanet models are created.

The research was published May 26 in the Proceedings of the National Academy of Science.

Source: NASA

Posted on by Elizabeth Howell

Push. Pull. Run. Lift! How Do We Make These Exercises Work In Zero G?

Expedition 38/39 astronaut Koichi Wakata (Japanese Aerospace Exploration Agency) uses the advanced Resistive Exercise Device (aRED) in the Tranquility node of the International Space Station in February 2014. Credit: NASA

Here’s the thing about going to the International Space Station: No one can predict what you’ll need to do during your six-month stay there. Maybe something breaks and you need to go “outside” to fix it, in a spacesuit. Maybe you’re going to spend a day or three in a cramped corner, fixing something behind a panel.

Your body needs to be able to handle these challenges. And a big key behind that is regular exercise.

To get ready, you need to change things up frequently on Earth. Weights. Kettleballs. Pull-ups. Squats. Deadlifts. Interval training on cycles and treadmills. And more.

“Preflight, we throw everything but the kitchen sink at [astronauts],” said Mark Guilliams, a NASA astronaut health specialist who gets them ready before orbit. “We try to work as many different movements, using multiple joints and as many different planes of motion as possible “.

Some astronauts hit the gym every single day, such as the enthusiastic Mike Hopkins who did a whole YouTube series on exercising in orbit during Expeditions 37/38 earlier this year. Others prefer a few times a week. The astronauts also receive training on how to use the exercise devices they’ll have in orbit. Because time is precious up there, even when it comes to preserving your stamina.

Now imagine yourself in a weightless environment for half a year. Many of the exercises you do on the ground are impossible, unless you make certain modifications — such as strapping yourself down. Nevertheless, to make sure astronauts’ physiological systems remain at healthy levels, the space station has a range of gym equipment and the astronauts are allotted 2.5 hours for exercise daily.

That sounds like a lot, until you start factoring in other things. Setting up and taking down equipment takes time, such as when the astronauts harness themselves to the treadmill to avoid floating away. The resistance exercise machine has to be changed around for different exercises. This means that their “active” time is roughly 60 minutes for weightlifting and 40 minutes for aerobic, six days a week.

Compare that to what is recommended by the American Heart Association– 30 minutes, five days a week for light aerobic activity and two days of weightlifting — and you can see the time astronauts spend on exercise is not unreasonable. Also remember that the rest of the day, they have no gravity. Treadmill stats show the astronauts take only roughly 5,000 to 6,000 steps each day they use they use the treadmill, compared to some people’s goals of reaching 10,000 steps a day on Earth.

“When you compare the actual time the crew spends on exercise to that recommended by the AHA, it’s not a significant portion of their day that we’re asking them to participate in order for them to try and maintain their physiological health,” said Andrea Hanson, an exercise hardware specialist for the space station.

Expedition 26's Cady Coleman (NASA) calibrates a device intended to measure oxygen production while sitting on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station. Credit: NASA
Expedition 26’s Cady Coleman (NASA) calibrates a device intended to measure oxygen production while sitting on the Cycle Ergometer with Vibration Isolation System (CEVIS) in the Destiny laboratory of the International Space Station. Credit: NASA

So what’s the equipment the astronauts get to use? The pictures in this article show you a range of things. There’s the Cycle Ergometer with Vibration Isolation and Stabilization System (CEVIS) — a fancy name for the exercise bike. It has remained pretty much the same since it was brought to the space station back in 2001, for Expedition 2. Its major goal is to keep an astronaut’s aerobic capacity up for demanding spacewalks, which can take place for up to eight hours at a time.

The weight device has changed over time, however. The initial Interim Resistive Exercise Device used rubber to provide the resistive force and ended up being not enough for some astronauts, who found themselves reaching the designed capability limits long before their missions ended. (Here’s a picture of it.) Astronauts stopped using it after Expedition 28 in favor of the advanced Resistive Exercise Device, which instead uses piston-driven vacuum cylinders.

“The new device actually enables us to go up to 600 pounds of loading,” Guillams said. The IRED device could only give 300 pounds of resistance. So now, even the strongest astronaut can get a challenge out of ARED, he said.

Expedition 32 astronaut Sun Williams uses the COLBERT (Combined Operational Load Bearing External Resistance Treadmill) in the Tranquility node of the International Space Station in August 2012. The treadmill was named after comedian Stephen Colbert. Credit: NASA
Expedition 32 astronaut Sun Williams uses the COLBERT (Combined Operational Load Bearing External Resistance Treadmill) in the Tranquility node of the International Space Station in August 2012. The treadmill was named after comedian Stephen Colbert. Credit: NASA

The treadmill aboard the station is also a newer one. The second-generation device allows for faster speeds, and to even save programs for each individual crew member so that they can have customized workouts when they arrive on station. (The first one, “Treadmill With Vibration Isolation And Stabilization System“, was put on to an unmanned Progress spacecraft in 2013 to burn up in the atmosphere.)

By the way, the new treadmill (T2) is called the COLBERT, or Combined Operational Load Bearing External Resistance Treadmill. It’s named after comedian Stephen Colbert, who in 2009 had his viewers vote to attach his name to a space station module when NASA held an open contest. When “Colbert” won, NASA elected to name the treadmill after him, and called the module Tranquility instead.

Whatever the treadmill’s name, the goal is to maintain astronaut bone and cardiovascular health while in orbit. A future story will deal with some of the scientific results obtained from more than a decade of ISS science in orbit.

This is part of a three-part series on astronaut health. Yesterday: Why human science is so hard to do in space. Tomorrow: How do you fight back against space health problems?

Posted on by Elizabeth Howell

Did This Martian Volcano Once Host Life?

A false-color view of Arsia Mons on Mars, including braided fluvial channels (seen in inset) from glacial deposits made 210 million years ago. Credit: NASA/Goddard Space Flight Center/Arizona State University/Brown University

Extremophiles teach us that life is found in unlikely places, which is why after looking at microbes happily living in hot springs or surviving after 18 months in space, scientists are trying to expand our definition of what a habitable environment is. So perhaps this ancient Martian volcano would be an example.

Meet Arsia Mons. It’s the third-tallest volcano on the Red Planet and one of the largest volcanoes we know of in the solar system.

New research shows that a combination of eruptions and a glacier on its northwest side could have formed something called “englacial lakes”, which is water that is created inside glaciers. (The researchers compare this to “liquid bubbles in a half-frozen ice cube.”) These in sum would have been massive, on the order of hundreds of cubic miles.

“This is interesting because it’s a way to get a lot of liquid water very recently on Mars,” stated Kat Scanlon, a graduate student at Brown who led the research, adding that she is also interested to see if signs of a habitable environment turn up in even older regions, of 2.5 billion years old or more.

“There’s been a lot of work on Earth — though not as much as we would like — on the types of microbes that live in these englacial lakes,” Scanlon added. “They’ve been studied mainly as an analog to [Saturn’s moon] Europa, where you’ve got an entire planet that’s an ice covered lake.”

While the glacial ice idea is not new — it’s been talked about since the 1970s — Scanlon’s team pushed the research forward by bringing in new information from NASA’s Mars Reconnaissance Orbiter.

Mars Reconnaissance Orbiter
Artist Illustration of the Mars Reconnaissance Orbiter

“Scanlon found pillow lava formations, similar to those that form on Earth when lava erupts at the bottom of an ocean,” Brown University stated.

“She also found the kinds of ridges and mounds that form on Earth when a lava flow is constrained by glacial ice. The pressure of the ice sheet constrains the lava flow, and glacial meltwater chills the erupting lava into fragments of volcanic glass, forming mounds and ridges with steep sides and flat tops. The analysis also turned up evidence of a river formed in a jökulhlaup, a massive flood that occurs when water trapped in a glacier breaks free.”

Scanlon estimated that two of the “deposits” would have had lakes of 9.6 cubic miles (40 cubic kilometers) each, while a third would have had 4.8 cubic miles (20 cubic kilometers). They could have stayed liquid for hundreds or perhaps thousands of years.

That’s a short period in the history of life, but Scanlon’s team says it could have been enough for microbes to colonize the locations, if microbes were on Mars in the first place.

You can read more about the research in the journal Icarus.

Source: Brown University

Posted on by Elizabeth Howell

Everyday ‘Astronaut’ Photo Series Goes From Cooking Disaster To Toasting Apollo 13

One photo in the series "A day in the life of Everyday Astronaut". Credit: Tim Dodd

What’s an everyday astronaut to do when it’s not his turn to take a mission to space? Well, the same things as the rest of us — brush teeth, do a little cooking — but wearing a (pretend) spacesuit, just in case.

At least, that’s the vision of photographer Tim Dodd, who posted a series of photos of him going about the everyday actions of a wannabe astronaut during one day. He wakes up in a space-themed bed, mows the lawn and goes shopping bedecked in the suit, and then toasts the movie Apollo 13 before going to bed.

“In November of 2013, I found myself the lone bidder of a Russian high altitude space suit on an auction website called RRauction,” Tim Dodd wrote on his blog.

“Since then, I’d been scheming how to best use the suit. I have been revisiting my childhood love for space and my obsession was growing stronger and stronger. It was only natural to use this suit to project the inner child in me, still dreaming about space. With that, I present to you: ‘A day in the life of Everyday Astronaut.’ ”

The series is full of a few jokes, including a reference to Canadian astronaut Chris Hadfield — that social media sensation who went on to write a bestseller called “An Astronaut’s Guide To Life On Earth.”

(h/t Reddit)

Posted on by Elizabeth Howell

Launch Alert! Watch Live As Three People Rocket To Space Today

The Expedition 40/41 crew prior to their launch to the International Space Station. From left, Alexander Gerst (ESA), Maxim Suraev (Roscosmos) and Reid Wiseman (NASA). Credit: NASA/Victor Zelentsov

In a few hours, you’ll be able to watch three crew members of Expedition 40/41 rocket to space — live from Kazakhstan!

At 3:57 p.m. EDT (7:57 p.m. UTC) a rocket carrying a Soyuz spacecraft is expected to lift off from the Baikonur Cosmodrome, carrying Reid Wiseman (NASA), Alexander Gerst (ESA) and Maxim Suraev (Roscosmos). Full schedule details are below.

NASA TV will turn on the cameras at 3 p.m. EDT (7 p.m. UTC) and stay on the crew until after they make it to orbit. If all goes to plan, NASA TV will then resume coverage at 9 p.m. EDT (1 p.m. UTC) for docking to the International Space Station 48 minutes later.

Next comes the hatch opening. NASA will start coverage at 11 p.m. EDT (3 a.m. UTC) for the opening about 25 minutes later. Greeting the arriving crew members will be the other half of the Expedition 40 crew: Steve Swanson (NASA), Alexander Skvortsov (Roscosmos) and Oleg Artemyev (Roscosmos). The incoming crew traditionally participates in a televised chat with their families once they are a little settled in.

Because these are live events, all schedules are subject to change. Make sure to follow the NASA Twitter feed for any adjustments. For example, during the last launch the Soyuz spacecraft failed to make a burn to bring the crew members to the station quickly, making the crew go to a standard backup procedure that brought them to the station about two days later. No one was at risk, NASA said, and the delayed docking happened flawlessly.

By the way, all three crew members are on Twitter: @astro_alex, @astro_reid and @msuraev.

Posted on by Elizabeth Howell

Space Robot Fixes Itself, Takes Selfie As Funny Livetweet Happens On The Ground

Dextre, the Canadian Space Agency's robotic handyman aboard the International Space Station. Credit: CSA/NASA

In a thrilling demonstration of space robotics, today the Dextre “hand” replaced a malfunctioning camera on the station’s Canadarm2 robotic arm. And the Canadian Space Agency gleefully tweeted every step of the way, throwing in jokes to describe what was happening above our heads on the International Space Station.

“Dextre’s job is to reduce the risk to astronauts by relieving them of routine chores, freeing their time for science,” the Canadian Space Agency tweeted today (May 27) .

“Spacewalks are thrilling, inspiring, but can potentially be dangerous. They also take a lot of resources and time. So Dextre is riding the end of Canadarm2 today instead of an astronaut. And our inner child is still yelling out ‘Weeeee…!’ ”

The complex maneuvers actually took a few days to accomplish, as the robot removed the broken camera last week and stowed it. Today’s work (performed by ground controllers) was focused on putting in the new camera and starting to test it. You can see some of the most memorable tweets of the day below.

The cookie you see in the first tweet is part of a tradition in Canada’s robotic mission control near Montreal, Que., where controllers have this snack on the day when they are doing robotic work in space.

Incidentally, the Canadian Space Agency bet NASA a box of maple cream cookies in February during a gold-medal Olympic hockey game between the two countries, which Canada won.

Posted on by Elizabeth Howell

NASA’s Mars Landing Idea Will Take To The Air In June

No rocket sleds were harmed in the making of this video. (NASA/JPL)

So what does an agency like NASA do after making a daring new type of landing with the Mars Curiosity rover? Try to make it even better for next time.

NASA is readying a new technology for landing on the Red Planet that is supposed to help brake the spacecraft in the atmosphere by inflating a buffer around the heat shield to slow things down. And after testing this so-called “Low-Density Supersonic Decelerator” on a rocket sled in January and April, the team is ready for the next major test: heading aloft.

As early as June 3, NASA will strap a test device below a high-altitude balloon and send it up to 120,000 feet — about the same altitude that Felix Baumgartner jumped from in 2012. The device will then drop from the balloon sideways, spinning like a football, and reach a velocity of four times the speed of sound. Then the LDSD will inflate, if all goes as planned, and NASA will evaluate how well it performs.

The agency hopes to use this technology to land heavier and heavier spacecraft on the Red Planet. If the testing goes as scheduled and the funding is available, NASA plans to use an LDSD on a spacecraft as early as 2018.

You can read more about LDSD at this website.

Posted on by Elizabeth Howell

Why You Shouldn’t ‘Buy Real Estate’ On Neptune’s Moon Triton

Neptune's largest Moon, Triton. Astronomers think that Triton is a captured Kuiper Belt Object. Credit: NASA/JPL

Leaving aside the complications of space treaties, a new video lays out another case for why you wouldn’t want to purchase property on Triton — at least, if you were buying for the ultra-long term, over millions of years. The moon is being slowed down by Neptune and will eventually crash or break up into a ring system.

All joking aside, the video also puts forward an interesting hypothesis: that Triton was once a dwarf planet, with a companion, and that Neptune captured Triton and flung the companion away when the giant gas planet moved further out into the solar system, billions of years ago.

Checking into the theory’s credentials, it’s worth noting that the author — Kurzgesagt — represents a startup company that has posted other videos about the solar system. They’re cutely done, although the company’s website does not appear to list any names, at least yet; they describe themselves as a “team of designers, journalists and musicians.”  (That might be because they’re operating in “stealth mode”, a term describing startups that aren’t quite ready to make their idea or founders public yet.)

The theory Kurzgesagt cites is peer-reviewed, however. A 2006 Nature paper called “Neptune’s capture of its moon Triton in a binary–planet gravitational encounter” describes Triton as being part of a binary system in the past, somewhat similar to Pluto and Charon.

NASA’s web page about Triton doesn’t mention the binary system or dwarf planet hypothesis, but says “scientists think Triton is a Kuiper Belt Object captured by Neptune’s gravity millions of years ago.” (The Kuiper Belt is a collection of objects near Neptune’s orbit.)

Some of the reasons include its strange orbital motion that is opposite to Neptune’ s rotation, and the fact that Triton is overwhelmingly the largest moon in the system — suggesting it ejected other ones when it was captured.

Makes you want to send another spacecraft to Neptune, doesn’t it? The first and only visitor there, Voyager 2, flew past there in 1989.

Posted on by Elizabeth Howell

Zero G Living: Tough To Sustain, Harder To Study

Expedition 40 NASA astronaut Reid Wiseman participates in a spacesuit fit-check prior to his scheduled flight to space in May 2014. Credit: NASA

Small populations make it really hard to do scientific studies, because the sample size may not be representative of the population being studied. And that’s the challenge with spaceflight, right before you start: only so many people head up there and take part of your experiments. With less than 20 people heading to space per year these days, that’s a tiny population to do medical studies from.

“One of the advantages that terrestrial medicine has is a lot of people to study,” said Jean Sibonga, the bone lead of NASA’s human spaceflight program. “While we’re acquiring our data using the conventional clinical methods for testing bone health here on Earth, terrestrial medicine is running these same studies and getting the results sooner.”

But for a small group being studied, the science is highly professionalized. NASA’s scientists are part of many professional societies ranging from anesthesia to bone science to nutrition. They collaborate with people all over the world. And slowly, as the results come in, they say they are making progress in understanding how space deconditions our bodies and how to make them stronger again.

With bone — where for decades, physicians have tried to figure out which populations are most at risk for fractures — comes an example of another hurdle. The astronauts are young, usually 50 or below, making them statistically one of the least at risk for fractures until they expose themselves to microgravity. This means that comparing them to seniors is “clearly not an appropriate test for our population,” Sibonga said.

One challenge of spaceflight is comparing data from astronauts, in the prime of their career, to seniors. Both groups can have similar health issues, but for different reasons: astronauts are exposed to microgravity, while seniors have aged. Pictured are Expedition 40's Maxim Surayev (age 41) and Reid Wiseman (age 38). Credit: NASA/Victor Zelentsov
One challenge of spaceflight is comparing data from astronauts, in the prime of their career, to seniors. Both groups can have similar health issues, but for different reasons: astronauts are exposed to microgravity, while seniors have aged. Pictured are Expedition 40’s Maxim Surayev (age 41) and Reid Wiseman (age 38). Credit: NASA/Victor Zelentsov

But for what it’s worth, NASA has adapted international clinical guidelines to identify astronauts who have optimal bone health, and to see if the “countermeasures” — weight-bearing exercises — are having any success. This also means looking at the astronaut’s entire picture of health, from family history to medication intake to hormone levels, to see if these variables have any sorts of effect. (More on the results of these tests tomorrow.)

The issue with astronauts, Sibonga said, is they go through very rapid bone losses — even faster than what postmenopausal women experience. Astronauts lose about 1% of their bone density on average per month from their hip and spine. In aging women, vertebrae are the most affected and they can find themselves with “compression fractures” where the vertebrae collapse and their backs are stooped over.

Astronauts may be at risk, but it’s hard with tests on the space station to see if this is happening real time. This work has to wait until they get back to Earth. Sibonga said NASA is trying to fix that. “We’re doing market surveys, and if we find a promising technology for inflight monitoring, we will work to develop and validate these tests in these astronauts.”

Regular exercise is one way that astronauts prepare for the rigors of orbit. Here, Expedition 32 JAXA astronaut Akihiko Hoshide does maintenance on the International Space Station during a spacewalk in 2012. Credit: NASA
Regular exercise is one way that astronauts prepare for the rigors of orbit. Here, Expedition 32 JAXA astronaut Akihiko Hoshide does maintenance on the International Space Station during a spacewalk in 2012. Credit: NASA

Sometimes that technology comes from other sectors. The idea of “loading” not only applies to human health, but also to engineering. So some of the same models could have relevancy between engineering and humans. One device NASA has been testing on the ground is a quantitative computed tomography (QCT), an imager that quantifies the amount of bone mass an astronaut has in true three dimensions. From these QCT data, engineers can develop models to estimate the mechanical loads that would cause a bone to fracture. But only a handful of people have applied this engineering model to biological systems, Sibonga said.

Naturally, NASA is also interested in how much bone mineral density (BMD) comes back after a mission. BMD tests are done every three years in astronauts from the time they are selected (bearing in mind the technology was not available until about the mid-1990s). Uniquely, NASA also invites its astronauts back after they leave or retire to continue the tests — a practice even the military branches in the United States don’t do. This allows the agency to do long-term population studies on its astronaut corps.

Sibonga added that NASA’s science is proceeding at an aggressive pace, given the small population and mission schedules, and cited a few examples of research papers on skeletal health and femoral strength as examples.

This begins a three-part series on astronaut health. Tomorrow: How to exercise in zero G. Two days from now: Battling against what space does to your health.