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Posted on Jun 11, 2014

In 2012, I announced that I was appointed as a National Academy of Sciences (NAS) committee member of a congressionally-requested study on the future of human spaceflight. Just last week, we released our 286-page report to the public (thankfully, there is a great summary section at the front!). I highly recommend reading it (you can download it for free at after logging in). There are a lot of highlights, as the report is large, complex and nuanced. I thought I’d share just a few high-level quotes from the report for now:

The committee was tasked with providing recommendations that “describe a high-level strategic approach to ensuring the sustainable pursuit of national goals enabled by human space exploration, answering enduring questions, and delivering value to the nation” and to consider the evolution of such a program out to 2030 (though our report went on to include considerations out to the 2050s).

“The committee appointed to carry out the task above should contain a breadth of backgrounds spanning not only expertise in human exploration but also areas such as space science, science more broadly, sociology, the science of public polling, political science and history, and economics.  In this regard, the membership of the committee that carried out this study looks different than committees that have carried out many previous studies related to human spaceflight by the NRC or other organizations, and thus the Committee on Human Spaceflight provides a fresh independent perspective on the issues involved in this much-studied area.” (page xiii)

“The committee asserts that the enduring questions motivating human spaceflight are these:
How far from Earth can humans go? and  — What can humans discover and achieve when we get there?” (page S-1)

“The nation must now decide whether to embark on human space exploration beyond LEO [low Earth orbit] in a sustained and sustainable fashion.” (page S-4)

“Given the expense of any human spaceflight program and the significant risk to the crews involved, in the committee’s view the only pathways that fit these criteria are those that ultimately place humans on other worlds.” (page S-6)

“However, to set course on such an endeavor, the nation will need its investment in the human spaceflight program to grow annually over the coming decades. To continue on the present course—pursuit of an exploration system to go beyond low Earth orbit (LEO) while simultaneously operating the ISS through the middle of the next decade as the major partner, all under a budget profile that fails even to keep pace with inflation—is to invite failure, disillusionment, and the loss of the longstanding international perception that human spaceflight is something the United States does best.” (page 1-1)

Rationales for human spaceflight

The committee outlined a set of pragmatic and aspirational rationales for human spaceflight. The pragmatic rationales being economic benefits, national security, national stature and international relations, inspiration of students and citizens, and scientific discovery. The aspirational rationales were human survival, and shared destiny/aspiration to explore.

“As discussed in Chapter 2, the pragmatic rationales have never seemed adequate by themselves, perhaps because the benefits they argue for are not unique to human spaceflight. Those that are—the aspirational rationales related to the human destiny to explore and the survival of the human species—are also the rationales most tied to the enduring questions. Whereas the committee concluded from its review and assessment that no single rationale alone seems to justify the value of pursuing human spaceflight, the aspirational rationales, when supplemented by the practical benefits associated with the pragmatic rationales, do, in the committee’s judgment, argue for a continuation of our nation’s human spaceflight program, provided that the pathways and decision rules recommended in this report are adopted.” (page S-2)

On human survival:

“Through space exploration, we have discovered the runaway greenhouse effect on Venus, realized that Mars effectively “dried up” 3 billion years ago, and monitored the decline of the ozone layer on our own planet. It is often said that it is difficult to know your own country until you visit other nations, and in this same manner, space exploration has provided the ability to better know our own planet as we contrast it with others. By continuing to unearth scientific knowledge of other planets and of our own, we our more aware of Earth’s fragile nature.” (page 2-26)

“It is not possible to say whether off-Earth settlements could eventually be developed that would outlive human presence on Earth and lengthen the survival of our species. This is a question that can only be settled by pushing the human frontier in space.” (page 2-27)

On shared human destiny:

“This rationale can be defined as the conviction that human space exploration is transpersonal in nature and that space is a frontier for humanity’s collective aspiration. In this context, human spaceflight aims to study humanity’s future—to dare how far humans can go and to investigate what they have a chance to become. From space stations and starships to planetary outposts and terraforming, human imagination acts as a forecaster of a potential future to be reached only via continued development of humankind’s capabilities for human spaceflight.” (page 2-27)

“Human spaceflight is seen as forging a sense of common destiny. “Shared human destiny” and aspiration is a world-view that humans are all in this—life, the universe, and everything—together, and thus should endeavor to explore new frontiers collectively, even if vicariously through the experiences of others. Notably, this rationale is distinguished from survival as a rationale; in this view, collective exploration as part of an intrinsic human experience is separate and independent from the question of survival.” (page 2-28)

U.S. human spaceflight in the context of the world

““Soft power,” or  “getting what you want (in international relations) by use of attraction rather than coercion” is a benefit of NASA’s human spaceflight programs.” (page 2-15)

“space exploration makes unique contributions to U.S. political and social culture. It plays a role in defining what it means to be “an American,” and reinforces the identity as explorers who take the risk of challenging new frontiers that has long been a part of the national culture and history.” (page 2-16)

“It is evident that U.S. near-term goals for human exploration are not aligned with those of our traditional international partners. While most major spacefaring nations and agencies are looking toward the Moon and, specifically, the lunar surface, U.S. plans are focused on redirection of an asteroid into a retrograde lunar orbit, where astronauts would conduct operations with it. It is also evident that given the rapid development of China’s capabilities in space, it is in the best interests of the United States to be open to its inclusion in future international partnerships. In particular, current federal law preventing NASA from participating in bilateral activities with the Chinese serves only to hinder U.S. ability to bring China into its sphere of international partnerships and reduces substantially the potential international capability that might be pooled to reach Mars.” (page 1-19)

“The prohibition on NASA speaking to Chinese space authorities has left open opportunities for collaboration that are being filled by other spacefaring nations.” (page 1-3)

The future timeline of human spaceflight

“Continued operation of the ISS [International Space Station] beyond 2020 will have a near-term effect on the pace NASA can sustain in exploration programs beyond LEO [low Earth orbit].” (page 1-3)

“Budget-driven affordability scenarios are based on the assumption that the three representative pathways to Mars are constrained by the HSF budget increasing with inflation. The lower bound of the budget uncertainty, or flat budget, was not considered, as this condition cannot sustain any pathway to land humans on Mars.” (page 4-56)

“Examination of the schedule- and budget-driven affordability scenarios for each pathway indicates, independent of the ISS extension, that the pathways using historical mission rates are not affordable, and affordable pathways based on an HSF budget increasing [only] with inflation are not sustainable.”  (page 4-57)

On a scenario of the budget increasing:

“Assuming the ISS [International Space Station] is extended to 2028 and the HSF [human spaceflight] budget is increased up to 5 percent per year (two times the rate of inflation), the earliest a crewed surface mission to Mars is likely to occur will be approximately 2040 to 2050. Again, these dates are likely to be optimistic because delays will inevitably occur as developmental challenges and potential failures delay the specific pathway schedule and modify its design. If the exploration budget grows at 5 percent per year, the benefit of terminating the ISS in 2020 is not that great from an affordability perspective, in that a human landing on Mars may be accelerated by just 2 to 4 years, depending on the pathway and the associated risk.” (page 4-59)

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On a scenario of the budget only keeping pace with inflation:

“The scenario shown in Figure 1.11 was generated to conduct a technical analysis and affordability assessment of a notional pathway to Mars, with a human spaceflight budget that increases at or about the rate of inflation, while also adhering to Pathway Principle VIa and VId by including targets that provide intermediate accomplishments and minimize the use of systems that do not contribute to achieving the horizon goal. Astronauts would explore new destinations at a steady pace: operation at L2 is achieved in 2024, a rendezvous with an asteroid in its native orbit in 2028, and the lunar sortie in 2033. Continuing, a lunar outpost would be constructed in 2036, and the martian moons would be reached in 2043. Humans would land on Mars at the midpoint of the 21st century. However, this scenario violates Pathway Principle VIf because the flight rate is too low to maintain proficiency (Chapter 4): on average, one crewed mission every 2.1 years, with gaps of up to 5 years with no crewed missions.71 This scenario could be modified to allow higher mission rates (see Chapter 4). However, that would require funding to increase at a rate substantially higher than the rate of inflation for more than a decade, which, in the current fiscal environment, would violate Pathway Principle VIe.” (page 1-34)

“Based on the lessons from these and other scenarios presented in Chapter 4, the committee has concluded:

As long as flat NASA human spaceflight budgets are continued, NASA will be unable to conduct any human space exploration programs beyond cislunar space. The only pathways that successfully land humans on the surface of Mars require spending to rise above inflation for an extended period.” (page 1-35)

1 Comment

  1. Carl Joseph
    June 12, 2014

    Congratulation, and I look forward to reading the report.

    From what you’ve written it sounds wonderfully ambitious. Would dearly love to see humans flying beyond LEO, and a lunar outpost in my lifetime would be extraordinary.


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