It's unexpected though because he was proposing a cut of $200 mil only a week ago. Not sure what changed his mind, but it's definitely a good choice.
I'd imaging Elon Musk being one of his advisers played a role in this.
The immediate uses of this will probably go toward a NASA payload aboard SpaceX's 2020 Red Dragon mission. NASA's current SLS project in junction with Boeing's Orion capsule has been quoted to be capable of a Mars orbit, however this is already funded and given NASA's and aerospace juggernaut's development pace, its unlikely this change in budget will yield any results while Annoying Orange is still in office. One can hope that some of this funding will be funneled to SpaceX's ITS/BFR development, which is set to launch 2022.
edit: I believe he's stressed a focus on manned travel to other celestial bodies as much of NASA's unmanned missions here around Earth work to study and add to the mountains of research supporting climate change, something his party insists doesn't exist.
edit2:
In before he tries to mine mars's resources for money
That'd be a great idea if mars had anything worth mining.
