About¶
These pages show a SysML v2 model of the Apollo 11 mission in the views engineers work with: a trajectory, a flight timeline, block diagrams, budgets, requirement traces and a cost estimate. Each view is computed from the model when the pages are built, so it shows what the model says, including where the model disagrees with itself.
The source model¶
The Apollo 11 SysML v2 model was built by Philipp Helle and Gerrit Schramm at Airbus Central R&T as a case study of SysML v2: what the language can express for a complex, real-world system, organized by their five-layer CoSMA framework (purpose, operational, functional, logical and technical). Its authors describe it as a scaffold, incomplete by design, and invite others to use, critique and extend it.
What these pages add¶
The pages leave the model unchanged and add analysis on top of it. Each page queries the model and evaluates its expressions, calculations, analyses and constraints with Sysight, then presents the answers as engineering views. No figure is typed in by hand: when the model changes, the views change with it. Only the explanatory text is written by hand.
Values on the pages are of three kinds, labelled where it matters:
- model value: a value or link written in the model's SysML text;
- model computes: the result of evaluating the model's own expressions and analyses;
- page computes: a calculation a page adds from the model's inputs, such as a corrected budget.
How to read the numbers¶
Neither the source model nor these pages set out to be the most accurate or detailed description of Apollo 11. The source model demonstrates SysML v2; these pages demonstrate adding analysis to such a model. The values in the model are facts taken from public sources, and some are inferred or estimated.
What the pages show is how a model brings conflicts between such statements to light: for example, a planned mission duration that differs from the recorded splashdown time (Timeline), or an ascent Δv requirement larger than the stages credited with it provide (Budgets). In an engineering project these are the conflicts one wants to find early and resolve. The Review notes list the ones found so far.
Credits¶
- Model: Philipp Helle and Gerrit Schramm, Airbus Central R&T, published under the Mozilla Public License 2.0 (repository).
- Pages and analyses: designed by Dr Maged Elaasar, Modelware.
- Review: David Wagner, whose review of these pages contributed to their current form.
- Photographs: NASA, public domain; each caption links to its source.
- Tooling: Sysight, from Modelware.