As workload increased for the final development phase, we completely forgot to keep you updated – sorry for that. Many things have been achieved since our last post: We released the flight software, finished the USB interface test, passed the EMC (Electromagnetic Compatibility) test and submitted our flight safety data package for ESA safety review. Way to go!
The flight software is the Operating System and additional Software that we install on micro SD cards to be run on the Astro Pi computer onboard. It is based on a Raspbian System with additional safety features to restrict access and prevent any harm to the space station. As we do not have continuous access to the Astro Pi, the software must be as autonomous as possible. Our RF spectrum analysis software is a slightly modified version of the open source software Soapy Power. It allows the recording and storing of RF spectrum measurements. More details will be shared in the Ops preparation phase this spring & summer.
USB interface test
As both our hardware and the Astro Pi are powered by USB chargers, we had to make sure that the system is compliant with the USB standard. Although USB compliance is not surprising for a USB COTS device, it still remains one of the mandatory items during safety process. At the same time, we had to analyze how much power is drawn by the system and if it can harm the USB charger or other upstream systems. We decided to conduct the USB interface test in-house and the hardware passed all tests.
The EMC test was more challenging. Jitendra and Martin travelled to ArianeGroup in Bremen, a joint venture of Airbus DS and Safran Launchers which is located on the same site as Airbus. EMC tests shall make sure that hardware cannot be harmfully affected by electrical and/or magnetic influences, both radiated or conducted. For MarconISSta, we were only asked to test for radiated emissions and susceptibility. In other words, we should check if our system creates strong electromagnetic fields or is influence by the same. Although our system does not intentionally emit any EM fields, there still is a chance that internal circuits create unwanted fields. At the same time, external fields could influence these circuits and with that change the performance of the system. Luckily (and as anticipated), our hardware stayed below all limits during radiation tests and “survived” all external fields without performance degradation. We were happy to attend the test engineer during these two days and learned a lot from the experienced staff.
Flight safety data package
With all qualification tests passed, we were now ready to submit our final flight safety data package (FSDP) for final review by the ESA safety panel. This data package includes analyses, test results and reviews-of-design (RoDs) of the experiment on many levels: materials, flammability, mechanical hazards, electrical hazards, commanding hazards and many more. Our final FSDP was prepared for the phase III ESA safety review which is the last safety review on the European side. Although we do not have the final safety certificate yet, we are very confident to get positive feedback by the end of this week.
Motivated by all these successes, we now check out the hardware and test all components for one last time. We finalize our label plan and discuss the Operations manual with our partners from ESA, DLR, ARISS etc. After that, we are ready to submit our system for final cargo review. With delivery of the experiment in the beginning of February, we are currently scheduled for a launch in May/ June 2018. We keep you updated!