The Mars Science Lab is exactly the sort of endeavor NASA should be undertaking (along with its chronically malnourished work in advancing aeronautics technologies). Planetary missions like this capture the imagination and can inspire a new generation to reach for careers in science, technology, engineering and mathematics—which is crucial to future of the aerospace industry.
When Congress shortchanges the agency's science budget to fund high-overhead, government-developed-and-managed launchers or to preserve redundant capabilities in multiple NASA centers, it myopically focuses on the workers of today at the expense of the technologies and the workforce of the future.
The $2.5 billion NASA will end up spending on MSL is a far better investment for America—and ultimately for the aerospace industry—than speeding up the development of a heavy-lift launcher. NASA cannot do everything and still live within the sort of annual budgets it has been getting. And so, while one cannot draw a direct line between the two, to those who wonder why NASA is not doing more in manned spaceflight, our answer would be: Because it puts rovers on Mars, and given the choices, that is a good thing.