As it celebrated its 60th birthday last week, NASA unveiled its new master plan for a return to the moon and manned trips to Mars and beyond.

The 21-page National Space Exploration Campaign is the agency’s response to President Trump’s Space Policy Directive-1, telling NASA to launch an “innovative and sustainable program . . . to enable human expansion across the solar system,” first with missions beyond Low Earth Orbit, aka LEO, leading to manned missions to Luna and eventually Mars.

Nearly 50 years after Neil Armstrong first walked the moon, mankind can’t go further out than LEO, where the International Space Station orbits. NASA aims to regain the ability to reach lunar orbit, first with the Orion craft being built jointly with the European Space Agency.

Even as private companies develop the capability to carry all needed cargo and personnel as far as LEO, NASA will build the Space Launch System, “the most powerful rocket in history,” to send 140-ton payloads into deeper space.

That will allow it to start construction in 2022 of the moon-orbiting Gateway platform, which will host missions to the lunar surface and serve as a base for assembling craft to go beyond the moon.

New technologies will be vital, including a way to power a manned interplanetary craft — almost certainly a nuclear drive supplemented by solar cells. Assuming engineers can solve such challenges, the agency aims to start sending crews to Mars orbit in the 2030s.

On a separate track, NASA is already planning an unmanned mission to reach and return from the Red Planet’s surface, bringing back the first sample from Mars. Steps toward that goal include sampling the 4.5 billion-year-old near-Earth asteroid Bennu in 2023, as well as landing a new Mars rover in 2020.

All in all, it’s a huge undertaking. But giant leaps for mankind start with small planning steps.