The aerospace sector is evolving due to reduced launch costs and standardization of small satellite platforms. This research, aligned with European Guidelines for Thermo-Elastic Verification, addresses the pointing precision gap in small satellites by assessing space telescope performance using uncertainty propagation in thermo-elastic models. The methodology will be directly applied to an Earth observation space telescope, VINIS, currently under development by the Instituto de Astrofísica de Canarias (IAC). This procedure helps to identify key design elements impacting its functionality. Thirteen elements were identified as main contributors to the deformations in the optical bench. Due to the bench's crucial role in the telescope's performance, this paper also explores how results vary with different sandwich panel modelling techniques and the enhancements from design modifications. While the focus is on space telescopes, this approach has broader applicability to thermo-elastic analysis of various space instruments.