1. Overview of Rocket Recovery
Rocket recycling can not only significantly reduce launch costs, but also increase launch frequency. In recent years, SpaceX has been making attempts at rocket recovery. At 9:29 am on December 22, 2015, SpaceX successfully launched the Falcon 9 rocket and successfully completed the recovery of the first stage of the core 10 minutes after launch. This is also the first time in human history that a first-stage rocket has been recovered. On October 13, 2024, SpaceX conducted the fifth orbital-stage flight test of Starship and successfully captured the first-stage super-heavy rocket booster through the robotic arm on the launch tower.
2. Falcon 9 recovery
At 4:52 a.m. on April 9, 2016, the Falcon 9 first-stage rocket landed steadily on the offshore platform and successfully recovered the rocket at sea.
(1) Composition of offshore recovery system
1. Offshore recovery platform
The offshore recovery platform was modified from a deck barge. The main modifications were as follows: first, the deck area was expanded to ensure a sufficient landing area for the rocket; second, a power system was installed on the barge to ensure that the barge could maintain a relatively stable position at sea; and finally, in order to prevent the first sub-stage of the rocket from failing to land successfully or causing an impact on the platform equipment when an explosion occurred, protective measures such as explosion-proof isolation boards were added.
2. Tow boat
SpaceX has equipped one tugboat for each of the two offshore recovery platforms currently in use: the Rhea tugboat and the Elsbeth 3 tugboat. The Rhea tugboat is basically the same as the Elsbet 3 tugboat. The tugboat has an overall length of 27.4 meters, a maximum width of 12.2 meters, a power of 3730kW, and a bollard pulling force of 50t.
3. Comprehensive support ship
SpaceX has equipped two comprehensive support ships for rocket recovery at sea. The two ships are basically the same size, with a length of 50 meters, a width of 10 meters, and a total tonnage of approximately 500 tons. During the recovery process, all operating personnel will evacuate to the integrated support vessel.
(2) Overview of maritime recycling
When the Falcon 9 rocket is recovered at sea, the rocket usually lands on the ship 8-9 minutes after launch. The maximum speed of the fleet when returning to port is about 8-12 knots, and the maximum entry water depth is greater than 10 meters. A total of 12 recovery accidents have occurred since 2015, mainly due to rocket return deceleration braking system failure, rocket landing bracket failure, sudden adverse sea conditions, sensor/radar failure, etc.
3. Starship recycling
The Starship adopts the tower cantilever recovery method, which shortens the time from separation to recovery of the rocket. Compared with the Falcon 9’s recovery at sea, the Starship’s recovery method avoids facing bad weather and complex sea conditions, and can further improve the launch efficiency. Because it saves the time for the fleet to return to port, the Starship’s booster can be directly inspected and docked again on the launch recovery tower. Of course, all this is based on the premise that the Starship’s transportation capacity is large enough.
4. Others
SpaceX has revolutionized the industry by recycling rockets. For my country’s rocket industry, if we do not develop reusable rockets, what are the advantages of private rocket companies compared with the system? How can private rocket companies compete with the system in terms of technology accumulation, talent reserves, funds, etc. for disposable rockets. At present, all rocket companies in our country mainly use VTVL recovery. The main reason is insufficient transportation capacity. Musk’s courage to use “chopsticks to hold rockets” is based on the premise of sufficient confidence in rocket transportation capacity. I hope we can also have such confidence as soon as possible.
