NASA’s ISS Transition Report — Executive Summary

The International Space Station is featured in this image photographed by an STS-133 crew member on space shuttle Discovery. (Credit: NASA)

International Space Station Transition Report
March 30, 2018

Full Report (PDF)


The NASA Transition Authorization Act of 2017 (P.L. 115-10) provided for an ISS Transition Report under section 303:

The Administrator, in coordination with the ISS management entity (as defined in section 2 of the National Aeronautics and Space Administration Transition Authorization Act of 2017), ISS partners, the scientific user community, and the commercial space sector, shall develop a plan to transition in a step-wise approach from the current regime that relies heavily on NASA sponsorship to a regime where NASA could be one of many customers of a low-Earth orbit non-governmental human space flight enterprise.

Uses of Low- Earth Orbit (LEO) Platforms

Preparing for Human Deep Space Missions

In order to prepare for human expeditions into deep space, the Agency must first conduct breakthrough research and test the advanced technology necessary to keep crews safe and productive on long-duration space exploration missions. An on-orbit platform like the ISS is necessary to mitigate 22 of the 33 human health risks in the portfolio identified by NASA’s Human Research Program in support of current and future deep space missions. NASA is also using the ISS as a testbed to fill critical gaps in technologies that will be needed for long-duration deep space missions. For example, elements of the ISS life support and other habitation systems will be evolved into the systems that will be used for deep space exploration missions and undergo long-duration testing. It is NASA’s plan to first develop and demonstrate many critical technology capabilities using the ISS (and potentially other future platforms) as a permanently-crewed testbed prior to deploying these capabilities beyond low-Earth orbit (LEO). This approach is much more cost-effective and faster than conducting this research in cislunar space because of the risks inherent in operating so far from the Earth.

Global Leadership in Human Spaceflight

Consistent with the President’s space policy directive, “Lead an innovative and sustainable program of exploration with commercial and international partners to enable human expansion across the solar system and to bring back to Earth new knowledge and opportunities”, the strength of the international partnership created through the ISS Program is a testament to U.S. leadership in space and to the aerospace expertise of all the nations involved. It serves as an example of how many countries can work together to design, build, operate, and maintain large, complex human space assets. As we consider the future of ISS and potential successors and prepare for human missions of exploration into deep space, it is important to reflect on the critical value of the proven partnership that has made the ISS possible, and to consider how to build on these relationships as NASA proceeds into cislunar space. The ISS partner agencies are looking for leadership in human spaceflight and LEO from the U.S. Informally, all of the partner agencies have indicated that they expect to continue cooperative activities with NASA as long as NASA continues to maintain America’s commitment to the partnership.

Enabling a LEO Commercial Market

NASA’s vision for LEO is a sustained U.S. commercial LEO human space flight marketplace where NASA is one of many customers. The vision includes one or more privately-owned/operated platforms–either human-tended or permanently-crewed–and transportation capabilities for crew and cargo, that enable a variety of activities in LEO, where those platforms and capabilities are sustained primarily by commercial revenue rather than relying on NASA and the U.S. Government as their main source of revenue as is the case today with the ISS. NASA must also communicate its forecasted needs in LEO to allow the private sector to anticipate that demand in their business cases. With this vision, NASA is able to share the cost of a LEO platform with other commercial, Government, and international users. This allows NASA to maximize its resources toward missions beyond LEO, while still having the ability to utilize LEO for its ongoing needs as described in Section 4.1.

In order to enable this vision, NASA is executing several public-private partnerships centered around the
ISS to foster the development of customers for LEO capabilities, but also is maturing the supply industry
to be able to meet future demands. NASA is also initiating the Commercial LEO Development program to further the development of private on-orbit capabilities beyond what is available today through the ISS.

The Commercial Resupply Services (CRS), the Commercial Crew Program, and the ISS National Lab are key complementary enabling activities to enable this vision. Under the CRS contracts, NASA’s two commercial cargo partners, Space Exploration Technologies (SpaceX) and Orbital ATK, have demonstrated not only the ability to provide cargo deliveries to ISS, but also the flexibility to recover effectively from mishaps. The addition of the Sierra Nevada Corporation as a third commercial service provider will add significant on-orbit and return capability. Both Orbital ATK and Sierra Nevada Corporation have begun to investigate options to perform significant on-orbit operations after their primary cargo mission is completed. These two providers are able to provide an on-orbit research capability independent of ISS. NASA’s commercial crew partners, SpaceX and the Boeing Company, are developing the Crew Dragon and CST-100 Starliner spacecraft, respectively. These companies have made significant progress toward returning crew launches to the U.S., and NASA anticipates having these capabilities in place by 2019 to regularly fly astronauts safely to and from ISS. The crew and cargo vehicles, as well as the launch vehicles developed by these providers, have the potential to support future commercial enterprises as well as ISS.

The Center for the Advancement of Science In Space (CASIS) manages the activities of the ISS National Laboratory to increase the utilization of the ISS by other Federal entities and the private sector. CASIS works to ensure that the Station’s unique capabilities are available to the broadest possible cross-section of U.S. scientific, technological, and industrial communities. The ISS National Laboratory is helping to establish and demonstrate the market for research, technology demonstration, and other activities in LEO beyond the requirements of NASA. Commercial implementation partners are now bringing their own customers to the ISS through the National Lab as well.

Benefitting Humanity

Across a range of disciplines and applications, research on a crewed space platform ultimately benefits people on Earth. In the physical and biological sciences arena, a LEO space platform can allow researchers to use microgravity conditions to understand the effect of the microgravity environment on microbial systems, fluid physics, combustion science, and materials processing, as well as environmental control and fire safety technologies. Technologies developed for use in space, such as water purification technologies, can have applications on Earth. Crewed platforms can also be the site of sensors that provide data used to support activities such as disaster relief.

ISS Transition

ISS Transition Principles

There are several key principles to any strategy or decision to be made regarding the ISS and the future of LEO and NASA’s role as one of many customers of services or capabilities that are provided by private industry as part of a broader commercial market. The following principles will ensure uninterrupted access to LEO capabilities to enable NASA and the Nation’s long-term interest in LEO and human spaceflight exploration including supporting National security objectives, such as a competitive industrial base and U.S. leadership:

  • Continuity among NASA’s LEO, deep space exploration, and development and research activities and missions toward expanding human presence into the solar system;
  • Expanding U.S. human spaceflight leadership in LEO and deep space exploration, including continuity of the relationship with our current ISS international partners;
  • Increase platform options in LEO to enable more ISS transition pathways, security through redundant capabilities, and industrial capability that can support NASA’s deep space exploration needs;
  • Spur vibrant commercial activity in LEO;
  • Maintaining critical human spaceflight knowledge and expertise within the Government in areas such as astronaut health and performance, life support, safety, and critical operational ground and crew experience;
  • Continuing to return benefits to humanity through Government-sponsored basic and applied on-orbit research;
  • Continuing Government-sponsored access to LEO research facilities that enable other Government agencies, academia, and private industry to increase U.S. industrial competitiveness and provide goods and services to U.S. citizens; and
  • Continuing to reduce the Government’s long-term costs through private industry partnerships and competitive acquisition strategies.

ISS Transition Strategy

As part of a cohesive exploration strategy, NASA intends to begin shifting responsibility for meeting its needs and requirements in LEO by leveraging private industry capacity, innovation, and competitiveness that would offer the prospect of lower cost to the Government to enable NASA to apply more personnel and budget resources on expanding human spaceflight beyond LEO and enhancing U.S. leadership in human spaceflight around the world. Among the benefits beyond the prospect of lower operational costs for a LEO platform, shifting focus to industry can additionally reduce the infrastructure burden on NASA has already been demonstrated at NASA facilities at Kennedy Space Center, Johnson Space Center, Stennis Space Center, and the Michoud Assembly Facility.

In order to ensure that private industry is prepared to provide the services and capabilities that support NASA’s needs in LEO, as outlined in the key principles above, and to enable private industry to develop markets and customers beyond the Government, NASA is proposing the following approach:

1. Begin a step-wise transition of LEO human space flight operations from a Government-directed activity to a model where private industry is responsible for how to meet and execute NASA’s requirements. Consistent with the ISS Transition Principles, this does not mean NASA is “commercializing the ISS.” Instead, NASA maintains leadership and governing responsibilities as outlined in the Partnership agreements, and continues to maintain the essential elements of human spaceflight such as astronaut safety and the high-risk exploration systems.

In order to effect a smooth transition, provide private industry with a vision of the future work, and allow NASA to plan and alter its activities, NASA is proposing that this transition LEO human space flight responsibility to private industry be essentially complete by 2025. This will give NASA time to engage with industry to begin transforming the many NASA-directed activities that are currently performed through several contracts into more of a public-private partnership and/or services contract(s) model where NASA’s current responsibilities are executed and managed by private industry. This time period will also provide the opportunity for NASA and private industry to engage with stakeholders and to only proceed when industry has matured and is capable of executing NASA’s requirements. The transition of ISS will ensure that there are private companies with the experience and expertise to operate various types of platforms in LEO by the mid-2020s. This transition to private industry must be done in a cost-effective manner and not exceed current operational costs.

Consistent with the ISS Transition Principles, NASA will continue discussions with the ISS International Partners to help shape the long-term future of LEO.

2. Solicit information from industry on the development and operations of private on-orbit modules and/or platforms and other capabilities that NASA could utilize to meet its long-term LEO requirements that are consistent with the ISS Transition Principles. The scope of the solicitation may include risk reduction development activities, or modules or elements that could either be attached to the ISS or be free-flying. The solicitation may also include private industry conducted studies on the future of the ISS platform that may be combined with private industry objectives in LEO.

NASA will begin with a solicitation in FY 2018 to gather broad industry input on interest in meeting NASA’s long-term needs and objectives that should lead to multiple awards in FY 2019 funded out of the Commercial LEO Development program.

Throughout this approach, NASA will also be requesting market analysis and business plans from private industry in order to gauge the depth of possible commercial markets as they apply to industry’s ability to meet NASA’s needs and requirements with a base where NASA is only one of many customers. This approach is also dependent on NASA identifying our long-term requirements for LEO, which are highlighted in Section 4.1.

ISS Considerations and the Eventual Future of the ISS Platform

From a structural integrity analysis standpoint, the ISS platform is expected to have significant structural life well beyond 2028 (based on the current assessment period). Many of the ISS modules, particularly the modules launched in the later years of ISS assembly, are likely to have structural life well into the 2030s (see section 4.4). Although it is thus likely technically feasible to continue to operate the ISS well beyond 2028, it is also necessary to consider the costs of operating this complex facility as we have been doing (approximately $1.1 billion per year for O&M in the outyears) as we consider the future of the ISS platform.

NASA’s international partners are likely to have different levels of interest in continuing the ISS and in moving to new LEO programs. There are common themes across the partnership, however, in considering the future of ISS and exploration, such as:

  • Reducing operational costs;
  • Offering frequent visible national astronaut opportunities;
  • Continuation and continuity of research and technology development activities;
  • Balancing LEO and exploration;
  • Maturation of commercial opportunities.

The eventual future of the ISS, whether it is transitioning the operations of the ISS platform to private industry through the use of public-private partnerships, augmenting it with privately developed modules, combining portions of the ISS with a new private platform, or beginning anew with a free-flying platform and de-orbiting the ISS, will be evaluated using the ISS Transition Principles.

Fast Forwarding to the Mid-2020s

Continuing with current policies, including the Commercial LEO Development program, NASA can project what the LEO landscape may look like in the mid-2020s. In predicting the LEO landscape, areas that have a high degree of certainty include maintaining our strong global leadership position with the continuation of the ISS through 2024, validating commercial cargo and crew transportation costs, and completing the majority of NASA exploration-related human and systems research and demonstration.

Other nations will have deployed their own space station(s). Examples of areas that will have a lower degree of certainty include whether or not private industry capabilities have matured enough to satisfy NASA’s needs and requirements, and whether or not a viable commercial market has matured in LEO that is not dependent on Government support. The Commercial LEO Development program, along with expanded ISS public-private partnerships, is targeted to address these uncertainties.

NASA’s Long-term LEO Requirements

NASA and the U.S. have a long history of human spaceflight leadership and LEO research and technology development that go all the way back to the Mercury program through Gemini, Apollo, Skylab, the Space Shuttle, and the ISS.

Regardless of the eventual fate of the ISS platform itself, NASA is expecting to maintain U.S. leadership in LEO and human spaceflight through lunar exploration and eventually to Mars consistent with the ISS Transition Principles. Within that context, NASA is planning to continue with the following LEO needs and objectives beyond the life of ISS:

  • Maintaining the Partnership with our current ISS international partners and possibly adding new international and domestic participants;
  • Regular LEO crewed operations, including short and long durations:
    • Enables operational space proficiency;
    • Shift from human health and performance countermeasures development (the ISS portion of which is expected to be complete by 2024) to validations of integrated long-duration system, habitation, operations, and crew isolation;
  • Long-term technology/systems development and demonstrations (e.g. life support);
  • Space life and physical sciences basic and applied research at current level and capabilities;
  • National Laboratory-based research and technology development;
  • Opportunities for astrophysics, space, and Earth science research.

These long-term requirements, while similar to that of the current ISS Program, could be met with various types of modules or platforms that do not necessitate a vehicle (or vehicles) as complex as the ISS. Many of the research activities could be conducted on shorter-duration platforms, similar to the Shuttle, or even crew-tended platforms. These requirements are expanded upon in Section 4.1.


NASA believes that this is a well-balanced approach where the Agency’s and other U.S. Government interests are protected and enhanced while offering the prospect of lower cost to the Government and opening new markets and new business models to the U.S. industrial base. This approach will also lay the foundation where NASA could be one of many customers in a LEO commercial marketplace and provides the basis for determining the long term future of the ISS Platform and LEO along with the ISS International Partners.

NASA looks forward to working with Congressional stakeholders along with researchers, private industry, and our ISS International Partners on the future of the ISS and LEO, to ensure that the U.S. maintains our human spaceflight leadership in LEO while shifting Government resources and focus towards expanding human presence into the solar system and returning benefits to U.S. taxpayers.