Examining the Re-entry of a Tumbling Object During Freefall

Hartmann, Gregory (2021) Examining the Re-entry of a Tumbling Object During Freefall. [USQ Project]

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HARTMANN Gregory dissertation_redacted.pdf

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A humanity continues to advance its knowledge and understandings in the field of science, technology and engineering, society will always continue to push and redefine their limitations and approaches towards gaining this knowledge and understanding of the universe. This includes but is not limited to the research related to astronomical studies, planetary bodies and the commercialisation of the space industry. However, there are problems that arise from these advancements, one of which is the risks and hazards associated with launching, monitoring, tracking and deorbiting of old spacecraft and debris orbiting the Earth. These risks and hazards are is currently being observed today, where one of the most recent uncontrolled atmospheric re-entries occurred on the 8th May 2021. Which involved the core 5B booster from the Chinese Long Mach CZ-5B rocket, where it re-entered and performed an uncontrolled re-entry into the Earth’s atmosphere. Due to the uncontrolled re-entry of this object, private and government institutions struggled to determine the exact location for where the object would make impact. Therefore, this uncertainty increases the risks and likelihood of an object impacting and damaging a populated area. This research project identifies and examines the effect and trajectory of spacecrafts or pieces of debris that have re-entered into the Earth’s atmosphere in an uncontrolled flight path. Therefore, main aim of this research project is to design an apparatus that can artificially simulate and examine the re-entry trajectory of an object tumbling at high speed during freefall from orbit within a hypersonic wind tunnel.

In order to conduct this research project, the limitations and design requirements for the proposed apparatus needed to be outlined and established before testing could commence. This was achieved by examining the design of the TUSQ facility and the release mechanism. These limitations where then used in design stages of the apparatus and were used to explore three possible apparatus designs, however, only one was utilised in this project. In addition, these limitations and operating conditions of the TUSQ facility was also utilised in the theoretical calculations used to determine the mass, drag force, frictional force and the force applied to the test objects during the project.

Further, the apparatus underwent three stages of testing before the final test could be performed. These were the freefall test, the performance test and the preliminary/bench test performed at the TUSQ facility. Initially four different test objects were going to be tested within the hypersonic wind tunnel, however, only one object (cube) was tested. This was due to time restraints.

After conducting the final test within the TUSQ facility at USQ Toowoomba, Queensland and analysing the collected results, the results revealed the following; the calculated RPM and the drag coefficient of the test object and the temperature, pressure and density of the fluid’s flow was approximately 6975.22, 1.33, 70.33 K, 772.35 Pa and 0.0000048 kg/m3 , respectively. Furthermore, when comparing the RPM and drag coefficient back to the theoretical data used in the design stage of this research project, there was a calculated percentage error of approximately 52.19, and 26.67, respectively. However, due to some errors the accuracy of the data may have affected the final results. These include; the increase surface area that the fluid’s flow has on the test object, as the object continues to change its angle of attack, the increase voltage supplied to the motor and speed controller, the accuracy of the dimensions of the test object, the positioning of the test object with respect to the centre of gravity of the apparatus, the interference from the separation of the test platform and the test object and the effect from the vibration from the DC motor.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021)
Supervisors: Buttsworth, David
Qualification: Bachelor of Engineering (Honours) (Mechanical) / Bachelor of Science (Physical Sciences)
Date Deposited: 03 Jan 2023 01:47
Last Modified: 26 Jun 2023 01:21
Uncontrolled Keywords: freefall, object, tumbling, model, space, debris, re-entry
URI: https://sear.unisq.edu.au/id/eprint/51816

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