CAPE CANAVERAL, Fla. – Space shuttle Discovery buzzed metropolitan Washington, D.C., Tuesday morning, soaring over the Washington Monument, the White House and the Capitol before landing to begin its new life as a museum relic -- following three decades of space service for NASA's oldest and most traveled shuttle.
Discovery will be towed Thursday to its installation at the Smithsonian's National Air and Space Museum annex near Dulles in northern Virginia.
Thousands had packed the National Mall in front of the Capitol to watch the pair swoop by, as Discovery took a leisurely spin at an easy-to-spot 1,500 feet (450 meters) overhead. And they took to Twitter, using the tag #spottheshuttle to compare notes.
"Just saw the shuttle fly by. Hoping to see it again on its return into Dulles. Cool moment in history!" wrote one user.
"There are actually no words for how cool that was. Not ashamed to say I cried," another user wrote.
"Look at that -- that thing is mammoth," said Terri Jacobsen. She brought her 12-year-old son to the mall to watch the flyover.
Discovery departed Florida's Kennedy Space Center at daybreak Tuesday aboard a modified jumbo jet bound for Washington, where it will become a Smithsonian exhibit. The shuttle-jet combo is set to land at Dulles International Airport.
TWITTER WATCH: Thousands used Twitter to compare notes as space shuttle Discovery sailed over D.C. Tuesday. Here are a few of those comments.
Ju Lee: #spottheshuttle the thing went right over us in Arlington! It's apparently doing a few loops!
Ken Ryan: OK Congress, Mr. President: Take a look around at all those outside to #spottheshuttle. Still think space flight is not worth funding?
Kris Anne Bonifacio: Just watched space shuttle Discovery fly around DC on a carrier plane. So cool #spottheshuttle
Nearly 2,000 people -- former shuttle workers, VIPs, tourists and journalists -- gathered along the old shuttle landing strip earlier in the morning to see Discovery off. A cheer went up as the plane taxied down the runway and soared into a clear sky.
The plane and shuttle headed south and made one last flight over the beaches of Cape Canaveral -- thousands jammed the shore for a glimpse of Discovery -- then returned to the space center in a final salute. Cheers erupted once more as the pair came in low over the runway it had left 20 minutes earlier and finally turned toward the north.
A similar flyover was planned over the monuments in the nation's capital, later in the morning.
Discovery -- the fleet leader with 39 orbital missions -- is the first of the three retired space shuttles to head to a museum. It will go on display at Dulles International Airport in Virginia, taking the place of the shuttle prototype Enterprise. The Enterprise will go to New York City.
Endeavour will head to Los Angeles this fall. Atlantis will remain at Kennedy.
NASA ended the shuttle program last summer after a 30-year run to focus on destinations beyond low-Earth orbit. Private U.S. companies hope to pick up the slack, beginning with space station cargo and then, hopefully, astronauts. The first commercial cargo run, by Space Exploration Technologies Corp., is set to take place in just another few weeks.
For at least the next three to five years -- until commercial passenger craft are available in the United States -- NASA astronauts will have to hitch multimillion-dollar rides on Russian Soyuz capsules to get to the International Space Station.
The Associated Press contributed to this report.