The company found that the likely cause was frozen oxygen, which burst a high-pressure tank containing helium, which is used for pressurization during the second stage of the rocket's launch.
The high heat comes from engine plumes, separation motors, tank pressurization gas and air flow, the manual said.
One originality of the present formulation is to take into account the effect of the pressurization of the tank on the dynamics of the system, particularly in the case of a compressible liquid.
Their version is also designed to be pressurized via heat exchanges with the engines used to pressurize fuel tank and oxygen tank, which is simpler than systems with Falcon 9 where helium is used to pressurize fuel tank, and nitrogen for further pressurization.
Experimental and simulated results indicated that the tank pressure decreases during the N2O self-pressurization process.
The gas also self-pressurizes, which could eliminate the need for tank-pressurization systems.
Sufficient knowledge of thermal performance and pressurization behaviors in cryogenic tanks during rocket launching period is of importance to the design and optimization of a pressurization system.
Residual heat loads, due to heat conduction in the launcher structure or solar radiation, induce cryogenic propellant vaporization and tank self-pressurization.
During the last mission, of the Endeavour in November, a piece broke off a valve that regulates the flow of hydrogen gas from the main engines to the external tank to maintain pressurization of the tank.
The consequences of some rollovers, if prevention/mitigation actions are not implemented, are uncontrolled venting of boil off gas in vapor form to the atmosphere, flammability hazards, tank structure over-pressurization with potential damage.
