Joost Hubbard

Joost Hubbard

Current MEng Aerospace Engineering student at Queen Mary University of London.

Update on progress; impulse vs non-impulse simulation

1 minute read

Published:

Building upon my prior work using the Clohessy-Wiltshire equations to create a trajectory simulation for a target and chaser satellite (as discussed in blog post 2), the next step was to utilize and develop this code to compare the effects of impulsive and non-impulsive manoeuvres modelling. This somewhat spiralled into me writing a short paper to summarise my work (still in progress but attached to this post nonetheless).

When simulating satellite manoeuvres, the tracking of the satellite’s resultant trajectory can be computed in a multitude of ways; the most prominent manners of modelling are impulsive and non-impulse models. An impulsive model assumes that a satellite undergoes an instantaneous velocity change where the position vector remains stationary at the burn point. This is obviously not realistic as it would require an infinite force across an infinitely small period1 but it can be close enough when approximating a high thrust, short burn. A non-impulsive manoeuvre (or extended burn) is a burn that occurs over a time period and as such is much more realistic. They can typically be used to represent low-thrust, extended burns.

Running these simulations allowed me to model two manoeuvres with the same magnitude of force applied - one instantaneously and one across an extended period - highlighting the disparities in trajectory between the two.

Click here to view images of manoeuvres
Impulsive Manoeuvre
Figure 1: Impulsive Manoeuvre - The trajectory resulting from an instantaneous velocity change.
Non-Impulsive Manoeuvre
Figure 2: Non-Impulsive Manoeuvre - The trajectory resulting from an extended burn.

To read more about the methodologies and results of these simulations, please refer to the following document: Read the full paper

  1. See Newton’s laws for an explanation of this, he was a bit better at explaining stuff than I am. ↩

Simplifying Jupyter Books Creation: A Windows Users Guide

1 minute read

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Over the summer in addition to personal research, I have been working as an active contributor to both a spacecraft dynamics textbook and a computational dynamics textbook created using Jupyter Books to complement modules taught at the Queen Mary University of London. As our project continues to evolve, we’ve recognized the need for a streamlined process to build and preview Jupyter Books locally on Windows machines. This capability is crucial for our team members to review their contributions before submitting pull requests on GitHub. To address this need, I’ve developed a comprehensive tutorial that walks through the process step-by-step.

What if? (Its a book not a question)

less than 1 minute read

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On and off over the past few months I’ve been reading ‘What if?’ by Randall Monroe. Since the book is so popular it feels almost pointless to explain it, but I will just in case. The premise centres around providing logical, scientific solutions to absurd questions, think things like: ‘What would happen if you tried to hit a baseball pitched at 90% the speed of light?’. These topics are covered in a way to keep the reader engaged, using humour while still actually answering the question somewhat accurately.

Clohessy–Wiltshire Simulation

1 minute read

Published:

The initial goal was to create a code snippet that to simulate the collisions between two objects in LEO, making use of the hill clohessy equations for relative motion. This is to be used to simulate the collision between the robotic arms and any debris it may want to capture. In addition, it could be used to estimate the required force needed to push the debris out of orbit. A final use could be to simulate rendezvous with the target.