Humans to Mars? The dialogue is on!


In response to yesterday’s blog post about grandiose visions for the human colonization of Mars, I received compliments from friends and a barrage of critiques and, well, some hate mail, from people (all male, as far as I can tell) who think the conquest and exploitation of space is a great idea. The Twitter stream is all over the place (good!). Rather than approving comments for posting here, I thought I’d do a blog post about them. (I’ve trashed some comments coming from people who seem to think females are born stupid. Really, gentlemen.)

My friend Keith Cowing, keeper of NASA Watch, posted about my blog today (he told me, “I thought that the issue needed airing given the Musk event”):

You Cannot Explore The Universe When Your Head Is Stuck In The Sand

“I have known Linda for 30 years and have a lot of respect for her work. But I thought this whole “but people are starving in [fill in the blank]” or “why spend money in space when we should spend it on Earth” mindset was a thing of the 1960 and 1970s. If you want to go after budgets to fix social inequalities then NASA is not the place to start – there is much more low hanging fruit elsewhere.

Decades of public opinion polls, popular media, and other cultural phenomena strongly point to a public viewpoint on space that is exactly opposite of what Linda claims. Moreover her viewpoint flies in the face of human history. People explore. Then they colonize. Then they move on to explore some more because that is what people do. In particular I am not certain why this tiny group of 30 space people (no doubt the usual suspects at meetings like this) meeting in their little echo chamber is in any way representative of what America’s 300+ million – or the billions who live elsewhere think about exploring space.”

I’ve told Keith, “We will always have to agree to disagree….”

This group of 30 people with whom I was in conference over the weekend (check them out) were not “space people” – definitely not “the usual suspects” in the space community. They were mostly college professors of philosophy, environmental science, ethics – people I’d never met before in my 35 years of working in the space community. They came from a diversity of campuses. The group included less than a handful who might qualify as “space people” (i.e. funded by NASA or otherwise employed in the space community), including me. We came together to discuss “broader issues in astrobiology and space exploration.” (By the way, NASA did not organize or sponsor this conference – it was an initiative of Kelly Smith, professor of philosophy at Clemson University.)

I surmise that these college professors (and the few grad students and undergrads who were there), who deal with new crops of students every year, might have a broader view of “public opinion” than the average hard-core space fan does.

As to public opinion, I disagree with Keith. I’ve studied historical misconceptions about public opinion regarding the space program – you can read about my findings here (this paper was published in the proceedings of NASA’s 50th anniversary history conference, held in 2008 – see section on “NASA and public opinion”). My colleague Roger Launius, historian at the National Air and Space Museum, has written more extensively about public opinion of the space program.*

Now for the comments from people I don’t know. I’ve included them verbatim and am not responsible for typos and misspellings.

From Thomas Lee Elifritz:

“If anything I want to go to Mars to get away from you, personally, and people who think, act and talk just like you. I wouldn’t want to be like you. That being said, you have a 0.7 Watt per square meter top of the atmosphere energy imbalance and none of your social theories seen to be able to conceptualize, let alone solve, that problem. So … see ya!”


From James Garry:

“Exactly when is a species mature enough to;

  1. a) sharpen a stick
  2. b) smelt iron
  3. c) discover nuclear fission
  4. d) establish a significant off-world presence?


Dr Garry”


From Wayne:

First I support all endeavors beyond our planet second I hate to be the one to say all those people in other countries should not be my problem our government had made them my problem


From Helder Cordoso:

Do you why Elon charges 200 000$ a ticket, making it an elitist enterprise? Because is not counting NASA funding. Obviously if NASA pays the bill, the US can send to Mars who they want, rich, poor, homeless, what ever, i agree with Mike interbartolo!


From Randy Campbell:

I’ve not any problems with the article as an opinion piece per-se other than your original assertion seems baseless, (libertarian space crowd support by government and media) and that your “deep moral qualms” are unsupported by either your examples or the fact on the ground. What I do have an issue with really is your use of straw man and fear-mongering in place of logical or fact supported support for what is obviously just an opinion.

[Billings: My “opinion” on this issue has evolved over 35 years of work in the space community, including plenty of research on the subject. I’m used to being dismissed by men who disagree with me. I don’t like it, it’s not fair, but I’m used to it.]

I can respect that this IS your opinion but in attempting to justify your opinion on supposed “ethical” and “moral” grounds and the obviously perceptive ‘case’ of human “maturity” as valid reasons to prevent anyone wanting to go to Mars from doing so is frankly more than a little disquieting from a professional. [Billings: Really? More dismissal.]

The latter “argument” specifically falls flat as “immaturity” is in fact a defining characteristic of youth and youth only become mature with time and experience. Which leaves your argument as one that youth should in fact be prevented and discouraged from ever becoming mature, because it should wait until it IS mature…

You are aware I’m sure that it is not the “mature” that move away from home and produce their own lives and experiences but the immature, the young. These lives and experiences then turn the immature into the mature, the young into the adult and on a species level we clearly do not have the experience yet to be “adults” but we will also never get that experience unless we expand our horizons and stretch ourselves to our fullest potential. [Billings: It may fall flat to you, but it does not fall flat for me or for many others with whom I’ve discussed this issue. I don’t do my work in a vacuum.]

We have the capability and technology to go out into space to explore, exploit and colonize if we so desire. Nothing short of the total collapse of our current civilization will take away that capability. The choice is not “if” but when, and who. Sooner is preferred and those that shall will not be some pampered elite but those willing to sacrifice, work, and possibly die attempting to make more of their lives and situations. It will not be easy, it will not be cheap, and it will not come without hardship and cost but that is also a part of how one grows up and becomes an adult.”

From Charles Houston:

“Very interesting article and discussion. Pardon me for descending into a bit of whimsey, let’s compare the Mars discussion to the early explorers who came to the Americas.

For similar reasons the English, Spanish, etc should NOT have permitted exploration of the Americas!!! Why allow the rich (people who could afford it) to go to Plymouth Colony to luxuriate in the resort that was America? Why were the poor left behind in Europe to deal with the leftovers??

Ok, as we all know, Jamestown and Plymouth Colony and Spanish Florida and all of the early settlements were places of great hardship and loss of life (for the settlers and eventually the Native Americans as well). Any settlers on Mars hopefully will not be so poorly prepared – but they will be ready for a life of sacrifice, hard work, no chance for vacation, etc. They would presumably be willing to risk everything to possibly provide a better future for their families. Fortunately there are no Martians to displace!! The people who stayed behind benefitted by the discoveries made in the New World (well, except for tobacco of course).

doctorlinda appears to be upset by more than the prospect of settlers going to Mars. She is apparently upset by our lack of concern for displaced people. Possibly governments are wasting money on “research” when it could be used to feed the poor. Let’s talk about what shared personal/government funding has accomplished for those displaced people. Bell Laboratories for instance got millions in government research money – they developed much of the electronics that allow us to now see what is happening to displaced people. Research – funded by the government and academia and corporations – has developed new industries, new capabilities, new careers.

Certainly humanity has a ways to go but I see a far, far, far better humanity than doctorlinda does. Humanity has written The Bill of Rights, has given minorities the right to vote, has created art and mathematics. We will never be perfect but the need to many of us to explore will open new opportunities for us all. We can “eat our seed corn” and be full today or we can plant some of that seed corn and harvest tomorrow.

There have always been people like doctorlinda – we see the Amish and the Mennonites and other wonderful communities today, communities that reject this bit of advance or that bit of advance. If they are not comfortable with buttons or electricity or whatever they are welcome to live in whatever era they are comfortable with.

But they must recognize that we will not all be willing to accept their limitations. We will explore the stars while they stay home and rage over the situation of the latest wave of refugees from the latest conflict zone. Charlie Bolden’s ancestors came from a conflict zone, Elison Onizuka’s ancestors came from a conflict zone. As refugees from the previous conflict in the previous conflict zone, we have places to go.”

It cracks me up that Mr. Houston compares me to the Amish and the Mennonites. People who know me will laugh about this too. I am deeply engaged in the modern world (or, as I call it, the post-postmodern world) and all of its problems and challenges. This is what a public scholar does, and that is what I am.

From Jason AW3:

“Doctorlinda, with respect, I must disagree with your position.

When observed from a limited perspective, much of what you say, does, on its surface, appear to be true. [Billings: We all have limited perspectives. No one has a god’s-eye view on any issue.]

However; when looked at from a larger perspective [Billings: I think you mean your perspective? I am very intentionally taking a broader view of the issue at hand.] , much of what you’ve stated tends to fall flat. Yes, there are many social inequities that we have yet to address, and there are issues that still need resolving. But, on the whole, we ARE becoming better people, we are reaching out and helping both those who are less fortunate than ourselves, and we are correcting the wrongs and oppression that have been wrongly foisted upon so many different peoples.

And we are becoming better shepherds of our world. Turning away from a disposable society, using nonrenewable sources of power, and turning to more environmentally aware uses of industry and the land.

Yes, it IS taking an enormous amount of time to do this, but changing the minds and attitudes of seven and a half billion people takes an enormous amount of time and effort. This is, however, inextricably tied to our need to explore and go to other lands. We know that, not all the answers we need to make life better for all, can be found within our limited scope of experience. We need to stop gazing at our navels and see the broader universe.

It’s been said in the past, that the beginning of wisdom, is knowing how much you don’t know. While I know much, I know that there is a vast amount that I have yet to learn. Wisdom and maturity are gained from our efforts and our failures.

Yes, we fail at MANY things that we ought to do better. But we now know how much we don’t know, and while it will be the elite who, at first, go into space and start taming new worlds, they will also bring others with them, the poor and oppressed, for opportunities that can advance them as well.

It is better to give a man a hand up than a hand out. In other words, let us make the mistakes, lets us stumble through the dark, and yes, let us even die from those mistakes, so that those who follow can learn from these mistakes and make wiser choices than we did.

Indeed, it is our very lack of maturity that gives us the need to go to places that we do not know, to learn what we have yet to learn, to step out and BE better than we are today.

To deny this of those who would blaze the trails for all, is to deny what it is to be Human and humane.”

From ZachF:

“Crab-bucket mentality at it’s finest.”

I have no idea what this means.

From “Mikey”:

“Same story, Same crying, Same questions. Biology cannot be discovered without Biology. back in 2009 How will extending human presence into the solar system affect society and culture on Earth? What legal, ethical, and other value systems should govern human settlements and other activities in space? Do humans have rights to exploit extraterrestrial resources and alter extraterrestrial environments? Does space exploration need reinvention to meet social needs? This article describes the current environment for space policy making and a framework of space law, ethics, and culture within which these questions can be considered.”

Your Dear Friend;

Michael D. Griffin

Immediate Past President

American Institute of Aeronautics and Astronautics”

I know Mike Griffin, and this doesn’t sound like him at all. I clicked on “Mikey” in the message I received and was directed to the web site of the Federal Corrections Institute in Morgantown, West Virginia.

From Mike Shupp:

“This sparked a post from Keith Cowling at Nasawatch ( and a rather good comment stream. I’d not say there’s a lot of agreement with Dr. Billing’s views, but the discussion pushed some of us space buff types into a more philosophical vein than normal.”

I would not expect to see much agreement with me among the readers of NASA Watch. But I’m happy to hear from Mr. Shupp. My aim, as always, is not to change minds but to get people thinking about things they may not have thought about before.

And finally, from lastof7:

“I don’t agree with Linda on this issue, but this is not an engineering discussion. In fact, that’s something I fear: that we have become so STEM focused that we’ve moving toward the assumption that all technology is good without taking the time to figure out the impact of the technology. This argument is worth having and it doesn’t require an engineering degree to have it.”

Thank you, lastof7.

To borrow a quote from Linda Richman (“Coffee Talk,” SNL), “Talk amongst yourselves.”

* See, for example, R. Launius, Public opinion polls and perceptions of human spaceflight, Space Policy 19(3), August 2003; R. Launius, Evolving public perceptions of spaceflight in American culture, Acta Astronautica 53(4-10), August-November 2003.

Humans to Mars: a deeply disturbing idea


Credit: “Mining Mars,”

One of many cultural phenomena that worry me as much as the U.S. presidential campaign (I voted for Bernie in the primary, and I am voting for Hillary on election day) is the persistent public cheerleading for the human colonization of Mars. The media repeat every bit of the libertarian narrative of progress and freedom that they’re feed with virtually no critical analysis.

I will not repeat much of what Elon Musk said yesterday about his “vision” for colonizing Mars, as it’s plastered all over the mass media. If you want to read a level-headed account of yesterday’s announcement, see Marcia Smith’s report on Space Policy Online.

As Marcia notes, “Elon Musk has made no secret of his passion to make humanity a multiplanetary species by creating a self-sustaining society on Mars as a backup plan in case Earth is destroyed in a cataclysmic event.” NASA’s embraced Musk and his wacky ideas as a way to promote its own “journey to Mars.” Musk said yesterday he wants to accomplish his goal by public-private partnership.

Really? I don’t want a penny of my tax dollars going into such a project. (Musk has already benefited from millions of dollars in direct subsidies, not to mention contracts, from the federal government.)

Musk said he will take people to Mars for $200,000 apiece, transporting 100 to 200 people at a time, starting in a few decades.

First, I don’t believe for a minute that he will accomplish that goal in the foreseeable future.

Second, I have deep moral qualms about this idea, as it appeals to a small fraction of humankind and proposes what would inevitably be an elitist enterprise. Would it be ethical to enable people with enough money to buy a ticket to leave our troubled Earth behind? Would it be ethical for government(s) to subsidize such an enterprise? In Musk’s disturbing “vision” – a nightmare in my mind – how many poverty-stricken Bangladeshis or Congolese, how many permanently displaced Syrian refugees, will come up with $200,000 – or $2,000, for that matter – to “start anew,” as the colonization zealots say they want to do?

I participated in a conference this past weekend about “social and conceptual issues in astrobiology.” Among the questions we 30 attendees were asked to consider in our discussions were:

“Should humans seek to exploit and/or colonize space? If so, how should this be done? Are there truly universal principals of biology, psychology, morality, etc. that would apply to extraterrestrial life?”

My views on these questions are: No. We should not do it. No.

Right now, at this point in time, humanity is too immature to leave home. We can’t even figure out how to take of ourselves – that is, all humanity – on our home planet. It’s crazy talk to claim that simply by moving to another planetary body we’ll reinvent society.

Human social behavior, intellectual capability, and psychology, will not “evolve” in any noticeable way over the next 10 or 40 or 50 years – probably not even in 100 years. We have not changed noticeably in these respects over the past 100 years, after all. What we have accomplished over the past 100 years is more technology. Hence, crazy talk about colonizing other planets and mining the asteroids.

Last year I blogged about these issues in a post about last year’s Mars Society conference. I’ll repeat what I wrote then: “As a taxyaper, citizen, and space policy analyst, I continue to be baffled by the current administration’s fondness for the ‘space libertarian’ crowd. Is it evidence of what neoliberals call the ‘triumph of neoliberalism’ – free trade, downsized government, lower taxes, privatization? It’s time to take a critical look at U.S. space policy and practice.”

More views on exoplanet terminology



In cleaning off my desk this morning, I unearthed the August 12 issue of Science, which contained yet another paper about a new exoplanet discovery (K. Wagner et al, “Direct imaging of a Jovian exoplanet within a triple-star system”).

Also in this issue was a lovely Perspective on the Wagner et al paper, “Making sense of the exoplanet zoo,” by astrophysicist Rebecca Oppenheimer at the American Museum of Natural History. Following up on my post of September 7, I though I’d share some of her thoughts.

“The single most certain statement about” exoplanets is “expect the unexpected,” she says. I certainly agree. As to the newly discovered Jovian exoplanet in a tripl0-star system, Oppenheimer observes, “Many such solitary objects…are being discovered routinely. All are different from each other, straining current classification schemes.”

She mentions another star, HD 41004, “that exhibits the ‘unexpected’ and draws into question what constitutes a solar system.” HD 41004 is “somewhat smaller than the Sun, with an object 2.5 times as massive as Jupiter on an orbit slightly more than Earth’s about the Sun. In addition, another star orbiting HD 41004, at the equivalent of Uranus’s orbit, has a substellar object orbiting it with about 20 times the mass of Jupiter.” “So,” she asks, “is our labeling of HD 41004 as a ‘solar system’ accurate?”

As I noted in yesterday’s post, Oppenheimer notes, “categorizing is an age-old practice in scientific thought.” However, she comments, “after 22 years of working on substellar objects, I suspect that” the labels now used to sort them may have lost their utility in advancing knowledge. Labels can become obfuscating terms.”

Hear hear.

“With fascinating discoveries, such as Wagner et al’s…and the thousands of objects intermediate between it and stars, what we know is that they consistently fail to conform to the stellar classification system intrinsic to the history of astrophysics. In such a confusing situation, the best we can do is rethink the basic assumptions,” Oppenheimer says. (Pardon me for such extensive quoting, but her piece is so well written….) She cites a paper by Chen and Kipping ( that proposes a new nomenclature: “Jovian, Neptunian, and Terran worlds. Whether this scheme will certainly be debated, but it is a fresh alternative to the confusing terms in use today.”

Finally, she notes – wisely, I think – “Perhaps it is too early to define classes of objects” in the universe. To do so may obscure their commonalities and differences, urging overspecialization in the study of objects assumed to be unrelated because of thought-constraining labels.”

Thank you, Dr. Oppenheimer!

The University of Surrey put out a press release today about newly published research that “has shone light on a globular cluster of stars that could host several hundred black holes, a phenomenon that until recently was thought impossible.” A September 7 press release from the Carnegie Institution for Science reports, “Dwarf galaxies are enigmas wrapped in riddles. Although they are the smallest galaxies, they represent some of the biggest mysteries about our universe. While many dwarf galaxies surround our own Milky Way, there seem to be far too few of them compared with standard cosmological models, which raises a lot of questions about the nature of dark matter and its role in galaxy formation.” Every day I read of new research findings about things we didn’t know existed or didn’t believe could exist. It’s what gets me up in the morning….

Earth-like, Earth-sized, Earth-mass: habitable?




Maybe. Maybe not.

Dear readers, by now you must have heard or read news reports about the discovery of an “Earth-like” planet orbiting Proxima Centauri, the star that is closest to our solar system (4.5 light years away).

I put “Earth-like” in quotes because the term appears in many stories (especially in headlines) reporting the discovery. But what exactly does “Earth-like” mean? (See my blog post of July 23, 2015, about another announcement of a “near-twin” of Earth.) In this post I do not intend to criticize the research under discussion here or the media reporting on it. I am interested in exploring the optimistic and somewhat confusing framing of the discovery, the fuzzy terms used to describe it, the minimizing of considerable uncertainties.

The discovery of this “Earth-like” planet, Proxima b, apparently was first reported August 12 by the German magazine Der Spiegel. In the following week or so, a few science news outlets reported on Der Spiegel’s story. Some of the headlines: “Proxima Centauri may host Earth-like planet” (Spaceflight Insider), “Does an Earth-Like Alien Planet Orbit the Sun’s Closest Neighbor?” (, “Newly Discovered Earth-Like Planet Is Orbiting Proxima Centauri” (Nature World News), “Earth-like planet around Proxima Centauri discovered” (

The research paper reporting on this discovery – “A terrestrial planet in a temperate orbit around Proxima Centauri” – was published by Nature August 24 (Anglada-Escude et al, doi: 10.1038/nature19106): “we report…the presence of a small planet with a minimum mass of about 1.3 Earth masses… Its equilibrium temperature is within the range where water could be liquid on its surface.” In the last paragraph of their paper, the researchers note: “The habitability of planets like Proxima b – in the sense of sustaining an atmosphere and liquid water on its surface – is a matter of intense debate. The most common arguments against habitability are tidal locking, strong stellar magnetic fields, strong [stellar] flares and high ultraviolet and x-ray fluxes; but none of these have been proved definitive…. Proxima b suffers from X-ray fluxes that are approximately 400 times that experienced by Earth.”

A commentary in Nature on this paper (“Earth-like planet around Sun’s neighbor”) describes Proxima b as “Earth-like,” “Earth-mass,” “in the temperate zone” that “could theoretically support liquid water. ” Author Artie Hazes suggests that, “Until we understand what makes a planet habitable, it is better to say that Proxima…b lies in a temperate (the right temperature) rather than a habitable zone.” An accompanying news report in Nature (“Nearby star hosts planet”) describes Proxima b as “Earth-sized” and “potentially habitable,” though possibly “unlivable.”

Also on August 24, the European Southern Observatory (ESO) issued a public announcement (what we used to call a video news release) about this discovery: “the planet, Proxima b, falls within the habitable zone of its host star. The newly discovered Proxima b is by far the closest potential abode for alien life.” ESO defines “habitable zone” as a location in a planetary system where liquid water could (might?) exist. Toward the end of this announcement, uncertainties about habitability are mentioned.*

Media reports on the paper followed suit, emphasizing Proxima b’s alleged similarity to Earth and closing with a mention of uncertainties. Here are some headlines from August 24: “Potentially Habitable Planet Found Orbiting Star Closest to Sun “ (National Geographic), “Proxima b By the Numbers: Possibly Earth-Like World at the Next Star Over” (, “Proxima b: Alien life could exist on ‘second Earth’ found orbiting our nearest star in Alpha Centauri system” (The Telegraph).

You get the idea.

On August 26, Wired reported, “Y’all Need to Chill About Proxima Centauri b…. Astronomers have found other quote-unquote Earth-like planets in the habitable zone in recent years. According the Planetary Habitability Laboratory at the University of Puerto Rico, there are 15 “Earth-size” (in terms of mass or radius) potentially habitable exoplanets. And while, yes, Proxima Centauri b has the mass closest to Earth’s so far, its other characteristics may not be very earthy….” Also on August 26, my friend and colleague Sten Odenwald (who is an astronomer) blogged for the Huffington Post, “Proxima Centauri b: Earth-sized? Earth-like? Or Habitable?... The terms Earth-sized, Earth-like and habitable might sound very similar, but in fact they are not, and they are also not astronomically precise terms….”

Thank you, Sten.

On August 29, Popular Mechanics (predictably) asked about Proxima b, “How will we travel to that promising new planet?” On August 31, the Voice of America went way over the top with “Colonizing Proxima b, It’s Complicated.”

On September 4, Cosmos magazine addressed “The many potential lives of ‘Earth-twin’ planet Proxima b.” on September 6, Nature World News reported, “Co-Discoverer Says Proxima B is a Life-Friendly Planet; Life Outside Earth Possible?” And also on September 4 (I’m throwing this in just for fun), an alleged news website called Clapway claimed that the lead author of the Proxima b paper in Nature is “meeting with aliens from Proxima b.” (Sigh.)

So, Proxima b is described as habitable, Earth-like, Earth-mass, Earth-sized, terrestrial…have I forgotten anything?

I know that exoplanet scientists have thought about the imprecision of these terms – I’ve witnessed many a conversation among them on the subject (and thanks again, Sten, for your blog post). We all use fuzzy terms from time to time, knowing exactly what we mean in our own heads but not knowing what they might mean to others. In the case of the search for another Earth, I’m doubtful that we’ll find one. Over the 25-year course of the discovery of now 3,000-plus exoplanets, what amazes me most is not how many planets have been discovered but how different they all are. It appears to me that what scientists have discovered (so far) is that there’s no such thing as a typical planet or a typical planetary system.

We humans – and especially scientists – love to label and sort things into groups, in a never-ending effort to create order. In the case of exoplanets, we have “hot Jupiters” and “mini-Neptunes” “Earth twins” and “super-Earths” and so on and so on. I do hope that exoplanet scientists continue to work on more precise terms for characterizing their discoveries – especially when it comes to discussions of potential habitability.


* Habitability is complicated. As I noted in my blog post of July 1, 2015, among the many Big Questions yet to be answered by space science are: What is “habitable”? What is a “habitable zone”? How do we define the habitable zone of a planetary system?