From this plot it can be observed how the satellite height is calculated from the on board ADCS estimator. TLE is uploaded to the satellite and using time it calculates the satellite height that varies between apogee and perigee due to elliptical orbit and also the earth is not perfect sphere. Where there is no data, is where the on board estimator was not on. Satellite is currently at around 360km from >400km start, more than two years ago. Re-entry calculated around next time this year. This will be the last QB50 sat to re-enter launched form the ISS
nSight-1 altitude, slowly falling to earth. Would be great if other sats can add this to their telemetry. Of Course it is available from the many tle info.