Mission: ICESat-2 Arctic Ocean #4
Priority: High
 
This new flight for 2019 flies out-and-back along a single ICESat-2 ground track, selected and timed so that our aircraft and the spacecraft fly the track as closely as possible in time, and also with the track drift-corrected according to winds measured from the aircraft. The particulars of the technique we will use to fly the track will depend on knowledge of ICESat-2’s pointing accuracy just prior to the time of this flight. Options include out-and-back along the same or parallel and offset lines, varying the altitude of one or both lines, or even a four-segment line. The general idea is to obtain a composite swath wide enough to capture any likely pointing offset of the spacecraft. See Appendix D for more details on the design of these flights.
 
A delayed start today with high winds that temporarily induced Bravo conditions (buddy system). However, a promising forecast for this abbreviated long-line mission led us to takeoff once the brief winds lifted. We took off just in time, as a polar bear was sighted on-base shortly after we took off and base personnel had to shelter in place for an hour or so. After an uneventful transit we again arrived on-station for a shortened mission at 3,500 ft AGL, having missed ascending ICESat-2 RGT 0371, which crossed the start of our line at (13:28 UTC), whereas we got there at 14:06 UTC (38 minutes late). Winds were again mostly parallel to the line, but we drift-corrected regardless. We broke out of overcast conditions just before the start of the line, which was reassuring. We lost the surface about a quarter of the way through the mission for less than 15 minutes, but then regained it for the remainder of the mission. We broke off prior to the last two waypoints (J and K) to ensure the opportunity to collect a ramp pass. Headwall SWIR experienced multiple issues yet again and never really operated correctly today, while NVIR worked fine. ATM estimates 90% altimetry data collection. We conducted a ramp pass at 1,600 ft AGL.
 
Attached images/files:

1. Map of today’s mission (John Sonntag / NASA)
2. KML of today’s mission (John Sonntag / NASA)
3. P-3 in Hangar 8 (Jeremy Harbeck / NASA)
4. Flight Engineer Kurt Williams monitoring fueling following the brief blow (Jeremy Harbeck / NASA)
5. One of today’s few leads (Jeremy Harbeck / NASA)
6. Eye-shaped leads around a small floe (Jeremy Harbeck / NASA)
7. Subsun over sea ice, formed by atmospherically suspended ice crystals (Jeremy Harbeck / NASA)