Multipulse Solid Rocket Motors for MAV

The Mars Ascent Vehicle is undergoing extensive vehicle trades to fine tune the optimal performance for a two-stage rocket motor solution to bring a payload from the Mars surface to orbit. The key is this vehicle must provide a terminal velocity of approximately 4 km/s, remain small in length and weight, and ensure the payload does not exceed 4 g's of acceleration during vehicle ascent. Based on initial vehicle architecture optimization analysis completed by engineers at Arctic Slope Technical Services (ASTS), the acceleration limit places a significant impact on the grain profiles used on both the first and second stage rocket motors. Therefore, the use of a dual pulse rocket motor grain design enables the use of two subsequent pulses that are ignited so as to mimic a single grain along the optimal thrust profile. This solution burns down the risks associated with an end burning grain design. The dual pulse grain design leverages finocyl designs that offers significant grain stress relief because of the fins. Also this approach offers the ability for a smaller and lighter nozzle because of the shortened burn time. Moreover, this will provide significant opportunity for the motors to get smaller in length by being able to be packaged more efficiently. This reduction in motor length will enable for a more stable vehicle in flight as well as enable the vehicle to carry either a larger volume payload or reduce the impacts on the transportation vehicle as it takes the MAV to the Mars surface.