David CERANTOLA, Pradeep DASS
DOI Number: N/A
Conference number: HiSST-2025-198
Designing spacecraft for missions with wide velocity ranges is a challenging task given the monumental performance variations between subsonic and hypersonic. A trajectory analysis is a beneficial exercise early in the design process to help identify the critical operating conditions needed for component design. Existing publicly available trajectory evaluation tools do not have the functionality to trim the aircraft, quantify static margin, or have the necessary degrees of freedom to satisfy the performance needs. With few exceptions, the emphasis of existing trajectory analyses is on optimized solutions; however, developing a satisfactory performance coefficient data-set for a multi-phase cruise vehicle to yield feasible solutions is not obvious. This paper evaluates a trajectory for a turbo-ramjet spacecraft from a horizontal take-off to a Mach 5 at 30 km altitude mission objective and descent to a horizontal landing where the initial performance dataset is insufficient to find a solution. Trajectories were evaluated using the Dymos library built onto OpenMDAO where input lift, drag, and moment coefficients were obtained from CFD and thrust and fuel consumption coefficients from pyCycle. The methodology section introduces a trimming module and solver strategy that leverages specific excess power to advise an initial guess. The obtained trajectory with a minimize time objective shows the trimmed vehicle travelled 672 km in 872s, had longitudinal static stability, and required 11.6% of take-off mass to be fuel. A 20% thrust enhancement factor applied to the ramjet phase was necessary to achieve 30km altitude whereas 28km altitude was achieved without enhancement.