What's Qarman?

 

QARMAN is the ”QubeSat for Aerothermodynamic Research and Measurements on AblatioN” of  the von Karman Institute, developed in the framework of the QB50 project.

Design

ModemUHF modem which is used while the satellite is in orbit, is an AstroDev Li-100. This modem has extensive flight heritage.

The UHF antenna is selected as a turnstile dipole in order to keep omni-directionality and circular polarization. The antennae will be wrapped during launch in order to fit into the launcher pod. Some 20 minutes after orbit injection the antennae will be released by melting the holding wires by heating resistors. Below you see a picture of the satellite back plate, with the antennae wrapped around the turnstiles. After release, the antennae will unfold and spread along the diagonals of the plate.

Antennae

Iridium ModemThe Iridium modem, used right after the re-entry black-out phase tos end the scientific payload data to the Iridium constellation is a COTS Iridium 9523 modem.

Survival Unit:

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.
Survival Unit

AerogelThe 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)

 

 

All the simulations and analyses, needed to define the Thermal Protection System of QARMAN, have been performed with the software ESATAN-TMS.

The modelling has allowed to verify the compatibility of the very peculiar design of QARMAN with the expected orbital and reentry environment, but also to optimize some fundamental parameters like the thickness of the pyrogel insulation,

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