Approval of the detailed PRETTY Design
M. Moritsch1, C. Tscherne2, A. Dielacher1, H. Fragner1, M. Wind2, P. Beck2, A. Hörmer3, O. Koudelka3
1 RUAG Space GmbH, Austria
2 Seibersdorf Labor GmbH, Seibersdorf, Austria
3 Graz University of Technology, IKS, Austria
The consortium RUAG Space GmbH, TU Graz and Seibersdorf Laboratories have recently finalized the Critical Design Review (CDR) of the PRETTY (Passive REflecTometry and dosimeTrY) space mission together with ESA. While the instrument concepts have been presented in the frame of the RADHARD Symposium 2019 [RD1], the final design including all internal ICDs has now been approved for implementation.
The CDR was held on basis of several breadboarding activities that showed the viability of selected instrument concepts. While the satellite bus was a reuse from the OPSat mission relying heavily on commercial off the shelf (COTS) components from different vendors, the payloads rely on specific hard- and software based implementations.
Within this presentation we will provide some insight on the most relevant breadboarding results for the passive reflectometer and the dosimeter.
The reflectometer hardware is provided by TU Graz and requires an antenna that was specifically designed for this mission. The active patch antenna provides within the L1 Band a gain of 15 dBi on a small footprint of only 10 cm x 20 cm. TU Graz has built a first prototype, measured the antenna pattern and compared it to the simulated results during the phase B study.
The signal processing core, which will run on an Altera Cyclon V has been developed by RUAG Space (RSA) and was recently validated by using test data obtained within the CyGNSS mission. RSA is also part of the extended US mission science team and was thus in the lucky position to obtain raw data from this mission in order to use it for the PRETTY signal processing core validation.
The reference dosimeter payload is designed and developed by Seibersdorf Laboratories. Its objectives are to assess the radiation mission dose during the whole CubeSat space mission and in particular at geographic regions of interest with elevated radiation levels, such as the South Atlantic Anomaly (SAA), North Pole and the South Pole. The proposed dosimeter system is based on RADFET and FGDOS which are made of silicon and therefore their response can be used as reference dose for total ionizing dose (TID) effects. Further, the dosimeter payload will feature a single event upset (SEU) assessment system. The SEU assessment system will be based on COTS SRAM memories and is carried out as collaboration with CERN. The measurements are representative for other silicon-based electronic systems e.g. during reliability testing of electronic components, in particular for COTS on-board CubeSat.
With the provided CDR data the consortium has successfully demonstrated the viability of the instrument designs by use of representative breadboard results. The flight implementation can now be started and is expected to be finalized within 2021.
RD1: RADHARD 2019, Book of Abstracts, Concluding the preliminary design Phase: PRETTY results from the Phase B study
The phase C and B study for the PRETTY mission has been funded by ESA GSTP Programme. The according Phase A study was funded by ASAP/FFG.