The TARDIS experiment: An innovative VOR-based system for HAPS backup positioning and attitude determination

TARDIS (Tracking and Attitude Radio-based Determination In Stratosphere) is a stratospheric experiment that exploits the VHF Omnidirectional Range (VOR) signal to perform an in-flight attitude and position determination. This project has been conceived by a group of students of Aerospace Engineering from Sapienza University of Rome and selected for the Rocket and Balloon Experiments for University Students (REXUS/BEXUS) Programme cycle 12. The programme is managed by the Swedish Space Agency (SNSA) and the German Space Agency (DLR) in collaboration with the European Space Agency (ESA). The experiment will be launched from Esrange Space Centre in Kiruna (Sweden) in October 2019. VOR is a radio-navigation systems based on high power transmitting stations at ground and on passive airborne receivers. The navigational information decoded by the receivers is defined as “radial” and it represents the bearing angle of the receiver with respect to the ground station position. The balloon position is obtained by the integration of two radials. An attitude estimation can be done through the pseudo-doppler radio direction finding method with four different antennas electrically switched by a RF PCB. This process will give the signal source direction and integrated with the balloon position, it will determine the attitude. The investigation could demonstrate the applicability of a passive system, based on a mature ground-based radio-frequency infrastructure, for the implementation as back-up position and attitude determination for the future stratospheric vehicles. High Altitude Platform Stations (HAPS), planned to autonomously operate for months, could implement such a system for improving the reliability of their navigation systems

From stratospheric experiments to CubeSat development: Lessons learned from the S5Lab participation into ESA hands-on educational programmes

The Sapienza Space Systems and Space Surveillance Laboratory (S5Lab) at Sapienza University of Rome offers hands-on projects opportunities, focused on space systems development, to students in aerospace engineering. Particular effort has been dedicated in the recent years, to enhance the laboratory students participation within the European Space Agency (ESA) hands-on educational Programmes. At the moment, S5Lab is one of the only laboratories in Europe to be simultaneously involved into two of these ESA programmes. In late 2018, a group of ten students, predominantly third-year BSc, has been selected for the REXUS/BEXUS Programme, managed by SNSA (Swedish National Space Agency), DLR (German Aerospace Center) and ESA, for designing, manufacturing, testing and launching their experiment, named TARDIS, on-board a BEXUS stratospheric balloon. Another group of students from S5Lab is participating since 2017 in the ESA Fly Your Satellite! Programme, addressed at offering launch opportunities to University students team willing to manufacture, test and launch their CubeSat. The laboratory is participating with LEDSAT, a 1-U CubeSat equipping Light Emitting Diodes (LEDs) on all the satellite external surfaces, which will be launched in 2020. The participation into these Educational Programmes is a great opportunity to extend and complement the education of students at all academic levels, improving their soft skills, practical experience on real flight hardware and teamwork capabilities. Furthermore, these Programmes schedules can fit into the students academic curricula and comply with the gained knowledge at different stages of their University years. In particular, the manufacturing of a stratospheric experiment is usually applicable to third-year BSc or first-year MSc, even without any previous experience in small hands-on projects. A second-year MSc student, along with PhD students, is involved into nanosatellites development and testing. Last but not least, the students have the possibility to practically access Space Agencies' technical reviews procedures in their education years, as significant preparation step for their involvement in future space projects. The acquired knowledge during these hands-on projects represents the robust fundamentals for the prosecution of the students' career after graduation, both in the academic or industrial framework. This paper describes the lessons learned from the involvement of students at all levels in ESA hands-on educational programmes. By using the two on-going projects as study cases, the paper will focus on the obtainable education improvements offered when complementing academic theoretical education with the hands-on projects activities. Furthermore, examples of educational return during specific experiences or events will be discussed

ECG/echo indexes in the diagnostic approach to amyloid cardiomyopathy: A head-to-head comparison from the AC-TIVE study

Background and aims: The discordance between QRS voltages on electrocardiogram (ECG) and left ventricle (LV) wall thickness (LVWT) on echocardiogram (echo) is a recognized red flag (RF) of amyloid cardiomyopathy (AC) and can be measured by specific indexes. No head-to-head comparison of different ECG/echo indexes among subjects with echocardiographic suspicion of AC has yet been undertaken. The study aimed at evaluating the performance and the incremental diagnostic value of different ECG/echo indexes in this subset of patients. Methods: Electrocardiograms of subjects with LV hypertrophy, preserved ejection fraction and ≥ 1 echocardiographic RF of AC participating in the AC-TIVE study, an Italian prospective multicenter study, were independently analyzed by two cardiologists. Low QRS voltages and 8 different ECG/echo indexes were evaluated. Cohort specific cut-offs were computed. Results: Among 170 patients, 55 (32 %) were diagnosed with AC. Combination of low QRS voltages with interventricular septum ≥ 1,6 cm was the most specific (specificity 100 %, positive predictive value 100 %) ECG/echo index, while the ratio between the sum of all QRS voltages and LVWT <7,8 was the most sensitive and accurate (sensitivity 94 %, negative predictive value 97 %, accuracy 82 %). When the latter index was added to a model using easily-accessible clinical variables, the diagnostic accuracy for AC greatly increased (AUC from 0,84 to 0,95; p = 0,007). Conclusions: Among patients with non-dilated hypertrophic ventricles with normal ejection fraction and echocardiographic RF of AC, easily-measurable ECG/echo indexes, mainly when added to few clinical variables, can help the physician orient second level investigations. External validation of the results is warranted

Unmasking the prevalence of amyloid cardiomyopathy in the real world: results from Phase 2 of the AC-TIVE study, an Italian nationwide survey

Aim: To investigate the prevalence of amyloid cardiomyopathy (AC) and the diagnostic accuracy of echocardiographic red flags of AC among consecutive adult patients undergoing transthoracic echocardiogram for reason other than AC in 13 Italian institutions. Methods and results: This is an Italian prospective multicentre study, involving a clinical and instrumental work-up to assess AC prevalence among patients ≥55 years old with an echocardiogram suggestive of AC (i.e. at least one echocardiographic red flag of AC in hypertrophic, non-dilated left ventricles with preserved ejection fraction). The study was registered at ClinicalTrials.gov (NCT04738266). Overall, 381 patients with an echocardiogram suggestive of AC were identified among a cohort of 5315 screened subjects, and 217 patients completed the investigations. A final diagnosis of AC was made in 62 patients with an estimated prevalence of 29% (95% confidence interval 23%–35%). Transthyretin-related AC (ATTR-AC) was diagnosed in 51 and light chain-related AC (AL-AC) in 11 patients. Either apical sparing or a combination of ≥2 other echocardiographic red flags, excluding interatrial septum thickness, provided a diagnostic accuracy &gt;70%. Conclusion: In a cohort of consecutive adults with echocardiographic findings suggestive of AC and preserved left ventricular ejection fraction, the prevalence of AC (either ATTR or AL) was 29%. Easily available echocardiographic red flags, when combined together, demonstrated good diagnostic accuracy