According to the news on November 23, the research and development of SpaceX B5 super heavy booster is progressing rapidly, which means that two super heavy boosters may be used for the first orbital flight test of StarCraft by the end of the year < p > < / P > < p > on November 19, SpaceX began to lift the methane storage tank of B5 booster to the top of oxygen storage tank, marking the end of the assembly of the main structural parts of the 69m high booster. At this time, there is only 10 weeks to start the manufacturing of B5 booster. At present, welders are working around the clock to weld the two storage tanks together and lay a pipe to pass the methane propellant down through the oxygen storage tank < p > two days ago, Elon Musk, CEO of SpaceX, shared a photo of another super heavy booster B4 of SpaceX. He revealed that the "B4 booster" had a thrust of 5443 tons when it was launched. "For more than three months, the B4 booster has been slowly entering the test preparation stage. As B4 booster and B5 booster are nearing completion, SpaceX will soon need to decide which booster to use to complete the first orbital flight test of the Starship < p > once the two parts of B5 booster are welded, the progress of B5 booster and B4 booster can be caught up by only a few steps. In recent weeks, technicians began to install enclosures for B4 booster cables, fuel pipes and avionics, reinstall Raptor engine, and install heat shield around rocket engine for the first time. There are indications that the entire booster outer ring above the nozzles of 20 Raptor engines will be equipped with heat shields < p > after the heat shield is installed, it can protect the pipes and lines of each engine during static ignition test, rocket rise, overturn and landing. In order to slow down the impact, the Falcon rocket booster always carries out three engine "re-entry ignition" for about 30 seconds during recovery. Unlike it, SpaceX does not perform this process when recycling super heavy boosters. Theoretically, this will make the booster recovery more efficient and save more than ten tons of fuel for putting the Starship into orbit < p > by November 17, SpaceX had completed the reinstallation of all 29 Raptor engines for B4 booster, and some engine heat shields had also been installed. The technicians also prepared for the installation of heat shields for the middle 9 engines. Since the nine engines in the middle can turn freely, it is more challenging to install the heat shield. According to the work progress in the past few months, SpaceX may need a few weeks to complete the installation of the heat shield, and install seven "aviation covers" on the rack carrying sensitive equipment around the B4 booster base < p > in contrast, B5 booster is assembled in a slightly different way. Technicians have installed and laid most of the external pipes, cables and equipment racks before the assembly of the two parts of the B5 booster. In contrast, the B4 booster was initially assembled with only half the giant steel cans of Raptor engines. Because of this, SpaceX spent more than ten weeks assembling the B5 booster, while assembling the B4 booster took only two and a half weeks. At present, considering that B4 booster has not been completed about 18 weeks after assembly, B5 booster may take 4 to 6 weeks less to reach the test preparation state < p > If B5 booster is indeed completed ahead of B4 booster, SpaceX will have two ready starship boosters, but there is only one orbital stage launcher at present. (Chen Chen) < / P > < p >