[DOC]: Lunar Lander: Shell Thickness

### 🔗 Affected page or URL

https://fluent.docs.pyansys.com/version/stable/examples/00-fluent/lunar_lander_thermal.html#references

### ⚠️ What is wrong or missing?

The problem description states that the lander has 3 mm thick aluminium walls, but the boundary-condition setup assigns a 0.03 m, or 30 mm, aluminium shell to both the MLI-covered walls and the radiator:

```
"thickness": 0.03,
"material": "aluminum",
```

It is unclear whether 0.03 m is a typo for 0.003 m, or whether the thicker shell is intentionally being used as an equivalent representation of the original reference [[1]](https://doi.org/10.1155/2018/4236396) model’s 500 kg lumped thermal mass. A 30 mm aluminium shell would have substantially greater thermal mass and in-plane conductive capacity than a 3 mm shell, which can affect the reported minimum, average and maximum spacecraft temperatures, as well as the radiator louver switching behaviour.

The treatment of the MLI should also be clarified. The implementation represents the MLI through effective surface properties:

`{"solar": 0.05, "thermal-ir": 0.05}`

This is consistent with the referenced study, which models MLI using effective solar absorptivity and IR emissivity rather than modelling the blanket in detail. However, the current example does not explicitly state that the MLI’s internal layers and through-thickness thermal resistance are omitted.

### ✏️ Suggested improvement

1. If the aluminium wall is physically 3 mm thick, change the shell thickness from 0.03 m to 0.003 m.
2. If the 30 mm aluminium shell is intentional, explain that it is an equivalent modelling choice, for example to approximate the thermal mass and nearly isothermal behaviour of the original 500 kg lumped lander model. The description should not then state that the simulated aluminium wall is 3 mm thick without further explanation.
3. Explicitly state that the MLI is represented only through effective solar absorptivity and thermal-IR emissivity, and that its detailed layered construction and through-thickness thermal resistance are not modelled.

### 📌 Additional context

_No response_