Pence agreed that the timeline was short but maintained that it was possible, pointing to the Apollo 11 landing as an example of how quickly the US can move when it’s motivated. He suggested that it might require using private rockets if the Space Launch System isn’t ready in time.

There’s one main problem with the plans: it’s not clear the money is there to make this happen. Although the proposed fiscal 2020 budget did increase NASA’s funding slightly to $21 billion, astrophysicist Katie Mack noted that it would represent a much smaller fraction of the federal budget than the Apollo program represented in the 1960s. While the federal budget has clearly grown over the decades, so have the costs of space travel — the government may need to spend a lot more if it’s going to make its target.