Each presidential administration works to put its own stamp on America’s space program. In the Trump administration’s case, that reportedly involves cutting back on funds for the International Space Station and diverting them into funds for lunar exploration.
The proposal isn’t entirely a surprise; Vice President Pence announced the Trump administration would “refocus America’s space program toward human exploration and discovery” by launching a new lunar program followed by a manned Mars shot at some point in the indefinite future. But closing the ISS in 2025 and diverting that money to cislunar programs or even a lunar habitat represents a major change to US space policy. While this is still a draft, multiple sources have confirmed the directives will be in the final version, and the Trump administration has publicly stated it intends to return to the Moon first before tackling Mars.
Evaluating the Future of the International Space Station
It took 13 years to complete and launch the various ISS modules, from 1998 to 2011. Currently, NASA spends about $ 4B per year on the space station, out of a $ 19.5B total budget. At 21 percent of NASA’s total budget and roughly 40 percent of its human exploration outlay, it’s not chump change. One of the most significant complaints around NASA’s upcoming Space Launch System is that the agency lacks the funds to plan missions or launch the rocket. (It’s currently not clear if the SLS could fly even once per year, at a cost of more than $ 1B per launch, partly due to the cost of maintaining expensive manufacturing and test facilities for a rocket that almost never flies.)
Killing the ISS portion of NASA’s funding frees up that $ 4B in yearly cash. But we have no idea yet how that funding would be split between the SLS and any effort to put NASA back on the Moon, or what kind of exploration or even longer-term habitation plans the administration has in mind. Any kind of manned mission would require the development of lunar modules, longer-term habitation modules (if intended), and various support equipment. If the long-term goal is to create a lunar base as a stepping stone or useful waypoint for a Mars mission, it would also need to be outfitted with whatever tools it needs to make that effort successful.
Currently, the US has agreed to fund the ISS through 2024, though there’s previously been talk of extending its operational lifetime through 2028.
An exploded view of the ISS. Note that the Destiny and Unity modules are attached directly to one another. Image courtesy of Wikipedia
On the other hand, ending the ISS comes with significant cons as well. The space station has proven vital to the development of commercial spaceflight; companies like SpaceX have been sustained, in large part, by government resupply contracts for the International Space Station. Other firms, like Bigelow Aerospace, have used the ISS as a testbed for their own modules and projects.
Private space companies like SpaceX and Blue Origin are making real progress towards being able to launch their own project. Bigelow has even talked about its own space station. But such projects take years, even decades to come to fruition, and no company in the commercial space market today is close to being able to field such a replacement by 2024. Spaceflight companies have called for NASA to keep the ISS open through 2028.
One way to resolve this tension, of course, would be for Congress to appropriate more funding. This would let NASA put more funds into SLS development, keep the ISS running, and begin plans for a series of lunar exploration missions. Despite the fact that NASA consumes far less of the US federal budget than people tend to think it does — 0.47 percent, down from a high of 4.41 percent in 1966 — Congress has not historically increased NASA funding much in real (inflation-adjusted) dollars. The most recent high-water mark was in 1991, when NASA’s budget was worth $ 24.235B in 2014 dollars. The 2017 budget, in 2014 constant dollars, was worth $ 18.5B, a significant decline even from then.