Plume impingement avoidance in spacecraft rendezvous and docking applications

• Main Author: Kohli, Charulika
• Other Authors: Ling Keck Voon
• Format: Theses and Dissertations
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Electrical and electronic engineering
• Online Access: http://hdl.handle.net/10356/76035
• Institution: Nanyang Technological University

This dissertation aims to provide a brief overview of the satellite rendezvous and docking problem and its challenges. The main focus of this work is the plume impingement problem. When a target and a chaser spacecraft are in rendezvous; or when the chaser is in the process of docking onto the target, it fires its thrusters to perform a manoeuvre in order to achieve the desired position and orientation. While firing these thrusters, the exhaust plume from the thrusters can cause damage to the other spacecraft. When the spacecraft’s plume impinges on other spacecraft or docking stations, this is known as plume impingement. Plume impingement avoidance constraints’ study continues to be a virgin area in the vast scope of satellite rendezvous and docking. For this reason, this work aims to address plume impingement as one of the important challenges of rendezvous and docking. Plume impingement can have severe consequences such as damage to sensitive equipment on the surface of the impinged spacecraft. Plume can also generate large forces and torques which prove to be disruptive. This could lead to a situation where there may be a loss of control authority. Care must, therefore, be taken while firing the thrusters of the spacecraft when it is below a minimum distance of separation from other spacecraft or space stations. To this end, plume impingement avoidance constraints need to be incorporated into an optimization problem. Since this constraint is a complex one, addressing this is a challenge which must not be overlooked. In addition to impingement caused at the instant at which spacecraft fires its thrusters, impingement can also occur for an extended time period. The reason for this can be attributed to the time it takes for the plume to decay. This means that it must not be assumed that plume exists instantaneously. Instead, care must be taken such that other vehicles and docking stations are safe from impingement for the entire duration which the plume takes to decay. This work provides a concise summary of the advancements made so far; formulates an optimization problem incorporating plume impingement avoidance as a constraint; introduces the plume decay problem and incorporates decay into the constructed problem. Lastly it lays down the framework for incorporating plume decay into the formulated problem.