Rationales for Human Spaceflight after the Shuttle

cropped-shuttle.jpgI originally published this piece in Space News on February 11, 2013. The original may be read here. One respondent to it on April 15, 2013, thought I downplayed the importance of human spaceflight in the pursuit of scientific understanding too much, and that letter is available here. I don’t believe I did, but I’m curious what others might think. Let me know.


Since the retirement of the space shuttle, the U.S. space community has been collectively wringing its hands over the state of the nation’s human spaceflight program. Hardly a day goes by without some commentary on possible directions for human spaceflight. At Congress’s behest, the National Academies’ Committee on Human Spaceflight is beginning to assess the goals of NASA’s human spaceflight program. This comes on the heels of another National Academies study on NASA’s strategic direction, the report just issued that places emphasis on the human spaceflight enterprise. In addition, a new report by the Space Foundation, “Pioneering: Sustaining U.S. Leadership in Space,” seeks an alteration in NASA’s mission to focus on human pioneering of space and eliminating tasks that do not emphasize that objective.

Whether these efforts will provide a way forward beyond the quagmire in which human spaceflight is presently caught remains to be seen. That all of them take as a given that human spaceflight must continue — or even be emphasized beyond its current status — seems assured. But should this be the case? James Van Allen famously asked in 2004: “My position is that it is high time for a calm debate on more fundamental questions. Does human spaceflight continue to serve a compelling cultural purpose and/or our national interest? … Risk is high, cost is enormous, science is insignificant. Does anyone have a good rationale for sending humans into space?”

Ascertaining what rationales for human spaceflight are compelling remains a core issue before the United States in the second decade of the 21st century. From the defining event of Sputnik in 1957, I would contend that there have been five major rationales that have been used effectively to justify a large-scale spaceflight agenda:

  • Scientific discovery and understanding.
  • National security and military applications.
  • Economic competitiveness and commercial applications.
  • Human destiny/survival of the species.
  • National prestige/geopolitics.

Specific aspects of these five rationales have fluctuated over time but they remain the core reasons for the endeavor that have any saliency whatsoever. The first three, at least thus far, have not required human activities in space. Those have been accomplished with lesser cost and arguably greater efficiency using robotic spacecraft, thank you very much. That may change in the future — conceivably this could happen as a military human spaceflight mission emerges — but at present these goals do not require humans in space. This might also change in response to the rise of space tourism, a major venture that envisages hotels in Earth orbit and lunar vacation packages. While this has yet to find realization, it remains a tantalizing possibility for this century.

The human destiny rationale for spaceflight has been used repeatedly by astronauts and others, emphasizing that an integral part of human nature is a desire for discovery and understanding. At one level, there exists the ideal of the pursuit of abstract scientific knowledge — learning more about the universe to expand the human mind — and exploration of the unknown will remain an important aspect of spaceflight well into the foreseeable future. It propels a wide range of human efforts to explore the Moon and beyond projected for the 21st century. It also energized such efforts as the Hubble Space Telescope, which has revolutionized knowledge of the universe since its deployment in 1990. Clearly, this goal also motivates the scientific probes sent to all of the planets of the solar system.

But most importantly, this idea has privileged human spaceflight as the raison d’être of human destiny for the long term. With the Earth so well known, advocates argue, exploration and settlement of the Moon and Mars are the next logical step in human exploration. Humans must question and explore and discover or die.

There is also a terrifying aspect to this rationale; humanity will not survive if it does not become multiplanetary. The apocalyptic aspect of this — a “survival of the species” argument — might be true, but it is also terrible to consider. Carl Sagan wrote eloquently about the last perfect day on Earth, before the sun would fundamentally change and end our ability to survive on this planet. While this will happen billions of years in the future, any number of catastrophes could end life on Earth beforehand. The most serious threat is from human-caused destruction, but an asteroid or meteor could also impact the Earth. Throughout history, asteroids and comets have struck this planet, and a great galactic asteroid probably killed the dinosaurs when an object only 10 to 15 kilometers in diameter left a crater 300 kilometers wide in Mexico’s Yucatan Peninsula.

Finally, national prestige and concern for geopolitical relations have dominated so many of the spaceflight decisions that it sometimes seems trite to suggest that it has been an impressive rationale over the years. Yet there is more to it than that, for while all recognize that prestige sparked and sustained the space race of the 1960s we too often fail to recognize that it continues to motivate support for NASA’s programs. The United States went to Moon for prestige purposes, but it built the space shuttle and embarked on the space station for prestige purposes as well. Prestige may make likely that no matter how difficult the challenges and overbearing the obstacles, the United States will continue to fly humans into space indefinitely, but this is not a certainty.

Now we are at a crossroads, and the question that Van Allen asked — does anyone have a good rationale for sending humans into space? — deserves serious consideration. Should human spaceflight be continued as a national program? Is it an appropriate course for the nation’s effort in space? Are the traditional rationales in favor of human spaceflight sufficient to win support for the effort into the future? While Americans seemingly want the fruits of human spaceflight, too many are unwilling to invest in it. The rationales, as real as they might actually be, seem less compelling today than in the past. What compelling rationales offer a way forward for astronauts to push back the frontiers of the cosmos? I hope we will resolve the challenge of compelling rationales for human spaceflight into the future.

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12 Responses to Rationales for Human Spaceflight after the Shuttle

  1. Jeff Bingham says:

    Interesting commentary, as always. I have considerable amount to respond, but not going to try it at 3:00AM. Too great a percentage of Brain is shut down for the night! Will try to offer some thoughts when rested and recaffeinated tomorrow or soon thereafter.


  2. People who see the demise of US human spaceflight around every corner ignore the fact that American astronauts have reliable access to space through the Russians. They see reliance on Russia as somehow a risk when in fact it amounts to one half of a long-established reciprocal relationship. They’d rather accept the very real risk of reliance on wholly new “private” systems.

    To me this says that really getting Americans into space where they can do real things is less important to many space supporters than is ideology.



  3. GHK says:

    Roger; I think you are missing one important rationale for human space flight after Shuttle. That is technological advancement. Technology is the application of knowledge to new engineering-developing new equipment and new capability. Through Mercury, Gemini, Apollo and then Shuttle we were advancing technological capability. Advancement is usually accompanied by increasing capability and reducing effort, time and cost or production and operation. With reduced cost comes the opportunity to invigorate development and expand utilization. One of the things I heard this week at a session of the early Shuttle program management was that they felt that by turning away from Shuttle and back towards a capsule approach (Constellation), NASA had effectively turned its back on technological advancement. Many of us who have worked in human space flight have seen political and organizational agendas that discarded experienced elements of the workforce only to try and re-establish capabilities with inexperienced personnel. This has been costly and sometimes has not worked. I worry that if we do not maintain capability and continue to advance, then we will lose what had been gained previously. The earlier investment is lost and may never be regained. Sometimes a quantum leap in capability will re-establish and enhance capability without bringing along the earlier technology which would only serve to slow advancement. The quantum leap in aviation of going from piston engines to jet engines might be such an example. Perhaps Space-X will be such a quantum leap in human space flight, although I am not certain whether it represents a quantum leap in organizational efficiency rather than technological capability, but its success will only be assured if they can demonstrate regular and frequent repetition of mission at reasonable cost. Some would argue that Shuttle never got to that point, but others would argue that after Shuttle was first placed into use, NASA turned its back on advancing its technology in favor of expanding operational support.


    • launiusr says:

      Gary, thanks for your note on this. I do not include technological advance as a core reason for undertaking spaceflight. There is technology that results from the effort, of course, but I really do not believe it is not the reason that we engage in this activity. At some level this sounds like the spinoff argument. Those happen as well when engaged in spaceflight but they are not the reason we do it. I view technology advance as a serendipity rather than a core rationale. Others might differ, of course, on this perspective.


  4. Dan lester says:

    Roger, this is an important topic. Of course the NRC Committee on Human Spaceflight is being asked exactly this question.

    I have to be a little skeptical about the “species survival” argument. In order to preserve a species, it requires a diverse DNA set to avoid inbreeding. A dozen or two people in a habitat on Mars won’t do it. In fact, for each race, we are led to believe that it takes several thousand people to assure survival. That being the case, one has to consider the costs of shipping boatloads of people into the solar system, compared with the costs of protecting the Earth. For that cost, 100% detection and mitigation of asteroid impacts is easy. As to your most serious threat — human caused destruction, humans that can destroy people on Earth are going to be capable of destroying humans on Mars. No sweat.

    Now, that being said, if one is going to have thousands of people on a another world, I suppose it doesn’t hurt to start sending them, but the necessary result isn’t going to be achieved for a long, long time. I suspect species survival will be guaranteed more by fetus-on-ice spaceflight than by spaceflight by fully formed people. It’s likely that truly independent samples of our species will start to evolutionarily diverge anyway. It’s certainly true that colonization of the solar system isn’t a way to ensure survival of the nation. History tells us that those colonists will eventually break away and form their own nations. I have to suspect that’s why Congress hasn’t used that argument as a rationale for human spaceflight.

    You are right that the top three in your list don’t need human space flight. Human destiny doesn’t either. The scientific knowledge that drives this is covered in your first bullet. Our understanding of our place in the cosmos certainly hasn’t come from human space flight. That’s exactly right that the rationale for human spaceflight isn’t as compelling as it was in the past. Forty years ago, to learn what we learned about the Moon, we needed human space flight to tell us. There wasn’t any other way. But what Apollo did then, we could do now telerobotically. The understanding we’d get is the same, except we wouldn’t leave footprints. The historical definition of exploration constrains us to see it as an activity that needs footprints. We’re smarter than that now.

    As to national prestige and geopolitical exceptionalism, human spaceflight used to count for a lot. Maybe it still does. But there are a lot of ways to express American technological exceptionalism, and human spaceflight may not be the most cost-effective way to do it, nor may it be the way that offers the most commercial potential.


  5. Great to hear someone saying this, first I totally agree that the idea of colonization as a reason for human spaceflight is limited, especially if you think in terms of colonizing other planets. I wrote a series of articles about this on my science20 column including “Ten reasons not to live on Mars, great place to explore”. Deserts on the Earth are far more hospitable than anywhere else in the solar system, with possible exception of the Europa oceans. We can create habitats for humans in the deserts for far less cost than on Mars, and indeed are ideas for doing that such as the seawater greenhouses project for Sahara desert. Put the same amount of money into that and into reversing desertification on Earth, and you could have an order of magnitude more colonists – and if they can be totally self sufficient on Mars, which I very much doubt with present technology – then they can be even more so totally self sufficient in the Sahara or Arizona or Gobi deserts for far less cost.

    Also the whole thing about colonizing Mars to escape possible disasters on Earth – I can’t see that working at all. It is hard to think of anything that would damage the environment of Earth so much that it becomes as inhospitable as present day Mars or even Mars after a century or so of attempts to terraform it (which I think is something we are nowhere near the level of understanding of planets to attempt).

    However I do see a future for humans for space exploration – especially for telerobotics, and especially for Mars there. Because our rovers on Mars are so slow. I think once we start to return rovers to the Moon we’ll see that rather clearly. If you could drive Curiosity as fast as 5 miles per hour then you would get to where it is now in less than a day and would have reached the foot of Mount Sharp by the day after its landing. For the scientific experiments, too, you have to plan everything for the next day, after first analysing the images, and those would go far faster too if you could do it in anything like real time. You could do months or years worth of exploration in a day or two if you had humans in orbit around Mars to operate the rovers there.

    If Dennis Tito does his Mars flyby I think would be a major missed opportunity if they don’t do a technology demo of telerobotic exploration of Mars – that would require some planning, to send another rover there powerful enough with enough fuel to travel at 5 mph or faster over the surface for the duration of the fly by – and with ability to be operated from orbit.

    This also I see as the best way to search for life on Mars. With the HERRO project, then they worked out and that’s a few years back, that one mission to orbit working via telepresence could achieve as much science return as three missions to the surface. I don’t know how much cheaper that would be but no need for human rated lander, or habitat on surface, or surface rated space suits, I’d be surprised if it costs as much as a third of the cost of a surface mission. So combine those together and the total cost for the same amount of science value is at least an order of magnitude less.

    You could also send habitats in advance to orbit, just as for the surface – and so build up the beginnings of a space colony around Mars, worth doing for the telerobotic exploration of the surface, and eventually using materials from Phobos and Deimos to expand the colony.

    Long term, I see space colonies and space mining as another reason for human space flight.

    If NASA focused on the idea of telerobotic exploration of the solar sytem, that’s a far more affordable aim, and means you can also explore without contaminating everything you explore with the micro-organisms and organics of a human habitat. We have instruments that can detect a single amino acid in a gram of soil. But what’s the point in sending those along with a human expedition – to anywhere, even the poles of the Moon, which may have interesting organics? (At least until it is thoroughly explored without humans first).

    In case of Mars I think there is a serious risk of contaminating the planet with Earth life before we even have a chance to study it, if we send humans to the surface. If anyone thinks it is possible to send humans to the surface without doing that, I think this needs to be proved beyond reasonable doubt before any expedition like that gets underway. With many new discoveries of micro-organisms able to survive in hostile conditions like those on Mars, even lichens able to metabolize and grow in Mars like conditions using the 100% night time humidity, without water, and use by other micro-organisms of deliquescing salts to grow, I think it will be hard to prove that humans won’t contaminate Mars and I think at least a fair risk of doing so. Certainly a far higher risk for humans than for the rovers, which are all currently carefully decontaminated in a way that is totally impossible for a human mission.

    Otherwise we are going to lose an amazing wonderful opportunity to explore Mars in its current pristine state. Again I’ve written a lot about this too on my science20 column.


  6. Paul D. says:

    I have to be a little skeptical about the “species survival” argument.

    As a thought experiment, try to imagine a disaster that would leave Earth less habitable than any location in space already is. Nuclear war wouldn’t do it. A dinosaur-killing-scale asteroid impact wouldn’t do it.


  7. Dale says:

    I believe that the US government is taking a pure Military/Capitalism approach to the “Manned Space Flight” issue.

    1) The Russians provide a public platform for manned space flight access to the ISS and possibly other low Earth orbit missions (think Hubble-ish).

    2) The US government has it’s own covert manned space flight program (which is used every day) for access to space for “National security and military applications.”

    3) The US Government isn’t going to truly back any “large scale” public manned space flight program, ever since it was able to take it’s own quite successful military (and organizations with 3 and 4 letter acronyms) manned space flight program to black/gray ops. There just isn’t any need for a public program expenditure to satisfy the goals of the covert, public programs – certainly any discoveries to be made would more benefit the private sector of the capitalism market (“Economic competitiveness and commercial applications”) and thus there has been the building emphasis, by NASA and others sources, for private space investments and “adventures.”

    4) “Scientific discovery and understanding” can be accomplished, for the greater part, by non-manned space flight operations, either remotely or autonomously, unless, those discoveries and understandings involve direct research on the human organism and it’s sub-systems in space.

    5) Addressing “National prestige/geopolitics,” I think that the US Government has accessed the value of such a “soft-value” notion compared with the hard, massive financing/funding facts necessary for a manned space program and since there is no direct financial income from manned space programs, that it is willing to forego the “National prestige/geopolitics” of a manned space flight in favor of the “worldly awe and fear” of it’s war systems. Those of us that have been in the aerospace industry have witnessed the slide in national importance gaged by whole school attendance of televised manned space flight missions to barely mention of manned space flight missions on the second or third page of local newspapers. In other words, manned space flight has very little effect on more than 90% of the world’s population. Earthly life and strife goes on, whether there’s humans in space or not.

    6) “Human destiny/survival of the species” is even more of a remote notion to most people of Earth. Unless there is an immediate need, the nature of the “adolescent” human species, is to ignore the immediate calm of a potential “storm” rather than to actively plan for the certainty of such a “storm.” An ideal answer might be to first create/maneuver an orbital body of planetary size to a “Goldy Locks” position in relation to this system’s sun (perhaps an orbit directly opposite Earth’s, if gravitational and other studies indicate no other dangers from it’s presence) and after conditioning the body (“terra-forming”) to begin to populate that body with humans either directly from Earth or via advanced artificial womb sciences. By this time, no doubt robotic explorations may have located other habitual bodies in space (and perhaps other species of similar design). This also raises the question of whether the human species, resident on Earth, is even worthy of continued existence, beyond chance. I also think the humans of Earth will find the “human model” to be of a more universal design than presently thought, e.g. “THEY look a lot like US” (with exceptions for evolutionary adaptations).

    In any case, Earthly propulsion systems to be used in space will need to advance to designs which support interstellar distances, e.g. “chemical” and “light sail” systems are not the answer. Current, covertly used technologies (electro-gravitics) are a start on these journeys.


  8. Doug Plata says:

    ■ Security
    ■ Politics
    ■ Advancement & Survival
    ■ Commerce
    ■ Exploration, Scientific


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