For further information email dsmith (David Smith) at scipp.ucsc.edu.
Wednesday, Dec 17
After bouncing up and around Mt. Discovery, the MINIS payload broke free and rose up again to about 3 km, moving southwest. A helicopter reconnaisance flight confirmed that it was aloft again, and that it had lost its booms. It made it over the Royal Society Range and out to the plateau, continuing to rise to 9 km, the height of the tropopause. After that, it turned westward and very gradually came down. The last position it reported was 77.6869 S, 127.8722 E, 3332 meters altitude, at 05:58 UT on December 17. This is only a few hundred meters above the altitude of the plateau at that position -- we conclude that it probably came down shortly afterwards and we lost telemetry (which had already been spotty since the original landing(s?)) once it hit the ice. The distance, the probable degree of damage, and the lack of remaining battery life make a recovery unlikely.
Our best guess as to what happened is that there was a hole in the balloon about halfway down. When it reached 14km (well above the tropopause), the helium bubble was big enough to see the hole, and it leaked a lot of helium quickly, bringing it down to the ground. On landing, it bounced and dragged up the mountain losing its booms, so that with less weight it had some positive lift -- enough to bring it up to the tropopause but not enough to cross it, and therefore not enough to trigger further leakage -- thus the second descent was several times slower than the first.
Monday, Dec 15
Launch occurred at 09:40 UT and went fairly smoothly, with all systems active, however upon reaching 13.8 km the payload came back down, probably due to a leak in the balloon (since it passed the tropopause without slowing badly, there was initially plenty of lift). The payload came down on the lower South flank of Mt. Discovery, and as of this writing is still bouncing and/or dragging slowly along. Most systems (including the scintillator, flight computer, and Iridium uplink) are still functioning. A helicopter recovery is being considered for tonight.
Sunday, Dec 14, 00:00
Testing of the payload continues at Williams Field, after successfully moving from McMurdo Station two days ago. Launch is possible within 24 hours.