Thread by @ProfHughLewis

First up this morning is Anne Bennett from CCAR, now talking about identifying and assessing debris strikes in NASA spacecraft telemetry #orbitaldebris2019 #spacedebris

The work uses changes in spacecraft angular momentum. The spacecraft corrects for the torque resulting from an impact and the delta-H is detected and used to identify a strike

Need to filter out anything that is not a debris strike (slews, thruster firings) and any gradual changes in angular momentum

For a single spacecraft in GEO, the algorithm detects several impacts each day (up to 30 or 40 at most). Possible micrometeoroid impacts but delta-H is quite high for some. There are also some temporal patterns.

MMS data: 4 spacecraft in formation, 300 days in 2016. Known debris strike in this period but this single event is "overwhelmed" by other detections. Also some "mystery" repeated torques observed, probably mission related.

Detection methods do accurately identify momentum changes. Small detections may be noise but they repeat on yearly basis so some doubts remain. Algorithms permit any spacecraft to become an in-situ debris detector (depending on telemetry differences)