The space shuttle program, set for retirement next year, appears to be limping to its death. First, the shuttle Discovery's mission to the International Space Station was delayed this week—again.

Discovery had been set to launch on Saturday, but this delay, its fourth overall, has delayed the mission indefinitely. Meanwhile, the May shuttle launch to service the Hubble Space Telescope is now in doubt. NASA will decide next month whether the debris from this month's satellite crash poses too much of a risk for the shuttle to launch.

The pending shuttle retirement raised all kinds of consternation because it leaves a five-year gap between the end of shuttle flights and the anticipated ready date of its successor, the Orion capsule. As of now, hitching a ride on a Russian Soyuz looks like the only way for NASA to reach the space station during that window, giving Russia political leverage over the U.S. While that's an unfortunate political reality, the alternative—prolonging shuttle flights—seems like a poorer and poorer idea with every mechanical malady and delayed launch.  

While America's space agency hurries to develop its newest spacecraft, perhaps its leaders will have the chance to follow the advice astrophysicist Neil deGrasse Tyson gave when he visited Big Think: NASA should be dreaming big, and by doing so, inspiring the next generation to become America's next great scientists.