Contingency Operations for Failures in a Generalized Mars Transit Architecture

Ambitious goals for exploring Mars in the coming decades will push human spaceflight into new territory in duration, distance and isolation. In this regime, loss of system functionality due to some critical failure becomes especially dire. To that end, much meaningful work has centered on designing reliable, supportable space systems with low susceptibility to failure. Recent work has also focused on resilient systems capable of withstanding shocks and deviations in operating conditions. However, a gap exists in understanding the survivability of a manned exploration system experiencing critical failure; that is, the ability of the system to prevent loss of crew via impact mitigation and contingency operations. This paper proposes a general methodology for enumerating and analyzing the efficacy of such responses.

Bounds are established on the severity of failures investigated under this survivability methodology. On the lower bound, the failure must be beyond the capabilities of standard maintenance strategies, which are widely considered in the literature. As an upper bound, the failure must not lead to immediate crew loss – there must be a chance to respond. Thus, a window exists in which contingency responses can extend survival time, alter mission objectives, destinations and trajectories, and allow for rescue or abort operations.

The proposed methodology is developed for a generalized Mars transit architecture. Elements are abstracted to perform high level functions required of any plausible architecture. A failure is considered which critically inhibits one or more of these functions. The key product is a classification, enumeration and decision framework for contingency responses to such a failure taken from historical examples, proposed architectures, and subjective ideation. An understanding of contingency responses in a generalized architecture allows mission planners to design for survivability from the earliest stages of the architecting process, trading a perhaps narrowly optimal design for one robust to failure.