EU:s Sentinel 5 Precursor satellite is intended to measure greenhouse gases in city-sized blocks to help tell how air pollution changes day-to-day. It wa launched by a Rockot launcher from the Plesetsk cosmodrame at 0927:30 UT (some sources say 0927:44 UT) on 13 October 2017. Here is the flight sequence as far as I can make it out:
Signals were picked up by me in Stockholm (actually in Sollentuna, a suburb) on about 1020.600 MHz at the following times:
0931.12-0935.00 UT: Clear but weak signal,
momentarily with multiple sub-carriers
1100.35-1110.50 UT: Very strong signal with multiple sub-carriers. Closest approach to Stockholm was at about 1107 UT.
1239.46-1246.50 UT: Carrier only
So, interestingly, the first signals appeared shortly after shroud separation but before Briz-KM ignition. Perhaps that is when the antennas on the Briz-KM were exposed and signals could be picked up. When I lost the signal at 0935 UT the Briz-KM was still burning.
The next pass over Europe was almost overhead in Stockholm and strong signals were picked even though my fixed-azimuth helix (see description of antenna and receiving gear here ) was not pointing in an optimum direction. From the ground track below it appears that the Briz-KM may already have been placed in its "disposal orbit" at 415-768 km at the 1100 UT pass over Sweden.
Here are the spectrograms recorded by my receiving set up:
Overhead pass in Stockholm
Pass over the UK
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