Virgin Orbit LauncherOne - ELaNa 20 - 2021-01-17

Hi,
Polarcube is a 3U CubeSat by the Colorado Space Grant Consortium. For more info on the satellite you can see the NASA brief in the ELaNa 20 fact sheet.

Operations for the satellite will be done out of CU Boulder where we have a ground station but would love to hear beacons from around the world, particularly in the bus commissioning phases so I am reaching out here to see if we can get it integrated into the system for people to use.

Launch is currently projected some time in January 2021. It has been delayed many many times but I am hopeful it will finally be going to space.

A few important details about the beacons. The frequency/modulation/format is very nonstandard. We are at 401.365MHz. The radio was designed around a SPIRIT1 transceiver which is configured to do 2-FSK at 4800 baud with a +/-2.4kHz deviation. It uses an [0x88 0x88 0x88 0x88] sync to indicated start of packet followed by an length byte, payload and CRC. The length+payload is data whitened with the built in function of the SPIRIT1 which is a rather odd LSFR implementation described in the linked documentation.

I am working to create a Kaitai decoder for the beacons as well as to figure out what the best way to integrate the GNU radio blocks into the SatNOGs framework is. Right now we use a custom block from an OOT module to detect the sync, dewhiten the packet, and check the CRC. All of the FSK demod and filtering is done with standard blocks.

Any advice moving forward on this is appreciated.

Here is a link to the initial documentation.

Thanks

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We have an updated launch date of January 13th, 2021.

I have created an issue for added Polarcube to the database.

Can FSK4800 be decoded from the baseband audio recordings? Launch is very soon and I imagine it will take a bit to get new blocks integrated so would be useful to download audio to extract telemetry until the decoder is ready.

I have setup a SatNOGS system to start testing gnuradio block decoder:

Working on integrating in a block for decoding polarcube into gr-satnogs.

Kaitai Struct for downlink beacons still in progress.

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Thanks for the info and the issue, the PolarCube satellite and its transmitter is now added in DB.

I’m going to change the title so we can track the whole ELaNa 20 launch in this thread.

These are the satellites of this launch with their issues I’ve opened in order to add them also in DB:

PolarCube -https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/145 (closed)
MiTEE - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/147
CACTUS-1 - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/151
Q-PACE - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/148
RadFXSat-2 - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/150
EXOCUBE-2 - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/146
CAPE-3 - https://gitlab.com/librespacefoundation/satnogs-ops/-/issues/149

TechEdSat-7 and PICS 1 and 2 seems to transmit in frequencies that we don’t currently track.

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@dryerzinia do you know if there is any preliminary TLE set or details about the state vectors of this launch?

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Launch goes for Jan 17.

Launch is gonna be today… you can track the airplane in one of the links bellow:



Satellite have been added in DB and as soon as we have TLE set we are going to schedule them in Network.

@dryerzinia or anyone else, as soon as you have any TLE set or launch vectors, let us know here, so we start scheduling.

I will provide as soon as we are given them. Expecting them shortly after launch.

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@dryerzinia just in case… do you have any info about inclination and altitude?

Last I was updated, 500km x 500km orbit at 61-degree inclination. Believe that is still the case.

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@dryerzinia thanks for the info! And congratulations for your deployment!

Some first TLE from @cgbsat calculations:

1 79001U          21017.82222222  .00000000  00000-0  50000-4 0    02
2 79001  61.0000 134.0000 0000727   0.0000 160.0000 15.20776870    00

I’ve used them to schedule ~40-50 observations for each satellite for the first 8h. Have in mind that these TLE may not be accurate so avoid to schedule observation with them in the far future. Waiting for TLE set from the satellite teams for more accurate orbit.

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Finally got state vectors for our deployment:

Time at Payload Separation 6 [sec]
Name of Payload PolarCube
January 17, 2021 20:31:30.184

Deployment Position 6 ECI X [ft]
19299362.00
Deployment Position 6 ECI Y [ft]
6744400.50
Deployment Position 6 ECI Z [ft]
-9560183.00

Deployment 6 Velocity ECI X [ft/sec]
3963.72
Deployment 6 Velocity ECI Y [ft/sec]
15688.10
Deployment 6 Velocity ECI Z [ft/sec]
19038.39

Deployment 6 Position ECI X [m]
5882445.54
Deployment 6 Position ECI Y [m]
2055693.27
Deployment 6 Position ECI Z [m]
-2913943.78

Deployment 6 Velocity ECI X [m/sec]
1208.14
Deployment 6 Velocity ECI Y [m/sec]
4781.73
Deployment 6 Velocity ECI Z [m/sec]
5802.90

Deployment 6 Position ECEF X [ft]
11977781.31
Deployment 6 Position ECEF Y [ft]
16567590.85
Deployment 6 Position ECEF Z [ft]
-9560183.00

Deployment 6 Velocity ECEF X [ft/sec]
-4509.45
Deployment 6 Velocity ECEF Y [ft/sec]
14263.83
Deployment 6 Velocity ECEF Z [ft/sec]
19038.39

Deployment 6 Position ECEF X [m]
3650827.74
Deployment 6 Position ECEF Y [m]
5049801.69
Deployment 6 Position ECEF Z [m]
-2913943.78

Deployment 6 Velocity ECEF X [m/sec]
-1374.48
Deployment 6 Velocity ECEF Y [m/sec]
4347.62
Deployment 6 Velocity ECEF Z [m/sec]
5802.90

Apogee 6 [km]
514

Perigee 6 [km]
500

Inclination 6 [deg]
60.69

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MiTEE is alive: https://network.satnogs.org/observations/3488984/

Decoding using direwolf:

Dire Wolf version 1.5
Includes optional support for:  gpsd hamlib
Setting such a small audio statistics interval will produce inaccurate sample rate display.
ERROR - Could not open config file /home/tobias/direwolf.conf
Try using -c command line option for alternate location.
Audio input device for receive: stdin  (channel 0)
Audio out device for transmit: default  (channel 0)
Channel 0: 9600 baud, K9NG/G3RUH, +, 48000 sample rate x 2.
The ratio of audio samples per sec (48000) to data rate in baud (9600) is 5.0
Increasing the sample rate should improve decoder performance.
Note: PTT not configured for channel 0. (Ignore this if using VOX.)
Ready to accept AGW client application 0 on port 8000 ...
Ready to accept KISS TCP client application 0 on port 8001 ...

Audio input level is too high.  Reduce so most stations are around 50.
[0.5] WL9XJH>WL9XJH:Mi�<0x00>�<0x01><0x01><0x01><0x01><0x00>�JD<0x01><0x00><0x00>C<0x01><0x00><0x00><0x00><0x00><0x00><0x00>�A<0x01><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x12><0x05><0x00><0x00><0x12><0x05><0x00><0x00>ӟ<0x01><0x00>�t<0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00>�<0x02><0x00><0x00>�<0x02><0x00><0x00>Q<0x01><0x00><0x00>�<0x02><0x00><0x00>�y<0x00><0x00><0x00><0x00><0x00><0x00><0x05><0x00><0x00><0x00><0x03>�<0x01><0x01><0x00><0x00>(�<0x06><0x00>(�<0x06><0x00>WL9XJHWL9XJH<0x05><0x00><0x05><0x00><0x00><0x01><0x01><0x00><0x00>O<0x06><0x00><0x00>�<0x18><0x00>p<0x00><0x00><0x00><0x00>�T<0x01><0x00>�(L@�<0x01><0x04><0x00>�<0x04>'<0x1f><0x03><0x00><0x00><0x00><0x00><0x00><0x01><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x00><0x03><0x00>�<0x08><0xfe><0x07>\<0x05>i<0x05><0x04><0x00>o<0x00><0x7f><0x00>7<0x00>�<0x00>`<0x01><0x01><0x0d><0x02><0x00><0x00><0x00><0x00><0x00>�
------
U frame UI: p/f=0, No layer 3 protocol implemented., length = 271
 dest    WL9XJH  0 c/r=0 res=3 last=0
 source  WL9XJH  0 c/r=1 res=3 last=1
  000:  ae 98 72 b0 94 90 60 ae 98 72 b0 94 90 e1 03 f0  ..r...`..r......
  010:  4d 69 a0 00 f1 01 01 01 01 00 c9 4a 44 01 00 00  Mi.........JD...
  020:  43 01 00 00 00 00 00 00 bd 41 01 00 00 00 00 00  C........A......
  030:  00 00 00 00 00 00 00 00 00 00 12 05 00 00 12 05  ................
  040:  00 00 d3 9f 01 00 80 74 00 00 00 00 00 00 00 00  .......t........
  050:  00 00 00 00 a2 02 00 00 a2 02 00 00 51 01 00 00  ............Q...
  060:  a2 02 00 00 80 79 00 00 00 00 00 00 05 00 00 00  .....y..........
  070:  03 8e 01 01 00 00 28 ae 06 00 28 ae 06 00 57 4c  ......(...(...WL
  080:  39 58 4a 48 57 4c 39 58 4a 48 05 00 05 00 00 01  9XJHWL9XJH......
  090:  01 00 00 4f 06 00 00 ce 18 00 70 00 00 00 00 de  ...O......p.....
  0a0:  54 01 00 f6 28 4c 40 b1 01 04 00 9c 04 27 1f 03  T...(L@......'..
  0b0:  00 00 00 00 00 01 00 00 00 00 00 00 00 00 00 00  ................
  0c0:  00 00 00 00 00 00 00 03 00 e3 08 fe 07 5c 05 69  .............\.i
  0d0:  05 04 00 6f 00 7f 00 37 00 af 00 60 01 01 0d 02  ...o...7...`....
  0e0:  00 00 00 00 00 cc ff e1 ff d6 ff fc ff fa ff 0a  ................
  0f0:  00 85 fe 92 00 93 00 94 00 91 00 1b ff 1d 01 de  ................
  100:  fe ca 02 75 01 e2 00 42 fe 36 fe 27 01 14 71     ...u...B.6.'..q
------

End of file on stdin.  Exiting.

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Not sure if I just don’t know what I’m doing but getting a very different orbit using the state vectors than what I get with the above TLE.

Except from MiTEE and EXOCUBE-2(CP12) none of the rest satellites have been received.

Given that we have received satellites with this TLE set, either something is wrong with the data or the calculations. Unfortunately I’m not familiar and I can not help. :frowning:

I saw the transmitter frequency got changed to 401.35MHz, that was a typo in my first post. I double checked when I created the issue for the satellite it is at 401.365MHz.

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Hi all, Patrick Walton from the BYU PICs team here. I noticed we’re out of your typical frequencies, but we should have a beacon transmitting automatically every 30 seconds on the 903.65-903.95 MHz band (PIC-A) and the 903.25-903.55 MHz band (PIC-B). So if any of you want to try and listen for the beacon, please let us know.

Also, are there any other communities that we might reach out to that might be interested in helping us make first contact?

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Those frequencies are right in the middle of a 3G band (UTRA band 8) in Europe, Africa, and Australia. In fact, that frequency is right in the middle of an uplink to a Optus (phone provider) tower near my house.

How were you assigned those frequencies? They seem to be a terrible choice, and I’m surprised it would be legal transmit on them if you are not over North America at the time.

Certainly pretty much all stations outside of the US will have great troubles trying to receive anything on those bands due to interference from cell towers.

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