There’s Something Massive Buried Under the Moon’s Far Side

And it’s likely the massive metallic corpse of an ancient asteroid

This false-color graphic shows the topography of the far side of the Moon. The warmer colors indicate high topography and the bluer colors indicate low topography. The South Pole-Aitken (SPA) basin is shown by the shades of blue. The dashed circle shows the location of the mass anomaly under the basin. [NASA/Goddard Space Flight Center/University of Arizona]

It may be Earth’s only natural satellite and our closest alien world, but the Moon still hides a multitude of mysteries under its surface—including something massive embedded in its far side.

As detailed in a new study published in the journal Geophysical Research Letters, researchers led by Baylor University analyzed data from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission that orbited above the lunar surface for a little under a year in 2012.

The two GRAIL spacecraft flew one in front of the other, precisely measuring the distance of their separation in order to detect very small fluctuations in the Moon’s gravitational field. When the spacecraft passed over a region of higher density, the local gravitational field would become enhanced, slightly accelerating the leading spacecraft (called “Ebb”) before the trailing spacecraft (“Flow”) experienced that acceleration. By mapping these acceleration fluctuations, scientist have gained an invaluable understanding of density fluctuations deep below the Moon’s surface that would have otherwise remained invisible.

During this recent analysis, the researchers discovered a gravitational “anomaly” beneath the South Pole-Aitken basin—a vast depression on the lunar far side spanning 2,000 miles wide and several miles deep. This anomaly represents a huge accumulation of mass hundreds of miles below the basin.

“Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That’s roughly how much unexpected mass we detected,” said Peter B. James, of Baylor University and lead author of the study, in a statement.

How did all that material end up buried inside the Moon’s mantle? The South Pole-Aitken basin was created four billion years ago in the wake of a massive asteroid impact. In fact, the basin is known to be one of the biggest impact craters in the solar system. If this crater was formed by an impact, it stands to reason that the gravitational anomaly is being caused by the dense metallic remains of the massive asteroid that met its demise when the Earth-Moon system was in the throes of formation.

“When we combined [the GRAIL data] with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin,” added James. “One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon’s mantle.”

There may be other explanations, one of which focuses on the formation of the Moon itself. As the lunar interior cooled after formation, the large subsurface mass could be an accumulation of “dense oxides associated with the last stage of lunar magma ocean solidification,” the researchers note.

The metallic corpse of an ancient asteroid is the leading candidate, however, and computer simulations carried out by the team indicated that if the conditions are right, the dense iron-nickel core of an asteroid can be dispersed inside the Moon’s mantle where it remains embedded today without sinking into the lunar core.

Although there were certainly larger asteroid impacts throughout the history of our solar system, the Moon’s South Pole-Aitkin basin is the largest preserved impact crater known, making it a prime candidate to study ancient impact sites

“[It’s] one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today,” said James.

It just so happens that we currently have a mission at the basin, exploring this strange and unexplored place. On Jan. 3, the Chinese Chang’e 3 mission achieved the first soft touchdown on the lunar far side, landing inside Von Kármán crater and releasing a robotic rover, Yutu-2, to explore the landscape. At time of writing, the mission is ongoing.

How Gaia Is Already Shaping Our Interstellar Adventures

The space telescope has refined the stellar flybys of the Voyager and Pioneer probes—how might it help us chart our way to the stars in the future?

The Gaia space telescope [ESA]

When looking up on a starry night, it can be difficult to comprehend that those stars are not fixed in the sky. Sure, on timescales of a human lifetime, or even the entirety of human history, the stars don’t appear to move too much. But look over longer timescales—tens of thousands, to millions of years—and it becomes clear that the stars in the sky are in motion. This means the constellations we see today will be misshapen (or even non-existent!) in a few hundred thousand years’ time.

This poses an interesting question: If humanity were to send a spacecraft on an interstellar mission—an endeavor that could take thousands of years, depending on how ambitious the target—aiming it directly at a distant star would be a mistake. Depending on how far away that star is, by the time the spacecraft reaches its target, the star could have moved a few light-years away. This is why precision astrometry—the astronomical measurement of a star’s position, speed and direction of motion—will be needed to predict where a target star will be, and not where it currently is, when our future interstellar mission gets there.

To test this, we don’t need to wait until humanity has the means to build a starship, however. We have a bunch of interstellar probes that have already started their epic sojourns into the galaxy.

Interstellar Interlopers

Earlier this year, NASA’s Voyager 2 spacecraft departed the Sun’s sphere of influence and became humanity’s second interstellar mission, six years after its twin, Voyager 1, made history to become the first human-made object to drift into the space between the stars. Both Voyagers are still transmitting telemetry to this day, over 40 years since their launch. Another two spacecraft, the older Pioneer 10 and 11 missions, are also on their way to interstellar space, but they stopped transmitting decades ago. A newcomer, NASA’s New Horizons mission, will also become an interstellar mission in the future, but it has yet to finish its Kuiper belt explorations and still has fuel to make course corrections, so predictions of its stellar encounters will remain unknown for some time.

Both Voyager 1 and 2 have left the Sun’s heliosphere to become humanity’s first interstellar missions [NASA]

Having explored the outer planets in the 1970’s and 80’s, the Voyagers and Pioneers barreled on, revealing stunning science from the outer solar system. In the case of Voyager 1 and 2, when each breached the heliopause (the invisible boundary that demarks the limit of the Sun’s magnetic bubble, between the heliosphere and interstellar medium), they gave us a profound opportunity to experience this distant alien environment, using their dwindling number of instruments to measure particle counts and magnetic orientation.

But where are our intrepid interstellar interlopers going now? With the help of precision astrometry of local stars observed by the European Space Agency’s Gaia space telescope, two researchers have taken a peek into the future, seeing which star systems the spacecraft will drift past in the next few hundred thousand to millions of years.

Previously, astronomers have been able to combine the spacecrafts’ trajectory with stellar data to see which stars they will fly past, but in the wake of the Gaia Data Release 2 (GDR2) last year, an unprecedented trove of information has been made available for millions of stars in the local galaxy, providing the most precise “road map” yet of those stars the Voyagers and Pioneers will encounter.

“[Gaia has measured] the positions and space velocities of nearby stars more precisely than before and so has more precisely characterized the encounters with stars we already knew about,” says astronomer Coryn Bailer-Jones, of the Max Planck Institute for Astronomy in Heidelberg, Germany.

[NASA]

Close Encounters of the Voyager Kind

Bailer-Jones and colleague Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., published their study in Research Notes of the American Astronomical Society, adding another layer of understanding about where our spacecraft, and the stars they’ll encounter, are going. Although their work confirms previous estimates of some stellar close encounters, Bailer-Jones tells Astroengine.com that there have been some surprises in their calculations—including encounters that have not been identified before.

For example, the star Gliese 445 (in the constellation of Camelopardalis, close to Polaris) is often quoted as being the closest encounter for Voyager 1, in approximately 40,000 years. But with the help of Gaia, which is giving an extra layer of precision for stars further afield, the researchers found that the spacecraft will come much closer to another star, called TYC 3135-52-1, in 302,700 years.

“Voyager 1 will pass just 0.30 parsecs [nearly one light-year] from that star and thus may penetrate its Oort cloud, if it has one,” he says.

This is interesting. Keep in mind that the Voyager and Pioneer spacecraft include the famous Golden Records and plaques (respectively), revealing the location, form, and culture of a civilization living on a planet called “Earth.” For an alien intelligence to stumble across one of our long-dead spacecraft in the distant future, the closer the stellar encounter the better (after all, the likelihood of stumbling across a tiny spacecraft in the vast interstellar expanse would be infinitesimally small). Passing within one light-year of TYC 3135-52-1 is still quite distant (for instance, we currently have no way of detecting something as dinky as a Voyager-size probe zooming through the solar system’s Oort Cloud), but who knows what the hypothetical aliens in TYC 3135-52-1 are capable of detecting from their home world?

The Pioneer plaque is attached to the spacecrafts’ antenna support struts, behind Pioneer 10 and 11’s dish antennae, shielding the plaques from erosion by interstellar dust [NASA]

Another interesting thought is that these Gaia observations can help astronomers find stars that are currently very far away, but now we know their speed and direction of travel, some of those stars will be in our cosmic backyard in the distant future.

“What our study also found, for the first time, is some stars that are currently quite distant from the Sun will nonetheless come very close to one of the spacecraft within the next few million years,” says Bailer-Jones. “For example, the star Gaia DR2 2091429484365218432 is currently 159.5 parsecs [520 light-years] from the Sun (and thus from Voyager 1), but Voyager 1 will pass within 0.39 parsecs [1.3 light-years] of it in 3.4 million years from now.”

In some cases, given unlimited time, you may not have to go to a star, the star will come to you!

Our Interstellar Future?

While pinpointing the various stellar encounters for our first interstellar probes is interesting, the observations being made by Gaia will be important for when humanity develops the technology to make a dedicated effort to travel to the stars.

“It will be essential to have extremely precise astrometry of any target star,” explains Bailer-Jones. “We must also measure its velocity and its acceleration precisely, because these affect where the star will be when the spacecraft arrives.”

Although this scenario may seem a long way off, any precision astrometry we do now will build our knowledge of the local stellar population and boost the “legacy value” of Gaia’s observations, he adds.

“Once a target star has been selected, we would want to make a dedicated campaign to measure its position and velocity even more precisely, but to determine the accelerations we need data measured at many time points over long periods (at least tens of years), so Gaia data will continue to be invaluable in the future,” Bailer-Jones concludes.

“Even now, astrometry from the previous Hipparcos mission—or even from surveys from decades ago or photometric plates 100 years ago!—are important for this.”

An artist’s impression of the Icarus Interstellar probe, a concept for a fusion-powered, un-crewed starship that may be used to travel to the stars [Icarus Interstellar/Adrian Mann]

Update (May 23): One of the reasons why I focused on the Voyager missions and not the Pioneers is because the latter stopped transmitting a long time ago. Another reason is because we already know Pioneer 10 doesn’t make it very far into interstellar space:

For more on how Gaia observations are being used, see my previous interview with Coryn on how these data were used to find the possible origins of ‘Oumuamua, the interstellar comet.

Ten Years Later: The Cosmos Remembers Brian the Bat

Gather ’round the campfire kids, it’s time to tell the sad story of a brave bat named Brian.

On March 15, 2009, we watched in terror as Brian, a Florida free-tailed bat, stubbornly remained attached to Space Shuttle Discovery’s external fuel tank moments before launch (left). On Thursday, ten years later, the European Southern Observatory released a stunning photo feature of the Bat Nebula (right). A coincidence? I think not. [NASA/ESO]

On March 15, 2009, Twitter was days away from its third birthday, Ashton Kutcher was one month away from becoming the first tweep to reach one million followers, and a community of space enthusiasts habitually live-tweeted the final space shuttle launches from the comfort of their homes. They were simpler times.

Wikipedia recognizes Brian’s sacrifice.

One launch, however, became infamous — nay, historic — not for the fact it was one of the last handful of launches of NASA’s shuttle program, but because there was a tiny stowaway attached to the shuttle’s bulbous orange external fuel tank minutes before ignition.

That stowaway was an ill-fated bat named “Brian.” And “he” became a legend overnight.

A Legend Is Born

During the countdown to the launch of STS-119, as we watched in anticipation of the successful start of Space Shuttle Discovery’s International Space Station (ISS) servicing mission, something seemed amiss at Discovery’s launch pad. At the time, the assumption was that a fruit bat (a common species in Florida) had mistakenly thought the orange external fuel tank of the shuttle was a tree to latch itself onto. Follow-up investigations identified the bat as a free-tailed bat and, though its intentions were unclear, zoologists posited that the unfortunate critter may have broken its wing. This would explain why it didn’t fly away when the shuttle’s boosters ignited, carrying the bat to the heavens — literally and metaphorically.

No one really knows how long the bat held on for, but some creative-thinkers hypothesized that the bat remained attached for the duration, making it into space. I don’t think I have to explain why this didn’t happen — it was more likely booted from the fuel tank in the first seconds of launch enduring a fiery death via rocket booster exhaust — but it was a poetic thought. Regardless of the bat’s fate, it’s ultimate sacrifice made this routine launch special. What was “just another” live-tweeted shuttle launch, became a spectacle that rapidly evolved into an international news story. That bat was special.

And that bat’s name was Brian.

Why “Brian”? A bit of background: For some personal reason that I cannot fathom, I like to name things “Brian.” I’ve always done it. The squirrel that lives in my backyard? Brian. An interesting and unnamed rock on the surface of Mars? Brian. My first car? Brian. That gopher that demolished my newly-planted garden of impatiens in 2011? Brian. A random free-tailed bat hanging off the shuttle’s external fuel tank? Brian. There’s no reason and no logic behind this, Brian just seems to fit. It’s a personal mystery.

So, when lightheartedly tweeting about the bat on March 15, 2009, I called the bat Brian and the name stuck. I had no idea about its gender, and it didn’t have a nametag, but that bat was a Brian alright. Suddenly, other space enthusiasts following the launch called him Brian and, for reasons I have yet to understand ten years later, in those minutes before launch, “Brian the Bat” went viral and suddenly everyone was personally invested in that “routine” space launch. Yes, there were billions of dollars of hardware on that launchpad with seven brave astronauts on board, but everyone was talking about Brian who was shivering on the side of the vehicle, a place that no living creature should have been.

Was Brian confused? Was he frozen to the cold tank? Would he fly away in the nick of time? No one knew, but the clock was ticking and the commentator on the NASA live video stream seemed confident that, as the boosters began their ignition sequence, the bat would be scared by the vibrations and fly to safety.

For reasons known only to Brian, he remained attached. And as the boosters roared to life, he held tight. As the plume of smoke and steam enveloped Kennedy Space Center Launch Complex 39, I sat with the computer screen nearly pressed to my nose, seeking out the dark pixels of Brian in the place where he was last seen. But the resolution was too low and Brian’s fate was unknown. (Days later, NASA analysts reviewed infrared imagery from the launch, revealing two very sad facts. 1) Brian was warm while attached to the fuel tank, so he hadn’t frozen to death and was alive up to launch, and 2) he remained in place when Discovery lifted off.)

As the adrenaline ebbed and Space Shuttle Discovery soared into the atmosphere, solid rocket boosters separating and tumbling back to Earth, the sad reality crept in. Brian was, in all likelihood, toast.

But his legacy would live on.

Assuming that little space-launch chapter was over, I wrote a summary about Brian’s adventures for Universe Today and on Astroengine with the assumption that Brian would be soon lost to the annals of shuttle-era history. Little did I know, however, that Norwegian journalist Geir Barstein was paying close attention…

Brian makes waves in the Norwegian press on March 16, 2009. Read the full article here. [Dagbladet]

Then, a couple of days later, the new spread to the UK tabloid press


Brian landed as a science headline in the Mail Online on March 19, 2009. Read the full article here. [Mail Online]

Brian also made appearances in The Sun newspaper (but the article has since disappeared) and other smaller publications, and I participated in a number of radio shows devoted to that now-famous shuttle launch.

Not only was the whole event a poignant one, it also made me realize something about the power of social media. In all my years covering space stories, particularly when I was a producer at Discovery News (now called “Seeker”), shuttle launches would receive very little attention. Apart from a few outliers, such as the final shuttle launch, the articles I’d publish about one of NASA’s most significant programs would receive very little readership. The routine nature of these launches meant that, unless you were at Cape Canaveral, interest in seeing shuttles launch into space was lukewarm at best. As a space enthusiast, I was frustrated. Every launch in my eyes was special and certainly not “routine.”

Brian, however, made me realize by accident that you have to seek out the unique thing about that one launch that will hook readers to that story. Granted, not all launches have a “Brian the Bat” moment, but that doesn’t mean they’re not special.

Remember the Lunar Atmosphere and Dust Environment Explorer (LADEE) launch? Thought not. But do you remember Frank the Frog? Probably:

NASA’s LADEE launch also had a “Brian the Bat” moment in 2013. Read more about it in my Discovery News analysis. [NASA]

Eerie Timing, ESO

Not only is it the TEN YEAR anniversary tomorrow (Friday) of when Brian met his maker, today the European Southern Observatory (ESO) released this stunning observation of the Bat Nebula, a reflection nebula that contains baby stars being birthed in a stellar nursery. Yes, I know, eerie, right?

Text from ESO: “Hidden in one of the darkest corners of the Orion constellation, this Cosmic Bat is spreading its hazy wings through interstellar space two thousand light-years away. It is illuminated by the young stars nestled in its core — despite being shrouded by opaque clouds of dust, their bright rays still illuminate the nebula. Too dim to be discerned by the naked eye, NGC 1788 reveals its soft colors to ESO’s Very Large Telescope in this image — the most detailed to date.” [ESO]

I like to think that the cosmos is doing Brian a solid by commemorating that brave little bat’s ultimate sacrifice.

The event may have been a footnote in humanity’s quest to explore our universe, but I truly believe that the viral social media (and then mainstream media) attention Brian whipped up created a buzz around a launch that may not have otherwise made an impact.

As a science communicator, I’m always on the lookout for interesting hooks to stories that wouldn’t otherwise be of interest, and on March 15, 2009, Brian was that hook — who knows what kind of impact that little free-tailed bat had on viewers who wouldn’t have otherwise been paying attention to one of the biggest endeavors in human exploration history.

So, tomorrow, on March 15, 2019, raise a drink to Brian’s legacy. He will live on in the spirit he inspired when he left our planet attached to the space shuttle’s external fuel tank.

Humanity Gains Another Foothold in Space

The private spaceflight company SpaceX has done it again, and this latest achievement is an important one.

Crew Dragon berthed with the space station at 2:51 a.m. PT [NASA]

We space writers are very familiar with Elon Musk’s human spaceflight dreams that can be encapsulated in his well-known goal to “make humanity multi-planetary,” starting with a Mars settlement. And today, that goal took another step closer to reality.

I’ve been following Musk’s rocket adventures ever since his early days of exploding single-engine rockets in the South Pacific. Back then, Musk was a “dreamer” and more than a little eccentric. His eccentricities are well documented, but the world’s best known billionaire-entrepreneur is a dreamer no more. The first successful flight of a Falcon 1 happened on Sept. 28, 2008. (You can read my 2008 Space Lifestyle Magazine article on that topic, page 36) A little over a decade later, the Falcon 1 has rapidly evolved into the reusable Falcon 9 workhorse and the Falcon Heavy and, with key partnerships with NASA and companies that need to get stuff into orbit cheaply, SpaceX has developed the human-rated Dragon spacecraft to ultimately get astronauts to the space station, and beyond.

After proving itself in the cargo-delivery arena, the Dragon has now won its human-spaceflight wings: an (uncrewed) Crew Dragon is now attached to the International Space Station’s Harmony module and the outpost’s astronauts have entered the vehicle.

Building a commercially-viable space infrastructure is paramount if humanity is to truly become multi-planetary, and through partnerships between private business and government contracts, today’s achievement is proof that this model can work.

Too often, governments lack the long-term vision for human space exploration, instead plowing money into bloated, politically motivated, and ultimately doomed federally-funded projects. SpaceX may be an exhausting company to work for, but its ultimate mission is crystal clear. It’s not a satellite-launching company, it’s just doing that to build funds to do the Next Big Thing. Dragon’s autonomous berthing with the space station is That Big Thing that will drive more investment into getting stuff beyond Earth orbit.

Musk’s interim target — before getting humans to Mars — is the moon, to create a permanently-crewed lunar base. How that will shape up remains to be seen, but if there’s one thing I’ve learnt from following his dreams of getting into space on a reusable spaceflight infrastructure, it’s don’t bet against SpaceX and Elon Musk’s “eccentricities.”

InSight Mars Lander Gets Used to Its New Digs, Snaps a Selfie

The NASA mission looks like it’s getting comfortable in Elysium Planitia.

The view from InSight’s Instrument Deployment Camera (IDC), which is attached to the lander’s robotic arm, looking over the flat and rock-strewn plane of Elysium Planetia, on sol 14 of its mission. The lens flare is caused by the Sun that is just out of shot [NASA/JPL-Caltech]

Like any self-respecting social media influencer, Mars’s latest resident is hard at work snapping photos of its new digs. The robot has even thrown in a beautiful selfie for good measure.

NASA’s InSight lander touched down on the Red Planet on Nov. 26 and since then its mission controllers have been hard at work checking out the instrumentation and surroundings. Using its Instrument Deployment Camera, or IDC, InSight has been giving us a tour of its permanent home. Fans on social media have even been nominating names for the rocks that can be seen embedded in the dusty regolith — the only rocks we’ll see close up for the duration of the mission. 

Dusty with a dash of small rocks, perfect ground for InSight’s work [NASA/JPL-Caltech]

Very early on, NASA scientists knew they’d landed in the right place. The beautifully-flat plain of Elysium Planitia has a landscape that is in stark contrast to Curiosity’s Mount Sharp environment; instead of seeing a smorgasbord of geological features — created by ancient water action and ongoing aeolian (wind-blown) processes — Elysium is flat, dusty and appears to only have small-ish rocks strewn over its surface. You see, InSight cares little for what’s on the surface; the science it’s after lies below the stationary lander, all the way to the planet’s core.

“The near-absence of rocks, hills and holes means it’ll be extremely safe for our instruments,” said InSight’s Principal Investigator Bruce Banerdt of NASA’s Jet Propulsion Laboratory in Pasadena, Calif., in a statement. “This might seem like a pretty plain piece of ground if it weren’t on Mars, but we’re glad to see that.”

One of InSight’s three legs can be seen here slightly sunken into the Martian regolith, showing us how soft and powdery the uppermost layers of the mission’s landing zone is. Oh, and that rock to the right? Luckily InSight missed it [NASA/JPL-Caltech]

Now that InSight’s raw image archive is churning out new pictures daily, mission scientists are scoping out its “work space” directly in front of the lander’s robotic arm. Over the coming weeks, optimal positions for InSight’s two main experiments — the Seismic Experiment for Interior Structure (SEIS) and Heat Flow and Physical Properties Package (HP3) —will be decided on and then commands will be sent to the lander to begin the painstaking task of retrieving them from its deck and setting them down on the ground. The main task will be to determine exact locations that are smooth, flat and contain small rocks that are no bigger than half an inch. This will ensure stable contact with the ground so seismic and heat flow measurements can be continuously carried out. InSight is basically going to give Mars an internal examination 24/7, listening to the slightest seismic waves like a doctor would listen to your heartbeat. And it looks like InSight has landed inside a depression, likely created by an ancient crater that has been filled with loose material over time — this is great news for HP3 that has a self-digging probe (called the “mole”) that will now have an easier task of burrowing meters underground.

But what about that selfie? Well, here you go:

InSight says hi! [NASA/JPL-Caltech]

This photo is a mosaic composed of 11 different images snapped by the lander’s robotic arm-mounted camera. You can see the lander’s open solar panels and stowed instrumentation on the deck, including SEIS and HP3. And no, the selfie isn’t a fake; by sticking a bunch of individual photos together, they’ve overlapped to edit out any trace of the arm itself. Curiosity does the same thing; so did Opportunity and Spirit. InSight’s older sibling, Phoenix also did it. Selfies are as much the rage on Mars as they are on Earth. Not only do they look cool, they are also useful for mission controllers to monitor the build-up of dust on solar panels, for example.

For now, as we await the science to start flowing in (well, there’s been some early science before the robot has even gotten started), enjoy checking back on InSight’s raw photos, it won’t be long until we’ll be browsing through potentially thousands of snaps from Elysium Planitia. Oh, and don’t forget about Curiosity that’s still going strong on the slopes of Mount Sharp!

Voyager 2 Has Left the (Interplanetary) Building

The NASA probe was launched in 1977 and has now joined its twin, Voyager 1, to begin a new chapter of interstellar discovery

Both Voyager 1 and 2 are sampling particles from the interstellar medium, becoming humanity’s furthest-flung missions into deep space [NASA/JPL-Caltech]

Carolyn Porco, planetary scientist and lead of the NASA Cassini mission imaging team, probably said it best:

Voyager 1 made us an interstellar species; 6 yrs later, Voyager 2 makes it look easy. While these are historic, soul-stirring achievements, I am most happy right now that Ed Stone, the best Project Scientist who ever lived, lived to see this moment. 

via Twitter

It can be easy to lump today’s announcement about Voyager 2 entering interstellar space as “simply” another magnificent science achievement for NASA — but that would be too narrow; the Voyager spacecraft have become so much more. They represent humanity at our best; our will to explore, our need to push boundaries, our excitement for expanding the human experience far beyond terrestrial shores. They also act as a means to understand the sheer scale of our solar system. And what better way to measure that scale than with a human life. 

Ed Stone started working on the Voyager Program in 1972 as a project scientist. Now, at 82 years old, he’s still working on the Voyagers nearly half a century later as they continue to send back data from the frontier beyond our solar system. When we start measuring space missions in half-centuries, or missions that have lasted entire careers, it becomes clear how far we’ve come. Not only does NASA build really tough space robots that surpass expectations routinely, returning new discoveries and revelations about the universe that surrounds us, the Voyagers have become a monument to the essence of being human, something with which Stone would probably agree.

Although most of the instruments aboard the Voyagers are no longer functional, both missions are still returning data from the shores of the interstellar ocean and, on Nov. 5, mission controllers noticed that one of Voyager 2’s instruments, the Plasma Science Experiment (PSE), had detected a rapid change in its surrounding environment. Used to being immersed the comparatively warm and tenuous solar wind flowing past it, its plasma measurements detected a change. The spacecraft had passed into a region of space where the plasma was now denser and cooler. Three other particle experiments also detected a dramatic change; solar wind particle counts were down, but cosmic ray counts precipitously increased. Voyager 1’s PSE failed in 1980, so couldn’t measure this boundary when it entered interstellar space in 2012, so Voyager 2 is adding more detail about what we can expect happens when a spacecraft travels from the heliosphere, through the heliopause and into interstellar space. 

[NASA/JPL-Caltech]

“There is still a lot to learn about the region of interstellar space immediately beyond the heliopause,” said Stone in a NASA statement.

The heliosphere can be imagined as a vast magnetized bubble that is generated by the Sun. This bubble is inflated by the solar wind, a persistent stream of solar particles that ebb and flow with the Sun’s 11-year cycle. When the Sun is at its most active, the bubble expands; at its least active, it contracts. This dynamic solar sphere of influence affects the flux of high-energy cosmic rays entering the inner solar system, but the physics at this enigmatic boundary is poorly understood. With the help of the Voyagers, however, we’re getting an in-situ feel for the plasma environment at the boundary of where the Sun’s magnetism hits the interstellar medium.

To achieve this, however, we had to rely on two spacecraft that were launched before I was born, in 1977. Voyager 2 is now 11 billion miles away (Voyager 1 is further away, at nearly 14 billion miles) and it took the probe 41 years just to reach our interstellar doorstep. Neither Voyagers have “left” the solar system, not by a long shot. The gravitational boundary of the solar system is thought to lie some 100,000 AU (astronomical units, where one AU is the average distance from the Earth to the Sun), the outermost limit to the Oort Cloud — a region surrounding the solar system that contains countless billions of icy objects, some of which become the long-period comets that intermittently careen through the inner solar system. Voyager 2 is barely 120 AU from Earth, so as you can see, it has a long way to go (probably another 30,000 years) before it really leaves the solar system — despite what the BBC tells us.

So, tonight, as we ponder our existence on this tiny pale blue dot, look up and think of the two space robot pioneers that are still returning valuable data despite being in deep space for over four decades. I hope their legacy lives on well beyond the life of their radioactive generators, and that the next interstellar spacecraft (no pressure, New Horizons) lives as long, if not longer, than the Voyagers.

Read more about today’s news in my article for HowStuffWorks.com.

  

Meanwhile, Curiosity Has Found Something Shiny On Mars

My precious…


This image was taken by Curiosity’s ChemCam: Remote Micro-Imager (CHEMCAM_RMI) on Sol 2242 (Nov. 26) [NASA/JPL-Caltech/LANL]

It’s always fun to browse through the raw image archive for any Mars mission. You see rocks, dust, more rocks and more dust, but then you see something strange, sitting atop the dirt that is like nothing you’ve seen before.

Once, there was a piece of plastic on the ground in front of Curiosity. Plastic! Not alien plastic though, it was likely something that fell off the rover. Mars rover Opportunity even found strange “blueberries” scattered over Meridiani Planum that turned out to be spherical hematite inclusions, basically little balls of mineral that were formed via water action in Mars’ ancient past.

Now there’s a shiny rock just sitting there, in front of Curiosity. 

Mars isn’t known for its shiny objects. Everything is a ruddy color (because of the iron-oxide-laced dust that covers everything) and dull. So, when mission controllers saw this small shiny object, it became a focus of interest. They’ve even named it “Little Colonsay.” Don’t get too excited for an explanation that’s too outlandish, but it will be an interesting find if it turns out to be what scientists think it is.

“The planning team thinks it might be a meteorite because it is so shiny,” writes Susanne Schwenzer, Curiosity mission team member.

Meteorites have been discovered on Mars before by the Mars rovers — and Curiosity is no stranger to finding space rocks strewn on the ground — though it would still be a rare find by Curiosity if it does turn out to be a (likely) metallic chunk of space rock. As pointed out by Schwenzer, the team intend to carry out further analysis of the sample, as well as some other interesting rocks, with Curiosity’s ChemCam instrument to decipher what it’s made of.

So as we welcome the InSight mission to the Red Planet to begin its unprecedented study of Mars’ interior, always remember there’s still plenty of gems sitting on the surface waiting to be found.

We Have a New Robot Heartbeat On Mars

After following InSight’s journey and dramatic landing on Mars, I’m now emotionally attached to the space robot.

The view from InSight’s Instrument Deployment Camera (IDC) that is attached to its robotic arm [NASA/JPL-Caltech]

It’s funny how our perception of the robots we send into space changes with the experiences we have with them. Take NASA’s InSight lander, for example.

I was thrilled to be able to see the mission launch on May 5 from my backyard. I was following the launch feed from my office in the early hours of the morning — lift-off was just after 4 a.m., so I was particularly proud that I hadn’t fallen asleep in my home office. Going outside, I looked to the northwest in hopes of glimpsing the light of the Atlas V-401 rocket as it rose into the dark pre-dawn skies. After I’d seen confirmation via the live-stream video of launch from Vandenburg Air Force Base (130 miles to the northwest of my home in Woodland Hills), I stood precariously on a patio chair to get a better view over my roof and… there it was! A bright plume rising and moving very fast toward the south. And then it was gone; the first ever mission to Mars launched from California was on its way into interplanetary space.

Needless to say, I quickly became invested in this space robot, but before I witnessed its launch from afar, it was another anonymous piece of cold space hardware. As soon as I saw its rocket plume, the mission became “real” and InSight was warmly embedded in my emotions.

NASA likes to play up the dangers of sending missions to Mars — and I can’t blame them; more Mars missions have failed than have succeeded. But in recent years, NASA has beaten the odds and landed all of their surface missions and inserted a bunch of satellites into orbit successfully. The last failed NASA mission to Mars was nearly 20 years ago (the Mars Polar Lander in 1999), everything else since — Mars Odyssey, the two Mars Exploration Rovers, Mars Reconnaissance Orbiter, Phoenix lander (InSight’s twin), Curiosity, MAVEN — have all been resounding successes. 

JPL’s “lucky peanuts” at mission control obviously paid off.

Then, on Monday (Nov. 26), after nearly seven months since I saw it fly over my roof, InSight landed on the dusty surface of Mars. 

I was fortunate to be at NASA’s Jet Propulsion Laboratory (JPL) on that day, covering the event for Scientific American and HowStuffWorks, and it was a thrill to be in the hub of all the festivities and spend time with my fellow science communicators. JPL always puts together a great event — whether that be the landing of Curiosity over six years ago, or the sad farewell of Cassini last year — and this was no different. The air was thick with anticipation, and all of the mission scientists, managers and engineers were more than willing to share their stories with the dozens of journalists, reporters, social media peeps and TV crews who were in attendance.

Then it was time for landing. 

Sending a mission to Mars is risky and, as already pointed out, in the earlier days of humanity throwing stuff at Mars the majority of the missions failed. So, understandably, everyone had a healthy level of nervousness that there was always a chance that InSight might just make another (expensive) crater in the Martian dirt. But that wasn’t to be. And by all accounts, the landing couldn’t have gone better.

InSight and MarCO mission controllers celebrate the landing with NASA Administrator
Jim Bridenstine (far left) at NASA JPL 

The two Mars Cube One (MarCO) spacecraft that were flying with InSight during its time cruising from Earth became the undisputed silicon heroes of the day. Their purpose was to relay telemetry data from InSight as the lander slammed into the Martian atmosphere to commence its hair-raising entry, descent and landing (EDL) on Mars — a.k.a. the Seven Minutes or Six and a Half Minutes Of Terror, depending on who you talk to. As InSight would be landing in a region where there wouldn’t be a satellite overpass for several hours after landing, MarCO became the relay that, in real time (minus the several minute lag-time that it takes for any signal to travel at the speed of light between Mars and Earth) prevented too many chewed fingernails and passed the message to mission control that the lander had landed safely and everything was, well, just perfect.

In the media area, with a live feed streaming from just next door on the JPL campus, any nervousness evaporated when we all cheered with the mission controllers who were celebrating on the screen. Memories of Curiosity’s landing came flooding back. NASA has done it again, we’re on Mars!

And then, despite warnings that it might be some time before we see the first view of Elysium Planitia from InSight’s camera, we became aware that the mood had changed in mission control. Managers were now huddled around a computer terminal. They were receiving the first image only a few minutes after touch down!

The first image from NASA’s Mars InSight mission was a dusty one — the black specks are dusty debris kicked up from the surface during landing. When NASA pops the lens cover, the fish-eye lens will have a clear view of its new, permanent home [NASA/JPL-Caltech]

Keep in mind that relaying this image would have been impossible without InSight’s MarCO travel buddies. The success of the mission didn’t depend on MarCO, but they sure made the landing event a more lively celebration, rather than a “yes we’re on Mars, but no pictures until tomorrow!” anticlimax. I asked a couple of the MarCO managers what was next for their robotic heroes, and they said that their mission was complete and that they were a proof of concept “that was now proven.” Apparently, managers for other robotic space missions are planning MarCO-like payloads for future missions. Justifiably so.

Monday was a blur, but I remember walking away from JPL feeling emotional and humbled. Humanity is capable of doing incredible, bold things, I thought to myself. Why can’t we be more like this? Discussing the nature of humanity and our contradictory ways can be saved for another day, however. 

Now that we’ve lived InSight’s dramatic journey to Mars, the lander has become more than a robot, it’s a bona fide Mars explorer that, like Curiosity and all the landers and rovers that have come before it, is an extension of the human experience. Designed to live in the Martian environment, InSight has arrived home. Hopes are high for some incredible scientific discoveries about Mars’ interior and its evolution, but I’m also hopeful that the mission will inspire people to embrace our natural urge to explore and discover new things about our universe. This time exploration will be done through the eyes of the newest space robot to join its Martian family, but some time in the next couple of decades, it will be human eyes exploring Elysium Planitia.

For more about the science behind InSight, read my articles for Scientific American and HowStuffWorks.com:

Water Could Kill Life On Mars

A view from the Viking 1 deck, showing trenches its robotic arm dug out to acquire samples for testing [NASA/JPL-Caltech/Roel van der Hoorn]

When rains came to one of the driest places on Earth, an unprecedented mass extinction ensued.

The assumption was that this rainfall would turn this remote region of the Atacama Desert in Chile into a wondrous, floral haven — dormant seeds hidden in the parched landscape would suddenly awake, triggered by the “life-giving” substance they hadn’t seen for centuries — but it instead decimated over three quarters of the native bacterial life, microbes that shun water in favor of the nitrogen-rich compounds the region has locked in its dry soil.

In other words, death fell from the skies.

“We were hoping for majestic blooms and deserts springing to life. Instead, we learned the contrary, as we found that rain in the hyperarid core of the Atacama Desert caused a massive extinction of most of the indigenous microbial species there,” said astrobiologist Alberto Fairen, who works at Cornell Cornell University and the Centro de Astrobiología, Madrid. Fairien is co-author of a new study published in Nature’s Scientific Reports.

“The hyperdry soils before the rains were inhabited by up to 16 different, ancient microbe species. After it rained, there were only two to four microbe species found in the lagoons,” he added in a statement. “The extinction event was massive.”

El Valle de la Luna (Valley of the Moon) near San Pedro de Atacama looks very Mars-like [photo taken during #MeetESO in 2016, Ian O’Neill]

Climate models suggest that these rains shouldn’t hit the core regions of Atacama more than once every century, though there is little evidence of rainfall for at least 500 years. Because of the changing climate over the Pacific Ocean, however, modern weather patterns have shifted, causing the weird rain events of March 25 and Aug. 9, 2015. It also rained more recently, on June 7, 2017. Besides being yet another reminder about how climate change impacts some of the most delicate ecosystems on our planet, this new research could have some surprise implications for our search for life on Mars.

Over forty years ago, NASA carried out a profound experiment on the Martian surface: the Viking 1 and 2 landers had instruments on board that would explicitly search for life. After scooping Mars regolith samples into their chemical labs and adding a nutrient-rich water mix, one test detected a sudden release of carbon dioxide laced with carbon-14, a radioisotope that was added to the mix. This result alone pointed to signs that Martian microbes in the regolith could be metabolizing the mixture, belching out the CO2.

Alas, the result couldn’t be replicated and other tests threw negative results for biological activity. Scientists have suggested that this false positive was caused by inorganic reactions, especially as, in 2008, NASA’s Phoenix Mars lander discovered toxic and highly reactive perchlorates is likely common all over Mars. Since Viking, no other mission has attempted a direct search for life on Mars and the missions since have focused on seeking out water and past habitable environments rather than directly testing for Mars germs living on modern Mars.

With this in mind, the new Atacama microbe study could shed some light on the Viking tests. Though the out-gassing result was likely a false positive, even if all the samples collected by the two landers contained microscopic Martians, the addition of the liquid mix may well have sterilized the samples — the sudden addition of a large quantity of water is no friend to microbial life that has adapted to such an arid environment.

“Our results show for the first time that providing suddenly large amounts of water to microorganisms — exquisitely adapted to extract meager and elusive moisture from the most hyperdry environments — will kill them from osmotic shock,” said Fairen.

Another interesting twist to this research is that NASA’s Mars rover Curiosity discovered nitrate-rich deposits in the ancient lakebed in Gale Crater. These deposits might provide sustenance to Mars bacteria (and may be a byproduct of their metabolic activity), like their interplanetary alien cousins in Atacama.

As water-loving organisms, humans have traditionally assumed life elsewhere will bare similar traits to life as we know it. But as this study shows, some life on Earth can appear quite alien; the mass extinction event in the high deserts of Chile could teach us about how to (and how not to) seek out microbes on other planets.

Source: Cornell University

Hitching a Ride on an ‘Evolving Asteroid’ to Travel to the Stars

evolvingaste
The interstellar asteroid spaceship concept that would contain all the resources required to maintain a generations of star travelers (Nils Faber & Angelo Vermeulen)

When ʻOumuamua visited our solar system last year, the world’s collective interest (and imagination) was firing on all cylinders. Despite astronomers’ insistence that asteroids from other star systems likely zip through the solar system all the time (and the reason why we spotted this one is because our survey telescopes are getting better), there was that nagging sci-fi possibility that ʻOumuamua wasn’t a natural event; perhaps it was an interstellar spaceship piloted by (or at least once piloted by) some kind of extraterrestrial — “Rendezvous With Rama“-esque — intelligence. Alas, any evidence for this possibility has not been forthcoming despite the multifaceted observation campaigns that followed the interstellar vagabond’s dazzling discovery.

Still, I ponder that interstellar visitor. It’s not that I think it’s piloted by aliens, though that would be awesome, I’m more interested in the possibilities such objects could provide humanity in the future. But let’s put ʻOumuamua to one side for now and discuss a pretty nifty project that’s currently in the works and how I think it could make use of asteroids from other stars.

Asteroid Starships Ahoy!

As recently announced by the European Space Agency, researchers at Delft University of Technology, Netherlands, are designing a starship. But this isn’t your run-of-the-mill solar sail or “warpship.” The TU Delft Starship Team, or DSTART, aims to bring together many science disciplines to begin the ground-work for constructing an interstellar vehicle hollowed out of an asteroid.

Obviously, this is a long-term goal; humanity is currently having a hard enough time becoming a multiplanetary species, let alone a multistellar species. But from projects like these, new technologies may be developed to solve big problems and those technologies may have novel applications for society today. Central to ESA’s role in the project is an exciting regenerative life-support technology that is inspired by nature, a technology that could reap huge benefits not only for our future hypothetical interstellar space fliers.

Called the MELiSSA (Micro-Ecological Life Support System Alternative) program, scientists are developing a system that mimics aquatic ecosystems on Earth. A MELiSSA pilot plant in Barcelona is capable of keeping rat “crews” alive for months at a time inside an airtight habitat. Inside the habitat is a multi-compartment loop with a “bioreactor” at its core, which consists of algae that produces oxygen (useful for keeping the rats breathing) while scrubbing the air of carbon dioxide (which the rats exhale). The bioreactor was recently tested aboard the International Space Station, demonstrating that the system could be applied to a microgravity environment.

Disclaimer: Space Is Really Big

Assuming that humanity isn’t going to discover faster-than-light (FTL) travel any time soon, we’re pretty much stuck with very pedestrian sub-light-speed travel times to the nearest stars. Even if we assume some sensible iterative developments in propulsion technologies, the most optimistic projections in travel time to the stars is many decades to several centuries. While this is a drag for our biological selves, other research groups have shown that robotic (un-crewed) missions could be done now — after all, Voyager 1 is currently chalking up some mileage in interstellar space and that spacecraft was launched in the 1970’s! But here’s the kicker: Voyager 1 is slow (even if it’s the fastest and only interstellar vehicle humanity has built to date). If Voyager 1 was aimed at our closest star Proxima Centauri (which it’s not), it would take tens of thousands of years to get there.

But say if we could send a faster probe into interstellar space? Projects like Icarus Interstellar and Breakthrough Starshot are approaching this challenge with different solutions, using technology we have today (or technologies that will likely be available pretty soon) to get that travel time down to less than one hundred years.

One… hundred… years.

Sending robots to other stars is hard and it would take generations of scientists to see an interstellar mission through from launch to arrival — which is an interesting situation to ponder. But add human travelers to the mix? The problems just multiplied.

The idea of “worldships” (or generation ships) have been around for many years; basically vast self-sustaining spaceships that allow their passengers to live out their lives and pass on their knowledge (and mission) to the next generation. These ships would have to be massive and contain everything that each generation needs. It’s hard to comprehend what that starship would look like, though DSTART’s concept of hollowing out an asteroid to convert it into an interstellar vehicle doesn’t sound so outlandish. To hollow out an asteroid and bootstrap a self-sustaining society inside, however, is a headache. Granted, DSTART isn’t saying that they are actually going to build this thing (their project website even states: “DSTART is not developing hardware, nor is it building an actual spacecraft”), but they do assume some magic is going to have to happen before it’s even a remote possibility — such as transformative developments in nanotechnology, for example. The life-support system, however, would need to be inspired by nature, so ESA and DSTART scientists are going to continue to help develop this technology for self-sustaining, long-duration missions, though not necessarily for a massive interstellar spaceship.

Hyperbolic Space Rocks, Batman!

Though interesting, my reservation about the whole thing is simple: even if we did build an asteroid spaceship, how the heck would we accelerate the thing? This asteroid would have to be big and probably picked out of the asteroid belt. The energy required to move it would be extreme; to propel it clear of the sun’s gravity (potentially via a series of gravitational assists of other planets) could rip it apart.

So, back to ʻOumuamua.

The reason why astronomers knew ʻOumuamua wasn’t from ’round these parts was that it was moving really, really fast and on a hyperbolic trajectory. It basically barreled into our inner star system, swung off our sun’s gravitational field and slingshotted itself back toward the interstellar abyss. So, could these interstellar asteroids, which astronomers estimate are not uncommon occurrences, be used in the future as vehicles to escape our sun’s gravitational domain?

Assuming a little more science fiction magic, we could have extremely advanced survey telescopes tasked with finding and characterizing hyperbolic asteroids that could spot them coming with years of notice. Then, we could send our wannabe interstellar explorers via rendezvous spacecraft capable of accelerating to great speeds to these asteroids with all the technology they’d need to land on and convert the asteroid into an interstellar spaceship. The momentum that these asteroids would have, because they’re not gravitationally bound to the sun, could be used as the oomph to achieve escape velocity and, once setting up home on the rock, propulsion equipment would be constructed to further accelerate and, perhaps, steer it to a distant target.

If anything, it’s a fun idea for a sci-fi story.

I get really excited about projects like DSTART; they push the limits of human ingenuity and force us to find answers to seemingly insurmountable challenges. Inevitably, these answers can fuel new ideas and inspire younger generations to be bolder and braver. And when these projects start partnering with space agencies to develop existing tech, who knows where they will lead.