Desirée has computed the lifetime due to drag of MIST if it tumbles randomly. She used NASA’s Debris Assessment Software and looked at two different satellite masses – 3 kg and the maximum allowed for a 3U Cubesat, i.e. 4 kg. The assumed starting date for the analysis was 21 June 2017. As you can see the lifetime stays below 25 years (the limit for an uncontrolled satellite so as to not create space debris) if the altitude is kept below about 660 km. The “wiggles” in the curves are caused by the solar cycle which makes the atmosphere expand and contract.