Design Process & Iteration

Overview

The spacecraft design process is highly iterative. Each phase refines earlier assumptions and updates subsystem requirements.

Figure: Space systems life cycle phases and their interactions. Source: Wilson & Vasile (2023)¹

These phases are based from Florian Kehls's lecture and use ESA as a reference. NASA uses a different set of phases.

Phase 0 (Mission Analysis / Needs Identification)
- Define broad objectives.
- Early feasibility checks.
Phase A (Feasibility Study)
- Rapid calculations and simulations (mass, power).
- Down-selection of concepts.
Phase B (Preliminary Definition)
- More detailed system designs.
- Subsystem-level trades and prototypes.
Phase C (Detailed Definition & Production)
- Hardware manufacturing starts.
- Subsystem qualification testing.
Phase D (Assembly, Integration & Test)
- Final assembly of spacecraft.
- Comprehensive environmental and functional testing.
Phase E (Operations)
- Launch and commissioning.
- Main science or operational phase.
Phase F (Disposal/Decommissioning)
- De-orbit or safe disposal.
- Final data analysis for mission close-out.

Requirements are revisited as trade studies expose conflicts (e.g., heavier payload forcing bigger propulsion).
Design changes can cascade: a small adjustment in power margins can alter thermal management, mass, etc.
Documentation of all decisions is crucial for technical and contractual clarity.

Concurrent Design Facilities (CDF) gather experts from each subsystem to simulate and iterate rapidly.
Active stakeholder communication can relax or tighten requirements based on feasibility.

Wilson, A. R., & Vasile, M. (2023). Life cycle engineering of space systems: Preliminary findings. Advances in Space Research. https://doi.org/10.1016/j.asr.2023.01.023 (Licensed under CC BY 4.0) ↩