Footprint Determination for Reusable Launch Vehicles Experiencing Control Effector Failures

摘要

The ability to compute the maximum area on the earth's surface (footprint) reachable by an autonomous air vehicle can be useful in planning for the vehicle's safe operations. The information can be important when the vehicle experiences subsystem failure causing it to be unable to maintain its nominal performance. In this paper, we present a method to calculate the footprint of a reusable launch vehicle that experiences a failure in one or more of its aero-control surfaces. During a control effector failure, the maximum attainable moments of the vehicle are reduced which may decrease the range of conditions that the vehicle can maintain a trimmed condition. Additionally, the lift and drag characteristics of the vehicle can change when control effectors are moved to off-nominal positions to correct for moment imbalance caused by failures or damage. As a result, the footprint of the vehicle is reduced. A technique for calculating the available effectiveness of the aero-control surfaces is used in conjunction with a footprint generation algorithm to include the effects of rotational trim on the vehicle footprint.