Share with friends and circle of friends with wechat scanning QR code < / P > < p > on January 5, recently, Elon Musk, CEO of SpaceX, said that the work on upgrading Raptor 2 engine of starship is progressing smoothly, and the conventional working pressure of engine main combustion chamber can reach 300bar (1bar = 100 kPa) < p > < / P > < p > in mid December last year, musk revealed that the Starship would be upgraded, including increasing the volume of propellant storage tank and adding three Raptor engines, which is expected to increase the maximum thrust of the Starship by 50%, so as to greatly improve the payload performance. Recently, SpaceX upgraded the rocket engine carried by the Starship to Raptor 2 engine, and adjusted the structural design and assembly process of the spacecraft < p > according to musk, as SpaceX continues to strengthen the ground test of the upgraded Raptor 2 engine, "the conventional working pressure of the main combustion chamber of Raptor 2 engine is 300bar." < p > on February 10, 2019, the main combustion chamber pressure of SpaceX's first full-size Raptor engine prototype was only briefly close to 269bar, barely breaking the pressure record set by Russian rd-270 and rd-180 engines. Subsequently, it took musk 18 months to clearly prove that the Raptor engine prototype can stabilize the high pressure in the main combustion chamber for one minute or more. The pressure peak of the same Raptor engine reached 330bar and briefly generated 225 tons of thrust, completely defeating Russia's rd-701 engine. In the following 18 months, the starship with Raptor engine carried out dozens of static ignition and seven flight tests < p > previously, the Starship equipped with Raptor 1 / 1.5 engine has not tried orbit test, but SpaceX has begun to upgrade Raptor 2 engine for the Starship. According to musk, all engine ground tests conducted at the company's R & D Park in McGregor, Texas, are now focused on the Raptor 2 engine < p > it is reported that the piping and wiring of Raptor 2 engine should be more concise. The biggest change of Raptor 2 engine is that the maximum thrust increases by nearly 25% compared with Raptor 1 / 1.5, from 185 tons to 230 tons. This is mainly achieved by expanding the nozzle throat diameter of Raptor engine, and obtaining higher power density by sacrificing a small amount of efficiency. In addition, the technicians also improved the design of Raptor 2 engine, so that it can work continuously and reliably under the main combustion chamber pressure of up to 300bar, and its conventional working pressure is 10% higher than Raptor 1.5 engine < p > musk previously said in a tweet, "Raptor 2 has a large throat diameter, so the thrust at 321bar is about 245 tons." < p > on October 24, 2021, musk broadcast the first static ignition test of Raptor 2 engine through personal social media, which showed that the main combustion chamber of the engine reached the peak pressure of 321bar and briefly generated about 245 tons of thrust before the explosion. Now more than two months later, musk said that the normal working pressure of Raptor 2 engine has reached 300bar, and there are no major problems, which means that they can burn under this pressure for a few minutes and then shut down safely. Since 300bar is the target pressure of the main combustion chamber of Raptor 2 engine under the maximum thrust, it means that the "normal" operation of Raptor 2 engine has reached the goal of SpaceX < p > of course, it may take months for the Raptor 2 engine to adapt to the new starship and super heavy booster. However, SpaceX made rapid progress in the first few months of Raptor 2 engine testing. (Chen Chen) < / P > < p >