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SpaceX Falcon-9 second stage

Page: Sats.Falcon9 - Last Modified : Fri, 26 Mar 21

S-band downlink signal spectrum

S-band downlink parameters

Frequency:2232.5 MHz + 2272.5 MHz
Modulation:3571400Bd GMSK (RC 0.12 shaped)
Framing:10232 bit CCSDS frames
Error correction:5x interleaved RS(255,239), duobinary
Scrambling:standard CCSDS scrambler

Frame format

Usual CCSDS frame format is not used, instead custom framing protocol is employed:

Frame starts with 32 bit header:

11100000CCCCCCCCCCCCCPPPPPPPPPPP
ID/FMT13bit frame counter11bit packet start offset

When packet start is 2047, previous packet continues and no new packet starts in this frame. Following header, there is 1191 byte long data area.

Packet format

All packets start with common 2 byte header:

11 LLLLLLLLLLLL
  Length in bytes -2

After packet header there is source and format ID which is 8 bytes long. This uniquely identifies data source, instrument and data format. At the end of each packet is CRC16 error check code.
If the first byte of ID is 0x01, packet contains variable length frames and there is extra 3 byte subheader after the ID: First byte is usually 0x08 or 0x02 and two following bytes contain length of data field.
Then 8 bytes of timestamp follows. Timestamp format is 64 bit number of nanoseconds since GPS time epoch (Jan. 6th 1980).


The juicy video stuff [ID: 01123201042E1403]

Drop the first 25 bytes of the packet and CRC at the end to get standard 188 byte transport stream. TS also contains KLVA metadata (timecode).

Here are all the decoded video streams in TS format, in original quality:

TimestampReceived byDownload linkContents
2021-01-20 13:24:50UHF-Satcomfalcon9_20210120_132450.ts (315kB)LOX tank
2021-01-20 14:56:48UHF-Satcomfalcon9_20210120_145648.ts (7808kB)LOX tank, Engine cams, Earth views
2021-03-04 11:27:58USA-Satcomfalcon9_20210304_112758.ts (1316kB)Starlink release cam, black space
2021-03-14 10:19:23UHF-Satcomfalcon9_20210314_101923.ts (8607kB)LOX tank, Engine cams, Starlinks
2021-03-14 11:52:09UHF-Satcomfalcon9_20210314_115209.ts (11621kB)LOX tank, Engine cams

(This list will be updated in the future, as new signals are decoded)


Combined video from multiple stations for 1st orbit 2021-03-14

Thanks to the recordings and frames from multiple stations (@uhf_satcom,@OK9UWU and @HA6NAB_Tomi),
I was able to combine the data and decode the best video yet, more than 3 minutes long. Enjoy!

Download links:


Combined video from multiple stations for 1st orbit 2021-03-24

Frame files and recordings by: @uhf_satcom @OK9UWU @HA6NAB_Tomi @eb3frn
Download links:

Combined video from multiple stations for 2nd orbit 2021-03-24

Frame files and recordings by: @uhf_satcom @HA6NAB_Tomi @eb3frn
Download links:


List of all IDs

ID bytes         Freq
---------------- ------
0012220100000C08 2232.5
0012220100020C08 2232.5
0012220100030C08 2232.5
00122201000C0C08 2232.5
00122201000D0C09 2272.5
00122201000F0C08 2232.5
0012220100100C08 2232.5
0012220100140C08 2232.5
0012220100150C08 2232.5
0012220100190C08 2232.5
0112220100620303 2232.5 VARLEN sfc1a ASCII debug log
0012220100690C08 2232.5
0012220100FD0C08 2232.5
0012220101080C08 2232.5
0012220103EE0C08 2232.5
0112220104240603 2232.5 VARLEN 
0012270100000102 2232.5 (no timestamp in hdr)
0012270100010102 2232.5 (no timestamp in hdr)
0012320100010C08 2232.5
0112320100620303 2232.5 VARLEN stmm1a ASCII debug log
0012320100AB0C08 2232.5
0012320100B40C08 2232.5
0012320100BF0C08 2232.5
00123201010A0C08 2232.5
00123201010D0C08 2232.5
0112320107D60504 2232.5 VARLEN 
0112320107D90504 2232.5 VARLEN 
0112320107DD0504 2232.5 VARLEN 
001232010BBA0C08 2232.5
0012420100140C08 2232.5
0012420100FD0C08 2232.5
0012420101080C08 2232.5
0112420104240603 2232.5 VARLEN 
0012470100000102 2232.5 (no timestamp in hdr)
0012470100010102 2232.5 (no timestamp in hdr)
00124C0100650108 2232.5
0112520100620303 2232.5 VARLEN stmm1b ASCII debug log
00125201010A0C08 2232.5
00125201010D0C08 2232.5
0112520107D70504 2232.5 VARLEN 
0112520107DA0504 2232.5 VARLEN 
0112520107E10504 2232.5 VARLEN 
0112520107E40504 2232.5 VARLEN 
0012620100140C08 2232.5
0012620100E60C09 2232.5
0012620100FD0C08 2232.5
0012620101080C08 2232.5
0112620104240603 2232.5 VARLEN 
0012670100000102 2232.5 (no timestamp in hdr)
0012670100010102 2232.5 (no timestamp in hdr)
0012720100010C08 2232.5
0112720100620303 2232.5 VARLEN stmm1c ASCII debug log
0012720100B90C08 2232.5
0012720100C40C08 2232.5
00127201010A0C08 2232.5
0112720107DF0504 2232.5 VARLEN 
001272010BBA0C08 2232.5
0112FA0800320303 2232.5 VARLEN GPS ASCII debug log
0012FA08D0420108 2232.5 GPS time
0012FA08D0440108 2232.5 GPS raw measurements
0012FA08D0470108 2232.5
0012FA08D0480108 2232.5 GPS positions
0012FA08D0490108 2232.5
0112FB8000020504 2232.5 VARLEN 
0112FD8000030504 2232.5 VARLEN 
0112FF8000040504 2232.5 VARLEN
0012220100110C09 2272.5
0012220100160C09 2272.5
00122201001B0C09 2272.5
01123201042E1403 2272.5 VARLEN The juicy stuff (Video)
0112320107D80504 2272.5 VARLEN 
0112320107DE0504 2272.5 VARLEN 
0112320107E20504 2272.5 VARLEN 
00124201000D0C09 2272.5
0012420100110C09 2272.5
0012420100160C09 2272.5
00124201001B0C09 2272.5
0012420100640C08 2272.5
0012420100650C08 2272.5
00124D0100650108 2272.5
0112520107D50504 2272.5 VARLEN 
0112520107DA0504 2272.5 VARLEN 
0112520107DC0504 2272.5 VARLEN 
00126201000D0C09 2272.5
0012620100110C09 2272.5
0012620100160C09 2272.5
00126201001B0C09 2272.5
0012620100640C08 2272.5
0012620100650C08 2272.5
0012620100690C08 2272.5
00126201006A0C08 2272.5
0012620103EE0C08 2272.5
00127201010D0C08 2272.5
0112720107DF0504 2272.5 VARLEN 
0112720107E30504 2272.5 VARLEN 
0112720107E50504 2272.5 VARLEN 
0117FE0800320303 2272.5 VARLEN GPS ASCII debug log 
0017FE08D0420108 2272.5
0017FE08D0440108 2272.5
0017FE08D0480108 2272.5

(this table will be updated in the future as various data types are analyzed)


GPS debug log example [ID: 0112FA0800320303]

To get clean text, again drop the first 25 bytes of the packet and CRC at the end.

1299487058287683082> 1 synced @ 505 ms, 38.2 dBHz, 24295 Hz, -0.36 code err
1299487058588236857> 21 synced @ 1470 ms, 21.6 dBHz, 9358 Hz, -0.41 code err
1299487058670234273> 21 PLL stress
1299487058979751972> Tracking! PRN:6
1299487058983987447> Found 6 over 120.0 kHz in 402 ms, CN0:37.3 dB
1299487059077897517> Running hot start for sid:7 TOW_ms 376658994!
1299487059078061407> Tracking! PRN:7
1299487059082010557> Found 7 over 1.0 kHz in 15 ms, CN0:37.0 dB
1299487059082966346> Channel 5, SID 7 got TOW @ 01299487060609766103> SPI Usage: 34%
1299487060611405705> Track: [19s 01e 14s 30s 15s 07e  .  . 05s  . 28s  . 13s 17s  .  . | 12e 18e 08e 05c 24s 10s 23s 21e 20s 06f  .  .  .  .  .  . ]
1299487060611612626>    dB: [46  37  47  46  45  41   .  . 43   . 46   . 44  50   .  . | 41  49  34  38  42  43  39  36  43  20   .  .  .  .  .  . ]
1299487060626545985> Running hot start for sid:21 TOW_ms 376660543!
1299487060626745860> Tracking! PRN:21
1299487060631387657> Found 21 over 1.0 kHz in 16 ms, CN0:37.3 dB
1299487060632190103> Channel 6, SID 21 got TOW @ 0: 376660543
1299487061610698345> 6 no sync, dropping
1299487061803684047> solution x/y/z: 4271040.9 1162233.8 4864322.9 PDOP=1.3 n_sats=12
1299487061803769213> solution tow:376661.41299487063577734024> Tracking! PRN:3
1299487063582517717> Found 3 over 80.5 kHz in 262 ms, CN0:37.8 dB
1299487063611549247> 21 low CN0 too long, dropping (@ 125123230348000000.000)
1299487063949911671> Running hot start for sid:21 TOW_ms 376663866!

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