Ph.D. Thesis Proposal

Akshiti Parashar

(Faculty Advisor: Professor Dimitri Mavris)

"An Integrated Reverse-Logistics Framework to Enable Circular Post-Mission Management of End-of-Life LEO Satellites"

Thursday, June 4

10:00 a.m. - 1:00 p.m.

Weber, CoVE

Abstract:

The rapid proliferation of low earth orbit (LEO) satellite constellations is transforming access to space but is also intensifying the long-term challenge of post-mission disposal (PMD). Current End-of-life (EOL) practice is dominated by a linear paradigm in which satellites are deorbited and allowed to demise during uncontrolled atmospheric re-entry. Although this approach reduces orbital congestion, it implicitly assumes that spacecraft retain little residual value after mission completion. As LEO satellite production scales, this deorbit-and-burn model risks repeated material loss, atmospheric contamination from ablation products and aluminum-oxide particulates, and a weakening of the incentives that would otherwise encourage manufacturers to design spacecraft for circular EOL pathways. On-orbit servicing could, in principle, support circular-economy (CE) strategies such as repair, refurbishment, and remanufacturing. However, it has not yet matured to the point of routine application in LEO, with most demonstrated capability and economic analysis concentrated on geostationary orbit (GEO) assets, whose higher unit value and longer operational lifetimes have historically made life-extension and servicing missions easier to justify.

This challenge is particularly important at constellation scale, where thousands of structurally similar spacecraft are produced and retired on short replenishment cycles. As alternatives to destructive disposal, emerging technologies and space infrastructure, such as heat-shield-assisted return, active debris removal tugs, orbital warehouses, and reusable launch vehicles, could provide an operational basis for return-to-Earth (RTE) recovery of space assets.

The first obstacle to such recovery is that current satellites have not been designed or evaluated for circularity in the first place. To examine where this gap originates, a review of state-of-the-art product circularity indicators was conducted. The study revealed that the technical evaluation of design-for-X attributes, where X may refer to modularity, disassembly, material recovery, and related properties, lacks a defensible quantitative grounding when applied to spacecraft. A transparent and quantitative method for evaluating satellite circularity is therefore needed so that manufacturers can align design decisions with circular objectives from the earliest stages of architecture definition. Enabling circularity through design, however, is necessary but not sufficient. A circular architecture must also support a defensible business case under the cost, performance, and operational uncertainties that govern the RTE paradigm.
Existing studies provide limited support for evaluating circular PMD alternatives as stakeholder-facing investment opportunities. The business model layer therefore develops a structured project-value evaluation template for comparing feasible CE strategies and EOL recovery routes against the business-as-usual (BAU) baseline. The methodology first defines the BAU pathway, identifies feasible alternatives, and translates reverse-logistics assumptions such as collection rate, depot inventory, and return cadence into pathway-specific costs and revenues. Uncertainty distributions are then assigned to key technical, market, and financial inputs, and a Monte Carlo simulation is used to generate NPV distributions for each alternative. From these distributions, the analysis computes ENPV, VaR, CvaR, and the probability of outperforming BAU. This allows each pathway to be evaluated not only by expected economic value, but also by its exposure to downside-risk conditions that may prevent adoption and its likelihood of outperforming the baseline.
Finally, the adoption of sustainability-oriented practices on Earth has often required government intervention, especially when the market does not fully reward long-term environmental or social benefits. The policy layer therefore models candidate schemes, including fees, rebates, and

Committee:
Dr. Dimitri Mavris (advisor), School of Aerospace Engineering
Prof. Koki Ho, School of Aerospace Engineering
Prof. Thomas Gonzalez Roberts, Sam Nunn School of International Affairs
Prof. Mariel Borowitz, Sam Nunn School of International Affairs
Dr. Tristan Sarton Du Jonchay, School of Aerospace Engineering