-- They're three of a kind in a very exclusive club.
The trio of Falcon 9 rockets that SpaceX has successfully landed back on Earth cozied up for a photo opp inside a hangar at Kennedy Space Center in Florida -- but only one of these historic rockets will likely fly again.
SpaceX nailed its first Falcon 9 landing last December when the company's Falcon 9 launched a satellite into orbit and made a precise landing at Cape Canaveral. A second rocket was successfully landed at sea in April. Higher velocity missions, such as launching a satellite high into geosynchronous orbit, require drone ship landings since they don't have as much fuel leftover for the landing.
Earlier this month, SpaceX landed its third rocket at sea after giving it "unlikely" odds due to extreme velocities and re-entry heating.
SpaceX CEO Elon Musk said the company plans to keep the first Falcon 9 since it marks a milestone for the company. Despite a clean landing, the most recently landed rocket experienced "max damage," due to its high entry velocity, Musk tweeted. He said the rocket will be "our life leader for ground tests to confirm others are good."
Mastering rocket landings has long been a goal for the company. Musk has said the ability to reuse a rocket -- which cost as much as a commercial airplane -- will "revolutionize access to space" and significantly cut costs.