The following set of principles declares how The Planetary Society will evaluate, support, and critique proposed plans for human spaceflight. They are focused on NASA’s programs and policies, though they can also be applied to efforts in the private sector and other nations.

These principles were informed by The Planetary Society’s history, vision, and mission; survey data and feedback from its membership; and by the expertise and experience of its Board of Directors and policy team.

As you will see below, we believe the most important goal for human spaceflight is to extend its presence beyond low-Earth orbit. To that end, the Moon, cislunar space, and Lagrange points are all “deep space” as used below.

NASA should...

Send humans beyond low-Earth orbit, with the ultimate goal of landing humans on Mars

There is no more important, immediate goal for humans in space than extending their presence beyond Earth orbit, and doing so in a sustainable manner.

While Mars is the ultimate goal of human spaceflight efforts, there is no getting to Mars without first succeeding in deep space. Just like any child must learn to stand up before they walk, and to walk before they can run, so too must humanity prioritize the effort to extend its presence beyond low-Earth orbit for ever-increasing durations.

Develop a plan that includes clear milestones toward sending humans to Mars, and publicize a timeline and budget by which external parties and Congress can measure NASA’s progress to this end

The public provides funding to the national space agency, and it should, therefore, exercise oversight of its plans and progress. To this end, deep space exploration and humans to Mars projects should have clear metrics by which the public and Congress can evaluate progress. In particular, providing a set of milestones on a timeline provides clarity and realism to buttress the space program’s ambitions. Accountability and transparency will help provide enduring public and political support for these efforts.

A timeline and budget also help to hold Congress accountable, ensuring that support is not just relegated to positive statements, but by encouraging the delivery of the resources needed to reach these timelines and to create the coalitions and support necessary to succeed.

If the timeline is not met or is seen as too far or too slow, there are political fixes that are also—conveniently—clarified by this commitment to transparency.

Prioritize human spaceflight technology development in areas that sustain human psychological and physical health for long-duration spaceflight

Technology development will be crucial to the future success of deep space exploration and landing on Mars, as many key technologies necessary for the long-duration survival of humans in space have not yet been demonstrated. In particular, technologies related to human physical and psychological health should be prioritized. By having Mars as the ultimate program goal, deep space exploration as the interim goal, and a clear timeline and set of milestones, NASA can assemble a framework by which it can prioritize the most important technology development projects by evaluating their comparative complexities, timeliness, feed-forward capability, and cost.

Engage the scientific community from the earliest stages of planning to ensure significant scientific return from its human spaceflight program

Scientific investigation of the cosmos provides an enduring return on investment from space exploration, not just for its enrichment of human knowledge but in the vast potential value of the discoveries themselves to improve our lives and our understanding of the cosmos.

In order to ensure significant and valuable scientific return on the public’s investment in human spaceflight, the science community should be incorporated into the planning and design of human spaceflight projects as early as possible. Science can provide definition and helpful constraints on mission and hardware design, and can help to sustain a strong coalition of support from the world’s scientific community.

Work with international and private sector partners to build a broad coalition of support for these efforts

Human spaceflight programs are large, complex endeavors that can be leveraged to engage allies and adversaries alike in peaceful, cooperative, mutually beneficial efforts.

There is a proud history of this cooperation in human spaceflight, from the Apollo-Soyuz mission to the multinational coalition that supports the International Space Station. Sending humans into deep space and to Mars provides a ready opportunity to continue these cooperative efforts.

With the emergence of a capable, ambitious commercial space ecosystem, new partners can be incorporated in these opportunities presented by deep space exploration. Industry, working under more flexible contracting methods, has moved from a contractor to a partner in exploration, and full advantage should be taken of this new role as humanity stretches its presence beyond Earth.

Plan for an orderly transition away from the International Space Station (ISS), unless adequate budget increases are provided to support deep space exploration efforts

The International Space Station is a triumph of engineering and international cooperation. It also represents a significant annual cost of approximately $4 billion to operate, supply, and crew. NASA and its partners do not currently have the budget to sustain both the ISS and develop a robust human deep space exploration program. If new funding is not forthcoming, the nation's priority must be on the deep space exploration effort, and NASA, therefore, must transition away from its primary funding and management responsibility of the ISS. Doing so would free up critical resources that could be spent on projects that directly support efforts to send and sustain humanity beyond low-Earth orbit and on Mars.

Utilize low-Earth orbit primarily for training and technology development that enables deep space exploration

To the extent that NASA’s resources are used to sustain human access to Earth orbit, the priority should be on training and testing hardware and crew for deep space exploration.

Create a pathway for the U.S. private sector to take on activities previously led by NASA in low-Earth orbit

The growing capabilities of the private sector can provide avenues for human-tended science in low-Earth orbit, tourism, or other support services related to public needs. While NASA can help establish pathways and initial support for companies to explore providing these services, it must take care to avoid creating a monopsony and allow the private sector to exist on its own strength.