Test Flights of the Revised ULDB Design

Abstract

Development of the National Aeronautics and Space Administration’s Ultra Long Duration Balloon has focused over the previous year on ground testing and analysis to understand the previously observed issue of balloon deployment. A proposed a new approach to the pumpkin balloon design and fabrication has been the subject of these ground tests and analytical efforts. This new approach should increase the probability of balloon deployment, does not require foreshortening, and will significantly reduce the balloon handling during manufacture reducing the chances of inducing damage to the envelope. The scaled models have provided a subset of the required information to determine if the deployment issue has been fully addressed. Analytical predictions demonstrate that the proposed flight balloon designs are stable and should fully deploy. The only way to fully assess the suitability of the proposed design approach is to actually build and fly flight structures. The test flight structures are intended to be increased in a stepwise development approach with successive test flight balloons increasing in both suspended weight carrying capability and in increased float altitude. This paper documents the first test flight of this revised Ultra Long Duration Balloon design; a short domestic test flight from Ft. Sumner, NM. A brief overview of the fabrication of these ~176,000 m (~6.2 MCF) flight structures, based on knowledge gained from testing and analyses, will be presented. A description of the test flight balloon will be given. The test flight goals and success criteria for will be highlighted along with the test flight plans. An assessment of the balloon deployment will be given. Test flight results including flight performance will be presented. A brief lessons-learned and information on future Ultra Long Duration Balloon test flights will also be presented.