Its funny, using the term "robust" for astro and then only mention PCs and servers is daft. From my experience PCs get full of dust, corrode (from dew) and inevitably become unreliable in a typical OBs (unless its in a seperate warm room etc). Theres nothing "robust" about a regular PC or server in what really is close to an industrial application.
These are robust. Sealed, no fan.