One of the main challenges of the mission is to ensure the survival of at least some critical parts of the satellite during the re-entry. To achieve this challenge QARMAN is divided in two different parts, where the non-critical parts of the satellite are allowed to overheat during the re-entry, but re-entry active systems are thermally insulated in so-called survival units (SU). The survival units are heavily insulated boxes in which all electronics that must survive re-entry are placed. Amongst those are the OBC, the INS, the Iridium modem, batteries, regulators and switches. The figure below shows the OBC PCB with INS, modem, flash card and batteries.
The insulation is done using a novel material called aerogel. This is a ultralight (only slightly heavier than air, which earned it the nick-name “frozen air”), ultra-isolating material (thermal conductivity of the order of a few mW/m2). Below is a picture of a block of aerogel (source: Wikipedia)