title: Coupled trajectory and economic analysis of asteroid resources
Creators: name: Vergaaij, Merel
Publisher: name: University of Glasgow
Year: 2022

description: To reduce the cost of space missions, asteroid resources have gained significant attention. By using resources from asteroids, water for example, expensive launches from Earth can be minimised. Water obtained from asteroids holds great potential, not just for human life support, but split in its constituents it forms a highly effective propellant: liquid oxygen and liquid hydrogen. This means that asteroid resources can be used as building blocks for sustainable in-space infrastructure to aid with interplanetary exploration. Several commercial companies have expressed interest in pursuing asteroid mining. This fuels the need for cost estimations and economic models for asteroid mining, as both public and private ventures need to be convinced of the profitability of asteroid mining before investing in expensive space missions. To investigate the profitability of asteroid mining missions, this thesis has integrated economic modelling and trajectory optimisation at an appropriate level of detail and accuracy for each. Due to the coupling of the economic model and trajectory optimisation, trajectories can be designed for cost objectives rather than the more traditional minimum time and minimum propellant objectives. A parametric model has been developed, which can be used to investigate different mining missions, focused on but not limited to asteroid mining. Using this economic model and mission analysis, applied to a range of different missions with varying customer and mining locations, allows for an impartial comparison of the different missions. Potentially profitable value chains can be identified, influential parameters in the model can be found (e.g., certain cost estimates), or trade-offs between variations in mission architectures can be carried out. Using the model, a trade-off between chemical propulsion and solar sailing to transport asteroid resources has shown that while solar sails have the great advantage that they do not require any propellant, long mission durations have a significant impact on the Net Present Value and Internal Rate of Return, causing these missions to be not competitive with missions utilising chemical propulsion to transport asteroid resources to Earth orbit (e.g., geostationary orbit). A key finding is the importance of accurate specific launch costs in economic models for asteroid mining. Where other economic models often include specific launch costs in the order of 10,000 $/kg, commercial launch providers are driving down these costs by orders of magnitude by decreasing launch costs and increasing payload capacity. It is shown that this significantly impacts the profitability of asteroid mining, which can only sell resources at a price that is competitive with launching the same resources from the Earth. Assuming high specific launch costs therefore results in overestimating the profitability of asteroid mining. Another essential conclusion is that for any in-space propellant customer beyond low-Earth orbit, off-Earth mining (e.g., on asteroids, the Moon or Mars) can bring down the cost, mass and risk of future human and robotic space missions. While asteroid mining cannot compete financially with resources mined and processed on the same surface as customers (e.g., on the Moon or Mars), asteroids are likely to financially compete with other sources for customers in geostationary orbit, Sun-Earth or Sun-Mars Lagrange points, in orbit around or near the Moon or Mars, or in the main asteroid belt. Finally, it is shown that in a thriving space propellant economy with in-space propellant depots, near-Earth asteroids will be the first asteroids to run out of volatiles, due to their attractive orbits and small size. While asteroid resources are not expected to run out for a long time, this is mainly due to the wealth of resources in main-belt asteroids, which are expensive to mine, especially to supply a depot near Earth. These findings indicate the need for an international regulatory organisation allocating asteroid resources, either to preserve resources for future generations, or to reserve resources for use near Earth.