In several posts to the list, Kevin Fetter has provided video showing bright flashes from AEHF 1, recorded on Aug 29 UTC. My analysis of the times, suggests a period of variation of about 301 s, which may indicate that the spacecraft is rotating at 0.1 RPM. I judged the frame of peak brightness of each recorded flash as follows: Aug 29 UTC 04:50:31.245 05:10:35.135 05:25:38.294 05:40:42.321 The space between the first and second time is ~20 min, but the space between subsequent times is ~15 min, which suggests there were fainter flashes at ~5 min intervals between the above times. In response to my query off list, Kevin seemed to recall noticing fainter flashes lasting a fair number of seconds, followed by brighter flashes of much shorter duration. Numbering the above flashes as 0, 4, 7, 10, and fitting a linear equation to the elapsed time since flash 0, yields a coefficient of determination of almost exactly unity, indicating a strong correlation; with slope of 301.1 s, and intercept of -0.26 s. Kevin, if you can find and report other flash times on your video, regardless of brightness, the information would be useful in testing the hypothesis of a ~301 s period. If it is confirmed, then the spacecraft may be rotating at 0.1 RPM or 0.2 RPM depending on symmetry. Rotation of AEHF at 0.1 RPM would not be unexpected, since it is built on an A2100 bus, and as part of some research last summer, I found evidence (in several launch press kits) that satellites based on the A2100 bus rotate at 0.1 RPM at deployment. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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