On April 9, 2016 (March 3, 2016 in the lunar calendar), SpaceX completed the world's first sea rocket recovery. Launch trajectory diagram, sea recovery allows the rocket to use the optimal landing site without wasting more fuel to go to the land landing area. After several tragic failures, at 4:52 am on April 9, 2016, SpaceX of the United States finally Successfully recovered the Falcon 9 first-stage rocket in the Atlantic Ocean, which is also the first time in human history that a rocket has been recovered at sea. Reports from foreign media said that the launch took place at 4:43 a.m. Beijing time today, and the launch site was located at Cape Canaveral, Florida, in the eastern United States. Before launch, SpaceX pre-parked the offshore recovery platform in the Atlantic Ocean about 300 kilometers east of the launch site. Nine minutes after liftoff, the rocket landed accurately on a barge (sea recovery platform) in the Atlantic Ocean. The entire landing process was quite perfect. This was the company's fifth attempt at sea recovery. Aviation industry insiders believe that SpaceX's completion of maritime rocket recovery is of great significance, mainly reflected in the savings in launch costs. According to SpaceX sources, the successful recovery and reuse of the first-stage rocket can reduce launch costs by 30%. As the number of reuses continues to increase, the cost of each launch will become lower and lower. As for why SpaceX has always loved maritime recycling, the official explanation is also based on cost reduction considerations. At present, almost all rockets launched by various countries fly eastward. During the flight, the trajectory of the neutron-stage rockets is obliquely upward. After separation, the sub-stage rockets will continue to fly obliquely upward for a certain distance, and then naturally fall along the parabola. The landing point should be farther from the launch site than when separating. At this time, maritime recovery allows the rocket to fly back to the land landing site without consuming precious fuel. It can land directly naturally. The barge can park in advance at the rocket landing position and wait. The rocket can consume the remaining fuel on the most important landing deceleration. Ensure that the landing is successful. The picture shows the launch picture. The picture shows the picture of successful recycling. The picture shows the picture of successful recycling.