Air traffic management and conflict analysis for reusable launch vehicles

Abstract

Increasing demand for commercial utilization of space is accelerating the development of technologies that have the potential of providing safer and more economical access to space. Reusable Launch Vehicles (RLVs) are expected to take over a significant portion of the launch markets. Increased utilization of Spaceports will increase the frequency of interruptions to normal airspace operations and new methods of Aircraft-RLV separation need to be examined to reduce the impact of these operations on the National Airspace System. In this work, the issues relating to conflict detection and avoidance for mixed Aircraft-RLV operations were examined and compared with conventional special use airspace (SUA) operations. The characteristics of RLVs such as performance and predictability were used in conjunction with conventional ATC separation standards and avoidance maneuvers to develop conflict avoidance procedures based upon Alert Zones. The geometry of the Alert Zone for a given avoidance strategy provides information on the sensing requirements, and other conflict metrics. Alert Zones for the expected types of intruders and their flight phases in the horizontal and vertical planes were determined, and parametric variations were examined to determine the sensitive variables. Limited probabilistic analysis for bounded uncertainties in intruder trajectories was performed. The maneuvering costs in time and distances associated with these avoidance maneuvers were discussed. A strategy for comparing RLV operating modes employing SUA concepts, against tactical one-to-one avoidance mode concepts was formulated to evaluate the desirability of integrating RLV operations into the air traffic system. Conflict avoidance options using measures of Alert Zone size and deviation from track were compared. Preliminary analysis of required traffic deviation as a function of heading uncertainty was used to compare SUA to tactical conflict resolution for head-on conflicts. This allowed initial partitioning of when SUA is appropriate and when tactical separation is appropriate. For example, for equal speeds and uniform distributions of traffic, it was found that up to ±24° heading uncertainty could be accepted for tactical resolution before a 60NM diameter SUA became the more efficient solution.