Will America still aspire to space greatness?

In today’s era of $14 trillion budget deficits, $18 billion seems like chump change. But with every penny of federal spending on the chopping block, that amount is eye-catching.

NASA needs that money over the next five years to build its new space launch system —a behemoth rocket that would eventually carry our astronauts to Mars. The rocket will be topped with a space capsule similar to Apollo, which carried Americans to the moon and back 40 years ago.

The new rocket will be tested in an unmanned flight in 2017, with the first manned flight four years later — if everything goes well and the p...