"Rocket engines are extremely sensitive to malfunctions, so the production process must be planned and all production stages must be thoroughly checked"

This was said by the CEO of the Israel Space Agency, Menachem Kidron, who in his previous position as Rafael's VP was responsible for the production of the rocket engines, following the failure in the launch of the supply spacecraft.

"Rocket engines are extremely sensitive to malfunctions, so the production process must be planned and all production stages must be thoroughly tested." This is what Israel Space Agency CEO Menachem Kidron, who in his previous position as Rafael's VP was responsible for the production of the rocket engines, said in an interview with the website Hidan, following the malfunction in the launch of the supply spacecraft that caused the explosion of the Antares launch vehicle in Virginia on Tuesday.

Kidron emphasizes that he does not have inside information from NASA about the case, but he can assess as a rocket propulsion expert what the main possible causes of such malfunctions are. Kidron was also a member of the committees that examined the failures in the Ofek 4 and 6 satellite launches.

"If you look at the history of failures in space and compare it to car accidents or even aviation disasters, it can be said that these are much rarer events. While there are a few memorable launch failures such as the Challenger disaster in 1986, rocket explosions in mid-air are not such a common occurrence. There are other types of malfunctions, such as the recent malfunction in which the Ariane satellite put two Galileo satellites into a different orbit than planned."
"I am very familiar with the field of rocket propulsion, where I worked for 40 years at Rafael, from beginning engineer to division head and vice president who was responsible for the rocket engines that Rafael produced and marketed to other entities such as the aerospace industry and space industries abroad as well as the European Space Agency. From this point of view, I can assess where in the launch process faults can happen."
"When talking about rocket propulsion, you have to differentiate between engines that run on solid fuel and engines that run on liquid fuel. Solid fuel engines are very sensitive to cracks where large combustion areas can develop when suddenly the pressure rises and the tank does not hold up to pressure, and from here a chain reaction begins that can ignite other components. Additional faults in solid fuel engines can result from seals that were not performed well, material defects, human errors. You cannot burn the engine to test its operation because it is like a match (unlike a liquid fuel engine which can be tried). Therefore, the engine components are checked at various stages of production and at the end X-rays or even tomography are taken. After all that, they also take large safety factors. By the way, such engines are common not only in spacecraft launchers but also in surface-to-surface or air-to-air missiles."

"Liquid fuel, as in the case of the Hunters, is a different story. There, liquid oxygen and kerosene - a type of kerosene - are kept in separate tanks and transported through pipes and pumps, and the control system controls the flow quantities through valves. It flows the two liquids in the right quantities so that the combustion is effective. Usually when there is contact between the oxygen and the crocin the reaction is immediate combustion. There are even known cases where people touched a leaking oxygen pipe with a glove smeared with a little grease, and this immediately caused an explosion."

"Malfunctions in such an engine can occur due to leakage, errors in the design of the thermal infrastructure or even a disruption of the control system that provides non-stoichiometric relations between the two liquids that, instead of driving the missile, cause an explosion. The malfunction can also be caused by external factors that caused the ignition of the materials stored in the engine. We must not forget that we keep stored energy inside the containers and it is necessary to release it in a controlled manner, at the right pressure, at the right flow, and in this process there are stages in which small faults may cause the gases to escape."

"The fact that the explosion occurred after six seconds can indicate that it was not a warm-up event. Although high temperatures are generated during launch, they should still not be enough to cause an explosion. The fact that the explosion occurred in the first seconds indicates that something in the storage of the liquid oxygen and the fuel went wrong, perhaps due to a failure in the control system."

"I am sure of one thing according to the tradition of NASA and assuming that the fault is in the rocket engine, they will conduct a serious investigation. I appreciate that they will come up with the reasons for the malfunction or at least evaluate what was most likely to happen and also draw the right conclusions."

Israel experienced two failures in the 4th and 6th launches, what did we learn from them?

Kidron: "Each of the breakdowns had a different reason. In both cases we conducted a general inspection of the design to make sure that there was no factor at the beginning of the process that caused the events at the end. The committees sat for long periods and came to conclusions and recommendations on how to tighten the design or production. Since then we can be satisfied when all the launches have been successful, and I hope it will continue that way."