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Participants at the October, 2014 Second Affording Mars Community Workshop at the Keck Institute for Space Studies at Caltech.

The Second Mars Affordability and Sustainability Community Workshop: structure, findings, and recommendations

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Shortly after the first in our series of Mars Affordability and Sustainability Community Workshops (AM I) adjourned in December 2013, planning began on successors to address topics that arose in the first workshop that deserved further consideration. As with the first workshop, the second (AM II) was invitation-only and co-sponsored by Explore Mars, Inc. and the American Astronautical Society. About sixty professionals from twenty institutions participated. The complete workshop reports from both AM I and AM II may be found at the Explore Mars website.

Here we discuss the background and motivation for the workshop, as well as selected findings and recommendations from AM II.


A human mission to Mars is the oft-stated “ultimate” goal for NASA, likely international partners, and the US Congress, including in the NASA authorization act the House approved earlier this month. However, widely cited enormous costs—perhaps as much as a trillion dollars for a many-decade campaign—seem to be an impossible hurdle, although political and budget instability over many years may be equally challenging.

Widely cited enormous costs—perhaps as much as a trillion dollars for a many-decade campaign—seem to be an impossible hurdle.

Over the past few years, a handful of increasingly detailed architectures for initial Mars missions have been widely presented by aerospace companies and academia. They have been accompanied by estimated costs roughly comparable with previous major human spaceflight programs: the International Space Station (ISS) and the Space Shuttle. Overviews of these studies were presented and discussed at AM I and were promising enough to justify a subsequent workshop that would assess them in greater depth.

In early 2014, a multi-institutional planning team began developing the content and invitee list for an autumn workshop that would critically assess concepts, technology priorities, and priority early initiatives that claimed to reduce significantly the costs of human exploration of Mars. More specifically, existing scenarios and architectures would be compared and common features identified to develop recommendations to NASA and stakeholders. Notably, the planners included Mars scientists and science as essential features for a successful second workshop, a major recommendation from AM I.

The output of the workshop—findings and recommendations—is in the process of being presented in a number of forums and discussed with national leaders in human spaceflight. It is also available to potential international partners and the general public. AM II was planned from the start to be the second in a series. Planning for AM III has already begun, which we intend to hold in mid-summer.

To make progress in short meeting, a handful of ground rules were adopted by the planning teams for both workshops and agreed to by the participants. Perhaps the three most notable such ground rules were (1) the Space Launch System (SLS) and Orion would be available during the time frame considered by the participants; (2) the ISS would remain the linchpin through the mid-2020s in preparation for Mars exploration over the coming decade; and (3) space agency budgets for human exploration are likely to be flat for the next few years, perhaps growing only with inflation. Anticipating a finding from AM II, the workshop concluded that budgets for initial human missions to Mars must grow at least a few percent greater than inflation for such missions to be affordable within two decades.

A major issue for both workshops was the definition of affordability. After extensive discussion, a workable definition was adopted, including a significant corollary:

Workshop Definition of Affordability: An affordable mission is an activity that people are willing to pay for. A Level 0 requirement for Mars human exploration architectures is identification of the sustained source of funding.

In other words, no matter how “lean” or minimal, no human mission to Mars will be undertaken until and unless the source of funding is identified. And the source of the funding (in some detail) should be part of the Level 0 requirements for a credible mission.

We note that neither workshop discussed much the motivations for human missions to Mars or the goals for such missions, with the exception of purely science goals discussed in AM II. Motivations and goals for Mars exploration have been major topics in perhaps hundreds of international conferences over many decades. The organizers felt that three-day workshops that had many other topics to consider could add nothing new. In any case, human exploration of Mars is a formal goal of NASA and widely popular among space exploration professionals. Thus, the emphasis of the workshops would be on community-based assessments of issues that are relatively rarely assessed elsewhere, especially cost-management and the reality of “lean” minimal human missions to Mars.

The AM I and AM II organizers sought representation from a broad and representative sample of experienced American aerospace professionals in the government, industry, and academia. International partners will be an essential component of all future human exploration and the planning team benefitted from international colleagues. The list of workshop participants is included the final report referenced above.

The workshop was organized around three topical breakout sessions:

  • Breakout 1: Comparing and contrasting the architectures and strategies: strengths, challenges, key milestones and architectural elements in common, investment and design priorities, etc.
  • Breakout 2: Science enabled and enhanced by humans in the vicinity of Mars.
  • Breakout 3: Sustainability: the international context, programmatic priorities, characteristics that promote sustainability and affordability, comparing/contrasting NASA strategy with the recent National Research Council (NRC) report on the future of human space flight, priority next steps, priority investments, recommended community activities, etc.

A summary of the AM II deliverables was presented at the February 5, 2015 Future In-Space Operations (FISO) telecon colloquium.

In this essay we discuss in greater depth some of the consensus findings and recommendations produced by AM II. Readers are encouraged to read the full report. In general, the findings and observations were supported by a significant majority and in a few cases they were almost unanimous. The report includes minority opinions.

Summary workshop findings and observations

Quoting from the workshop summary that opens the full report:

An international human mission to the surface of Mars in the 2030s is recommended, although such a mission will require sufficient and stable long-term funding, as well as a critical series of risk-reduction activities in the 2020s. A key example is a long-duration crew habitation system in cis-lunar space that transitions from the essential facility, the ISS, to the systems necessary for human Mars exploration.

The “story” of human space exploration must be comprehensive and coherent with each activity on the way to the surface of Mars readily understandable by the general public.

Initial human missions to the surface of Mars should include elements necessary for eventual establishment of sustainable surface outposts broadly analogous to the initial phases of science-guided Antarctic exploration on Earth. Our workshop did not endorse one-way missions to Mars, where the humans on the first mission are settlers. AM II concluded that significant public support and inspiration derives from the national pride of having astronauts from participating countries return to Earth to be celebrated.

The workshop concluded that a robotic sample return mission may be required to learn how to protect against forward and backward contamination before humans land on Mars.

Human-enabled science exploration of Mars should be a major element of any human space flight architecture. One potentially advantageous precursor activity is an all-robotic sample return to demonstrate high-mass entry, descent, and landing capabilities scalable to human-scale landers.

Human missions to Mars orbit or the Martian moons may be essential for risk reduction as immediate precursors to surface missions, although are not considered a satisfactory substitute for a landed mission.

Workshop subject matter experts in Mars geology and astrobiology with experience with high-latency telepresence (HLT; long light-travel time: e.g., Curiosity, the twin Mars Exploration Rovers) assessed advantages of low-latency telepresence (LLT; short light-travel time). Quantitative studies of scientific benefits of LLT operations made possible by astronauts in proximity to surface robots would be required to adequately compare LLT versus HLT operations. As such studies are presently unavailable, they were not a factor in developing the findings on telerobotic exploration of Mars. Future work in this area is recommended.

Space agencies should more fully engage the broad community of partners in the definition of human exploration architectures and should employ the effective processes exemplified by the Global Exploration Roadmap.

The scientific goals for lunar exploration are compelling (i.e., see the 2011 National Research Council Planetary Decadal Survey and 2007 Scientific Context for Exploration of the Moon). However, it was the near-unanimous conclusion of the workshop that human operations on the lunar surface, including landing, mobility, power, and environmental control and life support systems (ECLSS), are not required in advance of initial human Mars missions.

NASA and its partners must further develop new management processes and efficiencies, as well as acceptance of reasonable risk.

Space agencies, along with their academic and industrial partners and national policymakers, must continue to develop together and effectively communicate the motivation and quantifiable goals for the future of human space exploration. The “story” of human space exploration must be comprehensive and coherent with each activity on the way to the surface of Mars readily understandable by the general public.

Selected findings and observations

Priorities Programs, Projects, and Facilities that Should be Completed Within the Coming Decade

The workshop participants were charged with identifying priority activities that should be undertaken and, as appropriate, completed within about a decade. As discussed in the final report, these recommendations were intended to be specific and actionable, representing, with one exception, a strong majority at the workshop.

  • Fully utilize the capabilities of the ISS.
  • An affordable, crew-tended habitat in the vicinity of the Moon intended to be a prototype Mars transfer habitat. This should include international participation.
  • Flying astronauts beyond low Earth orbit at least once per year beginning with EM-2. This means the SLS Block 1B should be implemented by the EM-2 flight. This does not exclude crewed missions on other vehicles, for example to ISS.
  • Taking advantage of the opportunities for human exploration to support meaningful science missions in the 2020s using co-manifest capability on SLS Block1B.
  • Although there are other viable mission concepts that could demonstrate high-power solar electric propulsion (SEP), the Asteroid Redirect Mission (ARM) mission is a useful step toward demonstrating SEP for Mars missions.
In the current budget and economic environment, it is paramount that the space agencies and industrial partners concentrate their efforts on enabling the capabilities—and only those capabilities—necessary to achieve human exploration beyond low Earth orbit.

Evidence of progress by an international human spaceflight program is more likely to encourage a willingness to provide additional funding even if the final scenario or the ideal budget agreement has not been finalized. Moreover, as discussed throughout both AM I and AM II, policymakers should be regularly provided with a broad range of examples of demonstrated progress. Both workshops were nearly unanimous in recommending that NASA, working with international partners, design, develop, and deploy a cis-lunar, long-duration habitation system to bridge the capabilities of ISS and those needed for transfer to Mars. Such a habitation system could, in addition, carry out other desirable activities in the vicinity of the Moon.

We note that a minority of AM II participants felt that, if effective aerobraking in the Martian atmosphere could be demonstrated, an all-chemical propulsion solution to travel to Mars may be more attractive than one that includes SEP.

Science and Scientists in Architecture Development for Human Mars Exploration

Both workshops, although especially AM II, found active participation by representatives of the science community, including planetary protection, to be valuable. Science priorities will eventually be incorporated within human exploration architectures, so the sooner that scientists are engaged in the process of developing the designs, operations, and key elements of human space flight, the better. Likewise, achievable science goals will depend upon the architecture adopted for exploration. Scientists and science should be an intimate and early component of Mars architecture planning.

Unprioritized Activities in Human Space Flight

There was discussion at AM II on the dissipation of effort on developing capabilities not unambiguously directed toward NASA’s “ultimate” goal of human exploration of Mars. In the current budget and economic environment, it is paramount that the space agencies and industrial partners concentrate their efforts on enabling the capabilities—and only those capabilities—necessary to achieve human exploration beyond low Earth orbit. This includes robust use of the ISS, especially given its recently announced additional four years of operational life. Moreover, time is of the essence: although it is two decades before the likely first opportunity for NASA to send humans on a round-trip mission to Mars, priority capabilities must be identified and management decisions implemented within the next few years if that ambitious goal is to be realized.

It was the overwhelming consensus that initial human missions could be made far less costly than widely believed. It is the responsibility of government agencies and private industry jointly to make the decisions to make this possible. Furthermore, it was a constant theme of the workshop that multiple stakeholders—NASA, academia, international partners, and aerospace companies of all sizes—must coordinate their efforts toward this common goal.


The authors benefited from numerous conversations with the second community Affording Mars workshop writing team and other meeting participants.