ISS CubeSat Deployment NRCSD#27 (Voyager Space/Nanoracks) - ELaNa 51 - 2024-04-18 11:26 UTC

From this launch to ISS: SpaceX F9 : ISS CRS-30 ELaNa 51 : CCSFS SLC-40 : 2024-03-21 20:54 UTC

We have these deployments from ISS by Voyager Space Exploration Systems (Formerly Nanoracks):

Deployment 1, SNoOPI (6U) & BurstCube (6U): 7:26am ET (11:26 GMT)
Deployment 2, HyTI (6U): 7:36am ET (11:36 GMT)

3rd Deployment, Killick-1 (2U), QMSat (2U), VIOLET (2U): 1:55pm ET (17:55 GMT)
4th Deployment, Big Red Sat-1 (1U): 2:05pm ET (18:05 GMT)


Preliminary TLE

1 98908U          24109.14033565  .00025198  00000-0  44232-3 0  9990
2 98908  51.6383 253.1445 0004931  74.4072 274.2042 15.50359438449222
1 98909U          24109.14033565  .00025198  00000-0  44232-3 0  9991
2 98909  51.6383 253.1445 0004931  74.4072 274.2042 15.50359438449223
1 98910U          24109.14033565  .00025198  00000-0  44232-3 0  9993
2 98910  51.6383 253.1445 0004931  74.4072 274.2042 15.50359438449225

These gr-satellites yml files should work with KILLICK-1, QMSAT and VIOLET, please share your experience.

name: KILLICK-1
norad: 98908
  &tlm AX25 telemetry:
    telemetry: ax25
  19k2 G3RUH FSK downlink:
    frequency: 437.230e+6
    modulation: FSK
    baudrate: 19200
    framing: AX.25 G3RUH
    - *tlm

name: VIOLET
norad: 98910
  &tlm AX25 telemetry:
    telemetry: ax25
  9k6 BPSK AX.25 G3RUH downlink:
    frequency: 436.830e+6
    modulation: BPSK
    baudrate: 9600
    framing: AX.25 G3RUH
    - *tlm

name: QMSAT
norad: 98909
  &tlm AX25 telemetry:
    telemetry: ax25
  9k6 G3RUH FSK downlink:
    frequency: 437.370e+6
    modulation: FSK
    baudrate: 9600
    framing: AX.25 G3RUH
    - *tlm

We are ready and scheduled for the next batch of the satellites. For Violet for sure and maybe also for the two satellites from Canada (Killick-1 and QMSat), transmissions will be only over Canada (and part of the US). We know that Violet will transmit only after command from its team.

Until now we have received HyIT in UHF band, mainly over US, maybe it transmits only over US.


Hi …
gr_satellite is already installed on my station…
How can I add thoses new yml files?
Just create SatName.yml with those info or some other files muste be edited?



Place the newly created files in ${PYTHONPATH}/satellites/satyaml make sure you have the correct yml structure otherwise gr_satellites will not work.

Running gr_satellites --list_satellites is a nice way to check if you newly created files are ok.

The files I created/shared will become part of the gr_satellites repository when they are checked and working.
That will also be the moment to correct name and NoradID will be in there.


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Many thanks for reply…
Correct permission, but didn’t add the new QMSat for me(?)


I also include EIRSAT-1.yml from github distro, and not available on checking cmd.

Could is or other control file…(??)



Thank you for having VIOLET into the SatNOGS database after the deployment on April 18. VIOLET’s downlink is on 436.830 MHz.

We are trying to track CubeSat VIOLET to send an uplink command from our ground station,. We have been using Ham Radio Deluxe (HRD) to control our azimuth-elevation rotator. We will check how to put the TLEs into HRD.

To check our work, I was going to compare the times of the passes of VIOLET and the passes of the ISS on SatNOGS 3044. I scheduled passes of VIOLET on SatNOGS 3044; this worked. I tried to schedule passes of the ISS, 25544, Mode U Imaging, 437.800 MHz, but the SatNOGS scheduler said no passes are available.

Are no ISS passes available because I already filled SatNOGS 3044 with VIOLET and there is no room to schedule the ISS?

Are no passes available because VIOLET and the ISS already have significantly different TLEs? This seems unlikely to me.

Best regards,

Brent Petersen
Co-principal investigator CubeSat VIOLET
VIOLET’s radio page: VIOLET's Radio | CubeSat NB | NBCC | UdeM | UNB
SatNOGS 2685, available to everyone
SatNOGS 3044, in testing


This is exactly the reason, as we still using previous ISS TLE set and its orbit hasn’t changed a lot the passes are overlapping so you can schedule one of them.

For VIOLET, may I have the Service type changed from Amateur to unknown at
VIOLET transmitters?

The reason for this request is motivated by the discussion regarding VIOLET’s Service type.

At this time VIOLET is intended for scientific data download.

SatNOGS community:

This weekend, our Earth station uplink VHF Yagi is pointed at zenith; it has a 52 degree 3 dB beamwidth, 26 degrees on each side of zenith. We send a unique encrypted uplink packet every 6 seconds. Our downlink (436.830 MHz) is close to the third harmonic of our uplink (145.910 MHz). At Observation #9424548 one can see the transmissions, every 6 seconds. VIOLET’s software was programmed to wait an intentional 0.5 seconds before beginning a transmission on the downlink. The current TLE was fetched 8 days ago and still is the TLE of the ISS. A day after deployment I heard that VIOLET was around 4 minutes behind the ISS. It has been 9 days since deployment and I would guess that VIOLET is 36 minutes behind the ISS. I have no experience in estimating TLEs. My point is that the observation linked above is less than 7 minutes in duration. If VIOLET answered, it seems like it would not appear in that observation.

We are considering a five ways to determine if VIOLET is transmitting.

  1. Our Earth station uses GNU Radio (GR) in the receiver with a LimeSDRmini. We are not confident in the ability of the computer and GR code to decode a packet from space where the packet would have a low signal-to-noise (SNR) ratio. We have less experience than the SatNOGS community at decoding weak signals.
  2. We are considering setting up another computer with GR that just records the sampled spectrum and allows us to see it, even though this will generate gigabytes of data. The students who are more familiar with GR are not around at this time. We are tempted to ask the CSA for their spectrum recording GR code. We have an unused Ettus USRP B205mini and a LimeSDR.
  3. To use SatNOGS, we could wait until VIOLET’s TLE gets updated, but if it never transmits, I think this might take a while.
  4. To use SATNOGS, we scheduled a variety of observations, on SatNOGS 3044, under testing of other satellites with a downlink frequency close to ours, hoping to capture VIOLET’s signal.
  5. To use SatNOGS, I also read about How to bodge an immediate observation in for testing purposes

Do you have any suggestions about which of these to pursue or do you have other suggestions?

Best regards,
Brent Petersen
Co-principal investigator CubeSat VIOLET

Greetings! Do I understand correctly that Violet will absolutely NOT transmit any downlink until / unless it receives an uplink command from your ground station?

Or, is there any fallback or ‘safe mode’ where it will beacon world-wide?

On the subject of tracking / TLE… were any other objects deployed at the same time as Violet? If not, do we know what other object was deployed NEAREST to Violet’s release? It’s often helpful to use an object that HAS been located to at least get in the neighborhood of another object that we do not have confirmed communications with.

Finally, you may be aware that in the past, Project Teams in a similar situation have actually posted their UPLINK command details (freq, modulation, payload) and requested that anyone & everyone try to see if by some chance they can get a command to a lost satellite. I know that sounds drastic, but Teams who unfortunately find themselves in these situations have nothing to lose after exhausting all their other options.

Best of luck!

-Scott, K4KDR

We have TLE for all the seven satellites deployed from ISS in

1 59559U 98067WJ  24118.67229346  .00074456  00000-0  11705-2 0  9990
2 59559  51.6366 205.7845 0004258  40.0261 320.1042 15.52940464  1479
1 59560U 98067WK  24118.54136723  .00126062  00000-0  19030-2 0  9994
2 59560  51.6362 206.4104 0006432  49.8498 310.3055 15.53797558  1377
1 59561U 98067WL  24118.93339841  .00046546  00000-0  76369-3 0  9991
2 59561  51.6371 204.5280 0002594  71.8346 288.2926 15.51959089  1483
1 59562U 98067WM  24118.54466293  .00080657  00000-0  12740-2 0  9994
2 59562  51.6367 206.4313 0002559  92.8411 267.2872 15.52779284  1434
1 59563U 98067WN  24118.93187617  .00082073  00000-0  13062-2 0  9990
2 59563  51.6368 204.5191 0002970 100.1548 259.9777 15.52560953  1499
1 59596U 98067WP  24118.67131605  .00089298  00000-0  13832-2 0  9994
2 59596  51.6366 205.7781 0004433  38.6996 321.4312 15.53268540  1486
1 59597U 98067WQ  24118.67129169  .00089336  00000-0  13830-2 0  9998
2 59597  51.6371 205.7781 0004461  38.5339 321.5969 15.53283886  1450

I’ll add them later today in DB so we can have more accurate tracking and maybe identify the objects.

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Here is a more or less random assignment of the above TLE sets to the satellites, for now it is just for following, no identification as we don’t have any receptions. I tried to figure out the TLE by checking the order of the satellites comparing it with the deployment order and the perigee and apogee described by the TLE sets since started to track them (see the image below). As there are a couple of changes in TLE which give different order the last days and different apogees/perigees this method is not accurate, so for now we follow for:

SNoOPI (6U): OBJECT WL(59561)
BurstCube (6U): OBJECT WN(59563)
HyTI (6U): OBJECT WM(59562)
Killick-1 (2U): OBJECT WJ(59559)
QMSat (2U): OBJECT WP(59596)
Big Red Sat-1 (1U): OBJECT WK(59560)

Here is the diagram for perigee and apogee based on @cgbsat script for checking tle swapping:

PS It seems has skipped the OBJECT WO, not sure why but this could change the opinion above that all these objects are from this launch.

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My suggestion would be to get the latest TLE sets from this launch and during the whole pass of all of them (~20min), point to the highest elevation of the pass and transmit continuously the command for downlink. At the same time schedule SatNOGS stations near your location to track VIOLET, if VIOLET works fine, one of these objects will respond and will give us a signal curve to work on and try to identify it or limit the possible objects that the satellite could be.


Observation #9444952

It seems it work !!! Let see the following receptions.
Congrats !

I don’t think this is a valid frame, there is no AX.25 information present and based in the transmitter definition it should be.

For VIOLET, we transmit every 6 to 7 seconds on our VHF uplink, 145.910 MHz, whose third harmonic at 437.73 MHz is close to our UHF receive frequency, 436.830 MHz. The horizontal lines, every 6 seconds, in Observation #9444952 are from the third harmonic. VIOLET would add an intentional pause for about 0.5 second before it starts transmitting.

The software will never beacon. Also, the ITU licence does not allow it to transmit over countries other than Canada.

Best regards,

Brent Petersen