Development and Mass Tracking of the P-17 Prospector Launch Vehicle

摘要

The Prospector-17 (P-17) is a low cost suborbital launch vehicle designed to test wireless sensor technologies for aerospace control. Specifically, the goal of the project is to investigate the ability of distributed wireless sensors (accelerometers or strain gauges) for reconstructing elastic mode shapes onboard the vehicle and in real time in order to incorporate vehicle dynamics in the flight control system. The vehicle design is derived from previous Prospector vehicles but modified to decrease the mass for higher performance. It is propelled by a 500 Ibf thrust liquid oxygen (LOX)/ethanol rocket engine. The aluminum structure previously used was replaced with a composite structure composed of four carbon fiber/epoxy sections connecting the two stainless steel propellant tanks with some fiber glass/epoxy reinforcements. To further lessen the mass, some changes were done to the propulsion system, primarily moving the main valve actuation assembly (MVA) from inside the vehicle to the outside, thus becoming part of our ground support equipment (GSE). Also, since the MVA is usually placed towards the aft end of the vehicle, removing it shifts the center of mass forward, making the vehicle more stable. With all these changes, the mass of the vehicle is predicted at 70 Ibm, compared to 120 Ibm for previous Prospector vehicles of similar size. The predicted mass of the vehicle is derived from our mass tracking approach, which is done simultaneously with the vehicle design and manufacturing. An Equipment List and Mass Properties (EL & MP) datasheet is constantly updated to keep track of predicted total mass and center of mass using American Institute of Aeronautics and Astronautics (AIAA) standards for mass tracking, allowing us to work on mass dependent aspects of the vehicle, such as fin design and the recovery system, before the vehicle is completely finished. The paper will introduce the wireless sensor network approach, present in detail the design of the P-17 vehicle and how our mass tracking practices of this and previous vehicles affected our design choices. P-17 was launched in early March 2014 in the Mojave Desert north of Edwards Air Force Base. The predicted performance will be compared with the actual flight test data.