Non-catastrophic perforation of a composite overwrapped pressure vessel

Most spacecraft have a pressurized tank on board, such as a liquid propellant tank or a breathable air supply tank. Because of the serious damage that might result following an on-orbit micro-meteoroid or orbital debris (MMOD) particle impact, a primary design consideration of such (often highly) pressurized tanks is the mitigation of the damage that might occur in the event of such an impact. While catastrophic failure (i.e. rupture) following a high-speed MMOD particle impact would be disastrous, a puncture and the resulting thrust caused by the expulsion of fluids or gas from the perforated tank could result in the de-stabilization of the spacecraft's orbit which could, in turn, also lead to loss of the spacecraft. As such, in the event that catastrophic failure does not occur, risk assessments must still consider whether or not a perforation of a pressurized tank might occur and, in the event of a perforation, what size hole is created by the impact. This paper presents the development of a ballistic limit equation for highly pressurized COPVs that would differentiate between combinations of impact parameters and operating conditions that would result in a hole (without rupture) in the front side of the impacted pressure vessel from those that would not. Empirical models for the hole-out area in the composite overwrap and in the interior liner material in the event of a front side perforation are also developed and discussed.