NASA’s goal of returning humans, including a female astronaut, to the moon with the 2024 Artemis mission is approaching, and engineers are getting ready.

They’ll land on the lunar surface from an orbiting spacecraft called the Gateway, which will serve as a lunar outpost, then embark on a search for wate-ice and other resources. Artemis is also part of a larger plan to travel to Mars from a lunar way station. 

Looking for Water With a ‘Lunar Flashlight’

One of the tools NASA will use to explore the moon is Lunar Flashlight, a low-cost spacecraft no bigger than an airline carry-on bag. The small satellite will launch in November 2021 as part of an advance, uncrewed mission. It will probe the cold, permanently shaded floors of the moon’s polar craters for signs of ice. 

Finding lunar ice would be extremely exciting, because of its scientific value as a potential source of chemical clues to the history and formation of our solar system. It’s possible the ice could also be tapped as a source of drinking water and breathable oxygen, or mined as raw material to power hydrogen fuel cells or to make rocket fuel in long-term expeditions or moon bases.

The Lunar Flashlight will loop around the moon in an elliptical pole-to-pole orbit. The spacecraft will use infrared lasers and a spectrometer to probe the shadowed floors of craters as it swoops to within 20 kilometers of the south pole, where hints of water-ice have been detected by previous missions. 

From its orbit above, Lunar Flashlight’s laser beams will rake across the cold crater floors, reflecting off materials on the surface and bouncing back to the spacecraft. A spectrometer will measure the spectral “fingerprints” of substances in the reflected light, mapping the location and composition of concentrations of ice with an accuracy of 1-2 kilometers.

Though the presence of water was confirmed by an earlier mission in 2009, we know little about what form it might exist in. Sheets or blocks of solid ice? Permafrost mixed in with the lunar soil? Frozen “cocktails” of different volatile compounds?

Shadowy Polar Craters

The Apollo missions of the late 1960s landed in the moon’s equatorial regions and found no traces of water. 

But measurements made from orbit by Lunar Prospector in 1999 indicated the presence of concentrated hydrogen within shadowy polar craters, a hint that frozen water (or other hydrogen-bearing volatiles) might exist in cold recesses untouched by sunlight. 

The discovery raised the possibility that lunar “cold traps” have, over time, captured molecules of water originating from comets and asteroids, interactions between lunar soil and solar wind and perhaps lunar volcanic activity.

The 2009 Lunar Crater Observation and Sensing Satellite mission confirmed the presence of water, after flying to the moon on a Centaur rocket. NASA used the rocket stage as a high-speed impact projectile, sending it crashing into the shadows of a crater at the moon’s south pole. The satellite, following only minutes behind the rocket, used its spectrometer to search for the chemical signature of water in the dust cloud of the blast, and it made a successful detection before crashing into the moon.

All Eyes on the Lunar Flashlight, a CubeSat

Lunar Flashlight will be configured from six standard, 10-centimeter cube modules. 

The low-cost, modular CubeSat design was developed as an alternative to considerably more expensive conventional satellites, so that universities, private companies and other entities could test technology and conduct scientific research from space.

Because they are small, CubeSats can piggyback as secondary payloads on other missions. This puts short-term proof of concept tests and narrowly scoped scientific experiments within the financial reach of many organizations and groups.

The Lunar Flashlight planned for launch in 2021 will be the first CubeSat to travel to the moon, and the first spacecraft of any kind to look for water using a laser. 

And if it finds some, the first female astronaut to walk on the moon as part of the Artemis mission might just collect a sample and bring it back to Earth.

Scientists have made an exciting discovery in deep space — but not with an existing telescope or space probe.

Combing through a backlog of data collected several years ago by NASA’s now defunct Kepler space telescope, they ran across a previously overlooked gem in the cosmos: an extrasolar planet, or “exoplanet,” estimated to be almost exactly the size of Earth, in what’s called the “habitable zone,” at the right distance from its star to potentially harbor liquid water and a life-friendly environment.

Kepler-1649c

The exoplanet, Kepler-1649c, orbits a small red dwarf star about 300 light years away in the constellation Cygnus — which means we won’t be visiting it anytime soon. But with an estimated size of only 1.06 times that of Earth, and getting about 75% of the sunlight from its star that Earth receives from the sun, this exoplanet is the closest to Earth in size and solar heating of any discovered to date.

Whether Kepler-1649c possesses an atmosphere capable of supporting liquid water on its surface is not yet known, but follow-up investigations may give us a more complete picture of this tantalizing world.

Catching What a Computer Algorithm Overlooked

NASA’s Kepler space telescope, the most productive exoplanet-finding spacecraft yet launched, was retired in 2018, after running out of the fuel needed to continue scientific observations. But over its nine years of service, Kepler amassed a huge amount of data — so much so, that scientists are still making new discoveries.

Here’s how scientists look for evidence of exoplanets in the data. Kepler searches for the minor dimming of a star’s light caused by an orbiting planet crossing in front of it, or “transiting.” This “transit method” is responsible for most exoplanet detections made since the first discoveries nearly three decades ago.

Each measured dip in a star’s brightness must be carefully analyzed to determine if it was caused by a transiting exoplanet or some other factor, like a fluctuation in a star’s luminosity, or a random celestial object passing momentarily between us and the star.

With so much data to analyze, a first pass through it is done by computer programs, with algorithms designed to weed out all the non-transit events. Only about 12% of detections turn out to be transiting exoplanets, with the rest classified as “false positives.” However, sometimes the algorithm gets it wrong, which is what happened with Kepler-1649c. Scientists in the Kepler False Positive Working Group discovered the mistake as they double-checked the computer’s results.

Potentially Habitable?

Exoplanets that interest astronomers and astrobiologists most are the potentially Earth-like ones: planets close to Earth’s size, and within their star’s “habitable zone” — the right distance for liquid surface water to potentially exist.  

Other exoplanets have been found that are closer to Earth’s size than Kepler-1649c, like TRAPPIST-1f and Teegarden-c. Still others are known that receive more sunlight, that are closer to the warmth of the Earth. But none come as close as Kepler-1649c in both factors, making this once-overlooked exoplanet the nearest we’ve come to spotting another planet with Earth-like characteristics in the cosmos.

But, as Earth-like as Kepler-1649c might appear, there are some significant differences between it and planet Earth. The exoplanet orbits close to a small, dim, red dwarf star — so close that it zips around it once in only 19.5 days, instead of 365. It also shares its system with at least one other planet, also close to Earth in size, but about half the distance from its star, and because of that, probably very hot. There is also some evidence for a possible third planet in the system. 

Buried in the Data

Discoveries made from Kepler’s hoard of backlogged data are not unique. Other completed space missions have piled up their own mountains of observations that scientists review and revisit to gain new understandings.

Examples include NASA’s Galileo and Cassini spacecraft, whose missions were terminated in fiery burnups in the atmospheres of Jupiter and Saturn. But they gathered enough data on the gas giant planets and their systems of rings and moons that scientists are still studying it today. 

NASA’s Opportunity rover, which went silent two years ago following a major dust storm, collected enough images and other data along its 28 mile, 14-year trek across Mars that scientists are still analyzing it all. 

How Many Exoplanets Have We Found?

As of June 30, 2020, a total of 4,183 exoplanets have been confirmed to exist in 3,092 planetary systems. The Kepler space telescope found 2,751 exoplanets. 

Of the grand total, 160 are classified as “terrestrial” — rocky planets around Earth’s size, with iron-rich cores, like Venus and Earth.

As more exoplanets are discovered by ground-based observatories and active spacecraft like NASA’s Transiting Exoplanet Survey Satellite (TESS), more examples of Earth-sized planets within their stars’ habitable zones are being found. An understanding is emerging that planets with potentially Earth-like conditions may be more commonplace in our galaxy than we previously thought.

Four years after arriving at the planet Jupiter, NASA’s Juno spacecraft is still making fresh discoveries and sending us breathtaking pictures of the gas giant and its entourage of at least 79 moons. 

The most recent finding is a bizarre meteorological phenomenon, something not seen on Earth: “shallow” lightning, accompanied by slushy hailstones made of an antifreeze-like mixture of water and ammonia, dubbed “mushballs” by NASA’s Juno science team. 

These mysterious weather phenomena have helped us better understand the distribution of ammonia in the Jovian atmosphere. And, they can help improve our overall understanding of distant planets orbiting stars in other solar systems, too far away for us to study in detail. 

What Makes Lightning ‘Shallow’?

Since 1979, observations made by spacecraft before Juno — Voyagers 1 and 2, and Galileo — detected powerful flashes of lightning through the cloud layers of Jupiter’s turbulent atmosphere. Unlike Earth, the gas giant planet has no solid surface, and is made up of ever deeper and thicker layers of gas, mostly hydrogen and helium. The potent electrical discharges — detected by earlier missions — are believed to occur as far as 40 miles below the visible cloud tops, where temperatures and atmospheric pressure are right for the formation of lightning as we understand it on Earth. 

On Earth, lightning is generated where water is found in all its states — gas, liquid droplets and solid particles of ice. Water vapor feeds the growth of liquid droplets in a cloud, and strong updrafts carry the droplets to altitudes where freezing temperatures turn them to ice particles. The ice particles fall downward, colliding with the upwelling liquid droplets, and the friction of their interaction knocks electrons from water molecules. Static electric charge builds up until it’s too strong to remain static, then discharges into the air, another cloud, or the ground. The same thing happens on a much smaller scale when you drag your shoes across a carpet and build up static electricity from the friction, until you touch another electrical conductor (metal, or another person) and discharge the electrons in a tiny, sometimes painful zap of mini-lightning. 

To scientists’ surprise, Juno, passing within a few thousand miles of Jupiter’s cloud tops on the night side, detected flashes of lightning much smaller than the powerful strikes earlier missions had seen coming from beneath the clouds. Estimates place the number of these lightning strokes at about 3.75 billion per year, across Jupiter’s entire surface — that’s about 119 per second on average! These fainter flashes appear to come from much higher in the atmosphere, where it is too cold — below negative 126 degrees Fahrenheit — for droplets of liquid water to exist. 

This was baffling at first, until one Juno scientist had an idea that could not only explain the high-altitude lightning in Jupiter’s atmosphere, but also another mystery that has puzzled scientists for years: much lower than predicted amounts of ammonia in Jupiter’s upper atmosphere. 

The Mushball Connection

This explanation for the shallow lightning and Jupiter’s “missing” ammonia in the upper atmosphere goes like this: Jupiter’s powerful thunderstorms and the strong updrafts of air and liquid water droplets eject plumes of water as high as 16 miles above the tops of the thunderheads, which freeze into ice crystals in the extreme cold above. There, the ice particles encounter a layer of ammonia gas, which melts the ice and blends with the water to form a liquid water-ammonia antifreeze mixture. 

As the droplets of water-ammonia rise and fall, they collide with the water-ice crystals flung upward by the thunderhead far below. As with Earthly lightning, the friction of collision between the liquid “antifreeze” and solid ice particles generates static electricity, and high-altitude lightning is born.  

Why there is less ammonia in some parts of Jupiter’s upper atmosphere than previously thought may be explained by what happens next.

In the cold, high-altitude layers where the lightning is generated, a crust of water ice forms around the liquid water-ammonia core of a droplet, growing thicker and enlarging the so-called “mushball” until the atmosphere can no longer support it. It falls like a hailstone, deep into Jupiter’s atmosphere, below the visible surface of its cloud tops where it cannot be detected by spacecraft like Juno. Only then, far below the clouds, does the mushball’s icy crust melt and its water-ammonia core evaporate, potentially forming a layer of ammonia beneath the clouds. 

Why Are Shallow Lightning and Mushy Ammonia Hailstones Important?

There is a great diversity in planets and moons within our own solar system, each with very different compositions and environments. As we explore Jupiter’s stormy weather, or Mars’ global dust storms, or Pluto’s nitrogen-methane glacial flows, we are learning how different planets work.

As we begin to study more closely the thousands of extrasolar planets discovered in the last 30 years, we can use what we’ve learned in our solar system as a framework to understand what lies beyond.

The year 2020 is clearly out to make its mark in a big way: a global pandemic, massive wildfires across the Western United States,  huge demonstrations for social justice around the globe.

Here’s another one: a record observed near-miss of Earth by a rock from space. 

On Aug. 15, at 9:08 p.m. PDT, the robotic sky-scanning survey telescope at the NSF/NASA-funded Zwicky Transient Facility at Palomar Observatory in California captured an image of a previously unknown asteroid, 10-20 feet in diameter, whizzing by Earth at a speed of 8 miles per second. The image was taken only six hours after the rock’s closest approach, 1,830 miles from Earth’s surface over the southern Indian Ocean, closer than any previously known near-Earth asteroid, or NEA.

A student in India, examining images captured by the ZTF telescope in California, first spotted and reported the object.

Too Close for Comfort, Too Small to Notice?

The asteroid, named 2020 QG, set a record for the nearest miss of the Earth ever observed — just 1,830 miles or about a quarter of Earth’s diameter — yet it wasn’t spotted until after it passed!

This is normal for encounters with near-Earth asteroids of this size. Too small to be discovered until getting breathtakingly close to the Earth, these car-sized chunks of rock, often fragments from collisions between larger asteroids much farther away that took place long ago, lurk invisibly throughout the solar system. Estimates place their population in the hundreds of millions, though most of them pass no closer to Earth than the distance to the moon.

Asteroid 2020 QG may be small enough to sneak up on us unnoticed, but it would also do little damage, if any, if it did hit Earth. It would mostly burn up and disintegrate during its high-speed dash through our atmosphere, with possibly some small fragments reaching the ground. Since three-quarters of Earth’s surface is covered by ocean, such remnants often fall into water.

The Chelyabinsk meteor that exploded and mostly disintegrated in the sky over Russia in 2013 was at least three times the size of 2020 QG. It caused a powerful shock wave that broke windows, tumbled brick walls, and injured almost 1,500 people. Luckily, there were no fatalities. Despite these effects, only a few small fragments survived to reach the ground.

The Chelyabinsk meteor, by the way, was not detected until it entered our atmosphere and announced itself in an aerial blast with an estimated explosive power between 400-500 kilotons. 

Space Stuff Hitting Earth: How Concerned Should We Be?

It might surprise you to learn that space rocks and other debris fly close to and even impact the Earth all the time.

Every day about a 100 tons of space rock filters down to Earth’s surface, most of it in the form of dust grains that vaporize in the atmosphere and rain down as microscopic specks. You can see the larger particles flash through the night sky as meteors if you’re patient enough, but most of this space debris showers down on us unseen and unfelt.

Larger chunks of rock and metal that reach the ground before burning up completely are called meteorites, and are prized finds by collectors who can distinguish them from Earth rocks. Some meteorites can fetch a good price from the right buyer.

Scientists from the Jet Propulsion Laboratory say that about every 10,000 years, on average, an asteroid in the 100-meter (328 foot) class strikes the Earth, causing big problems in the region it hits: a huge impact blast and shock wave, or a tsunami, if the object hits the ocean. The famous “Meteor Crater” in northern Arizona, east of Flagstaff, is a near mile-wide, 600-foot-deep impact hole. It was formed 50,000 years ago when an asteroid measuring about 160 feet across hit the ground. Though this asteroid would have wreaked havoc across the local Pleistocene landscape, there were likely no global effects from the blast.

Every few hundred thousand years a larger object, half a mile or more across, collides with the Earth. Objects of this size produce global complications, throwing dust and other debris into the atmosphere around the planet, which can block off sunlight, cause acid rain, and ignite firestorms with the heat of reentering debris. These larger collisions also cause devastating shock waves and tsunamis.

The global effects of these major impacts have caused mass extinctions of plant and animal species. Take it from the dinosaurs, the poster-children of global collision catastrophe, who were wiped out by the impact and aftermath of a six-mile-or-more wide object that struck the northern tip of the Yucatan Peninsula about 65 million years ago, forming the Chicxulub impact crater, now mostly buried under sediment.

What’s to Be Done?

With all that space rock flying around out there, are we doing anything to protect us from it?

In short, yes. Since at least 1994, NASA has worked to discover and characterize asteroids and comets that have the potential to collide with Earth and inflict significant damage.

In 2005 the U.S. Congress handed NASA the goal of finding 90% of all potentially hazardous near-Earth asteroids, ones larger than 460 feet across, by the end of 2020. NASA’s NEO (Near-Earth Object) Observations Program is still working toward this target, using evolving technologies.  Fortunately, asteroids of this size are much easier to detect than small ones like 2020 QG, and they can be discovered and tracked years before coming close to Earth.

This gives us time to predict future collisions, and possibly do something to prevent them.  

On the ground, advance warning of the location and magnitude of a projected impact by an incoming asteroid could help us prepare, by evacuating the threatened region, for instance. 

Scientists are also thinking how we might alter the course of a threatening asteroid, turning a predicted collision into a near-miss scenario. With enough advance notice of a likely major impact — and we’re talking years — even a relatively small “nudge” to an asteroid’s trajectory could ultimately make the difference between hit and miss here on Earth. 

This may sound like something out of science fiction, but one concept being explored is the “gravity tractor,” a massive robotic spacecraft placed near an asteroid, which gives it a small but constant pull via its gravitational attraction. Flying alongside an asteroid, the spacecraft would use low-powered engine thrust to gradually “tug” the rock with mutual gravitational attraction, slowly steering the asteroid away from its Earth-bound path — kind of like a tiny tugboat guiding a huge ship onto a safe course.  

Sleep Well Tonight

Small asteroids like 2020 QG will continue to buzz and even hit the Earth multiple times each year. They will also often fly by or disintegrate in our atmosphere unnoticed.

But, NASA’s ongoing observation of near-Earth objects is a powerful tool for predicting when an asteroid or comet might impact the Earth. The good news is that no major impacts are foreseen anytime soon. 

Coming up in November: Election Day Near-Earth Asteroid.

In an era of deep space exploration, a tantalizing and surprising discovery has raised the possibility of life on Earth’s nearest, scorching-hot planetary neighbor Venus. 

Scientists observing with the James Clerk Maxwell Telescope in Hawaii detected the spectroscopic signature of the chemical compound phosphine in the Venusian clouds, about 35 miles above the surface. Follow-up observations with the Atacama Large Millimeter/submillimeter Array in Chile confirmed the discovery.

Phosphine, or PH3, a molecule composed of one phosphorus and three hydrogen atoms, is a “biomarker“ chemical that scientists hope to find in the atmospheres of distant Earth-like extrasolar planets to indicate possible biological activity.

On Earth, besides human industrial activity, the only known generator of phosphine is anaerobic life (which does not require oxygen to grow), either from microbial organisms or the decomposition of organic matter. And though there are nonbiological processes that produce phosphine deep in the hydrogen atmospheres of giant planets like Jupiter and Saturn, those conditions are not found on small rocky worlds like Earth and Venus.

Follow the Phosphine?

Astrobiologists have focused their search for extraterrestrial life on places that harbor liquid water. NASA’s life-seeking motto is “Follow the water,” since life as we understand it on Earth requires water to thrive, let alone originate.

Orbital spacecraft like NASA’s Mars Odyssey and Mars Reconnaissance Orbiter, and rovers like Spirit, Opportunity and Curiosity, have raked the dry surface of Mars to find and analyze mineral residues from its extinct seas. Soon, Perseverance will dig for signs of past Martian life that may have thrived in those waters. The Galileo spacecraft and Hubble Space Telescope have revealed signs of an ocean hidden under the icy crust of Jupiter’s moon Europa, and the Cassini probe sampled plumes of mineral-laden water erupting from Saturn’s moon Enceladus, believed to originate from a subsurface sea.

But one thing we have learned about life on Earth is that it keeps showing up in places where we least expect to find it. “Extremophiles,” earthly organisms that thrive in some of the hottest, coldest and most toxic watery environments on our planet, have been found deep within frigid Antarctic and alpine lakes, around superheated hydrothermal vents at the bottom of the ocean, and at the fringes of toxic geothermal hot springs. These highly resilient and adaptable life forms  give us hope of finding signs of life in the waters of completely alien worlds.

With very little water vapor in its atmosphere, Venus is not a place where scientists expect to find signs of life, but the discovery of the biomarker phosphine is fueling further investigation and possible future missions to Venus to explore the question.

If This Is Life, Where Did It Come From?

If the phosphine in Venus’ atmosphere is produced by non-oxygen-using microbial life and not abiotic chemical processes (processes not derived from living organisms) that we simply don’t yet understand, where did the critters come from? 

On Venus’ surface, temperatures soar to around 900 degrees Fahrenheit, and the atmospheric pressure is 90 times greater than sea level on Earth, equivalent to the water pressure half a mile deep in Earth’s oceans. It is challenging to imagine even a hardy form of Venusian life existing there. 

But at the altitude where Venus’ phosphine was detected, between 30 and 40 miles above the surface, the atmospheric pressure and temperature are similar to Earth’s surface, though the chemistry is very different, dominated by carbon dioxide gas and liquid droplets of sulfuric acid. 

Some scientists believe that conditions on Venus were very different in the past, and that billions of years ago Venus might have had a surface ocean of water and atmospheric conditions closer to that of the young Earth. And if life could arise in Earth’s primordial oceans and atmosphere, why not on Venus?

As the environment on Venus’ surface changed from more clement conditions to the hellish planetary pressure cooker it is today, some theorize that extremophile life forms could have fled skyward to survive, adapting to a less harsh environmental niche at higher altitude.

What’s Next in the Hunt for Life on Venus?

Researchers stress that the detection of phosphine in the clouds above Venus does not mean the certain presence of life there, and that there may be a nonbiological explanation that we have yet to understand.

Further telescopic observations will be made to learn more, but  verifying what’s going on in Venus’ atmosphere will require sending a spacecraft to investigate. NASA is currently considering mission proposals to do just that.

If there is life thriving in Venus’ clouds, it raises even more questions: Did life begin independently on Earth and Venus, and if so, which came first? Or could life on both planets share a common origin? And, if life sprung up readily on both sister planets, and possibly on neighboring Mars as well, what does that say about how common life may be in the universe?

Personally, I’m keeping my fingers crossed that a future robotic probe floating through the Venusian atmosphere will send us evidence of microscopic life floating in the clouds of our closest neighboring planet. 

A team of astronomers is hard at work analyzing an unusual radio signal detected early in 2019 by the Parkes telescope, a 64-meter radio dish in eastern Australia. The signal appears to have come from the direction of Proxima Centauri, the nearest star to our solar system, and its characteristics are more typical of an artificial broadcast than a natural radio source. 

Is this the long-awaited sign of intelligent life out there among the stars, proof that we are not alone in the universe? More exciting — or concerning, depending on how you feel about space aliens — are there ETs living in the next star system over, our closest neighbor in the galaxy? 

It’s tantalizing to imagine this. 

However, even the signal’s discoverers, researchers with a group called the Breakthrough Listen Initiative, caution that although the signal had very particular qualities that set it apart from typical natural radio emissions, it will most likely turn out to be noise or interference caused by our own communication technology here on Earth, or even a natural phenomenon that has simply not been observed before. 

Still, at this moment, the possibility has not been ruled out for an intercepted alien transmission, so there’s still some space to let our imaginations play with the idea a bit. 

The Signal

The radio signal that has stirred up so much excitement was detected during observations of flares erupting from the red dwarf star Proxima Centauri, the smallest member of the triple Alpha Centauri system. At a distance of only 4.25 light years, Proxima Centauri is a stone’s throw away, astronomically speaking.

The signal was concentrated in a very narrow slice of the radio frequency spectrum, at 982 megahertz, which is typical of an artificial transmission. Signals from natural sources contain a wider mix of frequencies. Researchers listen for exactly this kind of narrow signal as they monitor star systems for any of non-natural, non-human origin.  

It’s exciting to imagine that we have heard the radio whispers from extraterrestrial technology, whether it was a deliberate transmission aimed at us or merely ET’s television broadcasts drifting through space. Adding to the excitement, Proxima Centauri is known to possess at least two planets. One of them, a “super-Earth” called Proxima Centauri b, orbits within its star’s habitable zone, at the right distance for the star’s warmth to support liquid surface water and a potentially life-friendly environment. 

While researchers at Breakthrough Listen Initiative caution that with further analysis, the unusual signal will most likely turn out to be only radio interference from human technology — which has happened before — a final conclusion hasn’t been made. 

Breakthrough Listen Initiative

The Breakthrough Listen Initiative is a $100 million international effort to discover radio transmissions from extraterrestrial civilizations. Kicked off by Israeli-Russian billionaire Yuri Milner and Stephen Hawking in 2015, the Initiative is the most advanced and comprehensive ET-finding program humans have ever embarked on.  

The 10-year project will survey a million nearby stars, the entire plane of the Milky Way galaxy, and 100 nearby galaxies. The ambitious scale of these goals speaks loudly. There is still huge enthusiasm for answering the question: Is humanity alone in the cosmos, or do we share the galaxy with other intelligent, technological civilizations?

To help guide its search, the Breakthrough Listen Initiative is partnering with a NASA mission searching the nearest stars for extrasolar planets. The TESS spacecraft is expected to find thousands of exoplanets, including worlds the size of Earth, orbiting within their stars’ habitable zones. Targeting stars where TESS has discovered potentially life-friendly worlds improves the initiative’s chances of finding one with an intelligent, technological civilization. 

Search for Extraterrestrial Intelligence

Scientists have been using radio telescopes for decades to search for transmissions of intelligent origin, going back practically to the genesis of radio technology in the early 20th century. 

SETI, the Search for Extraterrestrial Intelligence, brought scientists together in the 1980s in a coordinated effort to detect ET radio signals, and was popularized in the 1997 movie “Contact,” adapted from the novel by Carl Sagan. 

Piecing together the facts around Proxima Centauri and the unusual signal detected by the Parkes radio telescope, it’s tempting to envision some far-out possibilities. A seemingly artificial signal coming from the closest star system? An Earth-sized planet with an environment possibly friendly to life? The discovery excites the imagination. 

Even if the signal ultimately turns out to be a trick of our own technology, while there’s still a fleeting chance of a world-changing event like discovering extraterrestrial intelligence, we can enjoy a moment reveling in the possibility.

Like an artist whose pleased patron commissions more masterpieces, NASA’s Juno spacecraft just earned an extension after four extraordinary years of discovery. And if you’ve seen any of Juno’s images of Jupiter, you may find the artist reference apt.

Before the Juno mission, little was known about the wind and cloud systems of the polar regions. The solar-powered robotic probe, whose adventure  exploring the atmosphere and interior of the planet Jupiter was scheduled to end this July, has been granted a four-year extension, through September 2025. It’s mission has also expanded, and it will now investigate the planet’s system of rings and three of its large and remarkable moons.

Juno’s Primary Mission

Since its arrival at Jupiter in 2016, Juno’s observations have focused on dynamics that scientists previously knew very little about: the gas giant’s complex atmosphere and storm systems at the high latitudes of the northern polar region.

Juno has captured breathtaking images of Jupiter’s cloud systems and other atmospheric phenomena at very close range. It’s also probed beneath the visible cloud layers. 

Using instruments that measure Jupiter’s powerful magnetic field and gravitational variations, Juno has divined processes and structures deep within the gaseous world. Among its many discoveries are stupendous strokes of lightning exploding dozens of miles beneath the planet’s thick layers of clouds; an abundance of water welling up at the equator; mighty auroras surging high in the atmosphere; “packs” of Earth-sized storms spinning around both poles; and wind systems whose roots are buried 1,000-2,000 miles below Jupiter’s cloud tops.

Juno’s Wild Orbit

To get close enough to Jupiter to do what it came for, Juno must pass through bands of intense radiation, captured in Jupiter’s surrounding magnetic field. To minimize exposure to radiation damage, NASA placed Juno in a highly elliptical orbit that keeps it well outside the radiation belts most of the time. At the far-flung end of its elongated orbit, Juno is 5 million miles away from Jupiter, 20 times farther than our moon is from Earth.

Once every 53 days, Juno’s orbit carries it swiftly through the danger zone and close to Jupiter, passing only 2,600 miles above the cloud tops in the northern regions, offering a view like no other in the solar system.

With each close pass by Jupiter, Juno’s orbit alters slightly due to interaction with the planet’s gravity. Over time, its point of closest approach has migrated northward, toward the pole, while the long loop of its extended orbit has shifted closer and closer to Jupiter’s large Galilean moons.

Targeting Jupiter’s Mystifying Moons

Over the four additional years of Juno’s extended mission, its shifting orbit will send it past three of Jupiter’s Galilean moons: Ganymede, Europa and Io. No spacecraft has flown close to these small worlds since the Galileo probe two decades ago.

Ganymede will be the first fly-by target, on June 7 this year. Ganymede is the largest moon in the solar system, half again bigger than Earth’s moon. Its surface is a patchwork of rough, ancient, cratered terrain overlapped by smooth, probably icy regions. It is the only moon in the solar system with a magnetic field of its own, and its poles are lit up with auroras. Strong evidence exists that a liquid water ocean lies hidden beneath Ganymede’s surface.

Io is the most volcanically active moon in the solar system, with hundreds of sulfurous eruptions spewing out lava and gas, in some cases dozens of miles into the sky. Volcanic Io will receive a pair of visits, on Dec. 30, 2023, and Feb. 3, 2024.

Most intriguing of all is Europa, which shelters a saltwater ocean beneath its icy crust. Europa’s ocean may be as much as 100 miles deep, and its waters are thawed by heat emerging from the moon’s interior. Scientists are excited by the possibility that within Europa’s ocean may exist conditions that could support life. On Sept. 29, 2022, Juno will have a close encounter with Europa. 

During its extended mission, Juno will also fly through trails of ions shed into space by Io’s volcanoes, and plumes of water vapor erupting from Europa’s icy crust. By sampling the composition of Europa’s water vapor plumes, scientists hope to better understand the nature of the moon’s ocean.

Recon for Upcoming Missions

Extending Juno’s exploration to include the Jovian moons will help pave the way for two upcoming missions: NASA’s Europa Clipper and the European Space Agency’s JUICE, scheduled to launch later this decade. Both of these spacecraft will investigate the Galilean moons in great detail, with a special focus on Europa and its tantalizing ocean.

By the end of its extended mission in 2025, Juno will have orbited Jupiter 76 times over eight years and collected enough data to keep scientists busy for many more years to come.

Then, Juno will be deliberately driven into Jupiter’s atmosphere, where it will be incinerated in a fiery finale, its atoms forever becoming part of the world it has explored.

After years of complicated preparations, NASA is expected to attempt its ninth Mars landing on Thursday at 12:55 p.m. PT.

The live landing commentary will begin at 11:15 a.m.

If it lands successfully, the rover, named Perseverance, will search for signs of ancient microbial life; collect broken rock and dust samples to be analyzed by researchers on Earth; study Mars’ geology and climate; and “pave the way for human exploration beyond the Moon,” according to NASA.

Perseverance also is carrying the Ingenuity Mars Helicopter, which will attempt the first powered, controlled flight on another planet, according to a NASA press release.

Here’s a schedule for Thursday’s events via NASA:

11:15 a.m. — Live landing commentary on the NASA TV Public Channel and the agency’s website, as well as the NASA App, YouTube, Twitter, Facebook, LinkedIn, Twitch, Daily Motion and THETA.TV.

In addition, an uninterrupted clean feed of cameras from inside JPL Mission Control, with mission audio only, will be available at 11 a.m. ET on the NASA TV Media Channel and at the JPLraw YouTube channel.

A 360-degree livestream of the Mars landing from inside mission control, including landing commentary, will be available at the NASA-JPL YouTube channel.

11:30 a.m. — “Juntos Perseveramos,” the live Spanish-language landing commentary show, on NASA en Español’s YouTube channel.

About 12:55 p.m. — Expected time of Perseverance touchdown on Mars.

No earlier than 2:30 p.m. — Post-landing news conference originating from Von Karman Auditorium.

Touchdown! No, it’s not football — unless you imagine a playing field 300 million miles long and a fiery 25,000 mph end-zone plunge.

The ball in play is NASA’s Perseverance rover, which successfully touched down on Mars on Thursday at 12:55 p.m. PST, following a seven-month voyage and seven nail-biting minutes blazing through its atmosphere.

Now safely on the ground in Mars’ Jezero Crater, Perseverance is set for what could be a game-changing mission of discovery: a search for signs of past Martian life in the river-deposited sediments of what was probably, long ago, a lake bottom.

First Images from Jezero Crater

Only minutes after landing, Perseverance captured a pair of images with two of its hazard avoidance cameras. The images were promptly relayed back to Earth via NASA’s Mars Reconnaissance Orbiter as it passed over the landing site. The pictures were so fresh that dust lingered in the air, stirred up by Perseverance’s landing stage rockets.

In the hours and days ahead, after the rover’s Mastcam camera is put into service, we should be able to enjoy sweeping, full-color, high-res panoramas from Jezero.

And more. “SuperCam” will use a camera, laser, and spectrometer to probe the chemistry of nearby rocks and soil to search for the spectral fingerprints of organic compounds. “RIMFAX” will send radar pulses into the ground to probe underground structures beneath the rover. And the rover’s long, robotic arm carries an array of instruments, including a rock drill and ultraviolet and X-ray spectrometers to dig into Mars’ mineral secrets.

In Search of Martian Critters

Perseverance is the first mission to look for signs of life on Mars since the Viking landers in the late 1970s. The Vikings carried instruments designed to detect biological activity of any organisms in Mars’ soil, though their findings were inconclusive.

Perseverance will look for evidence of life that may have existed on Mars perhaps billions of years ago, when we know the planet possessed a thicker atmosphere and liquid surface water.

NASA selected the 28-mile-wide Jezero Crater to give Perseverance the best chance of finding signs of life. Long ago, the crater was filled with water, all the necessary ingredients for life were present. If life did thrive there, its chemical and mineral remnants might be found preserved in the rocks of the ancient lake bottom and shoreline.

Jezero Crater also features an extensive deposit of river sediment, washed into the lake from the surrounding terrain at the mouth of a river, now long dry. This adds to the variety and abundance of material that Perseverance will have access to as it crawls around the dry lakebed and shoreline.

On Earth, the muddy sediments at lake bottoms are repositories of biological material: the remains of microbes that lived in the water and mud. Over time, the sediments harden into rock — mudstone or sandstone — and may preserve chemical residues of the long dead critters. On Earth we also find knobby rock formations, called stromatolites, created long ago by microorganisms living in the shallow waters along shorelines.

If scientists can detect and analyze the chemical traces and rock formations left behind by ancient life on Earth, why not Mars?  

If Perseverance’s sophisticated yet portable instruments are unable to definitively reveal any “biosignatures” of ancient organisms in Jezero’s rocks, it’s still possible that more powerful instruments in laboratories back on Earth could. To this possibility, Perseverance will store promising soil and rock samples in sealed metal tubes and leave them along its trail. A future mission to collect these samples and return them to Earth, the Mars Sample Return mission, is already being planned. 

Seven Minutes of Terror

Landing an SUV-sized robotic rover on Mars isn’t a job for the faint of heart. The sequence of critical maneuvers from atmospheric entry and descent to landing must be pulled off without a hitch, and thus has been coined the “Seven Minutes of Terror.”

It takes about seven minutes from when the spacecraft hits Mars’ upper atmosphere to when it lands on the surface, and every step of the process is carried out automatically through carefully preprogrammed commands and actions. Radio signals between Perseverance and its controllers at the Jet Propulsion Laboratory in Pasadena took over 11 minutes to travel through space, so a real-time remote-controlled landing by human hand was impossible.

Once the landing sequence began, controllers back on Earth could only sit back and hope for the best until it was all over. Jezero Crater’s rough terrain added to the stress, making this landing the most dangerous yet.

Fortunately, NASA’s getting pretty good at this, which is really saying something considering the nature of the challenges to overcome.

Ingenuity

Unlike the four previous Mars rovers, Perseverance didn’t go to the red planet alone. Hitching a ride on the rover’s underbelly is the tiny, 4-pound “Mars Helicopter,” named Ingenuity through the same student essay contest that gave us Perseverance.

The light-weight, double-rotor vehicle is a technology demonstration for aerial exploration of Mars in the future. Equipped with computer, navigation sensors, two small cameras, solar cells and wireless communication, Ingenuity will make one or more short flights sometime within the first month of the mission, after mission scientists and engineers find a suitable launch location and determine the most favorable weather conditions.

Life on Mars?

It’s exciting to think that we may be on the verge of finally uncovering hard evidence for the existence of extraterrestrial life. This will be a world-changing discovery, even if all we find is the chemical residue of single-celled microbes that lived a billion years ago. In whatever form the evidence comes, it will answer that age old question: Are we alone in the universe?

Imagine if Perseverance’s first high-resolution pictures of a Martian rock bore images of a fossilized life form of some sort? 

Unlikely — but not impossible.

Farming space with soil from asteroids “digested” by fungus?

Levitating across the lunar landscape? 

How about powering a moon base with sunlight? Or scaffolding enormous spinning space habitats? 

Sounds like a science fiction epic about taming the solar system with a high-tech plough through the sweat of an astronaut’s brow. These concepts, however, are a step closer to reality than mere science fiction. Their authors are researchers at various technology corporations, educational institutions, and NASA centers, and their inventive plot devices are not conceived merely to entertain, but to facilitate future expeditions to the moon, Mars and beyond.

More than a dozen researchers have been awarded grants by the NASA Innovative Advanced Concepts program to study the feasibility of their near-sci-fi technology concepts. Working in a gray zone between the real and the imagined, they are kicking ideas from the shadows of the fictional into the light of real potential. And with the $125,000 boost of each NIAC Phase 1 study grant, their speculations on future space technology have been reified just a titch.

Who are the grant recipients, and what kinds of ideas are they coming up with? A few examples.

Portable Magnetic Highway

A robotics engineer at NASA’s Jet Propulsion Laboratory is exploring a concept for a portable magnetic “rail” transportation system for use on the moon. 

When humans begin to establish long-term lunar habitats, there will be a need to regularly transport a lot of material around the surface. Mining lunar materials for air, water, and fuel components will involve moving the raw “ore” to processing facilities. Excavating rock and soil to build living and working structures will dig up a lot of debris that needs to be carted away. 

To do this, the initial concept calls for a flat “track” to be rolled out onto the moon’s surface between locations, creating a sort of instant roadbed without the need for permanent construction. Autonomous transport robots then levitate above the track on a magnetic cushion, carrying their loads across the landscape with no friction or air resistance, and without a need for constant human management.

Swimbots

The same JPL researcher is also exploring a concept for robotic exploration vehicles that can swim in the oceans of other worlds like Jupiter’s moon Europa and Saturn’s moon Titan, which has a methane sea. As we get closer to mounting expeditions to these remote and hazardous liquid environments, we’ll need more than wheels and helicopter blades to drive exploration forward.

Cultivating Space Soil

A researcher with Trans Astronautica Corporation is eyeing the asteroids as possible source material for creating arable soil, and putting Earth fungus to work to make it happen. The idea is for the fungus to break down or “digest” the sterile asteroid material into soil for growing plants.

Along with aspirations for humans to live on the moon and make the arduous voyage to Mars comes the need to feed them. Such expeditions will no doubt bring along food staples and water, but carrying cargo into space — even the short hop from Earth to the International Space Station — is costly, especially with a continual need to resupply. And sending supplies to a moon base, or a long-range Mars mission, is an even greater expense and challenge.

Any food that can be produced or grown on the ship or station where it is to be consumed will grant a mission greater autonomy and food security, and eventually may allow space-faring humans to become self-sufficient. Even today, plants are experimentally grown and harvested onboard the International Space Station, laying the groundwork for future space farms much farther from home.

The idea of mining asteroids for precious metals, either by traveling to one or relocating it to an orbit around Earth or the moon, has been envisioned for some time. But the thought of tapping the worthless rocky components of asteroids to produce a commodity far more valuable than gold to astronauts who need to eat is a stroke of brilliance.  

Since there are plenty of asteroids flying around the solar system, the potential to produce usable soil is practically unlimited, and the practice may one day feed large-scale space habitations.

Prefabbed Space Homes

A Carnegie Mellon University assistant professor is conceiving a lightweight collapsible apparatus as a deployable “building block” for constructing enormous, kilometer-scaled space structures.

This idea accepts an ambitious challenge set by science fiction writers over the decades: to engineer an artificial space habitat, or “space ark,” of a scale grand enough to accommodate a population of humans and a sustainable, even self-sufficient ecosystem.

Supercharged Solar Power

A researcher at NASA’s Langley Research Center is shining light on a concept to generate and distribute electrical power for use on the moon, using telescope optics to capture, redirect and focus sunlight.

Though concentrated solar energy systems are nothing new, engineering a system for the moon presents some unearthly technical challenges — for one, designing a system small and light enough to be transported from Earth to the lunar surface while still maximizing energy production to squeeze out as much power from the sun’s rays as possible.

Back to Sci-Fi

Science fiction may inspire the invention of new technologies and scientific endeavors, but the reverse is also true. Real achievements in space exploration and the tech that enables it inspire us to wonder more deeply about where the adventure can lead, which can inspire further innovation.

We may not see giant space habitats and crops harvested from asteroid dirt for some time, but thinking about how to do these things needs to start now. As humans gradually move farther from Earth and dwell in space for longer stretches of time, visions of this kind may inevitably become the reality of future generations.

More than four decades after launch, NASA’s Voyager 1 spacecraft is over 14 billion miles from Earth, cruising an eternal course through the stars of the Milky Way galaxy.

And Voyager 1 is not the only spacefaring vehicle to venture so far from home. 

The probe belongs to a cadre of five interstellar-bound spacecraft, three of which are still communicating with Earth through NASA’s Deep Space Network radio dishes. 

What have these interstellar five been doing over their decades of exploration, and where are they now?

New Horizons: Pluto or Bust

The youngest of NASA’s interstellar vehicles, New Horizons, launched 15 years ago with a singular goal: to become the first spacecraft to reach Pluto, the last unexplored planet in the solar system. Only after launch, in 2006, did the International Astronomical Union vote to demote Pluto to a “dwarf planet”.

With a boost in speed generated by a gravitational slingshot maneuver at Jupiter, New Horizons became the fastest interplanetary spacecraft up till that time, reaching a peak velocity of over 36,000 mph—a speed that would take you from the Earth to the moon in under seven hours.

Since Pluto’s discovery in 1930 by Clyde Tombaugh, little was known of this small, distant world; the best pictures of the dwarf planet, taken by the Hubble Space Telescope, had revealed little more than a blur of light and dark patches. 

So on July 14, 2015, the world waited with great anticipation of seeing the first up-close images–and were rewarded handsomely for a decade of giddy patience. After nine years in hibernation, New Horizons whizzed past Pluto at over 30,000 mph, passing within 4,800 miles of the dwarf planet’s surface.

Pluto, brought into sharp focus for the first time, was revealed as a far more interesting world than anyone expected. With mountains of solid ice reaching two miles high, vast planes of frozen nitrogen-methane “slush” that appear to be flowing like glaciers, and a thin hazy atmosphere reaching heights of 80 miles above the surface, we are still gasping at Pluto’s beauty and uniqueness six years after the encounter.

Following that flyby, New Horizons cruised onward into the Kuiper Belt, a wide swath of space beyond Neptune that contains multitudes of icy objects, mostly smaller than Pluto, circling the sun.

In 2019 New Horizons encountered one of these objects, later named Arrokoth, which is to date the most distant object visited by any spacecraft. Discovered with the Hubble Space Telescope in June 2014, Arrokoth was added to New Horizons’ post-Pluto itinerary as a target of opportunity. Scientists interested in how our solar system formed about 4.5 billion years ago wanted an up-close look at this example of a primitive “building block” object, the likes of which are believed to have come together to form the planets. 

New Horizons was bound for interstellar space since it launched, moving fast enough to escape the sun’s gravitational pull and coast forever outward into space, never to return home.  Today, it is more than 4.6 billion miles away, forging ahead through the vast region of the Kuiper Belt toward its inevitable departure from the solar system.

Voyagers 1 and 2: A Grand Tour

The twin Voyager spacecraft launched from Earth in 1977 on a five-year mission to explore the two largest planets of the solar system, Jupiter and Saturn. But as time went on, and the Voyagers continued in good health, NASA engineers became optimistic the spacecraft might operate for years beyond their expiration dates.

Then a rare alignment of planets offered an opportunity to send at least one of the Voyagers on to the planet Uranus and perhaps Neptune as well.

After capturing astounding close-up images of Jupiter and Saturn plus a host of their remarkable moons, mission planners engineered an end game that still tops all record charts.

Saturn’s gravity flung Voyager 2 toward Uranus, and the spacecraft arrived at the “ice giant” five years later, in 1986. Uranus, in turn, hurled Voyager 2 toward its final planet encounter, Neptune, in 1989. To date, Voyager 2 is the only spacecraft to have visited either of these worlds.

Voyager 1’s path through the Saturn system sent it by Titan, the ringed world’s largest moon. Titan’s size and thick atmosphere offered great scientific reward, trumping an alternative option to send the spacecraft to Pluto.

With most of their instruments still functioning after their final encounters, the Voyagers began new careers searching for the boundary of interstellar space, where the rarefied gases and magnetic fields flowing outward from the sun change like a shift in the wind to become the prevailing environment between stars.

Voyager 1 officially passed into interstellar space on Aug. 12, 2012. Voyager 2 made the crossing in 2018.

Today, Voyager 1 has traveled the greatest distance from home of any spacecraft, 152 astronomical units from Earth, or just over 14 billion miles—a distance that takes radio signals over 21 hours to cross.

Both Voyagers are still reporting back to Earth, more than four decades after their five-year missions began. Electrical power from their radioisotope thermoelectric generators has declined over the decades, and some of their instruments have been shut down to conserve what remains, but NASA estimates that Voyager 1 could remain functional until 2025.

Pioneers 10 and 11: Gone But Not Forgotten

Before the Voyagers’ epic tours came the first explorers of the outer solar system: Pioneers 10 and 11. Launched in 1972, scarcely a decade after the dawn of the space age, the Pioneers gave us our first up-close looks of Jupiter and Saturn and some of their moons. Before this, the gas giants’ enigmatic moons were known only as fuzzy points of light in Earth-based telescopes, and measurements of Jupiter’s magnetic field and intense radiation belts were crucial for designing the later Voyager and Galileo spacecraft. 

Pioneer 10 was the first spacecraft to cross the asteroid belt, to enter the outer solar system, and to fly past Jupiter, in 1973.  Afterward, Pioneer 10 continued on a solar escape trajectory that will carry it eventually to interstellar space, probably within the next three decades. The last radio signal we received from Pioneer 10 came in 2003.

Pioneer 11 flew past Jupiter, and then on to become the first spacecraft to visit Saturn, in 1979. The last radio signal received from Pioneer 11 came in 1995.

What’s Next for the Frontier Five?

While the youngster New Horizons may continue to actively explore objects and the environment of the Kuiper Belt for years to come, the ultimate fate of all five of our interstellar pioneers is to drift perpetually between the stars of the Milky Way, becoming galactic derelicts of human technology and space exploration.

More than a century ago the first propeller-driven aircraft took off on Earth.

On Monday, another one took flight for the first time on a different planet.

NASA’s experimental Mars Helicopter, Ingenuity, successfully lifted off the ground at 3:34 a.m. EDT — that’s around noon local Martian time in Jezero Crater, the current location of Ingenuity and the Perseverance rover. The flight data, sent from Perseverance and relayed by the Mars Reconnaissance Orbiter, was transmitted back to Earth almost three hours later. 

Ingenuity’s first flight took it straight up about 10 feet, where it hovered, made a small victory turn-in-place for Perseverance’s cameras, then settled back to the ground about 40 seconds after liftoff. Not a flight endurance record by tried-and-true Earth aviation standards, but certainly a one-small-hop-for-a-robot, one-giant-leap-for-interplanetary-exploration achievement. 

Ingenuity’s maiden flight had been scheduled for April 11, but was postponed when a software glitch failed to engage the system’s flight mode during a pre-flight rotor test. After some analysis and software testing, NASA Jet Propulsion Lab engineers worked out a fix and ran further tests before mission controllers approved another flight attempt. 

With more test flights planned in days ahead, engineers at JPL, located in Pasadena, California, will have further opportunity to hone their brand new Martian aviation skills. 

Proof of Concept

The Mars Helicopter is an add-on experiment to last year’s  Perseverance mission. Equipped with only an onboard computer, two small cameras and a wireless link to Perseverance, Ingenuity carries no science instruments; its entire mission is to provide proof of concept for aerial exploration of Mars, and maybe of other worlds. Even if it never leaves the ground again, Ingenuity has still achieved the mission’s primary goal.

As scientists and engineers conceive new designs for robots to move around the surfaces of other worlds, which to this point has all been done by wheeled rovers, Ingenuity’s successful flight opens a path to greater freedom for humans to explore areas where wheels cannot carry us. 

To achieve this flight, engineers at JPL had to meet some steep design challenges, not the least of which was to build a helicopter that can fly in Mars’ thin atmosphere, which is about a hundredth the density of Earth’s at sea level. Even helicopters on Earth that have reached the highest mountain peaks such as Mount Everest, where the air is still one-third as dense as it is at sea level, have strained the limits of conventional engine and rotor blade technology.

Ingenuity’s specially designed twin counter-rotating propeller blades must spin at around 2,500 revolutions per minute to lift the 1.8 kilogram (4-pound) craft off Mars’ surface. Mars’ lower surface gravity, which is 38% of Earth’s, makes the feat easier, but the low air density underscores the unearthly challenges of exploring other planets. 

Future missions may include airborne drones to perform aerial reconnaissance, collect rock and soil samples over a wider area, or even independently explore a much vaster region than a wheeled rover crawling carefully through an obstacle-laden terrain can. 

Perseverance landed on Feb. 18 in Mars’ Jezero Crater, on a mission to search for clues to ancient life locked in the rocks and soil of a dry lakebed and a formation of sediments washed into it long ago, when Mars possessed a wetter, more Earth-like climate.

The first Earth Day, on April 22, 1970, kicked off the modern environmental movement with more than 20 million Americans — 10% of the U.S. population — hitting the streets to demand action against unchecked pollution.

Now in its 51st year, the event has transformed into a global movement with participation by more than 1 billion people across 192 countries. This year’s theme is “Restore Our Earth,”  emphasizing the importance of enlisting natural processes, emerging green technologies and innovative thinking to restore ecosystems.

Last year, on its 50th anniversary, California EPA Secretary Jared Blumenfeld said Earth Day has had “a major impact on policy.”

“Back in 1970, we didn’t have the Clean Air Act, we didn’t have the Clean Water Act, we didn’t have any federal legislation, really, relating to the environment,” he said. “And people went out on the streets, made their voices heard.”

This year Earth Day will be mainly virtual again. But with the Bay Area slowly opening up, there are some in-person options, too. Just remember to mask up and social distance. Below are a few, mostly Bay Area events to put on your radar:

BANDALOOP
Earth Day Vertical Dance Rehearsal Outdoors
April 22 – 4-5 p.m., Oakland, In-Person Event
Celebrate Earth Day with aerial dance company BANDALOOP and special guests as the group unveils excerpts from its newest work, LOOM, weaving performance, research and education around the ancestral power and ecological impacts of textiles past, present and future. Event highlights include: Live music by Ben Juodvalkis, Chibueze Crouch, and Charles Peoples III. Special guest speakers include eco-somatic dance artist and inaugural BANDALOOP Artist-In-Residence Jes DeVille, and Phoenix Armenta from the West Oakland Environmental Indicators Project.

California Academy of Sciences
NightSchool: Earth Day for the People
April 22 – 7 p.m., Free Virtual Event
Get inspired by people and organizations radically changing both the health of the environment and their communities through “greenprint” projects that focus on sustainable development, environmental justice, and remaking the food system. Featured speakers include: Elizabeth Hiroyasu, landscape scientist at The Nature Conservancy of California; Dr. Mónica Ramírez-Andreotta, assistant professor at the University of Arizona and director of Project Harvest; and Ashley Yates, media director for Planting Justice.

Chabot Space and Science Center
Earth Day Screening: Saving the Dark
April 23 – 7 p.m., Free Virtual Event
Enjoy a special screening and discussion of “Saving The Dark,” a documentary about astronomy and light pollution. Event highlights include film producer Sriram Murali, joined by astronomers Richard Ozer and Gerald McKeegan, to discuss the costs of light pollution, including its effects on our health, wildlife and environment.

The Exploratorium
After Dark Online: Earth Day
April 22 – 7 p.m., Free Virtual Event
Discover the work of local organizations that expose inequitable impacts of climate change and advocate for environmental justice and legislation. Event highlights include: Conversations with youth leaders from Oakland-based Youth vs. Apocalypse and a virtual screening of the short film “My 25: The Ocean Between Us,” a student film that merges memories and reality to tell an intimate story of how our oceans have changed.

Golden Gate National Parks Conservancy
Earth Day Events
Make a Monarch Butterfly Kite for Earth Day!
April 22 – 11 a.m.-12 p.m., Free Virtual Event
Join National Park Service Ranger Rebecca Au and Price Sheppy as they take you step by step through building your own monarch butterfly kite to fly on Earth Day. You will also hear stories about the monarch butterfly and find out more about what you can do to help these beautiful animals.

Monitoring Frogs in the Golden Gate National Recreation Area
April 23 – Noon-1:30 p.m., Free Virtual Event
Learn about the common and uncommon frogs you can see in the Golden Gate National Recreation Area. Join the conversation and find out about efforts to reintroduce and monitor the California red-legged frog, a threatened population in the park.

International Ocean Film Festival (IOFF)
Earth Day Drive-in Screening at Fort Mason Center For Arts & Culture
April 22 – 8:30-10:30 p.m. Tickets Required, $49 Per Vehicle
IOFF is presenting a special screening of two of its 2021 award-winning films, “Ocean Souls” and “Whales in a Changing Ocean.” This screening is part of the 18th annual IOFF taking place virtually through May 2, showcasing more than 80 independent films, representing 17 countries, reflecting IOFF’s mission of restoring, protecting and balancing ocean biodiversity through independent films. If you can’t make it to the drive-in, these films are also screening virtually. Check out this year’s festival schedule at IntlOceanFilmFest.org

KQED
On Common Ground: Hyper-Local Climate Resilience
April 22 – 6 p.m., Free Virtual Event
Many people can adapt to climate change via migration, but for some, adaptation means finding the solutions to remain in place. KQED’s senior science editor, Katrin Snow, will moderate a conversation on how resiliency takes hold on a local level in two very different locations, Marin City and the Sierra Nevada. Special guests include: Terrie Harris-Green of Shore Up Marin City; Beth Rose Middleton Manning, professor and department chair of the Native American Studies Department at UC Davis; and guest reporter Janelle Marie Salanga, engagement reporting intern at the College Journalism Network.

National Aeronautics and Space Administration (NASA)
Earth Day 2021
April 21-23 – Multiday, Free Virtual Events
When you think of NASA, you might think of astronauts and missions to Mars. But NASA also has a variety of missions that focus on studying Earth, from sea level rise to hurricanes. NASA’s three-day Earth Day virtual event extravaganza features: Live presentations and chats with NASA Earth science experts; an interactive kid-friendly science fun zone with coloring and activity sheets; and Meet a Scientist videos. Plus, you can find out how you can be a scientist for NASA. There’s also an online scavenger hunt to kick off #GrowForLaunch, a chance to learn about plants grown in space and how you can start your own “space” garden.

Oakland Zoo
Earth Day Events
April 22-25 – 10 a.m.-3:30p.m., Timed Tickets Required, $24-$20, Free Virtual Activities
Celebrate animals and the planet and learn how to take action against the illegal wildlife trade. All guests must reserve a ticket for a specific date and entry time. Event highlights include an in-person scavenger hunt that will focus on animals that need saving from illegal wildlife trade. The zoo also has several online activities to help you act for the planet from the comfort of your own home, such as learning what plants attract pollinators such as bees, butterflies and hummingbirds.

The David Brower Center
Wild and Scenic Film Festival Earth Day 2021
April 22 – 7 p.m., Tickets Required, General $25, Student $15, Group Rates Available
The Wild and Scenic Film Festival, organized by Citizens Climate Lobby Alameda County, the David Brower Center, Earth Island Institute, Green the Church, and Communities for a Better Environment, is hosting a virtual Earth Day screening with films that tell extraordinary stories of local and global front-line communities fighting for environmental justice and restoration. After the live event on the 22nd, all films will be available on-demand from April 23-27. Included with every ticket is an on-demand bonus session featuring five films about threatened wildlife and efforts to protect their habitats and save them from extinction. Get $5 off with this special code: WSFFDBC.

Check your local event listings for additional Earth Day related community events in your neighborhood. And be sure to bookmark bayareascience.org for year-round science and environment events and festivals. Below is a reminder of a few things you can do to make every day Earth Day, courtesy of the National Oceanic and Atmospheric Association.

The only helicopter on Mars has done it again.

Ingenuity took off on its fourth flight Friday, reaching an altitude of 16 feet  and traveling a distance of almost three football fields — 872  feet — round trip, its longest sojourn yet. Airtime: Just short of two minutes.

Not even 2 feet tall, the spunky flier is part of NASA’s Perseverance mission, which has been exploring Martian terrain for over two months, and is still checking off first-ever achievements in planetary exploration from its ambitious to-do list. 

The Perseverance rover and its helicopter sidekick — nicknamed Percy and Ginny by some team members at NASA’s Jet Propulsion Laboratory — are just as busy proving technology concepts for future Mars missions as they are conducting scientific exploration. 

Besides the ever more daring flights by Ingenuity, the latest technical feats include Perseverance manufacturing oxygen directly from the Martian atmosphere.

Making 10 Minutes of Oxygen

To explore what valuable natural resources Mars offers future human missions, Perseverance has the MOXIE.

Actually, that’s the Mars Oxygen In-Situ Resource Utilization Experiment, a small, double-shoebox-sized device designed to produce up to 10 grams of oxygen per hour directly from the planet’s thin carbon dioxide atmosphere. 

On April 20, MOXIE produced 5 grams of oxygen by heating carbon dioxide to over 1,400 degrees Fahrenheit. Five grams may not seem like much, but it’s enough to last an adult for about 10 minutes of breathing. 

Future human missions would benefit hugely from making their own oxygen on Mars, not only for humans to breathe, but for making rocket fuel. On a planet where free oxygen is scarce, astronauts will breathe easier if they are not dependent on supplies brought all the way from Earth. The first quick visits to Mars will probably rely on stored oxygen, but longer habitations will require astronauts to tap such a valuable resource, as well as water,  where they find it, living off the land.   

Ingenuity Aces Flying Tests

The Mars Helicopter’s mission to demonstrate the feasibility of aerial exploration of the planet got off to a flying start on April 19 with the first-ever powered flight on another planet, a 40-second hover maneuver that lifted it about 10 feet off the ground. But this was only the beginning of a 30-day testing program still underway. 

If the altitude of 16 feet attained by the helicopter on Friday and the flight before doesn’t seem very high, consider that Mars’ atmospheric pressure at ground level is equivalent to Earth’s at an elevation of 100,000 feet. Ingenuity’s feathery 4-pound weight and specially designed twin rotors spinning at 2,500 rotations per minute allow it to fly where conventional helicopters couldn’t.  

What’s ahead for Ingenuity? NASA just announced that the helicopter’s mission has been extended by an additional 30 days, and will enter a new phase of flight testing following its sixth flight in about two weeks.

After that, unless NASA adds another extension, Ingenuity will be grounded and the rover will move on with its mission to search for clues of past life on Mars. 

Asked if “Ginny” could be used for reconnaissance to aid the rover’s scientific mission, one JPL team member commented there is no need since “Percy’s” general route has already been mapped out and the rover will drive autonomously between programmed points of scientific interest. 

Jon Brooks contributed to this post.

Venus is back on the menu for space exploration!

NASA announced the selection of not one, but two new missions to Earth’s closest planetary neighbor. 

The first mission — Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging, or just DAVINCI+ — will investigate Venus’s atmosphere, and launch a probe into its thick, hot, acidic clouds to measure their composition and conditions directly. DAVINCI+ will also capture the highest resolution images ever taken of Venus’s surface, including an unusual feature called “tesserae.” Some scientists believe these “tesserae” might be a Venusian version of Earth’s continents, minus the bordering oceans that define them. 

The second mission — Venus Emissivity, Radio Science, inSAR, Topography, and Spectroscopy, or VERITAS — will examine Venus’s surface, using radar to penetrate the planet’s thick clouds and create a detailed global geologic map. VERITAS will search for active volcanoes, and investigate a long-standing mystery. Venus appears to have suffered a global cataclysmic event that completely reshaped its surface in the past, but we don’t yet know why or what happened. 

Both missions are expected to launch sometime around 2028 to 2030. 

A Long Awaited Return

The last mission NASA sent to Venus was Magellan, over 30 years ago. Since that time, only spacecraft bound for other destinations, such as the Mercury explorer MESSENGER and the solar deep-dive Parker Solar Probe, have swung briefly by Venus, using the planet’s gravity to steer their course. 

The intensely hot, high-pressure environment on Venus is one reason for the dearth of active exploration there.  Also, researchers believed that it is not a world where they could hope to find life  — unlike Mars, where the missions Curiosity and Perseverance are intensely examining that possibility.  

Venus is a very different planet than Earth, and its harsh environment makes exploring its surface a huge technological challenge. Global surface temperatures hold constant around 470 degrees Celsius, hot enough to melt lead, and its atmospheric pressure is equal to the water pressure a kilometer deep under Earth’s oceans. The few spacecraft that have ever landed there did not last long before succumbing to the hellish conditions.

Is Venus Earth’s ‘Evil Twin’?

But there are striking similarities between Venus and Earth. Venus is almost the same size as Earth, unlike Mars, which has received so much attention from NASA and other space agencies over the decades even though it’s about half the size of Earth. 

And though Venus is closer to the sun, the extreme temperature of its atmosphere can be attributed in large part to a dominance of carbon dioxide, a greenhouse gas that traps solar energy in the form of heat. 

Observations of Venus’s atmospheric chemistry have fueled a hypothesis that the hell-world of today may have once been more temperate, with a cooler atmosphere, oceans of water, and possibly life-friendly conditions. What happened to change Venus’s environment so profoundly is a question NASA hopes its two new missions will help answer. 

Was There Ever Life on Venus?  Does Life Exist There Now?

The detection of the molecule phosphine high in Venus’s atmosphere by a team of researchers in the United Kingdom has raised new questions about the possibility of life on what was once thought to be an inhospitable world. 

Phosphine is a chemical found on Earth in association with certain biological processes, such as some anaerobic microbes (ones that do not need oxygen to live), the decomposition of organic matter, as well as human industrial activity, so its presence on Venus is an eye-opening surprise. 

Given Venus’s crushing surface pressure and roasting temperature, it’s hard to imagine any form of life existing there, but conditions at higher altitudes are more forgiving. At heights of 30 to 40 miles above Venus’s surface, the pressure and temperature in the atmosphere are similar to those on Earth’s surface. 

If oceans once existed on Venus, they likely evaporated as temperatures soared. But what happened to turn up the heat? 

Was there life on Earth’s closest sibling-planet? What was it like? Could life of some form still thrive there today, high up in the atmosphere, a safe distance away from Venus’s punishing surface?

Venus holds many tantalizing mysteries, and NASA is doubling down on solving them.

In 2018, a highly sophisticated instrument probing the surface of Mars called MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) detected radar echoes from an area deep beneath the dry, frigid surface of the planet’s southern polar region.

A group of researchers analyzing that data from the European Mars Express spacecraft were excited by a tempting possibility: the radar pings could have reflected off a lake of liquid water laying hidden below the surface of the planet, a protected underworld.

Later, the researchers identified several more similar reflections nearby. And just last month, two scientists from NASA’s Jet Propulsion Laboratory reported finding dozens of the unusual formations, deepening the mystery further.

The JPL scientists, examining 15 years of MARSIS observations, found the lake-like, radar-reflecting bodies were actually spread across an area much broader than suggested by the original findings from back in 2018, and at greater range of depths below the planet’s surface. The region surrounds Mars’ South Pole.

All of this research raises a tantalizing question: Are there lakes hiding on Mars?

Ghost Lakes, or Something Else?

If the MARSIS radar reflections are caused by pools of actual, liquid water, researchers will have found another place in the solar system with the potential to harbor a life-friendly environment; a possible gold mine for astrobiologists searching for life beyond Earth.

But, there’s reason to be skeptical.

Some of the so-called lakes are within a mile of Mars’ polar surface, where temperatures, as low as -63 degrees Celsius, should freeze water solid. Even briney water with a colder freezing point has little chance of remaining liquid under these frigid conditions.

Could heat flowing outward from deep within Mars keep temperatures near the planet’s surface warm enough to thaw ice? Might there be active volcanism going on down there?

Maybe.

Researchers have considered these possibilities, but find them unlikely. The flow of heat from Mars’ interior would need to be double what scientists understand the planet’s internal thermal dynamics are capable of.

And they haven’t identified any strong evidence of current or recent volcanic activity at the South Pole, which throws a brick of frozen ice on that idea.

So, lakes? Yes or no? At this time, the answer is not certain one way or the other.

The dozens of mysterious radar reflections spread around Mars’ South Pole are like a swarm of ghosts: we have sensed their presence, but so far their true nature eludes explanation.

Clues to Mars’ Past?

Whatever the unusual radar reflections detected by MARSIS turn out to be, their discovery and further investigation may yield more clues to secrets of Mars’ past.

Scientists are interested in what Mars’ southern polar region can tell us about the planet’s climate history.

Over the last billion or so years, Mars’ climate shifted between warmer, wetter conditions and cold, dry spells. Layer upon layer of water-ice, frozen carbon dioxide, and dust have built up to form a vast ice cap. By studying the layers, scientists can learn about the planet’s past, similar to how paleoclimatologists on Earth track ancient climate by studying the growth rings of trees or the surface of granite boulders embedded in glacial moraines.

The Hunt For Water on Mars

Mars exploration is all about the search for liquid water, and the possibly life-friendly environments it could nurture. Scientists are thirsty to find Martian water, wherever and whenever it may have existed: flowing down crater walls in seasonal bursts; underground, away from the dry, frigid conditions on the planet’s surface; or deep in Mars’ distant past.

That Mars long ago possessed copious amounts of liquid surface water is an almost indisputable fact, based on many observations and measurements by orbital spacecraft, landers and rovers.

The Curiosity rover is currently crawling up the slope of a mountain in a 90-mile wide crater that once held a vast lake. The newer Perseverance robot is prospecting the dry lakebed of Jezero Crater, as well as a complex of sediments deposited by a river that once flowed into it.

Both rovers are probing mineral and geological clues left behind by water now long dried up, piecing together a window into Mars’ past environment.

But can the life-giving liquid be found anywhere on Mars today?

Only further exploration can answer this.