Six years ago, Elon Musk was criticized for choosing stainless steel as the material for the reusable Starship rocket. Subsequent test launches of mockups and ships proved the owner of SpaceX right: stainless steel has proven itself as an inexpensive material for rocket bodies and fuel tanks. The example of SpaceX inspired the Chinese so much that they also began making rockets from stainless steel.
Image source: CALT
The China Academy of Launch Vehicle Technology (CALT) has announced that it has developed and manufactured a 10.6-meter stainless steel fuel tank for testing. That’s 1.6 meters longer than the diameter of the SpaceX Starship booster and spacecraft. Chinese engineers have gone further than Elon Musk’s company and now expect to make their future reusable Long March 9 lunar and Mars rocket out of stainless steel.
Before SpaceX’s innovation, rocket bodies and fuel tanks were made of aluminum alloys and multilayer carbon fiber. This is reliable, but labor-intensive and therefore expensive. This solution is unacceptable for the widespread commercialization of space. The use of sheet stainless steel significantly reduces the cost and simplifies the process of manufacturing rockets and their components. In fact, only by switching to steel has SpaceX been able to afford to blow up prototypes over and over again – to conduct tests at an unimaginably fast pace, each time making rockets better and more reliable.
China’s private space companies have already begun using stainless steel in some of their reusable rocket prototypes. But the 10.6-meter fuel tank for the upcoming reusable super-heavy Long March 9 rocket eclipses anything that has been done before.
«”The success of this prototype marks a significant breakthrough in the development of ultra-large-diameter stainless steel tanks and represents a solid first step toward the iterative development of large-diameter stainless steel structures for heavy-lift launch vehicles,” CALT said in a statement about the production of the 10.6-meter-diameter tank posted on the organization’s official Weixin social media account on April 29.