Where to next? It’s a simple question that NASA can’t answer. The veteran space shuttle fleet is months from being mothballed and the White House has nixed a previous plan to fly to the moon.

For the first time in decades, NASA has no specific space destination. Future space flight, officials say, depends on new rocket science.

That uncertainty may not sit well with Congress, which will be grilling NASA chief Charles Bolden today and Thursday in hearings.