CAPE CANAVERAL, Fla. — Shuttle Discovery and its astronauts returned safely to Earth this morning after making a rare flyover of America's heartland to wrap up their 15-day, 6 million-mile journey to the International Space Station.

The touchdown was delayed by rain and fog that dissipated as the sun rose, allowing Mission Control to take advantage of the morning's second landing opportunity.

Discovery swooped through a hazy sky before landing on the Kennedy Space Center runway. NASA briefly considered bringing the shuttle in to the opposite end of the strip because of puffy clouds, but the glare from the sun was too great and flight controllers stuck to the original plan.

In the end, commander Alan Poindexter made what appeared to be a smooth touchdown, a day late because of rain.

With the space shuttle program winding down, there weren't expected to be any more continental flyovers.

This was, in fact, Discovery's next-to-last flight. Only one more mission remains for NASA's oldest surviving shuttle. As soon as it's removed from the runway, it will be prepped for the final shuttle flight, scheduled for September.