Original image
An artist's rendering of the Europa mission's spacecraft. Main Image: NASA/JPL-Caltech Banner Image: NASA/JPL-Caltech

How Will the Europa Lander Search for Life?

Original image
An artist's rendering of the Europa mission's spacecraft. Main Image: NASA/JPL-Caltech Banner Image: NASA/JPL-Caltech

Water, chemistry, energy: three key components for life. We only have confirmation of life on Earth so far, but we're always looking elsewhere. One of the biggest targets in the solar system is Europa, one of Jupiter's moons. We're aiming for that target with the Europa lander, which will launch for the Jovian moon around 2024. The mission will be the first on-site search for evidence of life on another world since Viking 1 and Viking 2 landed on Mars in 1976.

Last month, the team behind the Europa Lander released the mission’s scientific objectives [PDF], and at the recent 48th Lunar and Planetary Science Conference in The Woodlands, Texas, scientists answered questions and led a discussion about the trip with the wider planetary science community.

They explained that the Europa lander is not like the spacecraft Cassini or the Mars rovers—expeditions with big initial objectives, but quiet hope for decades of continued operation and science experiments. In contrast, this mission will live hard and die young. It will have to: The radiation environment at Europa is punishing, so the communications relay orbiter that will act as go-between for the lander and Earth won’t last more than a month or two. The lander will have enough power to run for just 20 days on the surface and will run on batteries; nuclear power was considered but discarded as being too expensive and challenging to launch. Batteries also have the advantage of being “quieter,” providing less vibration, magnetic, and electromagnetic disruption to sensitive instruments.

The lander will launch on a Space Launch System rocket and will spend years traveling to Europa. Upon arrival, the relay orbiter―which during the cruise phase to Jupiter acts as a carrier―will release the lander to Europa’s surface. As the communications satellite establishes its Europan orbit, the lander will use a mini sky crane system to land, looking and acting much like the rover Curiosity on Mars.

But notably, the scientists don’t call this process “Entry, Descent, and Landing” (EDL), but rather DDL, for Deorbit, Descent, and Landing—there’s no atmosphere around Europa for a lander to “enter.” This makes the job of landing much easier than on Mars, whose tenuous atmosphere is insufficient for parachutes alone, and yet enough that it makes a pure supersonic retropropulsive landing a challenge.


This artist's rendering illustrates a conceptual design for a potential future mission to land a robotic probe on the surface of Europa. Image Credit: NASA/JPL-Caltech

The lander is a square about the size of a large riding lawnmower with four long, articulated cricket-like legs that will each compress independently on landing, allowing it to touch down on an uncertain or jagged surface and still remain level. (If it landed on a ledge, for example, one leg might remain fully extended along the drop, and three legs might compress fully, bringing the belly of the robot even and near the ground.) A communications antenna will then deploy and establish communications with the relay orbiter.

The lander will host a payload of science instruments weighing nearly 94 pounds. “That is a considerable mass for getting science done on any world,” Kevin Hand of the Jet Propulsion Laboratory, co-chair of the science definition team, said. To get the science done, the lander will carry five instruments: a gas chromatograph mass spectrometer and a Raman spectrometer, which can identify the contents of a sample; a context camera, which should return some spectacular images, including a giant Jupiter hanging in the black sky over the ice world; and a geophone, used for seismometry, the study of seismic activity. Except for the camera, these instruments will live inside of the lander, which will protect them from the worst of the radiation.

The most crucial tool for gathering material is a sample collection arm: essentially an angled, twin-bladed boring instrument that will carve strips of granite-hard Europan surface at a depth of 4 inches or deeper. (Regolith at such a depth is not radiation-processed, increasing the likelihood of observing indicators of life.) The collected material will be loaded into a dock in the lander’s side, and the instruments within will begin their analyses. Over the course of the mission, the lander will collect and analyze a minimum of five samples with a minimum volume of .4 cubic inches from five different regions within the lander “workspace”―that is, the radial reach of the collector arm.


Two views of the trailing hemisphere of the ice-covered Europa. Image Credit: NASA/JPL/DLR

An Earth day is called a “day.” A Mars day is called a “sol.” A Europan day is called a “tal.” The carrier relay will orbit Europa every 24 hours―this is a happy coincidence with Earth, but wasn’t planned that way―and return three to four gigabits of data per orbit. Mission operations are therefore planned in 24-hour intervals.

At the start of a tal―00:00—the carrier relay will receive its commands from Earth to determine that period’s working schedule. The lander receives those instructions at 01:00, when the carrier is in view of the lander in its orbit. On an ordinary tal, the lander will start collecting samples for the next five hours. At 06:00, the lander will upload engineering data to the relay, which will, in turn, send that data to Earth.

The lander will then get to work on sample analysis, and at 11:00, upload its findings, and go to sleep. At this point, the carrier relay orbiter will be out of range of the lander. Two hours later, it will have a clear shot at Earth, and will send the data back here for analysis. Humans will use this data to plan the science and engineering for the next day, and will generate commands to that effect. At 23:00, those commands and instructions will be sent to the relay orbiter, and the cycle will repeat itself.

The baseline science mission will be achieved in 10 days. Depending on what the lander finds, the team might decide to prioritize different things—for example, focusing on collecting samples or image acquisition.


Reddish spots and shallow pits pepper the ridged surface of Europa. Image Credit: NASA/JPL/University of Arizona/University of Colorado

There is no such thing as a “life detector.” Instead of a single magic reading, the lander will look for many organic biosignatures that, taken together, reveal life. Instruments will look for signs and abundance of organic material, cell-like structures, chirality (molecular properties, like those found in amino acids), and biominerals (minerals produced by living things)—among many other things.

Individually, none of these biosignatures can reveal life, but if found collectively, the evidence will be all but irrefutable. A biosignature matrix of positive and negative results is, in essence, plotted on a spreadsheet. Hand called this “biosignature bingo.” Not all of the biosignatures are necessary, but some combination of them are; finding, for example, an abundance of organics, cell patterns, chirality, and microscopic evidence but no signs of biominerals would still conclude life with certainty. On the other hand, if none of these features were found but biominerals and cell patterns were, we wouldn't call that evidence of life.

Sampling will be done in triplicate to confirm life findings. Three samples will have to confirm the biosignatures. The lander team is confident about this process. “It would be very hard to have a false positive, especially after replicating it three times,” Hand told mental_floss. “We use life on Earth as a guide, and so applying that matrix to life on Earth, both past and present, we would have a hard time leading to a false positive.”

The lander, of course, will not be the first spacecraft to arrive at the Jovian moon. The Europa Clipper spacecraft will have arrived and studied Europa years earlier, and will have ably characterized the habitability of that world. What Clipper finds, Lander will build upon. The Clipper’s work will determine one of four possible outcomes: Europa is not habitable, in which case the lander will figure out why (for example: geological activity); Europa is maybe habitable, in which case the lander will resolve the ambiguity of the finding; Europa is habitable, in which case the lander will try to find life; and Europa is inhabited―Clipper outright finds life on Europa, in which case the lander will confirm the finding and set the stage for future exploration. In addition, Clipper will act as a backup plan for the lander should the relay orbiter fail. The lander can talk to Clipper, which will in turn send the information back to Earth.

Despite the recent White House budget request that notably failed to earmark money for the Europa lander, these missions are realistically in no danger. Congressional appropriators have made it clear that the Europa lander is going to happen, and, just as in the case of Clipper (which the Office of Management and Budget ignored for years), it is still expected to receive billions of dollars over the next decade.


Images from the Viking mission on Mars. Image Credit: NASA

NASA undertook its last true life-finding mission—Viking’s mission to Mars—decades ago. There’s a reason for this time gap: Viking didn’t find life. Scientists had previously held out hope that animals might be scurrying about on the Martian surface. When the red planet was found to be creature-less, interest was quickly lost in the Mars program. Viking is thus sometimes criticized as being a failure. But Hand disagreed. “Viking is vindicated by Europa,” he said. “If Pathfinder had gone back and found a golf course on Mars, someone could say Viking made mistakes. Viking worked beautifully. Mars did not cooperate. Life detection experiments should provide valuable information, regardless of the biology results.”

Even in the absence of life, scientists will learn a lot about Europa as an ocean world, and as a world with liquid water recycling through the sea floor. In the absence of biology, they will still advance the sciences of geochemistry and oceanography.

“As exciting as a positive result for biosignatures would be, a negative result is equally profound. It gets to the question of what does it take for the origin of life to occur,” Hand said. Today, for example, hydrothermal vents are thought to have been critical to the birth of life on Earth. If Europa—which also has hydrothermal vents—is dead, perhaps hydrothermal vents are not that important after all.

Science has marched rapidly since the Viking missions, which means if life exists on Europa, we’re more likely to find it now than Viking scientists on Mars were. When the Viking landers set down in the mid-1970s, the structure of DNA had only been known for about 20 years. In the years since Viking, hydrothermal vents were discovered on Earth, and a whole new domain of life was discovered in the microbial realm, like cryptoendoliths in Antarctica—not to mention the “polymerase chain reaction” was developed, allowing the human genome to be sequenced. Last year, a new tree of life was created based on this research. So going into the lander mission, Hand and his team are cautiously optimistic.

“We don’t know if biology works beyond Earth,” Hand said. “We have every reason to believe it should and could, but we have yet to do that experiment.” The Europa lander team hopes to change that.

Original image
Eclipses Belong to Families That Span Millennia
Original image

If you’re lucky enough to see the solar eclipse when it passes over America on August 21, you’ll bear witness to a centuries-long legacy. That’s because total eclipses of the sun aren’t isolated incidents that occur at random. They belong to interconnected eclipse families that humans have been using to track the phenomena since long before the first telescope was invented.

In the latest installment of StarTalk on Mashable, Neil deGrasse Tyson chats with meteorologist Joe Rao about the science behind eclipse families. According to Rao, eclipses follow Saros cycles which repeat every 18 years, 11 days, 8 hours. Astronomers keep track of many different Saros cycles. The eclipse on August 21, for example, is a member of the family Solar Saros 145. Every 18 years a Saros 145 eclipse falls over a different third of the Earth. In 1999, the great American eclipse’s “cousin” appeared in the skies over Europe and south Asia, and 18 years before that another relative could be seen over modern Russia. The Solar Saros clan can be traced all the way back to 1639 and it will keep going until 3009.

Today, scientists have space-age technology that allows them to track the moment of totality down to a fraction of a second. But thousands of years ago, before such satellite-tracking equipment was invented, ancient Babylonians only knew what they could observe from Earth. Their eclipse calculations ended up serving them pretty well: They were able to predict the same 18-year cycle we know to be true today.

Saros 145 isn’t the only family of eclipses making its way around the Earth. There are enough solar eclipse cycles to make the event a fairly common occurrence. If you’re curious to see how many will happen in your lifetime, here’s where you can calculate the number.

[h/t Mashable]

Original image
7 Maps of Fun Eclipse Viewing Locations
Original image

Do you have your protective glasses and camera filter ready for the great American solar eclipse on August 21? Perfect. Now all you need to do is pick the ideal location for scoping out the event. Fortunately, the path of totality (the area from which the moon’s total coverage of the sun is visible) stretches from Oregon to South Carolina, and there are plenty of places in between where you can set up camp. We’ve tracked down maps of some of the most unique locations that will fall beneath the moon’s shadow on Monday.


What better place to witness one of the most stunning events in nature than from a national park? Using data from NASA’s Scientific Visualization Studio, the National Park Service has published a map of sites that will provide the best views of the celestial show. Several locations, from Great Smoky Mountains National Park in the East to John Day Fossil Beds National Monument in the West, fall in the path of totality. Click any marker in the interactive map to see if that place is hosting viewing events or other eclipse-related activities on August 21.


When viewed from Earth, a total eclipse lasts only a few minutes. One way to get the most out of the experience is to head into the sky. You don’t need to board an invitation-only flight to see the eclipse from a bird's-eye perspective. There are plenty of airports in the path of totality, and NASA has compiled them all into a helpful map. In addition to choosing your departure and arrival points carefully, you’ll need to get the timing right. According to The Points Guy, taking an eastbound flight from a Pacific Northwest airport around 9 a.m., or a Denver, Colorado area airport around 10 a.m. will put you in a golden position for eclipse chasing—that’s assuming you can book a last-minute flight.


On August 21, many Waffle House patrons will be treated to a mind-blowing experience—and we’re not talking about the topped and smothered hashbrowns. During the eclipse’s final hours it will be visible from dozens of Waffle Houses in the southern U.S. To choose a restaurant for viewing, refer to this map of Waffle Houses in the path of totality, put together by University of Georgia assistant geography professor Jerry Shannon. (He also tried making an eclipse map of Tim Hortons locations, but sadly fans of the Canadian chain won’t be so lucky.)


Want some chicken to go with your waffles? Eclipse gazers watching from the southern states should have no trouble doing that. Twitter user Taber Andrew Bain made this map of fast food chicken joints that intersect with the path of totality. Bojangles' represents a healthy portion of the spots with 86 locations in the strip, but Zaxby’s is the most abundant by far with 117.


One of the more bizarre side effects of a solar eclipse is the reaction animals have to the sudden darkness. As most creatures time their habits to the rising and setting of the sun, totality can prompt different species to wake up, prepare for sleep, or just go berserk. We recommend watching this bizarre behavior with something separating you from the animals. NASA published a handy map of zoos that fall in the eclipse zone where you can do just that.


It’s not every day a solar eclipse occurs in your backyard, and it’s definitely not every day that you get to watch it in the company of Bigfoot. This map from cartographer and data visualization guru Joshua Stevens plots reported Sasquatch sightings in relation to the trajectory of the solar eclipse. It’s too bad that a bona fide Bigfoot encounter is a lot less likely to happen than a total solar eclipse—and even if you do spot the hairy guy on the big day, it might be hard to convince others of The X-Files-worthy coincidence.


Map of libraries hosting eclipse viewing events.
STAR_Net's NASA@ My Library initiative, Space Science Institute, the Gordon and Betty Moore Foundation, NASA, and Google.

Your local library isn’t just a great place to pick up free protective glasses leading up to the eclipse. It can also be a fun spot to witness the event itself. Libraries around the country are hosting viewing events on the day of, where visitors will be provided with the proper equipment and information about what they’re seeing. Check out NASA’s map of libraries organizing such programs to find one close to you.


More from mental floss studios