NASA Advisory Council Recommendation 

National Research Council (NRC) Pathways to Exploration Report 

2015-03-02 (Council-02) 

Recommendation: 

The Council recommends that NASA provide a written response, in the form of a letter for the 

record, to the NRC Pathways to Exploration Report. This response should address the specific 

findings and recommendations of the report, identify which recommendations are accepted, and 

provide a brief rationale for choosing strategies that were different. 

Major Reasons for Proposing the Recommendation: 

The Council found the joint discussion on the NRC Pathways to Exploration Report and the current 

NASA Human Exploration Strategy extremely valuable in codifying areas of agreement in approach 

and areas where there are technical differences in approach or risk assessment. The NRC report is a 

comprehensive and independent assessment that has stimulated good technical review and debate. A 

written response will provide an opportunity to document decisions to pursue alternate paths, some of 

which were based upon analyses and decisions that have taken place since the completion of the 

report (e.g., the decision to maintain the International Space Station through 2024). 

Consequences of No Action on the Proposed Recommendation: 

There will likely be future externally directed studies ofNASA's exploration strategy, and NASA 

will be asked to explain what they did in response to the NRC study and why they chose not to accept 

some ofthe recommendations that were made. 

NASA Response: 

NASA concurs in part. NASA concurs in the value of sharing our exploration plan and explaining 

how it benefits from past external reviews and assessments; however, a direct response to the NRC 

report would only serve to show that its recommendations have been overtaken by events and 

progress to date. The NRC's report came out over a year ago, and given the NRC's internal review 

process, our interaction with them as they prepared this report occurred a year before that. In the past 

few years, NASA has made substantial progress in defining and articulating its approach to human 

exploration, and this has been shared numerous times with both the NAC and the NRC's standing 

committees (Space Studies Board and Aeronautics and Space Engineering Board) since the NRC 

report's release. Below is a summary of recent progress in NASA's exploration planning and 

communication of the same. 

NASA has been evolving its human exploration studies over the past few years in accordance with 

the guidance and direction in the 2010 NASA Authorization Act, and this planning has continued 

during and after the development of the NRC repmi. We engaged in dialogue with this NRC 

committee during its lifetime, with standing NRC committees since, and shared our progress with 

the NASA Advisory Council along the way and with our many partners and stakeholders in a variety 

of formal and informal settings. We continue to engage these communities and recognize the 

importance of their support for our long-term success. As a result of this work, it has become clear 

that we need to define and communicate an approach to human space exploration that embraces 

Mars as a horizon destination, is sustainable over multiple decades, and is achievable within 

reasonable budget expectations. In dialogue with those mentioned above and with our international 

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and commercial partners, we have formulated and matured a set of principles that guide our studies 

and are planning to ensure long-term sustainability in the journey to Mars. These principles, along 

with Agency strategic goals and constraints, have been shared with our stakeholder community, and 

these have been met with broad consensus. Within NASA, we have strengthened our coordination 

with the technology development and science Mission Directorates in many key areas - efforts 

designed to further inform and align technology investments and enhance benefits across science and 

human exploration missions. With advice and input from the spaceflight stakeholder community 

and across NASA, our exploration strategy, progress, and forward plans have been captured in the 

recently-released Journey To Mars - Next Steps in Space Exploration (12M), which is consistent 

with the Global Exploration Roadmap (GER), released by the International Space Exploration 

Coordination Group (ISECG). 

The Journey To Mars depicts an approach and explains the rationale for building up a capability 

through which NASA and its partners extend our presence into the solar system. We cast this 

framework as moving from an "Earth-reliant" phase in which crew return is measured in hours, to a 

"Proving Ground" phase in which we test out and build up deep-space capabilities in cislunar space 

where crew return times are measured in days, to an "Earth-independent" phase in which we can 

conduct missions to the vicinity or surface of Mars where crew return times are measured in months 

to years. In the Earth-reliant phase, we are conducting human research on the International Space 

Station (ISS) according to a well-defined plan to develop the mitigations for the risks to humans of 

long-duration spaceflight beyond low-Earth orbit (LEO). The environmental control and life support 

system technologies that will be used for Mars missions will be tested on ISS. In parallel, we are 

working to facilitate the growth of the market for commercial LEO services that will free NASA 

resources to move outward from LEO while fostering LEO space economies. We are building the 

Space Launch System (SLS) and Orion for missions in cislunar space and are defining the test 

objectives to be met by the missions in this Proving Ground regime. We are currently studying 

approaches to achieving deep-space habitation capability in this region in collaboration with our 

partners. The Asteroid Redirect Mission will advance the in-space propulsion and automated 

rendezvous and docking capabilities we will need for future Mars missions. Cislunar space will also 

be a staging area for both cargo and crewed missions to Mars. Robotic science missions at Mars 

today and going to Mars over the next decade are providing essential understanding of Mars 

atmospheric conditions, surface destinations, and resources. We are also conducting analyses of 

requirements for: crew and cargo transit systems; entry, descent, and landing on Mars; in situ 

resource utilization for fuel, oxygen, and food; surface power; and other elements of a humans-toMars architecture. 

Building off of the successful radiation monitor already operating on the Curiosity rover, the next 

Mars rover planned for launch in 2020 will also contribute to the preparation for human exploration 

of Mars by making significant progress toward addressing strategic knowledge gaps. Further, the 

Mars 2020 rover will potentially cache samples for possible return to Earth by future missions. In 

addition, the Mars Reconnaissance Orbiter is scanning the climate and surface of Mars and 

identifying the best possible landing sites for Mars 2020 as well as identifying landing locations for 

future human missions which maximize both science return while optimizing local resources in 

support of future human surface exploration. Simultaneously, the Mars Atmosphere and Volatile 

EvolutioN mission is exploring the Red Planet's upper atmosphere, ionosphere, and interactions with 

the sun and solar wind. Just as these rovers and orbiters help us answer the question of whether life 

ever existed on Mars in the past, they are also helping us to prepare to put human life on Mars in the 
future. One key to a sustainable program of space pioneering is to recognize what decisions need to 

be made and when. We have made decisions on: how to best use ISS (including the 

Administration's decision to extend ISS operations to at least 2024 to enable deep-space 

exploration); development of SLS and Orion, including SLS' evolution pathway (pursuing an 

Exploration Upper Stage before advanced boosters based on cislunar mission capture); sending 

Exploration Mission-I (EM-1) to a distant retrograde orbit around the Moon because of its utility for 

future deep space missions; and the utility of solar electric propulsion for moving large masses in 

deep space. We know the next set of decisions, to be made over the next few years, will include the 

areas of deep-space habitation and deep-space transit capability and on entry, descent, and landing 

needs and technology pathways. Future decisions will include whether to send human missions to 

the moons of Mars before missions to the Mars surface, based on the degree to which the former is 

enabling of the latter. 

But we do not need to make all these decisions today - in fact, it is better if we do not. Our strategy 

is to ensure we take advantage of new scientific discoveries, new technology advances, and new 

commercial and international partnerships during the long timeframe of exploration. Considering 

how each of these areas has advanced over the past five years, it is easy to imagine they will change 

substantially over the next five to ten years, and each area heavily influences the investment strategy 

and architecture construct necessary to safely cross the solar system and ensure sustainable progress 

along the way. Thus, as we pursue the development today of systems we know we will need for the 

"Proving Ground" phase of the 2020s, we can and should hold open some decisions for the "EarthIndependent" phase where NASA and partner capabilities will evolve before it is necessary to settle 

on the configuration and pathway of the first human mission to Mars. 

While the NRC report suggests alternative methods of planning for the future of space exploration, 

NASA identified an approach, based on our detailed technical studies and principles, reflected in the 

J2M, which both supports the overarching exploration goals desired by the NRC and does so in a 

responsible manner that is consistent with the capability and needs of the space exploration 

community here and abroad. NASA will continue to share progress and plans with the NASA 

Advisory Council and looks forward to a continued dialogue to ensure the Agency's success. 

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