Normal Extremal

Author: Tianjiang Shuo

Website: https://cislunarspace.cn

Definition

An extremal in the Pontryagin maximum principle for which the cost multiplier p0 is nonzero, conventionally normalized to p0=-1. When the transfer time exceeds the minimum time, no abnormal extremal exists for the minimum-fuel problem, so only normal extremals need to be considered.

Application Value

This concept is fundamental to understanding cislunar space dynamics and plays an important role in orbital mechanics modeling and mission analysis.

Related Concepts

• Time of Flight
• Hybrid Propulsion Earth-Moon Transfer
• Reference Ellipsoid
• Low-Thrust Propulsion

References

• Caillau et al. 2012 - Minimum fuel control of the planar circular restricted three-body problem