USA-179 - Orbital Adjustments in the First Half of 2007For the first five months of 2007, the pattern was a variation of what had been in seen in 2006. Major adjustments were interspersed with one ot two minor ones. Again, there were probably smaller tweaks in between but generally they would not be discernable with this particular measurement method. There was one departure from the norm during June when an adjustment was made in the opposite sense to normal- the mean motion was deliberately increased and the ground track shift was accelerated. There is no obvious reason for it - possibiliies are correction of an error in the previous adjustment (unlikely), or adjusting the phasing with the other satellites in the HEO constellation - 90025 and 90028. Whateber the reason, it is unlikely to surface. 90025's AFSATCOM transmitter had gone out of service a few months earlier and it is possible that something else aboard that satellite had failed at the same time, driving a need for USA-179 to interact more closely with 90028.
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