The White House’s call for a four-year extension of international space station operations, to 2024, represents a prudent compromise that will allow the orbital outpost to fully mature as a research platform without foreclosing the option for NASA and its partner agencies to chart a new course in human spaceflight in the relatively near future.
Although continuously occupied since 2000, the station was only completed in 2011, and to this day a large portion of the onboard astronaut time remains dedicated to operations and maintenance chores. As a government research laboratory it has yet to come into its own, either for studying the effects of long-duration spaceflight or for other scientific disciplines.
Commercial users, meanwhile, have barely begun to scratch the surface. By committing to at least four more years of operations, the administration of U.S. President Barack Obama gives these prospective users the assurance they’ll need to invest in station-based experiments and applications, some of which could take years to develop.
Full utilization of the space station probably won’t be possible until sometime after 2017, when NASA is scheduled to field an independent capability to transport crews to and from the facility. This should enable the station to support a larger crew size, from six to seven.
NASA and its partners — Canada, Europe, Japan and Russia — have collectively invested more than $100 billion in the space station, and the four-year extension will not require any additional capital investment. In fact, NASA has sufficient spare parts, either onboard the station or on the ground, to keep the facility operating until 2028.
There are no doubt some who would like to see the station operate at least until then, but the White House had good reasons for limiting its proposed extension to four years. For one thing, the current administration will leave office in 2016; committing the United States until 2028 would unnecessarily and unfairly tie the hands of a future president.
Moreover, a four-year extension should be easier to sell to NASA’s international partners, some of whom have expressed reservations about going even beyond 2020 and might balk at an eight-year deal. Currently, there is no consensus among European Space Agency member states on the future participation in the program, for example, and Japan and Canada are wrestling with budget issues.
At any rate, a future U.S. president can always propose another four years of space station operations without incurring additional capital investment costs. In other words, there was no economic advantage to be gained by making a longer-term commitment today.
It has been argued that as long as NASA is saddled with the roughly $3 billion annual cost of operating the space station, it will be difficult if not impossible to make headway on efforts to send astronauts to destinations beyond low Earth orbit. There’s truth to that argument — setting aside the possibility that the cost could come down as experience-based efficiencies are adopted — but it rests on the questionable assumption that the savings from shutting down station would stay with NASA. It also glosses over the station’s crucial role as a test-bed for long-duration human spaceflight, where there is still much work to be done.
NASA of course already is investing some $3 billion per year in a pair of deep-space exploration systems: the heavy-lift Space Launch System () and its companion capsule, Orion. But even in the highly unlikely event that neither project incurs significant delays, the SLS-Orion combo isn’t expected to launch its first astronauts until 2021. In other words, ending the station in 2020 would almost certainly mean introducing a gap of undetermined length in the U.S. human spaceflight program. Moreover, given the lack of consensus on the next destination for human explorers, NASA’s planned asteroid capture mission notwithstanding, it is difficult to imagine another four years of space station operations being the chief obstacle to deep-space astronaut missions.
The international space station might not be everyone’s choice as the cornerstone of U.S. human spaceflight policy, but it offers a tremendous capability that is available today and is far from reaching or even presaging its full potential. Hopefully, NASA’s partner agencies will recognize the proposed extension as an opportunity rather than a burden and climb onboard.