Is Human Hibernation Possible? Going to Sleep for Long Duration Spaceflight

Sleeping for Centuries?

We’ve spent a few articles on Universe Today talking about just how difficult it’s going to be to travel to other stars. Sending tiny unmanned probes across the vast gulfs between stars is still mostly science fiction. But to send humans on that journey? That’s just a level of technology beyond comprehension.

For example, the nearest star is Proxima Centauri, located a mere 4.25 light years away. Just for comparison, the Voyager spacecraft, the most distant human objects ever built by humans, would need about 50,000 years to make that journey.

I don’t know about you, but I don’t anticipate living 50,000 years. No, we’re going to want to make the journey more quickly. But the problem, of course, is that going more quickly requires more energy, new forms of propulsion we’ve only starting to dream up. And if you go too quickly, mere grains of dust floating through space become incredibly dangerous.

Based on our current technology, it’s more likely that we’re going to have to take our time getting to another star.

And if you’re going to go the slower route, you’ve got a couple of options. Create a generational ship, so that successive generations of humans are born, live out their lives, and then die during the hundreds or even thousands of year long journey to another star.

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

Imagine you’re one of the people destined to live and die, never reaching your destination. Especially when you look out your window and watch a warp ship zip past with all those happy tourists headed to Proxima Centauri, who were start enough to wait for warp drives to be invented.

No, you want to sleep for the journey to the nearest star, so that when you get there, it’s like no time passed. And even if warp drive did get invented while you were asleep, you didn’t have to see their smug tourist faces as they zipped past.

Is human hibernation possible? Can we do it long enough to survive a long-duration spaceflight journey and wake up again on the other side?

Before I get into this, we’re just going to have to assume that we never merge with our robot overlords, upload ourselves into the singularity, and effortlessly travel through space with our cybernetic bodies.

For some reason, that whole singularity thing never worked out, or the robots went on strike and refused to do our space exploration for us any more. And so, the job of space travel fell to us, the fragile, 80-year lifespanned mammals. Exploring the worlds within the Solar System and out to other stars, spreading humanity into the cosmos.

Artist’s impression of astronauts exploring the surface of Mars. Credit: NASA/JSC/Pat Rawlings, SAIC

Come on, we know it’ll totally be the robots. But that’s not what the science fiction tells us, so let’s dig into it.

We see animals, and especially mammals hibernating all the time in nature. In order to be able survive over a harsh winter, animals are capable of slowing their heart rate down to just a few beats a minute. They don’t need to eat or drink, surviving on their fat stores for months at a time until food returns.

It’s not just bears and rodents that can do it, by the way, there are actually a couple of primates, including the fat-tailed dwarf lemur from Madagascar. That’s not too far away on the old family tree, so there might be hope for human hibernation after all.

In fact, medicine is already playing around with human hibernation to improve people’s chances to survive heart attacks and strokes. The current state of this technology is really promising.

They use a technique called therapeutic hypothermia, which lowers the temperature of a person by a few degrees. They can use ice packs or coolers, and doctors have even tried pumping a cooled saline solution through the circulatory system. With the lowered temperature, a human’s metabolism decreases and they fall unconscious into a torpor.

But the trick is to not make them so unconscious that they die. It’s a fine line.

The results have been pretty amazing. People have been kept in this torpor state for up to 14 days, going through multiple cycles.

The therapeutic use of this torpor is still under research, and doctors are learning if it’s helpful for people with heart attacks, strokes or even the progression of diseases like cancer. They’re also trying to figure out if there are any downsides, but so far, there don’t seem to be any long-term problems with putting someone in this torpor state.

A few years ago, SpaceWorks Enterprises delivered a report to NASA on how they could use this therapeutic hypothermia for long duration spaceflight within the Solar System.

Currently, a trip to Mars takes about 6-9 months. And during that time, the human passengers are going to be using up precious air, water and food. But in this torpor state, SpaceWorks estimates that the crew will a reduction in their metabolic rate of 50 to 70%. Less metabolism, less resources needed. Less cargo that needs to be sent to Mars.

Credit: SpaceWork Enterprises, Inc

The astronauts wouldn’t need to move around, so you could keep them nice and snug in little pods for the journey. And they wouldn’t get into fights with each other, after 6-9 months of nothing but day after day of spaceflight.

We know that weightlessness has a negative effect on the body, like loss of bone mass and atrophy of muscles. Normally astronauts exercise for hours every day to counteract the negative effects of the reduced gravity. But SpaceWorks thinks it would be more effective to just put the astronauts into a rotating module and let artificial gravity do the work of maintaining their conditioning.

They envision a module that’s 4 metres high and 8 metres wide. If you spin the habitat at 20 revolutions per minute, you give the crew the equivalent of Earth gravity. Go at only 11.8 RPM and it’ll feel like Mars gravity. Down to 7.8 and it’s lunar gravity.

Normally spinning that fast in a habitat that small would be extremely uncomfortable as the crew would experience different forces at different parts of their body. But remember, they’ll be in a state of torpor, so they really won’t care.

Credit: SpaceWork Enterprises, Inc
Credit: SpaceWork Enterprises, Inc

Current plans for sending colonists to Mars would require 40 ton habitats to support 6 people on the trip. But according to SpaceWorks, you could reduce the weight down to 15 tons if you just let them sleep their way through the journey. And the savings get even better with more astronauts.

The crew probably wouldn’t all sleep for the entire journey. Instead, they’d sleep in shifts for a few weeks. Taking turns to wake up, check on the status of the spacecraft and crew before returning to their cryosleep caskets.

What’s the status of this now? NASA funded stage 1 of the SpaceWorks proposal, and in July, 2016 NASA moved forward with Phase 2 of the project, which will further investigate this technique for Mars missions, and how it could be used even farther out in the Solar System.

Elon Musk should be interested in seeing their designs for a 100-person module for sending colonists to Mars.

Credit: SpaceWork Enterprises, Inc
Credit: SpaceWork Enterprises, Inc

In addition, the European Space Agency has also been investigating human hibernation, and a possible way to enable long-duration spaceflight. They have plans to test out the technology on various non-hibernating mammals, like pigs. If their results are positive, we might see the Europeans pushing this technology forward.

Can we go further, putting people to sleep for decades and maybe even the centuries it would take to travel between the stars?

Right now, the answer is no. We don’t have any technology at our disposal that could do this. We know that microbial life can be frozen for hundreds of years. Right now there are parts of Siberia unfreezing after centuries of permafrost, awakening ancient microbes, viruses, plants and even animals. But nothing on the scale of human beings.

When humans freeze, ice crystals form in our cells, rupturing them permanently. There is one line of research that offers some hope: cryogenics. This process replaces the fluids of the human body with an antifreeze agent which doesn’t form the same destructive crystals.

Scientists have successfully frozen and then unfrozen 50-milliliters (almost a quarter cup) of tissue without any damage.

In the next few years, we’ll probably see this technology expanded to preserving organs for transplant, and eventually entire bodies, and maybe even humans. Then this science fiction idea might actually turn into reality. We’ll finally be able to sleep our way between the stars.

Weekly Space Hangout – Sept 23, 2016: Dr. Frank Timmes and Online Astronomy Education

Host: Fraser Cain (@fcain)

Special Guests:
Dr. Frank Timmes is an astrophysicist at Arizona State University and will be discussing online astronomy education and the Global Freshman Academy. His interests include the universe’s evolving composition and its implications for life in the universe. Dr. Timmes’ current area of research is nuclear astrophysics and the creation of the periodic table.

Guests:

Morgan Rehnberg (MorganRehnberg.com / @MorganRehnberg)
Dave Dickinson (www.astroguyz.com / @astroguyz)
Kimberly Cartier ( KimberlyCartier.org / @AstroKimCartier )
Nicole Gugliucci (cosmoquest.org / @noisyastronomer)

Their stories this week:

New bill targets serial harasses

Tiangong-1 to crash next year

The Final Days of Rosetta

Microlensing circumbinary planet detected

Repeat of Voyager’s “impossible” cloud

We are now using a tool called Trello to submit and vote on stories we would like to see covered each week, and then Fraser will be selecting the stories from there. Here is the link to the Trello WSH page (http://bit.ly/WSHVote), which you can see without logging in. If you’d like to vote, just create a login and help us decide what to cover!

We record the Weekly Space Hangout every Friday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch us live on Universe Today, or the Universe Today YouTube page.

Jupiter’s Moon Ganymede

Ganymede

In 1610, Galileo Galilei looked up at the night sky through a telescope of his own design. Spotting Jupiter, he noted the presence of several “luminous objects” surrounding it, which he initially took for stars. In time, he would notice that these “stars” were orbiting the planet, and realized that they were in fact Jupiter’s moons – which would come to be named Io, Europa, Ganymede and Callisto.

Of these, Ganymede is the largest, and boasts many fascinating characteristics. In addition to being the largest moon in the Solar System, it is also larger than even the planet Mercury. It is the only satellite in the Solar System known to possess a magnetosphere, has a thin oxygen atmosphere, and (much like its fellow-moons, Europa and Callisto) is believed to have an interior ocean.

Continue reading “Jupiter’s Moon Ganymede”

How Long Will Our Spacecraft Survive?

There are many hazards out there, eager to disrupt and dismantle the mighty machines we send out into space. How long can they survive to perform their important missions?

Every few months, an eager new spacecraft arrives on the launch pad, ready for its date with destiny. If we don’t blow it all to bits with a launch vehicle failure, it’ll be gently placed into orbit with surgical precision. Then it’ll carry out a noble mission of exploring the Solar System, analyzing the Earth, or ensuring we have an infinite number of radio stations in our cars, allowing us to never be satisfied with any of them.

Space is hostile. Not just to fragile hu-mans, but also to our anthropomorphized Number Five is alive robotic spacecraft which we uncaringly send to do our bidding. There are many hazards out there, eager to disrupt and dismantle our stalwart electronic companions. Oblivion feeds voraciously on our ever trusting space scouts and their tiny delicate robotic hearts, so many well before their time.

How long have they got? How long will our spacecraft survive as we cast them on their suicide missions to “go look at stuff on behalf of the mighty human empire”? When spacecraft are hurled into the void, all mission planners know they’re living on borrowed time.

The intrepid Mars Exploration Rovers, Spirit and Opportunity, were only expected to operate for 3 months. NASA’s Spitzer Space Telescope carried a tank of expendable helium coolant to let it see the dimmest objects in the infrared spectrum.

Sometimes the spacecraft wear down for unexpected reasons, like electronic glitches, or parts wearing out. Hubble was equipped with rotating gyroscopes that eventually wore out over time, making it more difficult to steer at its targets, and only an intervention by rescue and repair allowed the mission to keep going.

In general, a spacecraft is expected to last a few months to a few years. Spirit and Opportunity only had a planned mission of 3 months. It took Spirit more than 6 dauntless years to finally succumb to the hostile Martian environment. Opportunity is still kicking more than a decade later, thanks to some very careful driving and gusts of Martian wind clearing off its solar panels which didn’t surprise anybody.

Artist impression of Rosetta and Asteroid 2867 Steins. Credit:  ESA
Artist impression of Rosetta and Asteroid 2867 Steins. Credit: ESA

ESA’s Rosetta spacecraft needed to survive for 10 years in a dormant state before its encounter with Comet 67/P. It’s expected to last until the end of 2015. Then its orbit will carry it too far from the Sun to operate its solar panels, then it’ll go to sleep one last time.

As a testament to luck and remarkable feats of engineering, some survive much longer than anyone ever expected. NASA’s Voyager Spacecraft, launched in 1977, are still going and communicating with Earth. It’s believed they’ll survive until 2025, when their radioisotope thermoelectric generators stop producing power.

At which point they’ll return to the Earth at the heart of a massive alien spacecraft and scare the bejeebus out of us.

… And I know what you’re thinking. Once our spacecraft stop functioning, they’ll still exist. Perhaps getting close enough to another source of solar energy to start transmitting again.

So, how long will our spacecraft hold together in something roughly robot-probe shaped? Any spacecraft orbiting a planet or Moon won’t last long geologically before they’re given a rocky kiss of death with help from a big group hug from gravity.

This might take a decade, a hundred years or a million. Eventually, that spacecraft is racing towards a well distributed grave on its new home.

Solar Dynamics Observatory. Credit: NASA
Solar Dynamics Observatory. Credit: NASA

A spacecraft that’s orbiting the Sun should last much longer. However, a gravitational threesome with a planet or large asteroid could drag it into a solar death spiral or hurl it into a planet. There are asteroids whipping around from the formation of the Solar System, and they haven’t crashed into anything… yet.

A lucky spacecraft might last hundreds of millions, or even billions of years. Our little robot friends that leave the gravitational pull of the Solar System have a chance of making it for the long haul.

Once they’re out in interstellar space, there will be very few micrometeorites to punch little holes in them. Unless they happen to run into another star – and that’s very unlikely – they’ll travel through space until they’re worn away over billions of years, and who knows what that means for future alien archaeology students. The golden records on the Voyager spacecraft were designed to still be playable for a billion years in space.

Artist's concept of NASA's Voyager spacecraft. Image credit: NASA/JPL-Caltech
Artist’s concept of NASA’s Voyager spacecraft. Image credit: NASA/JPL-Caltech

It’s tough to keep a spacecraft operating in space. It’s a really hostile place, ready to fry their little silicon brains, scuttle them with a micrometeorite, or just erode them away over an incomprehensible length of time.

Are horrible space agency fiends tossing our trusting big eyed robot pals to their doom on one-way missions into the abyss? Don’t worry viewers, I have it on good authority this is what the robots want.

Beloved astronaut Chris Hadfield said if Voyager had stayed at home where it’s safe, it would’ve been sad forever, because it never would have discovered things. I think he’s right, Voyager is as happy as it could be exploring the parts of our Universe the rest of us aren’t able to go and see for ourselves.

What’s your favorite spacecraft survivor story? Tell us in the comments below.

Weekly Space Hangout – February 20, 2015 – Charles Black from SEN

Host: Fraser Cain (@fcain)

Guests:
Ramin Skibba (@raminskibba)
Dave Dickinson (@astroguyz / www.astroguyz.com)

Special Guest: Charles Black (@charlesblack / sen.com/charles-black)
Continue reading “Weekly Space Hangout – February 20, 2015 – Charles Black from SEN”

25 Years Since Voyager’s ‘Pale Blue Dot’ Images

A quarter of a century has passed since NASA’s Voyager 1 spacecraft snapped the iconic image of Earth known as the “Pale Blue Dot” that shows all of humanity as merely a tiny point of light.

The outward bound Voyager 1 space probe took the ‘pale blue dot’ image of Earth 25 years ago on Valentine’s Day, on Feb. 14, 1990 when it looked back from its unique perch beyond the orbit of Neptune to capture the first ever “portrait” of the solar system from its outer realms.

Voyager 1 was 4 billion miles from Earth, 40 astronomical units (AU) from the sun and about 32 degrees above the ecliptic at that moment.

The idea for the images came from the world famous astronomer Carl Sagan, who was a member of the Voyager imaging team at the time.

He head the idea of pointing the spacecraft back toward its home for a last look as a way to inspire humanity. And to do so before the imaging system was shut down permanently thereafter to repurpose the computer controlling it, save on energy consumption and extend the probes lifetime, because it was so far away from any celestial objects.

Sagan later published a well known and regarded book in 1994 titled “Pale Blue Dot,” that refers to the image of Earth in Voyagers series.

This narrow-angle color image of the Earth, dubbed "Pale Blue Dot," is a part of the first ever "portrait" of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990.  Credit: NASA/JPL-Caltech
This narrow-angle color image of the Earth, dubbed “Pale Blue Dot,” is a part of the first ever “portrait” of the solar system taken by Voyager 1 on Valentine’s Day on Feb. 14, 1990. Credit: NASA/JPL-Caltech

“Twenty-five years ago, Voyager 1 looked back toward Earth and saw a ‘pale blue dot,’ ” an image that continues to inspire wonderment about the spot we call home,” said Ed Stone, project scientist for the Voyager mission, based at the California Institute of Technology, Pasadena, in a statement.

Six of the Solar System’s nine known planets at the time were imaged, including Venus, Earth, Jupiter, and Saturn, Uranus, Neptune. The other three didn’t make it in. Mercury was too close to the sun, Mars had too little sunlight and little Pluto was too dim.

Voyager snapped a series of images with its wide angle and narrow angle cameras. Altogether 60 images from the wide angle camera were compiled into the first “solar system mosaic.”

Voyager 1 was launched in 1977 from Cape Canaveral Air Force Station in Florida as part of a twin probe series with Voyager 2. They successfully conducted up close flyby observations of the gas giant outer planets including Jupiter, Saturn, Uranus and Neptune in the 1970s and 1980s.

Both probes still operate today as part of the Voyager Interstellar Mission.

“After taking these images in 1990, we began our interstellar mission. We had no idea how long the spacecraft would last,” Stone said.

Hurtling along at a distance of 130 astronomical units from the sun, Voyager 1 is the farthest human-made object from Earth.

Solar System Portrait - 60 Frame Mosaic. The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever "portrait" of our solar system as seen from the outside.   Missing are Mercury, Mars and Pluto Credit:  NASA/JPL-Caltech
Solar System Portrait – 60 Frame Mosaic. The cameras of Voyager 1 on Feb. 14, 1990, pointed back toward the sun and took a series of pictures of the sun and the planets, making the first ever “portrait” of our solar system as seen from the outside. Missing are Mercury, Mars and Pluto. Credit: NASA/JPL-Caltech

Voyager 1 still operates today as the first human made instrument to reach interstellar space and continues to forge new frontiers outwards to the unexplored cosmos where no human or robotic emissary as gone before.

Here’s what Sagan wrote in his “Pale Blue Dot” book:

“That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. … There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.”

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

Astronomy Cast Ep. 362: Modern Women: Carolyn Porco

It hard to think of a more influential modern planetary scientist than Carolyn Porco, the leader of the imaging team for NASA’s Cassini mission exploring Saturn. But before Cassini, Porco was involved in Voyager missions, and she’ll be leading up the imaging team for New Horizons.?

Visit the Astronomy Cast Page to subscribe to the audio podcast!

We record Astronomy Cast as a live Google+ Hangout on Air every Monday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.

Astronomy Cast Ep. 362: Modern Women: Carolyn Porco

It hard to think of a more influential modern planetary scientist than Carolyn Porco, the leader of the imaging team for NASA’s Cassini mission exploring Saturn. But before Cassini, Porco was involved in Voyager missions, and she’ll be leading up the imaging team for New Horizons.

Visit the Astronomy Cast Page to subscribe to the audio podcast!

We record Astronomy Cast as a live Google+ Hangout on Air every Monday at 12:00 pm Pacific / 3:00 pm Eastern. You can watch here on Universe Today or from the Astronomy Cast Google+ page.

Bumper Car Moonlets Crash and Crumble in Saturn’s F Ring

Nothing stands still. Everything evolves. So why shouldn’t Saturn’s kookie, clumpy F ring put on a new face from time to time? 

A recent NASA-funded study compared the F ring’s appearance in six years of observations by the Cassini mission to its appearance during the Saturn flybys of NASA’s Voyager mission, 30 years earlier.

Example of a kink in part of Saturn's F ring. While the ring is held together by the shephard moons Prometheus and Pandora, which orbit just inside and  outside the ring, embedded moonlets are believed responsible for the kinks and clumps. Credit: NASA
A kink in part of Saturn’s F ring. While the ring is held together by the shepherd moons Prometheus and Pandora, which orbit just inside and outside the ring, embedded moonlets are believed responsible for the kinks and clumps. The rings is several hundred kilometers wide. Credit: NASA

While the F ring has always displayed clumps of icy matter, the study team found that the number of bright clumps has nose-dived since the Voyager space probes saw them routinely during their brief flybys 30 years ago. Cassini spied only two of the features during a six-year period.

Scientists have long suspected that moonlets up to 3 miles (5 km) wide hiding in the F ring are responsible for its uneven texture. Kinks and knots appear and disappear within months compared to the years of observation needed changes in many of the other rings.

Saturn's F ring is extremely narrow compared to the historic A, B and C rings. It measure just a few hundred kilometers across. Credit: NASA/Cassini
Saturn’s F ring is extremely narrow compared to the historic A, B and C rings. It measures just a few hundred kilometers across. Credit: NASA/Cassini

“Saturn’s F ring looks fundamentally different from the time of Voyager to the Cassini era,” said Robert French of the SETI Institute in Mountain View, California, who led the study along with SETI Principal Investigator Mark Showalter. “It makes for an irresistible mystery for us to investigate.”

A 2007 artist impression of the aggregates of icy particles that form the 'solid' portions of Saturn's rings. These elongated clumps are continually forming and dispersing. The largest particles are a few metres across.They clump together to form elongated, curved aggregates, continually forming and dispersing. Credit: NASA/JPL/Univ. of Colorado
A 2007 artist impression of small boulder-like chunks of ice that comprise Saturn’s rings. The largest are about 10-12 feet across.They clump together to form elongated, curved aggregates, continually forming and dispersing. Credit: NASA/JPL/Univ. of Colorado

Because the moonlets lie close to the ring and cross through it every orbit, the research team hypothesizes that the clumps are created when they crash into and pulverize smaller ring particles during each pass. They suspect that the decline in the number of exceptionally bright kinks and the clumps echoes a decline in the number of moonlets available to do the job.

So what happened between Voyager and Cassini? Blame it on Prometheus. The F ring circles Saturn at a delicate point called the Roche Limit. Any moons orbiting closer than the limit would be torn apart by Saturn’s gravitational force.

A possible culprit! Prometheus measures 74 miles (119 km) across and orbits the inner edge of Saturn's F ring. Credit: NASA
The culprit? Prometheus measures 74 miles (119 km) across and orbits the inner edge of Saturn’s F ring. Credit: NASA

“Material at this distance from Saturn can’t decide whether it wants to remain as a ring or coalesce to form a moon,” said French.  “Prometheus orbits just inside the F ring, and adds to the pandemonium by stirring up the ring particles, sometimes leading to the creation of moonlets, and sometimes leading to their destruction.”

Every 17 years the orbit of Prometheus aligns with the orbit of the F ring in a way that enhances its gravitational influence. The researchers think the alignment spurs the creation of lots of extra moonlets which then go crashing into the ring, creating bright clumps of material as they smash themselves to bits against other ring material.

Sounds like a terrifying version of carnival bumper cars. In this scenario, the number of moonlets would gradually drop off until another favorable Prometheus alignment.

The Voyagers encounters with Saturn occurred a few years after the 1975 alignment between Prometheus and the F ring, and Cassini was present for the 2009 alignment. Assuming Prometheus has been “working” to build new moons since 2009, we should see the F ring light up once again with bright clumps in the next couple years.

Cassini will be watching.