Application of ribozymes for knockdown of RNA targets requires the identification of suitable target sites according to the consensus sequence. For the hairpin ribozyme, this was originally defined as Y−2N−1*G+1U+2Y+3B+4, with Y = U or C, and B = U, C or G, and C being the preferred nucleobase at positions −2 and +4. In the context of development of ribozymes for destruction of an oncogenic mRNA, we have designed ribozyme variants that efficiently process RNA substrates at U−2G−1*G+1U+2A+3A+4 sites. Substrates with G−1*G+1U+2A+3 sites were previously shown to be processed by the wild‐type hairpin ribozyme. However, our study demonstrates that, in the specific sequence context of the substrate studied herein, compensatory base changes in the ribozyme improve activity for cleavage (eight‐fold) and ligation (100‐fold). In particular, we show that A+3 and A+4 are well tolerated if compensatory mutations are made at positions 6 and 7 of the ribozyme strand. Adenine at position +4 is neutralized by G6→U, owing to restoration of a Watson–Crick base pair in helix 1. In this ribozyme–substrate complex, adenine at position +3 is also tolerated, with a slightly decreased cleavage rate. Additional substitution of A7 with uracil doubled the cleavage rate and restored ligation, which was lost in variants with A7, C7 and G7. The ability to cleave, in conjunction with the inability to ligate RNA, makes these ribozyme variants particularly suitable candidates for RNA destruction.

With the number of man-made objects being launched into orbit steadily increasing, space debris is one of the big challenges for future space flight. In order to better assess the danger to humans on Earth’s surface, re-entry should be researched in more detail. SOURCE serves as a 3U+ satellite platform designed and developed by the small satellite student society (KSat e.V.) and the Institute of Space Systems (IRS) at the University of Stuttgart. It was selected by ESA in 2020 to be part of the ‘Fly your Satellite’ program, has successfully completed the CDR and is currently preparing for the MRR. SOURCE’s objectives are education, verification of several cost-saving, not yet space-proven technologies for orbital use, capturing images of meteoroids entering Earth's atmosphere and documenting its own demise during re-entry by analysing atomic oxygen, heat flux- and pressure data. In order to receive data for as long as possible during re-entry, the satellite switches from S-band to Iridium (inter-satellite link) communication at an altitude below 200 km. For the in-situ measurement during the re-entry, SOURCE is equipped with two Flux-Phi-Probe (FIPEX) sensors for the measurement of atomic oxygen and five additional sensor arrays. Each array contains one pressure sensor and two heat flux sensors, one commercial and one developed by the IRS. The arrays are placed at five positions in-line across the satellite to reduce effects of tumbling during the re-entry and to allow for the measurement of gradients. For a first estimation of the expected value ranges, simulations were performed with the software PICLas, developed by the IRS and the Institute of Aero-and Gas Dynamics (IAG) at the University of Stuttgart. In an iterative process, the collected data will be used to further improve this simulation software after the re-entry of the SOURCE satellite. The aim of this paper is to describe the design philosophy and development process of the sensor readout electronics. The tests carried out are presented and the first results are presented.