Space Science In Peril


NASA’s decades-long success at enabling ground-breaking discoveries about our planet, our solar system, our galaxy, our origins and the billions of other planets out there is one of the crown jewels of our nation’s collective inventiveness and will, and surely of our global soft power.

Others have of course made major contributions as well.  But from the Viking Mars landings of the 1970s on to the grand space observatories Hubble and Spitzer and Chandra, to the planetary explorations such as Cassini (Saturn), Galileo and Juno (Jupiter), New Horizons (Pluto and beyond) and Curiosity (Mars), to the pioneering exoplanet census of Kepler, the myriad spacecraft enhancing our understanding of our own planet and the sun, and the pipeline confidently filled with of missions to come, NASA has been the consistent and essential world leader.

What we know of our world writ large has just exploded in these decades, and we’re far richer for it.

But of late, the future of these efforts to ever expand our knowledge of the logic and make-up of our universe has become worryingly unclear.

First there are the recently revealed new problems with the James Webb Space Telescope, initially scheduled to launch years ago and now reportedly unlikely to meet its launch date next year.  It is also over budget again and under serious threat.

This news came as Congress wrestled with the White House decision to scuttle the WFIRST dark energy, planet and star formation, and exoplanet mission, planned as NASA’s major flagship mission of the 2020s.

And perhaps most worrisome, NASA now wants to fold its Space Technology Mission Directorate into the Human Exploration and Operations Directorate, surely to support the administration’s goal of setting up a human colony on the moon.

This is an Apollo-sized, many-year and very costly effort that would have to take funds away from potential space science missions unless the NASA budget was growing substantially. But the proposed 2019 NASA budget would cap spending for the next four years.

Might our Golden Era of space discovery be winding down?

An illustration of the James Webb Space Telescope after deploying in space.  The pioneering technology of the JWST is both its great promise and recurring pitfall. (NASA)

First the JWST situation.  The telescope, far more powerful and complex than anything sent into space, is expected to open up new understandings about the origins of the universe, xxx, and exoplants.

But late last month, the General Accounting Office released a report that said:

“The James Webb Space Telescope, the planned successor to the Hubble Telescope, is one of NASA’s most complex and expensive projects.

“NASA recently announced that JWST’s launch would be delayed several months, from October 2018 to no later than June 2019, because components of the telescope are taking longer to integrate than planned.

“Based on the amount of work NASA has to complete before JWST is ready to launch, we found that it’s likely the launch date will be delayed again. If that happens, the project will be at risk of exceeding the $8 billion cost cap set by Congress.”

That cost cap was put in place in 2011, after a House subcommittee voted to end the project entirely because of overruns.  The full Congress then agreed to continue funding but only to the $8 billion mark.

Will Congress agree to more money if the agency needs more time to complete launch preparations?  Or will the money have to come out of the existing NASA budget?  It seems highly unlikely that the project will be halted but all the overruns and delays — often based on the difficulties associated with new technologies — cast a pall of sorts over plans for big space science projects in the decades ahead.

The long-term ramifications of the JWST delays and overruns could be substantial.  The space community began pushing in the 1970s for the launching of a new grand space observatory every decade, and the science and public engagement results have been tremendous.  The process of selecting a grand observatory mission for the 2030s is underway now, with teams of scientists and engineers feverishly gathering ideas, data, technology know-how and cost predictions for four contenders.

Two focus on astrophysics and questions about the make-up and origins of the universe and two on exoplanets and the effort to determine if some might have the conditions that could support life and, perhaps, might actually do so.  Those two are the Habitable-Exoplanet Imaging Mission (HabEx), and Large Ultraviolet-Optical-Infrared Surveyor (LUVOIR).

Both are likely to be quite costly, and LUVOIR in particular.  But unlike HabEx, LUVOIR would have the power and kinds of instruments needed to determine not only if life might be possible on an exoplanet, but potentially if that life is present.  It would be a Hubble on steroids — a dream observatory that would have the ability to transform (or greatly deepen) space science.

If it is restored to the NASA budget, WFIRST would survey distant galaxies looking for the effects of dark matter, that mysterious stuff that can’t be seen or touched but outnumbers normal matter by roughly 5 to 1. The telescope would study Type Ia supernovas to track dark energy, that strange repulsive force that is causing the universe to expand faster and faster. The observatory could  use its instruments to explore the planets around other stars and to better understand how stars and planets are formed . (NASA)

But the enormous promise of a LUVOIR or HabEx helps explain some of the scientific dismay about the administration’s decision to cancel NASA’s  “flagship” observatory of the 2020s, the Wide Field Infrared Survey Telescope (WFIRST.)

Selected in 2010 by the space science community and later the National Academy of Sciences as the priority mission of the 2020s,  WFIRST would focus on the nature of dark matter, the expansion of the universe, and would push forward some exoplanet observing as well.

So cancelling of the mission — if Congress now allows that to happen — would not only eliminate an important observatory that would keep NASA in the forefront of space astrophysics, but would also send a message that even being selected as the top priority space mission for the decade does not provide ironclad protection.

At space subcommittee hearing of the House Science Committee with NASA Acting Administrator Robert Lightfoot, Rep. Ami Bera (D. Calif.) voiced that concern earlier this month.

“The decadal survey has served us well, and not looking at this scientific-based prioritization and moving away from that can certainty set a dangerous precedent,” Bera warned.

James Irwin on the moon during the Apollo 15 mission of the summer of 1971.  While Apollo was an enormous success, it took up large percentages of the NASA budget between 1964 and 1972.  The peak was 1967, when it accounted for 70 percent of the NASA budget.  In all, the program cost the 2016 equivalent of $107 billion.  (NASA)

The elephant in the room in this discussion is easy to identify — the administration’s well-publicized desire to set up an on-going human colony of Americans on the moon, or at least to get American astronauts back on the lunar surface during the 2020s.  The stated goals are exploration, commercial and international joint ventures and geopolitics, with seldom a mention of science.

The proposed 2019 budget does not set aside a great deal of money for the moon project, but it does do something that worries many former NASA leaders and NASA followers — the funding for space technology and innovation ($1 billion) will now be housed within the human exploration directorate, as “Exploration Research and Technology.”

The stated logic is that technological advancement should be directed toward human space exploration.

“The FY 2019 budget is restructured to align with the Administration’s new space exploration policy by consolidating and refocusing existing NASA technology development activities on space exploration,” the budget document reads.

This will inevitably take some funds away from technology projects that could be useful across NASA’s directorates, but more important sets the stage for a ramp up in funding for moon missions in the years ahead.  And since the proposed 2019 budget would cap NASA funds for the next four years, other NASA programs would have to suffer — most notably Earth sciences and other science exploration unrelated to the moon.

Seldom discussed by those excited by the prospect of continuing the legacy of the Apollo program and having Americans return to the moon is that Apollo was extraordinarily expensive and required great national sacrifice.

During the 1960s the NASA budget (which was directed in large part into the Mercury and Apollo manned missions) took up as much as four percent of the federal budget (the equivalent of $40 billion today.)  For six years it took up three percent or more of the budget.  The NASA budget is now at its lowest point since 1959 as a percentage of the federal budget — less than one-half of one percent of the budget —  and provides less than $20 billion and has for decades.

It seems pretty clear that ambitious humans-on-the-moon project would mean fewer Cassinis, fewer Hubbles, fewer Keplers.

Another sign of the lowering profile of NASA science is the proposal in the 2019 budget to launch the other NASA flagship science mission of the 2020s, the flyby of Jupiter’s moon Europa, on a commercial heavy-lift rocket rather than NASA’s Space Launch System.  The SLS was sold to Congress as the vehicle that could send spacecraft speedily to outer planets, but now both production delays and a desire to quickly get astronauts into space on the SLS has made that far less likely and some years further out, if it happens at all.

Heavy lift rockets other than SLS—including SpaceX’s Falcon Heavy and the Delta IV from United Launch Alliance —lack the power to blast the Europa Clipper directly from Earth to Jupiter. A conventional rocket would rely on three gravity assists from Earth and one from Venus, increasing the transit time from about 3 years to at least 6 years.

The search for life, or habitable conditions, beyond Earth in the 2020s will continue on Mars and is scheduled to expand to Jupiter’s moon Europa.  The moon orbits Jupiter every 3.5 days and that proximity, coupled with the fact that Europa has a slightly elliptical rather than circular orbit, creates the tidal “flexing” and resulting heating that can keep water liquid beneath its surface of ice. The Europa Clipper mission was set by Congress to launch in 2022, but that date looks near impossible.  A plan to have an accompanying lander was sidelined because of cost. (NASA)

Missions happen when they are a priority, and clearly now not just a scientific priority.  Nothing is settled, but the warning signs are there that the moon program will force space science down the priority list unless NASA suddenly gets a lot more money.

Marc Kaufman
Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.

To contact Marc, send an email to

The Northern Lights (Part Two)

Northern Lights at a latitude of about 70 degrees north, well within the Arctic Circle. These photos were taken about 30 miles from the town of Alta. (Lisa Braithwaite)

In my recent column about The Northern Lights, the Magnetic Field and Life,  I explored the science and the beauty of our planet’s aurora borealis, one of the great natural phenomenon we are most fortunate to see in the far North (and much less frequently in the not-quite-so-far North.)

I learned the hard way that an IPhone camera was really not up to the job;  indeed, the battery froze soon after leaving my pocket in the 10 degrees F cold.  So the column had few images from where I actually was — about a half hour outside of the Arctic Circle town of Alta.

But here now are some images taken by a generous visitor to the same faraway lodge, who was present the same time as myself.

Her name is Lisa Braithwaite and she is an avid amateur photographer and marketing manager for two popular sites in the English Lake District.  This was her first hunting trip for the Northern Lights, and she got lucky.  Even in the far northern Norway winter the lights come and go unpredictably — though you can increase your chances if you show up during a time when the sun is actively sending out solar flares.

She came with a Panasonic Lumix DMC-G5 camera and did a lot of research beforehand to increase her chances of capturing the drama should the lights appear.  Her ISOs ranged from 1,600 to 64,000, and her shutter speed from 5 to 15 seconds.  The aperture setting was 3.5.

In addition to showing some of her work, further on I describe a new NASA-led and international program, based in Norway, to study the still incompletely understood dynamics of what happens when very high energy particles from solar flares meet Earth’s atmosphere.

Partnering with the Japanese Aerospace Exploration Agency (JAXA,) the University of Oslo an other American universities, the two year project will send eleven rockets filled with instruments into the ionosphere to study phenomenon such as the auroral winds and the turbulence that can cause so much trouble to communications networks.

But first, here are some morre of Braithwaite’s images, most taken over a one hour period on a single night.

Arcs are a common feature of the lights, sometimes reaching across the sky. They form and then break up into smaller patches. (Lisa Braithwaite.)


The line of the Arctic Circle line can be seen a little more than half-way up the map. The Circle is the most northerly of the five major circles of latitude as shown on maps of Earth. At about 65 degrees North, it marks the northernmost point at which the noon sun is just visible on the December solstice and the southernmost point at which the midnight sun is just visible on the June solstice. (

Vast curtains of light are a common feature, often on the horizon but on good nights high up into the sky.  The lights can sometimes shimmer and dance, and can feature what appear to be vast spotlights.


The lights are often green — the result of interactions between high energy solar flares and oxygen.  If the lights are blue, then nitrogen is in play.  (Lisa Braithwaite)


At certain points in the night, large parts of the sky were lit up — leaving us turning and craning our heads to see what might be happening in different regions. (Lisa Braithwaite)


The light shows often start and end with green horizons.  (Lisa Braithwaite)

While the grandeur of the lights attracts an ever increasing number of adventurous lovers of natural beauty, NASA is also busy in Norway studying the forces that cause the Aurora Borealis — both for the pure science and to better understand the “space weather” that can effect astronauts in low Earth orbit as well as GPS and other communication signals.

The agency has partnered with Norwegian and Japanese colleagues, and other American scientists, in an effort to generally better understand the Earth’s polar cusp — where the planet’s magnetic field lines bend down into the atmosphere and allow particles from space to intermingle with those of Earthly origin.

Solar flares consist of electrically charged particles. They are attracted by the concentrated magnetic fields in the ionosphere around the Earth’s polar regions. This is the reason why the glorious light shows can be observed pretty much exclusively in the far north or the far south.

The two-year project will send eight rockets into space from Norway as part of collaboration of scientists known as The Grand Challenge Initiative – Cusp.

The first mission, the Auroral Zone Upwelling Rocket Experiment or AZURE, is scheduled to launch this month.  The rocket will take off from Norway’s Andøya Space Center, on an island off the far northwest coast of Norway, about 100 miles southwest of where I was near the town of Alta.

As a NASA release of March 1 described it, AZURE’s instruments will measure the atmospheric density and temperature of the polar atmosphere, and will deploy visible tracers — trimethyl aluminum (TMA) and a barium/strontium mixture, which ionize when exposed to sunlight.

Personnel from NASA’s Wallops Flight Facility in Virginia conduct payload tests for the AZURE mission at the Andøya Space Center in Norway. (NASA’s Wallops Flight Facility)

“These mixtures create colorful clouds that allow researchers to track the flow of neutral and charged particles, respectively,” the release reads. “The tracers will be released at altitudes 71 to 155 miles high and pose no hazard to residents in the region.

“By tracking the movement of these colorful clouds via ground-based photography and triangulating their moment-by-moment position in three dimensions, AZURE will provide valuable data on the vertical and horizontal flow of particles in two key regions of the ionosphere over a range of different altitudes.

“Such measurements are critical if we are to truly understand the effects of the mysterious yet beautiful aurora. The results will be key to a better understanding of the effects of auroral forcing on the atmosphere, including how and where the auroral energy is deposited.”

AZURE will focus specifically on measuring the vertical winds in these polar regions, which create a tumultuous particle soup that re-distributes the energy, momentum and chemical constituents of the atmosphere.

AZURE will study the ionosphere, the electrically charged layer of the atmosphere that acts as Earth’s interface to space, focusing specifically on the E and F regions. The E region — so-named by early radio pioneers who discovered that the region was electrically charge, and so could reflect radio waves — lies between 56 to 93 miles above Earth’s surface. The F region resides just above it, between 93 to 310 miles altitude.

The E and F regions contain free electrons that have been ejected from their atoms by the energizing input of the Sun’s rays, a process called photoionization. After nightfall, without the energizing input of the Sun to keep them separated, electrons recombine with the positively charged ions they left behind, lowering the regions’ overall electron density. The daily cycle of ionization and recombination makes the E and F regions especially turbulent and complex.

Aurora as seen from Talkeetna, Alaska, on Nov. 3, 2015. (Copyright Dora Miller)

It has been known for a century that solar flares create the fantastic displays of the Northern and Southern lights.  More recently, it has also become well known that solar flares cause problems for both satellites and navigation systems.

Despite decades of study, scientists still lack the basic knowledge required for predicting when such problems will occur. Once they understand this, it should be possible to make good space weather forecasts just like we do with our weather forecasts on Earth.

When solar storms rain down on the Earth, they cause turbulence in the ionosphere.  This turbulence is one of the major unsolved problems of classical physics and physicists are hoping that the rockets will lead to a far better understanding of the phenomenon.

“Without such an understanding of turbulence it is impossible to make the calculations needed for being able to predict severe space weather events,” said Joran Moen of the University of Oslo, and one of the project leaders. He spoke with the University of Oslo research magazine “Apollon.”

The rockets of The Grand Challenge Initiative – Cusp  mission will launch over the next two years from the Andøya and Svalbard rocket ranges in Norway. Nine of the rockets are from NASA, one from JAXA and one building built the at the University of Norway.

One particular “sounding” will be made with the launch of four rockets at once, an unusual and complex procedure.

Those involved say this will be among the most ambitious attempts ever using rockets for research purposes.

“We will try to launch four of the rockets at the same time. This has never been done before. It is a historic venture,” said Moen.

Yoshifumi Saito of JAXA further explained that “the four parallel rockets are important for us.  By using them we can obtain much better scientific results than would have been the case if we had just launched one rocket at a time.”

Important and compelling science.  And think of how many times the scientists will be able to experience the glories of the Northern Lights show.


Marc Kaufman
Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.

To contact Marc, send an email to

The Northern Lights, the Magnetic Field and Life

Northern Lights over a frozen lake in Northern Norway, inside the Arctic Circle near Alta. The displays can go on for hours, or can disappear for days or weeks. It all depends on solar flares. (

May I please invite you to join me in the presence of one of the great natural phenomena and spectacles of our world.

Not only is it enthralling to witness and scientifically crucial, but it’s quite emotionally moving as well.

Why? Because what’s before me is a physical manifestation of one of the primary, but generally invisible, features of Earth that make life possible. It’s mostly seen in the far northern and far southern climes, but the force is everywhere and it protects our atmosphere and us from the parched fate of a planet like Mars.

I’m speaking, of course, of the northern lights, the Aurora Borealis, and the planet’s magnetic fields that help turn on the lights.

My vantage point is the far northern tip of Norway, inside the Arctic Circle. It’s stingingly cold in the silent woods, frozen still for the long, dark winter, and it’s always an unpredictable gift when the lights show up.

But they‘re out tonight, dancing in bright green and sometimes gold-tinged arches and spotlights and twirling pinwheels across the northerly sky. Sometimes the horizon glows green, sometimes the whole sky fills with vivid green streaks.

It can all seem quite other-worldly. But the lights, of course, are entirely the result of natural forces.


Northern Lights over north western Norway. Most of the lights are green from collisions with oxygen, but some are purple from nitrogen. © Copyright George Karbus Photography

It has been known for some time that the lights are caused by reactions between the high-energy particles of solar flares colliding in the upper regions of our atmosphere and then descending along the lines of the planet’s magnetic fields. Green lights tell of oxygen being struck at a certain altitude, red or blue of nitrogen.

But the patterns — sometimes broad, sometimes spectral, sometimes curled and sometimes columnar — are the result of the magnetic field that surrounds the planet. The energy travels along the many lines of that field, and lights them up to make our magnetic blanket visible.

Such a protective magnetic field is viewed as essential for life on a planet, be it in our solar system or beyond.

But a magnetic field does not a habitable planet make. Mercury has a weak magnetic field and is certainly not habitable. Mars also once had a strong magnetic field and still has some remnants on its surface. But it fell apart early in the planet’s life, and that may well have put a halt to the emergence or evolution of living things on the otherwise habitable planet.

I will return to some of the features of the northern lights and the magnetism is makes visible, but this is also an opportunity to explore the role of magnetism in biology itself.

This was a quasi-science for some time, but more recently it has been established that migrating birds and fish use magnetic sensors (in their beaks or noses, perhaps) to navigate northerly and southward paths.

Graphic from Science Magazine.


But did you know that bacteria, insects and mammals of all sorts appear to have magnetic compasses as well?   They can read the magnetism in the air, or can read it in the rocks (as in the case of some sea turtles.) A promising line of study, pioneered by scientists including geobiologist Joseph Kirschvink of the California Institute of Technology (Caltech) and the Earth-Life Science Institute (ELSI) in Tokyo, is even studying potentially remnant magnetic senses in humans.

“There no doubt now that magnetic receptors are present in many, many species, and those that don’t have it probably lost it because it wasn’t useful to them,” he told me. “But there’s good reason to say that the magnetic sense was most likely one of the earliest on Earth.”

But how does it work for animals? How do they receive the magnetic signals? This is a question of substantial study and debate.

One theory states that creatures use the iron mineral magnetite — that they can produce and consume – to pick up the magnetic signals. These miniature compass needles sit within receptor cells, either near a creature’s nose or in the inner ear.

Joseph Kirschvink, a geobiologist with Caltech and ELSI (the Earth-Life Science Institute in Tokyo) has been studying for decades the ways in which creatures from bacteria to humans use magnetic forces in their lives. (Caltech)

Another posits that magnetic fields trigger quantum chemical reactions in proteins called cryptochromes, which have been found in the retina. But no one has determined how they might send signals and information to the brain.

Kirschvink was part of a team that demonstrated bacteria’s use of Earth’s magnetic field back to the Archean era, 3 to 3.5 billion years ago.   “My guess is that magnetism has had a major influence on the biosphere since then, via the biological ability to make magnetic materials.”

He said that when the sun is particularly angry and active, the geomagnetic storms that occur around the planet seem to interfere with these magnetic responses and that animals don’t navigate as well.

Kirschvink sees magnetism as a possibly important force in the origin of life. Magnetite that is lined up like beads on a chain has been detected in bacteria, and he says it may have provided an evolutionary pathway for structure that allowed for the rise of eukaryotes — organisms with complex cells, or a single cell with a complex structures.

Kirschvink and his team are in the midst of a significant study of the effects of geomagnetism on humans, and the pathways through which that magnetism might be used.

That’s rather a long way from some of the early biomagnetism discoveries, which involved the chiton.  A mollusk relative of the snail and the limpet, the chiton holds on to rocks in the shallow water and uses its magnetite-covered teeth to scrape algae from rocks.  The teeth are on a tongue-like feature called the radula and those teeth are capped with so much magnetite that a magnet can pick up the foot-long gumboot chiton, the largest of the species.

The underside of a gumboot chiton, with its teeth covered with magnetite, can be lifted up with a magnet.

Back at most northern and southerly regions of the planet, where the magnetic field lines are most concentrated, the lights put on their displays for ever larger audiences of people who want to experience their presence.

We had part of one night of almost full sky action, with long arches, curves large and small, waves, spotlights , shimmers and curtains.  It had the feel of a spectacular fireworks display, but magnified in its glory and power and, of course, entirely natural.  (I hope to post images taken by others that night which, alas, were not captured by my camera because the battery froze in the 10 degree cold.)

Our grand night was one of the special ones when the colors (almost all greens, but some reds too) were so bright that their shapes and movements were easy to see with the naked eye.

Good cameras (especially those with batteries that don’t freeze) see and capture a much broader range of the northern light presence.  The horizon, for instance, can appear just slightly green to the naked eye, but will look quite brightly green in an image.

Thanks to the National Oceanic and Atmospheric Administration, the National Weather Service and NASA, forecasting when and where the lights are likely to be be active in the northern and southern (the Aurora Australis) polar regions.

This forecasting of space weather revolves around the the eruption of solar flares.  The high-energy particles they send out collide with electrons in our upper atmosphere accelerate and follow the Earth’s magnetic fields down to the polar regions.

Models based on measuring solar flares, or coronal mass ejections, coming from sunspots that rotate and face Earth every 27 or 28 days.  Summer months in the northern hemisphere often make the sky too light for the lights to be seen, so the long winter nights are generally the best time to see them.  But they do appear in summer, too.  (NOAA)

In these collisions, the energy of the electrons is transferred to the oxygen and nitrogen and other elements in the atmosphere, in the process exciting the atoms and molecules to higher energy states. When they relax back down to lower energy states, they release their energy in the form of light. This is similar to how a neon light works.

The aurora typically forms 60 to 400 miles above Earth’s surface.

All this is possible because of our magnetic field, which scientists theorize was created and is sustained by interactions between super-hot liquid iron in the outer core of the Earth’s center and the rotation of the planet.  The flowing or convection of liquid metal generates electric currents and the rotation of Earth causes these electric currents to form a magnetic field which extends around the planet.

If the magnetic field wasn’t present those highly charged particles coming from the sun, the ones that set into motion the processes that produce the Northern and Southern Lights, would instead gradually strip the atmosphere of the molecules needed for life.

This intimate relationship between the magnetic field and life led to me ask Kirschvink, who has been studying that connection for decades, if he had seen the northern or southern lights.

No, he said, he’d never had the chance.  But if ever in the presence of the lights, he said he know exactly what he would do:  take out his equipment and start taking measurements and pushing his science forward.

Northern Lights in northern Norway, near Alta.  Sometimes they dance for minutes, sometimes for hours, but often they never come at all.  It all depends on the rotation of the sun; if and when it may be shooting out high-energy solar flares. (Wiki Commons)
Marc Kaufman
Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.

To contact Marc, send an email to

To Understand Habitability, We Need to Return to Venus


This column was written by my colleague, Elizabeth Tasker.  Based in Tokyo, she is a scientist and communicator at the Japanese Space Agency JAXA and the Earth-Life Science Institute (ELSI).  Her book, “The Planet Factory,” was published last fall.

This image shows the night side of Venus in thermal infrared. It is a false-color image using data from the Japanese spacecraft Akatsuki’s IR2 camera in two wavelengths, 1.74 and 2.26 microns. Darker regions denote thicker clouds, but changes in color can also denote differences in cloud particle size or composition from place to place.  JAXA / ISAS / DARTS / Damia Bouic

“You can feel what it’s like on Venus here on Earth,” said Kevin McGouldrick from the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder. “Heat a hot plate until it glows red, place your palm on its surface and then run over that hand with a truck.”

The surface of Venus is a hellish place. Suffocated by a thick atmosphere, pressure on the Venusian surface is 92 times greater than on the surface of Earth. Temperatures sit at a staggering 863°F (462°C), which is sufficient to melt lead.

The longest a spacecraft has survived in these conditions is a mere 127 minutes; a record set by the Russian Venera 13 mission over 35 years ago.

As the brightest planet in the night sky, Venus allured ancient astronomers into naming the world after the Roman mythological goddess of love and beauty. This now seems an ironic choice, but the contrast between distant observation and surface conditions produces an apt juxtaposition for exoplanets.

The comparison has led to an article in Nature Geoscience by McGouldrick and a nine author white paper advising on astrobiology strategy for the National Science Foundation. The conclusion of both publications echoes the irony of Venus’s name: we need to return to the inferno of Venus to understand habitable worlds.


A portion of western Eistla Regio is displayed in this three-dimensional perspective view of the surface of Venus. Synthetic aperture radar data from the spacecraft Magellan is combined with radar altimetry to develop a three-dimensional map of the surface. Rays cast in a computer intersect the surface to create a three-dimensional perspective view.  The simulated hues are based on color images recorded by the Soviet Venera 13 and 14 spacecraft. The image, a frame from a video released in 1991, was produced at NASA’s JPL Multimission Image Processing Laboratory.

In the last 25 years, scientists have discovered over 3,500 extrasolar planets. The vast majority of these worlds have not been imaged directly, but are detected by tiny influences on their host star. These observations provide a measurement of the planet’s size and the average energy received from the star, but no details of the conditions at the planet surface. This leaves modern astronomers as blind to exoplanets as the ancient Romans were to the worlds of our solar system.

While we cannot visit the surface of exoplanets, our knowledge may be about to take a major leap forward. New instruments such as NASA’s James Webb Space Telescope (launch date 2019) and ESA’s Ariel mission (launch 2026) are aiming to detect the atmospheres of these distant worlds. The enveloping gases are a product of the planet’s geology, chemistry and biology, producing a direct indication of what is occurring on the surface.

However, this signature is hard to measure for terrestrial worlds with thin atmospheres, requiring a large number of precious observing hours. This means we need to select our telescope targets carefully. An ideal choice would be a planet writhing with geological and biological activity that is imprinting its presence in the atmosphere.

In short, what we want is an exo-Earth. What we don’t want is an exo-Venus.

Surface photographs from the former Soviet Union’s Venera 13 spacecraft, which touched down in March 1982. Ten probes from the Venera series successfully landed on Venus and transmitted data from the surface of the planet between 1961 and 1984. In addition, thirteen Venera probes successfully transmitted data from the atmosphere of Venus.

At first glance, a tantalizingly simple way to distinguish these two planets is the circumstellar habitable zone. Broadly defined, this is the region around a star where the radiation levels are right to support liquid water on a planet’s surface. At the inner edge of the habitable zone, water evaporates and is rapidly lost from the planet in a process known as ‘runaway greenhouse’. At the outer edge, carbon dioxide condenses into clouds and is unable to trap sufficient heat to prevent global freezing.

With a thick atmosphere lacking in water, Venus shows signs of having undergone a runaway greenhouse phenomenon that would seem to support the habitable zone edges. But digging a little deeper reveals more complex story. The habitable zone edges are traditionally calculated via climate models for the Earth. Yet, there is evidence that Venus was never that similar to the home planet we know.

While the Earth’s crust is broken into plates, Venus is thought to have a ‘stagnant lid’; a non-mobile crust that does not cycle material and nutrients up from the planet’s interior. Possibly linked with that —or maybe not— Venus has no magnetic field and would likely have suffered a similar fate to Mars and lost most of its atmosphere if it did not have such a thick reservoir of gases. There are almost certainly other differences; we don’t know because we haven’t been back to the Venusian surface since the 1980s.

What this means is that the path that led Venus to be an unimaginable inferno likely started a long time before a runaway greenhouse could occur.

If the deviation from Earth were initially driven by geodynamics, formation or other non-climate differences (such as the failure to form crustal plates, or poor internal heat circulation preventing a magnetic field) then the boundary between Earth and Venus is likely unrelated to the climate-based habitable zone. Without understanding the history of this second Earth-sized planet in our own system, we have no hope of differentiating between a Venus or Earth around another star.

A topographic map of Venus, with sinusoidal projection, based on data from the Magellan spacecraft, which was one of the few missions launched from the space shuttle.  It left for Venus in 1989 and mapped the planet until 1994.  (NASA)

But is this concern unnecessary? While an exo-Venus would not be an interesting place to hunt for signatures of life, we might learn about the formation of our two worlds by exploring the atmosphere of similar planets around other stars.

And this is where we hit a second problem; we don’t understand the atmosphere of Venus.

Models predict that planets that have undergone a runaway greenhouse should have an oxygen rich atmosphere. This is from evaporated water molecules that are broken apart by the ultraviolet radiation from the Sun, causing the constituent hydrogen atoms to escape the planet’s gravity while the heavier oxygen is left behind.  Venus’s atmosphere isn’t oxygen rich. It’s full of carbon dioxide and clouds of sulphuric acid.

This leaves us trying to understand the distant signature of alien atmospheres without a good comprehension of the examples we have in our own Solar System.

These arguments present a compelling case for Venus. Yet although three out of twelve proposals for NASA’s New Frontiers Program were for Venus missions, none were selected as finalists last December. The same was true for the last call for the Discovery Program; two out of five finalists for this lower cost mission category were for Venus, but neither were selected despite Discovery proposals being typically more focussed on the inner Solar System.

Kevin McGouldrick of the University of Colorado, Boulder, says the primary focus of his research is the nature and evolution of the clouds of Venus. Some 35 to 55 miles above the surface of Venus,  temperatures and pressures resemble those at the surface of the Earth.

Is there a reluctance to go to Venus?

Undoubtedly, planet surface conditions that can melt a spacecraft curbs enthusiasm. The insulation required to protect a probe on the Venusian surface or conduct a short mission will drive costs skyward and may seem a poor return compared to other projects.

Missions to study the Venusian atmosphere would be substantially less risky. The only mission currently operating around Venus is Japan’s Akatsuki orbiter, which last year returned data suggesting mountainous terrain on Venus was sufficient to drive waves through the huge weather system.

In his Nature Geoscience article, McGouldrick proposes that detailed monitoring of Venus’s atmosphere is needed to understand the planet’s history. “To find out why Venus is how it is now, we need to know how it used to be,” he pointed out.

This information could be found in the abundances and isotopes (different variations of the same element) of the noble gases on Venus. These unreactive elements are acquired during planet formation, so changes in their quantities indicate losses in Venus’s past of strippable quantities such as atmosphere and water. Comparison with Earth can also indicate if the two planets formed from similar materials, or if part of the dichotomy between these Earth-sized worlds can be laid at the door of compositional differences.

But another orbiter loses out on basic appeal. NASA planetary exploration typically follows the pattern of fly-by spacecraft, orbiters, landers and rovers and then missions to return samples to Earth. Mars exploration is following this list, with the planned Mars 2020 mission collecting samples for possible later collection. Missions to Europa and Mercury are doing the same, albeit at an earlier stage.

But the hellish surface conditions of Venus make this pattern difficult, and the prospect of repeating the orbiter step with better instruments is significantly less enticing.

The solution might be a combined orbiter and lander mission, with data from the orbiter mitigating the risk associated with the lander. Alternatively, an aeroplane or balloon that travels through the upper parts of the Venusian atmosphere might combine originality with data that cannot be achieved in orbit. Designs like these have been proposed for a Russia-led mission with a contribution from NASA, known as Venera-D, but funding remains uncertain.

This image of the equatorial region of Venus taken by the Japanese Akatsuki probe provides striking detail of the equatorial, tropical, and extra-tropical clouds of the planet. Color changes indicate local variations in the amounts of a little-understood ultraviolet absorber and sulfur dioxide in the atmosphere. JAXA / ISAS / DARTS / Damia Bouic

While a Venus mission did not make into the finalists for the New Frontiers program, funding was given to develop a camera that could measure the mineralogy and composition of Venus’s rocks. This demonstrates a continual interest by mission experts in Venus, but publications by the community suggest this needs to be higher up the priority list.

The bottom line is that visiting our neighbor may present one of the biggest challenges in the Solar System. But exoplanet research may be lost without it.

Marc Kaufman
Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.

To contact Marc, send an email to

False Positives, False Negatives; The World of Distant Biosignatures Attracts and Confounds

This artist’s illustration shows two Earth-sized planets, TRAPPIST-1b and TRAPPIST-1c, passing in front of their parent red dwarf star, which is much smaller and cooler than our sun. NASA’s Hubble Space Telescope looked for signs of atmospheres around these planets. (NASA/ESA/STScI/J. de Wit, MIT)

What observations, or groups of observations, would tell exoplanet scientists that life might be present on a particular distant planet?

The most often discussed biosignature is oxygen, the product of life on Earth.  But while oxygen remains central to the search for biosignatures afar, there are some serious problems with relying on that molecule.

It can, for one, be produced without biology, although on Earth biology is the major source.  Conditions on other planets, however, might be different, producing lots of oxygen without life.

And then there’s the troubling reality that for most of the time there has been life on Earth, there would not have been enough oxygen produced to register as a biosignature.  So oxygen brings with it the danger of both a false positive and a false negative.

Wading through the long list of potential other biosignatures is rather like walking along a very wet path and having your boots regularly pulled off as they get captured by the mud.  Many possibilities can be put forward, but all seem to contain absolutely confounding problems.

With this reality in mind, a group of several dozen very interdisciplinary scientists came together more than a year ago in an effort to catalogue the many possible biosignatures that have been put forward and then to describe the pros and the cons of each.

“We believe this kind of effort is essential and needs to be done now,” said Edward Schwieterman, an astronomy and astrobiology researcher at the University of California, Riverside (UCR).

“Not because we have the technology now to identify these possible biosignatures light years away, but because the space and ground-based telescopes of the future need to be designed so they can identify them. ”

“It’s part of what may turn out to be a very long road to learning whether or not we are alone in the universe”.


Artistic representations of some of the exoplanets detected so far with the greatest potential to support liquid surface water, based on their size and orbit.  All of them are larger than Earth and their composition and habitability remains unclear. They are ranked here from closest to farthest from Earth.  Mars, Jupiter, Neptune an Earth are shown for scale on the right. (Planetary Habitability Laboratory, managed by the University of Puerto Rico at Arecibo.)

The known and inferred population of exoplanets — even small rocky exoplanets — is now so vast that it’s tempting to assume that some support life and that some day we’ll find it.  After all,  those billions of planets are composed of same basic chemical elements as Earth and are subject to the same laws of physics.

That assumption of life widespread in the galaxies may well turn out to be on target.  But assuming this result, and proving or calculating a high probability of finding extraterrestrial life, are light years apart.

The timing of this major community effort is hardly accidental.  There is a National Academy of Sciences effort underway to review progress in the science of reading possible biosignatures from distant worlds, something that I wrote about recently.

Edward Schwieterman, spent six years at the University of Washington’s Virtual Planetary Laboratory.  He now works with the NASA Astrobiology Institute Alternative Earths team UCR.

The results from the NAS effort will in term flow into the official NAS decadal study that will follow and will recommend to Congress priorities for the next ten or twenty years.  In addition, two NASA-ordered science and technology definition teams are currently working on architectures for two potential major NASA missions for the 2030s — HabEx (the Habitable Exoplanet Imaging Mission) and Luvoir (the Large Ultraviolet/Optical/Infrared Surveyor.)

The two mission proposals, which are competing with several others, would provide the best opportunity by far to determine whether life exists on other distant planets.

With these formal planning and prioritizing efforts as a backdrop, NASA’s Nexus for Exoplanet System Science (NExSS) called for a biosignatures workshop in the fall of 2016 and brought together scientists from many disciplines to wrestle with the subject.  The effort led to the white paper submitted to NAS and will result in and will result in the publication of series of five detailed papers in the journal Astrobiology this spring.” The overview paper with Schwieterman as first author, which has already been made available to the community for peer review, is expected to lead off the package.

So what did they find?  First off, that Earth has to be their guide.

“Life on Earth, through its gaseous products and reflectance and scattering properties, has left its fingerprint on the spectrum of our planet,” the paper reads. “Aided by the universality of the laws of physics and chemistry, we turn to Earth’s biosphere, both in the present and through geologic time, for analog signatures that will aid in the search for life elsewhere.

Considering the insights gained from modern and ancient Earth, and the broader array of hypothetical exoplanet possibilities, we have compiled a state-of-the-art overview of our current understanding of potential exoplanet biosignatures including gaseous, surface, and temporal biosignatures.”

In other words, potential biosignatures in the atmosphere, on the ground, and that become apparent over time.  We’ll start with the temporal:

These vegetation maps were generated from MODIS/Terra measurements of the Normalized Difference Vegetation Index (NDVI). Significant seasonal variations in the NDVI are apparent between northern hemisphere summer  and winter. (Reto Stockli, NASA Earth Observatory Group, using data from the MODIS Land Science Team.)

Vegetation is probably clearest example of how change-over-time can be a biosignature.  As these maps show and we all know, different parts of the Earth have different seasonal colorations.  Detecting exoplanetary change of this sort would be a potentially strong signal, though it could also have some non-biological explanations.

If there is any kind of atmospheric chemical corroboration, then the time signal would be a strong one.  That corroboration could come in seasonal modulations of biologically important gases such as CO2 or O2.  Changes in cloud cover and the periodic presence of volcanic gases can also be useful markers over time.

Plant pigments themselves which have been proposed as a surface biosignature.  Observed in the near infrared portion of the electromagnetic spectrum, the pigment chlorophyll — the central player in the process of photosynthesis — shows a sharp increase in reflectance at a particular wavelength.  This abrupt change is called the “red edge,” and is a measurement known to exist only which chlorophyll engaged in photosynthesis.

So the “red edge,” or parallel dropoffs in reflectance of other pigments on other planets, is another possible biosignature in the mix.

And then there is “glint,” reflections from exoplanets that come from light hitting water.

True-color image from a model (left) compared to a view of Earth from the Earth and Moon Viewer ( A glint spot in the Indian Ocean can be clearly seen in the model image.

Since biosignature science essentially requires the presence of H2O on a planet, the clear detection of an ocean is part of the process of assembling signatures of potential life.  Just as detecting oxygen in the atmosphere is important, so too is detecting unmistakable surface water.

But for reasons of both science and detectability, the chemical make-up exoplanet atmospheres is where much biosignature work is being done.  The compounds of interest include (but are not limited to) ozone, methane, nitrous oxide, sulfur gases, methyl chloride and less specific atmospheric hazes.  All are, or have been, associated with life on Earth, and potentially on other planets and moons as well.

The Schwieterman et al review looks at all these compounds and reports on the findings of researchers who have studied them as possible biosignatures.  As a sign of how broadly they cast their net, the citations alone of published biosignature papers number more than 300.

(Sara Seager and William Bains of MIT, both specialists in exoplanet atmospheres, have been compiling a separate and much broader list of potential biosignatures, even many produced in very small quantities on Earth.  Bains is a co-author on one of the five biosignature papers for the journal Astrobiology.)

All this work, Schwieterman said, will pay off significantly over time.

“If our goal is to constrain the search for life in our solar neighborhood, we need to know as much as we possibly can so the observatories have the necessary capabilities.  We could possibly save hundreds of millions or billions of dollars by constraining the possibilities.”

“The strength of this compilation is the full body of knowledge, putting together what we know in a broad and fast-developing field,” Schwieterman said. ”

He said that there’s such a broad range of possible biosignatures, and so many conditions where some might be more or less probable, that’s it’s essential to categorize and prioritize the information that has been collected (and will be collected in the future.)

“We have a lot of observations recorded here, but they will all have their ambiguities,” he said.  “Our goal as scientists will be to take what we know and work to reduce those ambiguities. It’s an enormous task.”


Marc Kaufman
Marc Kaufman is the author of two books about space: "Mars Up Close: Inside the Curiosity Mission” and “First Contact: Scientific Breakthroughs in the Search for Life Beyond Earth.” He is also an experienced journalist, having spent three decades at The Washington Post and The Philadelphia Inquirer. While the “Many Worlds” column is supported and informed by NASA’s Astrobiology Program, any opinions expressed are the author’s alone.

To contact Marc, send an email to