And Then There Were Three: ESA Follows NASA in Selecting a Mission to Venus

Artist illustration of the EnVision orbiter at Venus (ESA/VR2Planets/DamiaBouic)

It was quite a week for Venus scientists. Just seven days after NASA announced the selection of two Venus missions, DAVINCI+ and VERITAS, the European Space Agency (ESA) revealed that a third Venus mission had been chosen for the agency’s medium-class mission category.

(See last week’s post here on Many Worlds about DAVINCI+ and VERITAS)

The new mission is named EnVision, and will be ESA’s second Venus mission following Venus Express (2005 – 2014), which investigated the Venusian climate. While EnVision is an orbiter like Venus Express and VERITAS, its focus is the planet’s geological circulation system that links the atmosphere, surface and interior.

In case you are starting to get your Venus missions in a tangle, the set can be broadly divided up as follows:

Venus Express (ESA: 2005 – 2014) and Akatsuki (JAXA: 2015 – current) are both Venus orbiters focussed on the planet’s climate, returning information about the rapidly rotating upper atmosphere and acidic cloud deck of Venus.

DAVINCI+ (NASA: est. 2029 launch) is an orbiter and descending probe that will dive through the Venusian atmosphere to return top-to-bottom data on the planet’s stifling gases.

VERITAS (NASA: est. 2028 launch) is an orbiter focussed on Venus’s surface and the deep interior. VERITAS will bring us global maps in three-dimensions at a resolution of 30m. This will knock the socks off our current images from NASA’s Magellan orbiter (1989 – 1994), which had a resolution of around 200m.

EnVision (ESA: early 2030s) is the mission focused on how these environments are linked together. Equipped with an instrument suite that covers the top of the atmosphere through to below the planet surface, EnVision will probe how the different regions influence one another to create the planet’s internal systems.

“EnVision has a holistic approach,” explained Jörn Helbert who is a member of the EnVision team. “The larger and more complex payload studies Venus from the top of the atmosphere all the way to the subsurface, with a focus on understanding how the coupled system on Venus works.”

Artist illustration of the EnVision spacecraft, reflecting the goal of understanding why Venus and Earth are so different (NASA / JAXA / ISAS / DARTS / Damia Bouic / VR2Planets).

The coupled system is at the heart of how habitability can develop on rocky planets. A major player in the Earth’s environment is the ability to cycle carbon between the atmosphere, surface and planet mantle.… Read more

Return to Hell: NASA Selects Two Missions to Venus to Explore the Pathway to Habitability

Artists’ renderings show the VERITAS spacecraft (left) and DAVINCI+ probe (right) as they arrive at Venus (Lockheed Martin).

For NASA scientists, Venus missions must feel like buses. You wait thirty years for one, and then two come along at once.

Last week, NASA selected two Venus missions for the space agency’s Discovery Program; solar system exploration missions that can tuck under a lower cost cap than candidates for NASA’s New Horizons or Flagship categories. The first of these is DAVINCI+, which is an orbiter equipped with a descending probe that will take a big whiff of Venus’s stifling atmosphere. The second is the VERITAS orbiter that plans to peer through the clouds to scrutinise the Venusian surface.

While Europe and Japan have both visited Venus more recently than NASA (in fact, the Japanese orbiter is still there), there is little doubt that our inner neighbor is dramatically under-explored compared to Mars. But why the past neglect, and why go twice now?

The answer to the first question is perhaps the easiest.

Venus is hell.

The planet is wrapped in a thick atmosphere consisting of carbon dioxide and clouds of sulfuric acid that beat down on the Venusian surface with pressures nearly one hundred times higher than on Earth and create temperatures sufficient to melt lead.

These conditions have made it difficult to follow the usual pattern of planetary exploration from fly-bys and orbiters to landers and rovers. The Venusian surface is so inhospitable that a rover like NASA’s Mars Perseverance would become rover goop. Although recent engineering combined with high-temperature electronics means that the surface is no longer impossible, it does greatly add to the challenge (and therefore cost) of a lander mission.

Professor Stephen Kane, University of California, Riverside.

Hell-scape conditions have also resulted in Venus being overlooked for any astrobiological studies compared to (the still rather nasty but at least you can stand a rover on the surface) Mars. This makes the urgency to explore Venus now particularly surprising. The missions are a quest to understand habitability. The bottom line is that the hell world of Venus is essential to understanding how a planet becomes habitable and to discovering other habitable worlds outside our solar system.

“Imagine you live in a small town full of life,” explains Professor Stephen Kane from the DAVINCI+ team. “The nearest town is the same size and seems it was once identical. But now, it’s burned to the ground with no sign of life.… Read more

Sure UFOs Exist. But There’s No Reason To Conclude That Aliens Are Flying Them

An apparently unidentified object detected on a Navy plane’s infrared camera. (U.S. Department of Defense/Navy Times)

It seems to happen with some regularity.  Claims that Unidentified Flying Objects are visiting us have captured the public imagination once more and a big reveal is expected soon.

That will come, oddly, from a government report required to be released by the end of June that will supposedly detail the many sightings made by high-flying military pilots and unexplained detections by satellites.  The requirement was added to the Covid relief package that was passed by Congress in December and orders the Department of Defense and the Office of the DIrector of National Intelligence to release their unclassified findings on the subject, information that has been apparently collected for decades.

In terms of national defense, these reports could indeed be meaningful.  If other nations are sending

This well known poster was first introduced during an episode of the 1990s television show, “The X Files.” and featured in a subsequent movie.

drones or satellites of some sort (true UFOs) to get close to and study American assets, then that’s important news.

But, of course, the UFO drama is overwhelmingly about something else:  The claimed presence of intelligent aliens that are scoping out Earth for reasons ranging from awe-inspiring or extremely worrisome.

The report — which sources say concludes that there is insufficient evidence to confirm or conclusively rule out extraterrestrial UFO sightings —  will no doubt be widely consumed by a population with many “UFO believers.”  After all, a 2019 Gallup poll found that 33 percent of American adults said that alien spacecraft from distant planets and galaxies have been visiting us.

I find all this to be not only unfortunate but also misguided and potentially damaging.  The moment will pass with no intelligent aliens identified, and then will return again some time in the future for another round.

The potential damage is to the very real, very challenging, very cutting-edge science being conducted around the world that seeks to identify actual signs of actual extraterrestrial life in the cosmos, or at least to know what to look for when we have space telescopes and instruments with the necessary power.

And I’m concerned that a focus on UFOs imagined to be carrying intelligent alien life takes away from the hard-won seriousness of their enormous and so compelling scientific effort.  This is especially true now that the scientific search for extraterrestrial life is on the front burner for the National Academy of Sciences, which will soon make recommendations about a next grand observatory for the 2030s.… Read more

China’s Presence in Space Grows and So Do Its Accomplishments

The Chinese Mars lander, with photo taken by the Zhurong rover after it rolled down onto the surface of Mars. (Chinese National Space Administration)

These are heady days for the Chinese space program.

On the heels of a successful 2019 mission to the dark side of the moon and the launch of the core of an ambitious low Earth orbit space station,  the Chinese National Space Administration has done what only NASA has accomplished before — landing a rover on Mars and then setting it into motion on the surface of the planet.

The Zhurong rover, which is named after an ancient fire god in Chinese mythology, rolled off its lander on Saturday and has begun its planned three-month mission.

The rover carries instruments to study the planet’s surface rocks and atmosphere using radar, spectroscopy and a magnetic field detector. It will also look for signs of life, including any subsurface water or ice.

The solar-powered, 530-pound and  six-wheeled robot will be exploring Utopia Planitia in Mars’ northern hemisphere – the general area where NASA’s Viking 2 lander touched down in 1975.  Zhurong will join NASA’s much larger (more than 2,200 pound) Perseverance and Curiosity rovers now operating on Mars.

“We hope we can get a comprehensive covering of Martian topography, landform and environment, and the exploratory data of the radar detecting the Martian subsurface during one Martian year,” said deputy chief commander of the mission, Zhang Yuhua.

“By doing so, our country will have our own abundant and first-hand data about Martian resources,” she said.

The Chinese Mars lander is powered by solar panels and is expected to explore for at least three months.  (Rendering by the Chinese National Space Administration)

While the rover will itself not bring many new technologies and approaches to Mars science, the architecture of the mission is unprecedented.  The Tianwen-1 spacecraft that brought the rover to Mars orbited the planet for more than three months before deploying the lander and rover.  Part of the spacecraft will remain in orbit as a communications hub.

All NASA missions have flown directly to the surface without first going into orbit around Mars.

While the Utopia Planitia region was explored to some extent by Viking 2, much more is known about the region now then was known in the 1970s.

The plains are part of the northern lowlands of Mars, and some theorize that the region was once covered by a great “Northern Ocean.”  Read more

Breakthrough Listen Searches The Crowded Center of the Milky Way for Possible Signals From Intelligent Beings

The Galactic Center from radio to X-ray frequencies.  ( X-Ray: NASA, CXC, UMass, D. Wang et al.; Radio: NRF, SARAO, MeerKAT)

Searching for technologically advanced civilizations inhabiting distant exoplanets is the astrobiological equivalent of swinging for the fences.

While much of the search of extraterrestrial life is now focused on microbes and chemical biosignatures in exoplanet atmospheres that would likely be byproducts of life, the search for extraterrestrial intelligence (or SETI) takes a very different approach.

SETI practitioners scan the skies for radio signals, and now laser signals, that are irregular and different from what is naturally produced.  Were such a signal to be detected, then it would be studied as the potential work of extraterrestrial life that is highly advanced — perhaps far more so than we Earthlings.

This search has been going on since Cornell University astronomer Frank Drake began it 1960 and has advanced (in steps large and small) ever since.  The biggest financial boost to the search took place five years ago when techno-billionaire Yuri Milner, in partnership with Stephen Hawking and other prominent scientists,  set up the Breakthrough Listen project with $100 million to buy telescope time and to greatly expand the SETI search.

And as part of that expanded search, radio telescopes focused on the crowded galactic center of the Milky Way for 600 observing hours.  The thinking was that stars and likely exoplanets are most plentiful in that central region — some 60 million  stars in the line of sight into the galactic center at low astronomical frequencies; 500,000 at higher frequencies  — and so the chances of finding a signal were perhaps higher.

Some preliminary and partial results of that effort were recently released and, unfortunately, no signals were found.  That has been the fate of all SETI searches so far.

But as SETI scientists explain, the night sky is huge and the percentage of stars (and their exoplanets) that have been sampled remains quite small.

The Green Bank Radio Observatory in West Virginia is one of the two main sites for the Breakthrough Listen galactic center campaign.  The other is the Parkes Telescope in Australia . (NRAO)

This latest effort was unique in that it was the “most sensitive and deepest targeted SETI” survey ever done of the galactic center, as the SETI scientists write in a study set to be published in the Astronomical Journal (a preprint is currently available on the arXiv).… Read more

Novel Sights and Sounds on Mars


The helicopter Ingenuity has now flown three times on Mars and has proven itself to be a dependable (for now) and potentially ground-breaking addition to Mars science.

Ingenuity, brought to Mars as part of the Perseverance rover landing, took off early Sunday morning on its third and most ambitious Martian mission yet.  The 4-pound helicopter traveled a total of 330 feet laterally, stayed aloft for 80 seconds and reached a maximum speed of about 4.5 mph, handily breaking marks set on its previous two flights.

In the video above, you can see the helicopter taking off on the bottom left, crossing the screen, and then coming back a bit later to land in the same spot.

The “flight was what we planned for, and yet it was nothing short of amazing,” said Dave Lavery, the Ingenuity program executive at NASA Headquarters. “With this flight, we are demonstrating critical capabilities that will enable the addition of an aerial dimension to future Mars missions.”

If this capacity proves to be robust it will clearly have many positive implications for Mars science with successor rotorcraft — allowing scientists to quickly study areas surrounding a rover and to put their discoveries into larger geological contexts.

Ingenuity rover preparing to go airborne. The wings, legs and more were folded up for its long ride to Mars and then robotically unfurled on the Martian surface. (NASA)

The Mastcam-Z imager aboard NASA’s Perseverance Mars rover, which is parked at “Van Zyl Overlook” and serving as a communications base station, captured video of Ingenuity.

The Ingenuity team has been pushing the helicopter’s limits by adding instructions to capture more photos of its own – including from the color camera, which captured its first images on the second flight. As with everything else about these flights, the additional steps are meant to provide insights that could be used by future aerial missions.

The helicopter’s black-and-white navigation camera, meanwhile, tracks surface features below, and this flight put the onboard processing of these images to the test. Ingenuity’s flight computer, which autonomously flies the craft based on instructions sent up hours before data is received back on Earth, utilizes the same resources as the cameras.

If Ingenuity flies too fast, the flight algorithm can’t track surface features.

On Earth, NASA sought to simulate those conditions in NASA’s Jet Propulsion Lab vacuum chambers, which were filled with wispy air consisting primarily of carbon dioxide. … Read more

The Hows and Whys of Mars Sample Return

Combining two images, this mosaic shows a close-up view of the rock target named “Yeehgo” taken by the SuperCam instrument on NASA’s Perseverance rover on Mars. To be compatible with the rover’s software, “Yeehgo” is an alternative spelling of “Yéigo,” the Navajo word for diligent.

One of the fondest dreams and top priorities of space science for years has been  to bring a piece of Mars back to Earth to study in the kind of depth possible only in a cutting-edge laboratory.

While the instruments on Mars rovers can tell us a lot,  returning a sample to study here on Earth is seen as the  way to ultimately tease out the deepest secrets of the composition of Mars, its geological and geochemical history and possibly the presence of life, life fossils or of the precursor molecules  of life.

But bringing such a sample to Earth is extraordinarily difficult.  Unlike solar system bodies that have been sampled back on Earth — the moon, a comet and some asteroids — Mars has the remains of an atmosphere.  That means any samples would have to lift off in a rocket brought to Mars and with some significant propulsive power, a task that so far has been a technical bridge too far.

That is changing now and the Mars Sample Return mission has begun.  The landing of the Perseverance rover in Jezero Crater on Mars signaled that commencement and the rover will be used to identify, drill into and collect intriguing bits of Mars.  This is a long-term project, with the best case scenario seeing those Mars samples arriving on Earth in a decade.  So this entirely unprecedented, high-stakes campaign will be playing out for a long time.

“I think that Mars scientists would like to return as much sample as possible,” said Lindsay Hays, NASA Mars Sample Return deputy program scientist.  “Being able to return samples that we collected with purpose is how we take the next step in our exploration of Mars.”

“And it seems that there are still so many unknowns, even in our solar system, even with the planets right next door, that every time we do something new, we answer a couple of questions that we hoped to and but also find a whole bunch of new things that we never expected.”

“I am so excited to see what comes of this adventure.  And I think that is a feeling shared by Mars scientists and planetary scientists broadly.”… Read more

The Space Telescope That Could Find a Second Earth

This rare picture of an exoplanet (called 2M1207B) shows a red world several times Jupiter’s size orbiting a brown dwarf much smaller and dimmer than our sun. LUVOIR is after more elusive targets: small, rocky planets around bright stars. (ESO)

What will it take to capture images and spectra of a distant world capable of harboring life?
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For all the excitement surrounding the search for distant exoplanets in recent years, the 4,000-plus planets confirmed so far have been unseen actors on the cosmic stage. Except for a handful of very large bodies imaged by ground-based telescopes, virtually all exoplanets have been detected only when they briefly dim the light coming from their host stars or when their gravity causes the star to wobble in a distinctive way. Observing these patterns and using a few other methods, scientists can determine an exoplanet’s orbit, radius, mass, and sometimes density—but not much else. The planets remain, in the words of one researcher in the field, “small black shadows.”

Scientists want much more. They’d like to know in detail the chemical makeup of the planets’ atmospheres, whether liquid water might be present on their surfaces, and, ultimately, whether these worlds might be hospitable to life.

Answering those questions will require space telescopes that don’t yet exist. To determine what kinds of telescopes, NASA commissioned two major studies that have taken large teams of (mostly volunteer) scientists and engineers four years to complete. The results are now under review by the National Academy of Sciences, as part of its Decadal Survey for Astronomy and Astrophysics that will recommend government funding priorities for the 2030s. Past and current NASA mega-projects, from the Hubble Space Telescope launched in 1990 to the James Webb Space Telescope, which is scheduled for launch this year, have all gone through this same vetting process. Sometime this spring, the Decadal Survey is expected to wrap up its deliberations and make recommendations.

That puts four proposals in the running to become NASA’s next “Great Observatory” in space: an X-ray telescope called Lynx; the Origins Space Telescope for studying the early universe; and two telescopes devoted mostly, but not exclusively, to exoplanets. One is called HabEx, for Habitable Exoplanet Observatory. The other—the most ambitious, most complex, most expensive, and most revolutionary of all these concepts—is called LUVOIR, for Large UV/Optical/IR Surveyor.… Read more

What Happened to All That Water on Ancient Mars? A New Theory With a Surprising Answer

How did Mars lose the surface water that was plentiful on its surface 3 to 4 billion years ago?  New research says it did not leave the planet but rather was incorporated on a molecular level into Martian minerals.  (NASA)

Once it became clear in the past decade that the surface of ancient Mars, the inevitable question arose regarding what happened to it all since the planet is today so very dry.  And the widely-accepted answer has been that the water escaped into space, especially after the once thicker atmosphere of Mars was stripped away.

But NASA-funded research just made public has a new and bold and very different answer:  Much of the water that formed rivers, lakes and deep oceans on Mars, the research concludes, sank below the planet’s surface and is trapped inside minerals in the planet’s rocky crust.

Since early Mars is now thought to have had as much surface water as half of the the Earth’s Atlantic Ocean — enough to cover most of Mars in at least 100 meters of water — that means huge volumes of water became incorporated into the molecular structure of clays, sulfates, carbonates, opals and other hydrated minerals.

While some of the early water surely disappeared from Mars via atmospheric escape, the new findings, published in the latest issue of Science, conclude that atmospheric loss can not account for much or most of its water loss — especially now that estimates of how much water once existed on the surface of the planet have increased substantially.

“Atmospheric escape doesn’t fully explain the data that we have for how much water actually once existed on Mars,” said Eva Scheller, lead author and a doctoral candidate at the California Institute of Technology.  The rate of water loss was found to be too slow to explain what happened.

Scheller and others at Caltech set out to find other explanations. Based on modeling and data collected by Mars orbiters, rovers and from meteorites, they concluded that between 30 and 99 percent of that very early Martian surface water can now be found trapped in the minerals of the planet’s crust.

Mars mudstone, as imaged by the Curiosity rover.  (NASA/JPL-Caltech)

As described in a release for NASA’s Jet Propulsion Laboratory, the team studied the quantity of water on Mars over time in all its forms (vapor, liquid, and ice) and the chemical composition of the planet’s current atmosphere and crust through the analysis of meteorites as well as using data provided by Mars rovers and orbiters. … Read more

A Close Exoplanet Found That May Have An Atmosphere Ideal For Study

Planet Gliese 486b is close to us (in a relative sense), rocky, on the small side and may have an atmosphere.  These conclusions come from studying the planet using both the transit and radial velocity techniques, which have been the primary methods used by astronomers to find and characterize exoplanets.  Charts showing the presence of the planet using both techniques are in the blue boxes. (Render Area, Max Planck Institute for Astronomy, MPIA)

Different methods of searching for and finding distant exoplanets give different information about the planets found.

The transit method — where an exoplanets passed in front of its sun and dims the bright sunlight ever so slightly — gives astronomers not only a detection but also its radius or size.

The radial velocity method — where an exoplanet’s gravity causes its host star to “wobble” in a way that can be measured — provides different information about mass and orbit.

If a planet can be measured by both the transit and radial velocity methods, an important added dimension can be determined — how dense the planet might be.  This tells us if the planet is rocky or gaseous, watery or even if it has a central core and might have an atmosphere.  So many things have to go right that this kind of dual detection has seldom been accomplished for a  relatively small and rocky planet, but such a new planet has now been found.

The planet, Gliese 486b, is a super-Earth orbiting its host star at only 24 light-years away.  That makes the planet the third closest transiting exoplanet to Earth that is known, and the closest with a measured mass that transits a red dwarf star.

The authors of the study in the journal Science say Gliese 486b is an ideal candidate for learning how to best search for and characterize an all-important atmosphere, and to study potential habitability, too.  Future telescopes will make this kind of work more of a reality.

“Gliese 486 b is not hot enough to be a lava world,” lead author Trifon Trifonov of the Max-Planck-Institut für Astronomie and colleagues write. “But its temperature of ~700 Kelvin (800 degrees Fahrenheit) makes it suitable for emission spectroscopy and …. studies in search of an atmosphere.”

Artist impression of the surface of the newly discovered hot super-Earth Gliese 486 b. With a temperature of about 700 Kelvin (almost 800 degrees Fahrenheit), 486b possibly has an atmosphere.

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