Hi William, There is a good discussion of the ranging in Cyrus's paper about our differential-drag scheme: https://arxiv.org/pdf/1509.03270v1.pdf This is far outside my area of expertise, but atmospheric variation as you propose certainly seems likely. Another un-modelled factor is that once the satellite is deep enough into the atmosphere that it cannot maintain attitude control, it will start tumbling, which is very high-drag and will accelerate things quite quickly! Adam. On Wed, Oct 5, 2016 at 12:11 AM, William Stewart <William_Stewart_at_waters.com > wrote: > Hi Adam, > > Thanks for sharing. How frequently is the UHF ranging data collected and > are you able to quantify how this compares with the radar data from > Space-Track? > > Both your data and that from Space-Track suggested that decay would occur > a few hours later. > > There has been an increase in auroral reports recently (which we tend to > get around the time of the equinox - however recent activity appears to > have been higher and more prolonged than normal). Can the "early" decay be > attributed to the "puffing up" of the atmosphere that occurs when solar > activity is high (not sure how the decay models take account of this ... is > it an assumed "fixed" value or one than varies based on current data)? > > > Hope this question is "on topic". > > Best regards > > William > > =========================================================== The > information in this email is confidential, and is intended solely for the > addressee(s). Access to this email by anyone else is unauthorized and > therefore prohibited. If you are not the intended recipient you are > notified that disclosing, copying, distributing or taking any action in > reliance on the contents of this information is strictly prohibited and may > be unlawful. =========================================================== > > _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Wed Oct 05 2016 - 19:55:59 UTC
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