Nobel Laureate Jack Szostak: Exoplanets Gave The Origin of Life Field a Huge Boost

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Jack Szostak, Nobel laureate and pioneering researcher in the origin-of-life field, was the featured speaker at a workshop this week at the Earth-Life Science Institute (ELSI) in Tokyo.  One goal of his Harvard lab is to answer this once seemingly impossible question:  was the origin of life on Earth essentially straight-forward and “easy,” or was it enormously “hard” and consequently rare in the universe. (Nerissa Escanlar)

Sometimes tectonic shifts in scientific disciplines occur because of discoveries and advances in the field.  But sometimes they occur for reasons entirely outside the field itself.  Such appears to be case with origins-of-life studies.

Nobel laureate Jack Szostak was recently in Tokyo to participate in a workshop at the Earth-Life Science Institute (ELSI) at the Tokyo Institute of Technology on “Reconstructing the Phenomenon of Life To Retrace the Emergence of Life.”

The talks were technical and often cutting-edge, but the backstory that Szostak tells of why he and so many other top scientists are now in the origins of life field was especially intriguing and illuminating in terms of how science progresses.

Those ground-shifting discoveries did not involve traditional origin-of-life questions of chemical transformations and pathways.  They involved exoplanets.

“Because of the discovery of all those exoplanets, astronomy has been transformed along with many other fields,” Szostak said after the workshop.

“We now know there’s a large range of planetary environments out there, and that has stimulated a huge amount of interest in where else in the universe might there be life.  Is it just here?  We know for sure that lots of environments could support life and we also would like to know:  do they?

“This has stimulated much more laboratory-based work to try to address the origins question.  What’s really important is for us to know whether the transition from chemistry to biology is easy and can happen frequently and anywhere, or are there one or many difficult steps that make life potentially very rare?”

In other words, the explosion in exoplanet science has led directly to an invigorated scientific effort to better understand that road from a pre-biotic Earth to a biological Earth — with chemistry that allows compounds to replicate, to change, to surround themselves in cell walls, and to grow ever more complex.

With today’s increased pace of research, Szostak said, the chances of finding some solid answers have been growing.  In fact, he’s quite optimistic that an answer will ultimately be forthcoming to the question of how life began on Earth.

“The field is making real progress in understanding the pathway from pre-biotic chemistry to the earliest life,” Szostak told.  “We think this is a difficult but solvable problem.”

And any solution would inevitably shed light on both the potential make-up and prevalence of extraterrestrial life.

This artist’s concept depicts select planetary discoveries made by NASA’s Kepler space telescope.  With more than 4,000 confirmed exoplanets and estimates now that there are billions upon billions more, the question of whether some are inhabited has taken on a new urgency requiring the expertise of scientists from a wide range of fields.
(NASA/W. Stenzel)

Whether it’s ultimately solvable or not, that pathway from non-life to life would appear to be nothing if not winding and complex.  And since it involves trying to understand something that happened some 4 billion years ago, the field has had its share of fits and starts.

It is no trivial fact that probably the biggest advance in modern origin-of-life science — the renown Miller-Urey experiment that produced important-for-life amino acids out of a sparked test tube filled with  gases then believed to be prevalent on early Earth — took place more than 60 years ago.

Much has changed since then, including an understanding that the gases used by Miller and Urey most likely did not reflect the early Earth atmosphere.  But no breakthrough has been so dramatic and paradigm shifting since Miller-Urey.  Scientists have toiled instead in the challenging terrain of how and why a vast array of chemicals associated with life just might be the ones crucial to the enterprise.

But what’s new, Szostak said, is that the chemicals central to the pathway are much better understood today. So, too, are the mechanisms that help turn non-living compounds into self-replicating complex compounds, the process through which protective yet fragile cell walls can be formed, and the earliest dynamics involved in the essential task of collecting energy for a self-replicating chemical system to survive.

The simple protocells that may have enabled life to develop four billion years ago consist of only genetic material surrounded by a fatty acid membrane. This pared down version of a cell—which has not yet been completely recreated in a laboratory—is thought to have been able to grow, replicate, and evolve. (Howard Hughes Medical Institute)

This search for a pathway is a major international undertaking; a collective effort involving many labs where obstacles to understanding the origin-of-life process are being overcome one by one.

Here’s an example from Szostak:  The early RNA replicators needed the element magnesium to do their copying.  Yet magnesium destroyed the cell membranes needed to protect the RNA.

A possible solution was to find potential acids to bond with magnesium and protect the membranes, while still allowing the element to be available for RNA chemistry.  His team found that citric acid, or citrate, worked well when added to the cells.  Problem solved, in the lab at least.

The Szostak lab at Harvard University and the Howard Hughes Medical Institute has focused on creating “protocells” that are engineered by researchers yet can help explain how origin-of-life processes may have taken place on the early Earth.

Their focus, Szostak said, is on “what happens when we have the right molecules and how do they get together to form a cell that can grow and divide.”

It remains a work in progress, but Szostak said much has been accomplished. Protocells have been engineered with the ability to replicate, to divide, to metabolize food for energy and to form and maintain a protective membrane.

The perhaps ultimate goal is to develop a protocell with with the potential for Darwinian evolution.  Were that to be achieved, then an essentially full system would have been created.

How did something alive emerge from a non-living world? It’s a question as old as humanity and seems to pose more questions with every answer.  But Szostak (and some others) are convinced that the problem will in time prove to be solvable. Here blue-green algae in Morning Glory Pool, Yellowstone National Park, Wyoming.

Just as the discovery of a menagerie of exoplanets jump-started the origin of life field, it also changed forever its way of doing business.

No longer was the field the singular realm of chemists, but began to take in geochemists, planetary scientists, evolutionary biologists, atmospheric scientists and even astronomers (one of whom works in Szostak’s lab.)

“A lot of labs are focused on different points in the process,” he said.  “And because origins are now viewed as a process, that means you need to know how planets are formed and what happens on the planetary surface and in the atmospheres when they’re young.

“Then there’s the question of essential volatiles (such as nitrogen, water, carbon dioxide, ammonia, hydrogen, methane and sulfur dioxide); when do they come in and are they too much or not enough.”

These were definitely not issues of importance to Stanley Miller and Harold Urey when they sought to make building blocks of life from some common gases and an electrical charge.

But seeing the origin of life question as a long pathway as opposed to a singular event leaves some researchers cold.   With so many steps needed, and with the precisely right catalysts and purified compounds often essential to allow the next step take place, they argue that these pathways produced in a chemistry lab are unlikely to have anything to do with what actually happened on Earth.

Szostak disagrees, strongly.  “That just not true.  The laws of chemistry haven’t changed since early Earth, and what we’re trying to understand is the fundamental chemistry of these compounds associated with life so we can work out plausible pathways.”

If and when a plausible chemical pathway is established, Szostak said,  it would then be time to turn the scientific process around and see if there is a possible model for the presence of the needed pathway ingredients on early Earth.

And that involves the knowledge of geochemists, researchers expert in photochemistry and planetary scientists who have insight into what conditions were like at a particular time.

Szostak and David Deamer, an evolutionary biologist at the University of California, Santa Cruz, at the ELSI origins workshop.  Deamer supports the view that life on Earth may well have begun in and around hydrothermal springs on land.  That’s where essential compounds could concentrate, where energy was present and organic compounds on interstellar dust could have landed, as they do today. (Nerissa Escanlar)

Given the work that Szostak, his group and others have done to understand possible pathways that lead from simple starting materials to life, the inevitable question is whether there was but one pathway or many.

Szostak is of the school that there may well have been numerous pathways that resulted in life, although only one seems to have won out.  He bases his view, in part at least, on a common experience in his lab.  He and his colleagues can bang their collective heads together for what seems forever on a hard problem only to later find there was not one or two but potentially many answers to it.

An intriguing implication of this “many pathways” hypothesis is that it would seemingly increase the possibility of life starting beyond Earth.  The underlying logic of Szostak’s approach is to find how chemicals can interact to form life-like and then more complex living systems within particular environments.  And those varied environments could be on early Earth or on a planet or moon far away.

“All of this looked very, very hard at the start, trying to identify the pathways that could lead to life.  And sure, there are gaps remaining in our understanding.  But we’ve solved a lot of problems and the remaining big problems are a rather small number.  So I’m optimistic we’ll find the way.”

“And when we get discouraged about our progress I think, you know, life did get started here.  And actually it must quite simple.  We’re just not smart enough to see the answer right away.

“But in the end it generally turns out to be simple and you wonder 20 years later, why didn’t we think of that before?”

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The Very Influential Natalie Batalha

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Natalie Batalha, project scientist for the Kepler mission and a leader of NASA’s NExSS initiative on exoplanets, was just selected as one of Time Magazine’s 100 most influential people in the world. (NASA, TIME Magazine.)

I’d like to make a slight detour and talk not about the science of exoplanets and astrobiology, but rather a particular exoplanet scientist who I’ve had the pleasure to work with.

The scientist is Natalie Batalha, who has been lead scientist for NASA’s landmark Kepler Space Telescope mission since soon after it launched in 2009, has serves on numerous top NASA panels and boards, and who is one of the scientists who guides the direction of this Many Worlds column.

Last week, Batalha was named by TIME Magazine as one of the 100 most influential people in the world. This is a subjective (non-scientific) calculation for sure, but it nonetheless seems appropriate to me and to doubtless many others.

Batalha and the Kepler team have identified more than 2500 exoplanets in one small section of the distant sky, with several thousand more candidates awaiting confirmation.  Their work has once and for all nailed the fact that there are billions and billions of exoplanets out there.

“NASA is incredibly proud of Natalie,” said Paul Hertz, astrophysics division director at NASA headquarters, after the Time selection was announced.

“Her leadership on the Kepler mission and the study of exoplanets is helping to shape the quest to discover habitable exoplanets and search for life beyond the solar system. It’s wonderful to see her recognized for the influence she has had on the world – and on the way we see ourselves in the universe.”

And William Borucki, who had the initial idea for the Kepler mission and worked for decades to get it approved and then to manage it, had this to say about Batalha:

“She has made major contributions to the Kepler Mission throughout its development and operation. Natalie’s collaborative leadership style, and expert knowledge of the population of exoplanets in the galaxy, will provide guidance for the development of successor missions that will tell us more about the habitability of the planets orbiting nearby stars.”

Batalha has led the science mission of the Kepler Space Telescope since it launched in 2009. (NASA)

As a sign of the perceived importance of exoplanet research, two of the other TIME influential 100 are discoverers of specific new worlds.  They are Guillem Anglada-Escudé (who led a team that detected a planet orbiting Proxima Centauri) and Michael Gillon (whose team identified the potentially habitable planets around the Trappist-1 system.)

But Batalha, and no doubt the other two scientists, stress that they are part of a team and that the work they do is inherently collaborative. It absolutely requires that many others also do difficult jobs well.

For Batalha, working in that kind of environment is a natural fit with her personality and skills.  Having watched her at work many times, I can attest to her ability to be a strong leader with extremely high standards, while also being a kind of force for calm and inclusiveness.

We worked together quite a bit on the establishing and running of this column, which is part of the NASA Nexus for Exoplanet System Science (NExSS) initiative to encourage interdisciplinary thinking and collaboration in exoplanet science.

It was NASA’s astrobiology senior scientist Mary Voytek who set up the initiative and saw fit to start this column, and it was Batalha (along with several others) who helped guide and focus it in its early days.

I think back to her patience.  I was visiting her at NASA’s Ames Research Center in Silicon Valley and talking shop — meaning stars and planets and atmospheres and the like.  While I had done a lot of science reporting by that time, astronomy was not a strong point (yet.)

So in conversation she made a reference to stars on the Hertzsprung-Russell diagram and I must have had a somewhat blank look to me.  She asked if I was familiar with Hertzsprung-Russell and I had to confess that I was not.

Not missing a beat, she then went into an explanation of what is a basic feature of astronomy, and did it without a hint of impatience.  She just wanted me to know what the diagram was and what it meant, and pushed ahead with good cheer to bring me up to speed — as I’m sure she has done many other times with many people of different levels of exposure to the logic and complexities of her very complex work.

(Incidently, the Hertzsprung-Russell diagram plots each star on a graph measuring the star’s brightness against its temperature or color.)

I mention this because part of Batalha’s influence has to do with her ability to communicate with individuals and audiences from the lay to the most scientifically sophisticated.  Not surprisingly, she is often invited to be a speaker and I recommend catching her at the podium if you can.

By chance — or was it chance? — the three exoplanet scientists selected for the Time 100 were at Yuri Milner’s Breakthrough Discuss session Thursday when the news came out. On the left is Anglada-Escude, Batalha in the middle and Gillon on the right.

Batalha was born in Northern California with absolutely no intention of being a scientist.  Her idea of a scientist, in fact, was a guy in a white lab coat pouring chemicals into a beaker.

As a young woman, she was an undergrad at the University of California at Berkeley and planned on going into business.  But she had always been very good and advanced in math, and so she toyed with other paths.  Then, one day, astronaut Rhea Setton came to her sorority.  Setton had been a member of the same sorority and came to deliver a sorority pin she had taken up with during on a flight on the Space Shuttle.

“That visit changed my path,” Batalha told me.  “When I had that opportunity to see a woman astronaut, to see that working for NASA was a possibility, I decided to switch my major — from business to physics.”

After getting her BA in physics from UC Berkeley, she continued in the field and earned a PhD in astrophysics from  UC Santa Cruz. Batalha started her career as a stellar spectroscopist studying young, sun-like stars. Her studies took her to Brazil, Chile and, in 1995, Italy, where she was present at the scientific conference when the world learned of the first planet orbiting another star like our sun — 51 Pegasi b.

It had quite an impact.  Four years later, after a discussion with Kepler principal investigator Borucki at Ames about challenges that star spots present in distinguishing signals from transiting planets, she was hired to join the Kepler team.  She has been working on the Kepler mission ever since.

Asked how she would like to use her now publicly acknowledged “influence,” she returned to her work on the search for  habitable planets, and potentially life, beyond earth.

“We’ve seen that there’s such a keen public interest and an enormous scientific interest in terms of habitable worlds, and we have to keep that going,” she said. “This is a very hard problem to solve, and we need all hands on deck.”

She said the effort has to be interdisciplinary and international to succeed, and she pointed to the two other time 100 exoplanet hunters selected.  One is from Belgium and the other is working in the United Kingdom, but comes from Spain.

When the nominal Kepler mission formally winds down in September, she says she looks forward to more actively engaging with the exoplanet science Kepler has made possible.

The small planets identified by Kepler as one one year ago that are small and orbit in the region around their star where water can exist as a liquid. NASA Ames/N. Batalha and W. Stenzel

Batalha’s role in the NASA NExSS initiative offers a window into what makes her a leader — she excels at making things happen.

Voytek and Shawn Domogal-Goldman of Goddard founded and oversee the group.  They then chose Batalha two other leaders (Anthony Del Genio of the Goddard Institute for Space Studies and Dawn Gelino of NASA Exoplanet Science Institute ) to be the hands-on leaders of the 18 groups of scientists from a wide variety of American universities.

(Asked why she selected Batalha, Voytek replied, “TIME is recognizing what motivated us to select her as one of the leaders for….NExSS. Her scientific and leadership excellence.”)

This is the official NExSS task:  “Teams will help classify the diversity of worlds being discovered, understand the potential habitability of these worlds, and develop tools and technologies needed in the search for life beyond Earth. Scientists are developing ways to identify habitable environments on these worlds and search for biosignatures, or signs of life.  Central to the work of NExSS is understanding how biology interacts with the atmosphere, surface, oceans, and interior of a planet, and how these interactions are affected by the host star.”

She has encouraged and helped create the kinds of collaborations that these tasks have made essential, but also helped identify upcoming problems and opportunities for exoplanet research and has started working on ways to address them.  For instance, it became clear within the NExSS group and larger community  that many, if not most exoplanet researchers would not be able to effectively apply for time to use the James Webb Space Telescope (JWST) for several years after it launched in late 2018.

To be awarded time on the telescope, researchers have to write detailed descriptions of what they plan to do and how they will do it. But how the giant telescope will operate in space is not entirely know — especially as relates to exoplanets.  So it will be impossible for most researchers to make proposals and win time until JWST is already in space for at least two of its five years of operation.

Led by Batalha, exoplanet scientists are now hashing out a short list of JWST targets that the community as a whole can agree should be the top priorities scientifically and to allow researchers to learn better how JWST works.  As a result, they would be able to propose their own targets for research much more quickly  in those early years of JWST operations.   It’s the kind of community consensus building that Batalha is known for.

She also has an important roles in the NASA Astrophysics Advisory Committee and hopes to use the skills she developed working with Kepler on the upcoming Transiting Exoplanet Survey Satellite (TESS) mission.

Batalha preparing for the Science Walk in San Francisco on Earth Day.

A mother of four (including daughter Natasha, who is on her way to also becoming an accomplished astrophysicist), Batalha is active on Facebook sharing her activities, her often poetic thoughts, and her strong views about scientific and other issues of the day.

She was an active participant, for instance, in the National March for Science in San Francisco, posting photos and impressions along the way.  I think it’s fair to say her presence was noticed with appreciation by others.

And that returns us to what she considers to be some of her greatest potential “influence” — being an accomplished, high ranking and high profile NASA female scientist.

“I don’t have to stand up and say to young women ‘You can do this.’  You can just exist doing your work and you become a role model.  Like Rhea Setton did with me.”

And it is probably no coincidence that four other senior (and demanding) positions on the Kepler mission are filled by women — two of whom were students in classes taught some years ago by Natalie Batalha.

 

 

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A Vision That Could Supercharge NASA

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An artist rendering of an approximately 16-meter telescope in space.  This image was created for an earlier large space telescope feasibility project called ATLAST, but it is similar to what is being discussed inside and outside of NASA as a possible great observatory after the James Webb Space Telescope and the Wide-Field Infrared Survey Telescope.  Advocates say such a large space telescope would revolutionize the search for life on exoplanets, as well as providing the greatest observing ever for general astrophysics. (NASA)

Let your mind wander for a moment and let it land on the most exciting and meaningful NASA mission that you can imagine.  An undertaking, perhaps, that would send astronauts into deep space, that would require enormous technological innovation, and that would have ever-lasting science returns.

Many will no doubt think of Mars and the dream of sending astronauts there to explore.  Others might imagine setting up a colony on that planet, or perhaps in the nearer term establishing a human colony on the moon.  And now that we know there’s a rocky exoplanet orbiting Proxima Centauri — the star closest to our sun — it’s tempting to wish for a major robotic or, someday, human mission headed there to search for life.

All are dream-worthy space projects for sure.  But some visionary scientists (and most especially one well-known former astronaut) have been working for some time on another potential grand endeavor — one that you probably have not heard or thought about, yet might be the most compelling and achievable of them all.

It would return astronauts to deep space and it would have them doing the kind of very difficult but essential work needed for space exploration in the far future. It would use the very costly and very powerful Space Launch System (SLS) rocket and Orion capsule being built now by NASA and Lockheed Martin respectively.  Most important, it would almost certainly revolutionize our understanding of the cosmos near and far.

At a recent meeting of the House Science Committee, chairman Lamar Smith, said of the hearing’s purpose that, “Presidential transitions offer the opportunities to reinvigorate national goals. They bring fresh perspectives and new ideas that energize our efforts.”

That said, here’s the seemingly feasible project that fires my imagination the most.

It has been quietly but with persistence promoted most visibly by John Grunsfeld, the former astronaut who flew to the Hubble Space Telescope three times to fix and upgrade it, who has spent 58 hours on spacewalks outside the Shuttle, and towards the end of his 40 years with the agency ultimately became an associate administrator and head of the agency’s Science Mission Directorate.

A visualization of the assembly in space of a large segmented telescope, with work being done by astronauts and robots.  The honeycomb blocks are parts of the mirror, and the grey cylinders on the right are habitats for astronauts.  (NASA)

His plan:  Build a segmented space telescope mirror that is 16 meters (52 feet) in diameter or larger, package it into one or several payload fairings and launch it into deep space.  Accompanying astronauts would put it together either at its final destination or at a closer point where it could then be propelled to that destination.

This would provide invaluable humans-in-space experience, would put the Orion and SLS to very good use in advance of a projected human mission to Mars, and would deploy the most penetrating telescope observing ever.  By far.

No mirror with a diameter greater than 3.5 meters (11.5 feet)  has ever been deployed in space,  although the the James Webb  Space Telescope mirror will be substantially larger at 6.5 meters (21 feet) when launched in 2018.  The largest ground telescopes are in the 10-meter (33 foot) range.

John Grunsfeld working on the Hubble Space Telescope, some 350 miles above Earth. He said that based on his own experience with spacewalks and space repairs, he thinks that a crew of four astronauts could assembled a 16-meter segmented telescope mirror within four weeks. (NASA)

What Grunsfeld’s space behemoth would provide is an unprecedented power and resolution to see back to the earliest point possible in the history of the universe, and doing that in the ultraviolet and visible wavelengths. But perhaps more significantly and revolutionary, it would supercharge the agency’s ability to search for life beyond Earth.

Like nothing else currently in use or development, it would provide a real chance to answer what is arguably humanity’s most fundamental question:  Are we alone in the universe?

Grunsfeld has been introducing people to the project/vision inside NASA for some time.  He also told me that he has spoken with many members of Congress about it, and that most have been quite supportive.  Now he’s starting to make the case to the public.

“We need our leaders to be bold if we want to stay in the forefront of science and engineering,” he said.  “Assembling a 16-meter telescope in space would not be easy by any means.  But we can do it and — this is the key — it would be transformational. It’s a rational thing to do.”

His confidence in the possibility of launching the segmented mirror parts and having astronauts assemble them in space comes, he says, from experience.  Not only has he flown on the space shuttle five times and has his three very close encounters with the Hubble, but he has also overseen the difficult process of getting the JWST project — with its pioneering segmented, folding mirror — back on track after large budget overruns and delays.  He’s also trained in astrophysics and is enamored of exoplanets.

“If your goal is to search for inhabited planets, you just have to go up to the 16-meter range for the primary telescope mirror,” he said.

“Think about it:  if we sent up something smaller, it will give us important and potentially very intruiging information about what planets might be habitable, that could potentially support life.  But then we’d have to send up a bigger mirror later to actually make any detection.  Why not just go to the 16-meter now?”

The strongest driver on the size of the LUVOIR telescope is the desire to have a large sample of exoEarth candidates to study. This figure shows the real stars in the sky for which a planet in the habitable zone can be observed. The color coding shows the probability of observing an exoEarth candidate if it’s present around that star (green is a high probability, red is a low one). This is a visualization of the work of Chris Stark at Space Telescope Science Institute, who created an advanced code to calculate yields of exoplanet observations with different facilities.  (C. Stark and J. Tumlinson, STScI)

While all this may sound to many like science fiction, NASA actually has a team in place studying the science and technology involved with a very large space telescope, and has funded studies of in-space assembly as well.

The current team is one of four studying different projects for a grand observatory for the 2030s.  Their mission is called LUVOIR (the Large UV/Optical/IR Surveyor), and both it and a second mission under study (Hab-Ex) have exoplanets as a primary focus. It was Grunsfeld and Paul Hertz, director of NASA’s astrophysics division, who selected the four concepts for more in-depth study based in large part on astronomy and astrophysics community thinking and aspirations, especially as laid out in the 2013 Thirty-Year Astrophysics Visionary Roadmap.

The LUVOIR team started out with the intention of studying the engineering and technological requirements — and science returns — of a space telescope between 8 and 16 meters in diameter, while Hab-Ex would look at the 4 to 7 meter option for a telescope designed to find exoplanets.  Grunsfeld addressed the LUVOIR study team and encouraged them to be ambitious in their thinking — a message delivered by quite a few others as well.  What’s more, a number of study team members were inclined towards the 16-meter version from the onset.

Aki Roberge of the Goddard Space Flight Center is the team scientist for the LUVOIR Science and Technology Definition Team.

The LUVOIR team has not addressed the issue of assembly in space — their goals are to understand the science made possible with telescopes of different sizes, to design an observatory that can be repaired and upgraded, and to determine if the technology to pull it all together is within reach for the next decade or two.

A key issue is how large a folded up mirror the launch vehicle rocket nose cone (the fairing) can hold.  While the current version of the SLS would certainly not accommodate a 16-meter segmented mirror, team study scientist Aki Roberge — an astrophysicist at the Goddard Space Flight Center — said that the team just recently got the good news that a next generation SLS fairing looks like it could well hold a folded mirror of up to 15 meters. Quite a few “ifs” involved, but still promising.

“We’re still in the midst of our work, but it’s clear that a LUVOIR with a large aperture (mirror) gives us a major science return,” she said.  “Going up to nine meters would be a major leap forward, and going to 16 would be a dramatic advance on that.”

“But we have to assess what we gain in terms of going large and what we might lose in terms of added technical difficulty, cost and time.”  As is, the 9 or 16-meter project — if selected — would not be ready to launch until the mid 2030s.  All the great space observatories and missions have had decades-long gestation periods.

The results from the LUVOIR and other formal NASA study teams will be reviewed by the agency and then assessed by a sizeable group of experts convened by the National Academy of Sciences for the 2020 Astrophysics Decadal Survey.  They set the next decade’s topic and mission priorities for the astronomy and astrophysics communities (as well as others) — assessments that are sent back to NASA and generally followed.

One of Grunsfeld’s goals, he told me, is to make the assembled-in-space 16-meter telescope a top Decadal Survey priority.  While supportive of the LUVOIR efforts, he believes that including astronauts in the equation, deploying a somewhat larger mirror even if the difference in size is not great, and making a mirror that he says will be easier to fix and upgrade than a folded up version, gives the assembled-in-space option the advantage.

These images, which are theoretical simulations using the iconic Hubble Deep Field image, are adjusted to reflect the light collected by telescopes of different sizes. They show the increased resolution and quality of images taken by a 16-meter telescope, a 9-meter, and the Hubble Space Telescope, which is 2.4 meters in diameter.  They illustrate pretty clearly why astronomers and exoplanet hunters want ever larger telescope mirrors to collect those photons from galaxies, stars and planets.

Simulated views of galaxies in deep space, as seen with a proposed 16-meter telescope. This and the two images below are of the same part of the sky. The exposure time for each image was assumed to be the same, to make them comparable. Scientists get higher resolution images with the larger telescopes.  (G. Snyder, STScI /M. Postman, STScI.)

 

Deep space galaxies as seen with nine meter telescope.

 

Once again the same view, taken with Hubble’s 2.4-meter telescope for the same period of time as the images above.  The iconic Hubble Deep Field images are much clearer than this one, and that’s because the telescope was collecting light for a much longer period of time.

Whether or not the LUVOIR project is selected to be a future NASA flagship observatory, and whether or not it will be an assembled-in-space version of it, many at the agency clearly see human activity and habitation in space (as well as on planets or moons) as a necessary and inevitable next step.

Harley Thronson is the senior scientist for Advanced Concepts in Astrophysics at Goddard, and he has worked on several projects related to how and where astronauts might live and work in space.

Harley Thronson, the senior scientist for Advanced Concepts in Astrophysics at the Goddard Space Flight Center, standing outside the JWST clean room. (NASA)

He said this research goes back decades, having gained the attention of then-NASA Administrator Dan Goldin around 2000.  It has recently experienced another spurt of interest as the agency has been assessing opportunities for human operations beyond the immediate vicinity of the Earth.

“It’s inevitable that the astronomy community will want and need larger space observatories, and so we have to work out how to design and build them, how and where they might be assembled in space, and how they can be serviced,” Thronson said.  The JWST will not be reachable for upgrades and servicing, and Congress responded to that drawback by telling NASA will make sure future major observatories can be serviced if at all possible.

Thronson said that he supports and is inspired by the idea of a 16-meter space telescope, and he agrees with Grunsfeld that assembly in space is the wave of the future.  But he said “I’m not quite as optimistic as John that we’re ready to attack that now, though it would be terrific if we were.”

Part of Thronson’s work involves understanding operation sites where space telescopes would be most stable, and that generally involves the libration points, where countervailing gravity pulls are almost neutralized.  LUVOIR, like JWST, is proposed for the so-called Sun-Earth L-2 point, about one million miles outward from Earth where the Earth and sun create a gravitational equilibrium of sorts.

Thronson said there has been some discussion about the possibility of assembling a telescope at a closer Earth-moon libration point and then propelling it towards its destination.  That assembly point could, over time, become a kind of depot for servicing space telescopes and as well as other tasks.

As a sign of the level of interest in these kind of space-based activities, NASA last year awarded $65 million to six companies involved in creating space habitats for astronauts on long-duration missions in deep space.

One of the locations in relatively nearby space where a space telescope would have a stable gravitational environment. (NASA

At the time, the director of NASA’s Advanced Exploration Systems, Jason Crusan,  said that “the next human exploration capabilities needed beyond the Space Launch System rocket and Orion capsule are deep space, long duration habitation and in-space propulsion. We are now adding focus and specifics on the deep space habitats where humans will live and work independently for months or years at a time, without cargo supply deliveries from Earth.”

Not surprisingly, building and maintaining telescopes and habitats in space will be costly (though less so than any serious effort to send humans to Mars).  As a result, how much support NASA gets from the White House, Congress and the public — as well as the astronomy and astrophysics communities — will determine whether and when this kind of space architecture becomes a reality.

John Grunsfeld, who has walked the walk like nobody else, plans to be stepping up his own effort to explain how and why this is a vision worth embracing.

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A Solar System Found Crowded With Seven Earth-Sized Exoplanets

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Seven Earth-sized rocked planets have been detected around the red dwarf star TRAPPIST-1. The system is 40 light years away, but is considered to be an easy system to study — as explanet research goes. (NASA)

Seven planets orbiting one star.  All of them roughly the size of Earth.  A record three in what is considered the habitable zone, the distance from the host star where liquid water could exist on the surface.  The system a mere 40 light-years away.

The latest impressive additions to the world of exoplanets orbit the dwarf star known as TRAPPIST-1, named after a European Southern Observatory telescope in Chile.

Previously a team of astronomers based in Belgium discovered three  planets around this dim star, but now that number has increased to include the largest number of Earth-sized planets found to date, as well as the largest number in one solar system in the habitable zone.

This is a very different kind of sun-and-exoplanet system than has generally been studied.  The broad quest for an Earth-sized planet in a habitable zone has focused on stars of the size and power of our sun.  But this one is 8 percent the mass of our sun —  not that much larger than Jupiter — and with a luminosity (or energy) but 0.05 percent of that put out by our sun.

The TRAPPIST-1 findings underscore one of the recurring and intriguing aspects of the exoplanet discoveries of the past two decades — the solar systems out there are a menagerie of very different shapes and sizes, with exoplanets of a wild range of sizes orbiting an equally wide range of types and sizes of stars.

Michaël Gillon of the STAR Institute at the University of Liège in Belgium, and lead author of the discovery reported in the journal Nature, put it this way: “This is an amazing planetary system — not only because we have found so many planets, but because they are all surprisingly similar in size to the Earth.”

At a NASA press conference, he also said that “small stars like this are much more frequent than stars like ours.  Now we have seven Earth-sized planets to study, three in the habitable or ‘Goldilocks’ zone, and that’s quite promising for search for life beyond Earth.”

He said that the planets are so close to each other than if a person was on the surface of one, the others would provide a wonderful close-up view, rather like our view of the moon.

This diagram compares the orbits of the newly-discovered planets around the faint red star TRAPPIST-1 with the Galilean moons of Jupiter and the inner Solar System. All the planets found around TRAPPIST-1 orbit much closer to their star than Mercury is to the Sun, but as their star is far fainter, they are exposed to similar levels of irradiation as Venus, Earth and Mars in the Solar System.

The orbits of the Trappist-1 planets are not much greater than those of Jupiter’s Galilean moon system, and are considerably smaller than the orbit of Mercury in the solar system. However, TRAPPIST-1’s small size and low temperature mean that the energy reaching its planets is similar to that received by the inner planets in our solar system. TRAPPIST-1c, d and f, for instance, receive similar amounts of energy as Venus, Earth and Mars, respectively.

All seven planets discovered in the system could potentially have liquid water on their surfaces, the authors said, though their orbital distances make some of them more likely candidates than others.  So far there has been no confirmation of water on the planets, but the search has intensified.

“The energy output from dwarf stars like TRAPPIST-1 is much weaker than that of our sun,” co-author Amaury Triaud said.  “Planets would need to be in far closer orbits than we see in our solar system if there is to be surface water. Fortunately, it seems that this kind of compact configuration is just what we see around TRAPPIST-1.”

Climate models suggest the innermost planets, TRAPPIST-1b, c and d, are probably too hot to support liquid water, except maybe on a small fraction of their surfaces. The orbital distance of the system’s outermost planet, TRAPPIST-1h, is unconfirmed, though it is likely to be too distant and cold to harbor liquid water — assuming no alternative heating processes are occurring

TRAPPIST-1e, f, and g, however, represent the sweet spot for planet-hunting astronomers, as they orbit in the star’s habitable zone and could host oceans of surface water if other conditions were present.

As Sara Seager, an MIT pioneer in the study of exoplanet atmospheres, said in the NASA press conference, “with this discovery we’ve taken a giant, accelerated leap forward.  In one system, we have room so that if one planet in the habitable zones is not quite right (for study and possibly biology) we have many other chances.  This Goldilocks has many sisters.”

Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate, added: “This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life. Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

The telescope at the center of the discoveries is TRAPPIST-South (TRAnsiting Planets and PlanetesImals Small Telescope–South), s small 60 cm telescope at the La Silla Observatory in Chile devoted to the study of planetary systems.  The robotic telescope is operated from a control room in Liège, Belgium. The project is led by the Department of Astrophysics, Geophysics and Oceanography of the University of Liège, in close collaboration with the Geneva Observatory (Switzerland). TRAPPIST–South is mostly funded by the Belgian Fund for Scientific Research with the participation of the Swiss National Science Foundation. (ESO)

The discovery of the four additional Earth-sized planets was made during a global campaign of observataion, most especially by NASA’s infrared Spitzer Space Telescope.

Sean Carey, manager of NASA’s Spitzer Science Center at Caltech/IPAC in Pasadena, California, called it “the most exciting result I have seen in the 14 years of Spitzer operations…Spitzer will follow up in the fall to further refine our understanding of these planets so that the James Webb Space Telescope can follow up. More observations of the system are sure to reveal more secrets.”

Because the Trappist-1 system is so relatively easy to observe, and because it is providing such riches, many ground- based observatories have joined in the search.

Dips in the star’s light output caused by each of the seven planets passing in front of it — events known as transits — allowed the astronomers to infer information about their sizes, compositions and orbits. They found that at least the inner six planets are comparable in both size and temperature to the Earth.

These new discoveries make the TRAPPIST-1 system a very important target for future study. The Hubble Space Telescope is already being used to search for atmospheres around the planets and team leader Gillon said the James Webb Space Telescope, scheduled to launch in 2018, can potentially begin a rigorous examination of the atmospheres of the planets.

“These planets are accesible to observations with JWST.  We will be able to study the atmospheres, the greenhouse gas compositions.  We will search for gases that might be produced by life,” said Gillon.

This artist’s concept shows what the TRAPPIST-1 planetary system may look like, based on available data about the planets’ diameters, masses and distances from the host star. The system has been revealed through observations from NASA’s Spitzer Space Telescope and the ground-based TRAPPIST (TRAnsiting Planets and and PlanetesImals Small Telescope) telescope, as well as other ground-based observatories.  (NASA)

But there are also significant barriers to habitability in the TRAPPIST-1 system.

Because the planets are so close to their host star — the first has an orbit of 1.5 days, the second an orbit of 2.4 days and the third an ill-defined orbit of between 4.5 and 73 days — that means they are tidally-locked, as is our moon.  Not long ago, exoplanet scientists doubted that a planet that doesn’t rotate can be truly habitable since the extremes of hot and cold would be too great.  That view has changed with creation of models that suggest tidal locking is not necessarily fatal for habitability, but it most likely does make it more difficult to achieve.

A larger potential barrier is that the dwarf star once was quite different.  Jonathan Fortney, a University of California at Santa Clara specialist in dwarf stars and brown dwarfs (objects which are too large to be called planets and too small to be stars), focused on that stellar history:

“One thing to keep in mind is that this star was much much brighter in the past,” he said in an email a while back. “M stars (like TRAPPIST-1) are hottest when they are young and take a long time to cool off and settle down.  Their energy comes from contraction at first.  A star like this takes 1 billion years to even settle onto the main sequence (where it starts burning hydrogen).”

Gillon said that the age of the star system was not well understood, but that it was at least a half billion years old.

Shawn Domogal-Goldman, a research space scientist at the Goddard Space Flight Center with a focus on exoplanets, said that the big news of the day for him is that the questions raised about conditions on red or M dwarf stars is that “they’re all testable on the TRAPPIST-1 planets in the near term.

“We can do follow-up observations of these worlds with the Hubble and JWST. Yesterday, I would have said ‘you can test these hypotheses with Webb but you kind of need the perfect target.’ Well, today we kind of have the perfect target.”

This diagram shows how the light of the dim red ultra cool dwarf star TRAPPIST-1 fades as each of its seven known planets passes in front of it and blocks some of its light. The larger planets create deeper dips and the more distance ones have longer lasting transits as they are orbiting more slowly. These data were obtained from observations made with the NASA Spitzer Space Telescope. (NASA)

From the total of 2,687 stars known to have exoplanets (as of February 15, 2017), there are a total of 602 known multiplanetary systems, or stars with at least two confirmed planets. About 280 of these have only two confirmed exoplanets, but some have a significantly larger number.

The star with the most confirmed planets is our sun with eight (after the demotion of Pluto), while the stars with the most confirmed exoplanets are Kepler-90, HD 10180 and HR 8832, with 7 confirmed planets each.  In 2012, two more exoplanet candidates were proposed but not yet confirmed for HD 10180, which would bring the total to 9 exoplanets in that system.

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With the Main JWST Mirror Completed, Scientists Focus On How To Best and Most Fairly Use It Once In Space

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Engineers conduct a white light inspection on NASA's James Webb Space Telescope in the clean room at NASA's Goddard Space Flight Center, Greenbelt, Maryland. Credits: NASA/Chris Gunn
Engineers conduct a white light inspection on NASA’s James Webb Space Telescope in the clean room at NASA’s Goddard Space Flight Center, Greenbelt, Maryland. (NASA/Chris Gunn)

Recent word that the giant mirror of the James Webb Space Telescope is essentially complete is a cause for celebration, a milestone in the long march toward launching what will be the most powerful astronomical instrument ever.  NASA Administrator Charlie Bolden made the announcement at the Goddard Space Flight Center, with senior project scientist John Mather declaring that “we’re opening up a whole new territory of astronomy.”

Although liftoff isn’t scheduled until two years from now, the mirror’s completion has led to an intensifying of the far less public but also essential task of determining how precisely the JWST will be used.

This is a major issue because the observatory will be far more complicated with many more moving parts for astronomers than the Hubble Space Telescope and other predecessors, and a significant amount of the learning about how to make observations can’t be done until JWST is already in space.

But more pressing still is the fact that “JW” (as it is now commonly called) will fly for a limited time, and as of now cannot be repaired or upgraded once in space because it will be too far away.

So while astronomers and the public have grown accustomed to long-lived observatories like the Hubble and Spitzer space telescopes — which have been revolutionizing astronomy for decades now — JW has a planned mission duration of just five years. Should the instruments continue working after that, the observatory will nonetheless run out of necessary fuel in 10 years.

Especially for exoplanet astronomers who often have to focus on a particular star and planet over a substantial time, this means they need to learn the JWST ropes fast or miss out on a scientific opportunity of a lifetime.

Natalie Batalha, a member of the JWST Science Advisory Committee and project scientist for the Kepler mission, said that the logic of  the traditional proposal cycles and proprietary periods “threatens to stall the release of potentially important technical information keeping data out of the public domain until the five year nominal mission is well underway.”

“Because of the finite lifetime of JWST, we have an urgency here that we didn’t have with Hubble,” she told me.

“The JWST Science Advisory Committee recognized the need to get data into the hands of community scientists as early as possible to take full advantage of this so valuable but limited opportunity.”

WST is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate JWST after launch.
JWST is an international collaboration between NASA, the European Space Agency (ESA), and the Canadian Space Agency (CSA), and the development effort is being managed by the NASA Goddard Space Flight Center.  It is scheduled to launch in October, 2018 and be ready to begin observations after a six-month checkout. (ESA)

The issue is doubly important because the four instruments flying on JWST all operate in a variety of modes and at a broad range of wavelengths.  This makes understanding how to use the telescope and calibrate the data especially challenging.

To mitigate these problems, officials at the Space Telescope Science Institute (STScI) in Baltimore, which manages the JWST program, have agreed to set up an Early Release Science (ERS) program that will have no proprietary privileges and that will require researchers to share what they’ve learned with the community.

A limited but still significant 500 hours of JWST observation time will be given out of the Director’s Discretionary Time to the ERS.  Those hours will be split among the main science communities that will use JWST — those studying the very early cosmos, the dynamics of galaxy formation and stars, and the worlds of exoplanets and objects in our solar system.

“It is one of the first programs of its kind,” said Kevin Stevenson, an European Space Agency/Aura astronomer at STScI and the lead author of a recent white paper on transiting exoplanet science that could be done as part of the ERS the program.

It will probably be the first program of its kind, said Kevin Stevenson, an European Space Agency/Aura astronomer at STScI and the lead author of a recent white paper on the program.

ostdoc 2012 -- 2014, Sagan Fellow 2014 -- 2016 Now an ESA Astronomer at STScI
Kevin Stevenson, an ESA astronomer at the Space Telescope Science Institute, has played a leading role with the JWST Early Release Science program.

“As far as I know, an Early Release program like this has never been done before with other telescope programs,” he said.

Without the ERS program, researchers awarded JWST time in year 1 would have a proprietary period of 12 months after receiving their data, and they can use those results for Cycle (year) 2 proposals without anyone else having knowledge of how the telescope behaved for them.

“This creates a very unfair playing field for the rest of the community, which wouldn’t have that first year data until well into the second year — meaning they can make strong proposals only for (year) 3, when the nominal mission is half over.”

Under this Early Release Science program, the researchers have no proprietary rights to data and so must share everything promptly. “The goal is to do what’s good for the community and allow many researchers to have the information they need to make a strong case for JWST time,” Stevenson explained.

One consequence of the Early Release logic is that selected projects will most likely focus on easy to acquire, low-hanging fruit.  The ERS program will intentionally focus on providing essential and representative data for the community rather than aiming for scientific breakthroughs — although who ever knows where important surprises may be hiding.

While the Early Release program is important and novel, it remains quite small compared to standard calls for observing time that will also be in place.

Guaranteed time for researchers — who have often worked for years developing JW instruments– will account for about 1,500 hours during the first year of observing, and 5,500 hours will go to researchers whose proposals are selected by JWST peer review panels.

While these researchers will be under no obligation to share their data for those substantial periods, efforts are underway to encourage sharing of what they learn about the operations of the telescope and instruments in particular because of the relatively short time JWST will operate.

Transit data are rich with information. By measuring the depth of the dip in brightness and knowing the size of the star, scientists can determine the size or radius of the planet. The orbital period of the planet can be determined by measuring the elapsed time between transits. Once the orbital period is known, Kepler's Third Law of Planetary Motion can be applied to determine the average distance of the planet from its stars. Credit: NASA Ames
Transit data are rich with information. By measuring the depth of the dip in brightness and knowing the size of the star, scientists can determine the size or radius of the planet. The orbital period of the planet can be determined by measuring the elapsed time between transits. The JWST instruments will add substantially to this kind of information by allowing for more expanded and precise readings of the atmospheres of transiting planets.  (NASA Ames Research Center)

JWST was conceived and largely designed before the detection of the first exoplanet in 1996 and as a result many of the  observatory’s goals and capabilities lie elsewhere.  Still, some modifications have been made to the original plans, and new insights into how exoplanet researchers can use the telescope and its instruments have led to great excitement and anticipation.

While the Hubble mostly observes in optical wavelengths with some infrared, JWST is primarily an infrared telescope and will be able to detect radiation emitted at much longer wavelengths.

In practical terms for exoplanet exploration, that means the instruments are expected to detect important compounds from methane to ammonia, sulfur dioxide and onward to larger carbon-based molecules, all of which have been challenging to identify so far.  Using the fact that infrared radiation contains and transmits heat energy, the telescope should be able to see through the thick hazes and clouds that surround many exoplanets so its instruments can characterize the atmospheres and planets below based on thermal emissions.

Some researchers are convinced that JWST will be able to directly image some larger exoplanets — meaning that it will be able to collect and read the spectra of the atmospheres whether the planets are transiting or not.

Sasha Hinkley, an astrophysicist and expert in infrared instrumentation at the University of Exeter, said he is convinced JWST direct imaging of exoplanets is feasible and indicated he will  propose an Early Release observation with that in mind (they’re due next August.)  With direct imaging, he said, JWST could not only identify important compounds, but could also quite possibly identify “weather” on exoplanets.

“JW is just so versatile, and has so many bells and whistles,” he said.  “This will allow for breakthrough science, but will also take valuable time to master.  I think the community would really benefit if some of the early learning involved direct imaging.”

Stevenson has a somewhat different perspective.  The white paper he authored was based on a workshop for scientists eager to work with JWST, and the recommendation in the paper was to focus on transits of large and well-defined planets, and most preferably the gas giant planet WASP-62b.

Rendering of gas giant planet, WASP-62b
Rendering of gas giant planet, WASP-62b.  It has been put forward as a good candidate to observe under the JWST Early Release Science program.

 

But all involved agree that research communities should put forward a small number of proposals with broad community input for the Early Release Science Program.  This is in keeping with the goals of NASA’s Nexus for Exoplanet System Science, or NExSS, a research coordination network established to catalyze interdisciplinary and community collaboration. NExSS recently initiated a working group to draft a small number of ERS proposals to do transiting exoplanet science.

The STScI has also addressed the question of the observatory’s relatively short lifetime by commissioning development of a number of simulators to help guide scientists as they decide which planets and stars to explore, and in which observing modes to do it.  These tools use known exoplanet and host star characteristics, combined with the most current knowledge of how the JWST instruments behave, to help simulate what the observations will look like through the eyes of JWST.

Substantial effort by STScI is being put into the simulators, the main one called the JWST Exposure Time Calculator (Pandeia) and the exoplanet equivalent (PandExo).  Natasha Batalha, a graduate student at the Pennsylvania State University, has led the exoplanet simulator effort out of the Goddard Space Flight Center.

“PandExo will help researchers decide which JWST observing modes are best suited for the science they want to carry out. It will also help them to pin down exactly how many transits they need to observe to attain their desired level of precision, ” she said. “All of this information will be a crucial part of each researcher’s observing proposal.”

This ability is important when proposing observations of large planets but even more so with the smaller ones — the super Earths and sub-Neptunes.  Because those planets will require many more transit measurements, Batalha said it’s crucial to determine how much observing time is needed to get a handle on whether the proposals are feasible.

NASA sent astronauts to fix or upgrade the Hubble Space Station five times since it launched in 1993. As of now, it looks like JWST will be too far away to ever be serviced should something go wrong. This 2009 shows astronauts John Grunsfeld, left, and Andew Feustel working on the HST during the first of five STS-125 spacewalks. (NASA)
NASA sent astronauts to fix or upgrade the Hubble Space Station five times since it launched in 1993. As of now, it looks like JWST will be too far away to ever be serviced should something go wrong. This 2009 shows astronauts John Grunsfeld, left, and Andew Feustel working on the HST during the first of five STS-125 spacewalks. (NASA)

It is because JWST is primarily an infrared telescope that it will be sent to an area about one million miles away, the second Sun-Earth Lagrange Point.  That’s a gravitationally stable location where the observatory’s sunshade will always face the sun, and consequently defect most of the heat energy coming its way. This is essential since the telescope needs temperatures around -370 Fahrenheit to operate properly.

In contrast, the Hubble is in low-Earth orbit, about 375 miles away from home.  The difference in locations explains why the Hubble has been serviced by astronauts five times, while current plans discount the possibility ever having humans fly to JWST to fix or upgrade it.  NASA doesn’t now have the capability to send astronauts there, and if it did the mission would be enormously expensive.

So the astronomy community is left with this reality:  The most powerful and potentially important telescope ever developed will have a relatively short working lifetime, as major space observatories go.  And that’s why planning now for how it will be used during that window of time is so pressing.

 

 

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