On this week's supply run to the International Space Station, SpaceX will launch a Dragon capsule that's already traveled there. The milestone comes just two months after the launch of its first reused rocket booster.
This particular Dragon flew to the station in 2014. SpaceX refurbished it for Thursday's launch. The company says it's always reused Dragon parts, but never to this extent.
Most of this Dragon has already been to space, including the welded frame. It will carry 6,000 pounds of cargo, including mice and flies for medical research.