We just need to pick another country to race with. "Hey China! Bet we'll get to Mars faster than you!" Then we'll have Mars 2020.
We don't have that anymore. It was probably a worthwhile trade: there are other vectors we can get technological advance from: but if Obama made a speech about beating China to Mars tomorrow as a proof of how America is a great nation, the Republicans would assemble on the dot to burn him at the stake for it.
There's still a sense of national identity, such as can be seen in the Olympics, but it's barely an echo of what it was 50 years ago. Before we lost in Vietnam. Before the Civil War was re-enacted to gain universal suffrage. Before Reaganomics. Before Cuba. Before Bosnia. Before 9/11 and Iraq. Before Snowden. Before Ferguson.