On Friday, SpaceX successfully delivered a cargo ship, carrying an experimental, balloon-like habitat, to the International Space Station and pulled off a nearly impossible at-sea landing of its rocket booster.
"Fifth time's a charm!" a SpaceX webcast commentator said, as cheers erupted at company headquarters in Hawthorne, California.
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All four previous attempts to land the 14-story Falcon 9 rocket booster on a drone ship at sea have ended in flames.
During a post-launch press conference, Musk said the successful landing is a "milestone" in the future of space flight and an exciting day for his team of 5,000 people at SpaceX. What set Friday's launch apart, he said, was that "the rocket landed instead of putting a hole in the ship, or tipping over," drawing laughter from those in attendance.
Musk added it's likely the returned booster will be relaunched within a few months, following a series of test fires on the ground. In the future, he said, the hope is that reusing a rocket booster will require little more than giving it a wash and adding propellant.
Friday's launch from Cape Canaveral, Florida, is SpaceX's first cargo resupply mission to the space station since one of its Falcon 9 rockets, carrying 4,000 pounds in research equipment, exploded shortly after liftoff in June. (SpaceX has had recent successes deploying satellites into orbit, however.)
Onboard the Dragon spaceship currently en route to ISS are 7,000 pounds of supplies and payloads. Among the most anticipated is the 3,100-pound Bigelow Expandable Activity Module, or BEAM, an "experimental expandable capsule" that NASA says could one day be used as habitable structures by space crews traveling to the moon, Mars or other destinations.
Other experiments onboard Dragon, NASA said, will help the space agency "assess the impact of antibodies on muscle wasting in a microgravity environment, use microgravity to seek insight into the interactions of particle flows at the nanoscale level and use protein crystal growth in microgravity to help in the design of new drugs to fight disease."
While SpaceX's at-sea landings remain experimental, they've become the anticipated highlight of each mission. In the wake of last month's crash, Musk hinted that Friday's go-around might be the winner.
In December, SpaceX made history when a Falcon 9 landed successfully on land about 6 miles away from where it took off. Musk called it a “revolutionary“ moment and a “critical step along the way to being able to establish a city on Mars.”
By developing rockets that can be reused, SpaceX ultimately hopes to make space flight cheaper and easier. While it costs between $200,000 to $300,000 to refill the rocket, the rocket itself costs $60 million, Musk said during Friday's press conference.
Musk said the eventual goal is for such landings not to draw such interest.
"We’ll be successful, ironically, when it becomes boring," Musk said.
The space community came out in force Friday to congratulate SpaceX on its successful launch and landing. President Barack Obama chimed in with a word of congratulations too.
Watch the full webcast of SpaceX’s CRS-8 Dragon resupply mission.