ISS CubeSat Deployment (2020-02-17): Phoenix, QARMAN, RadSat-U, Argus-2, AZTECHSAT-1

sarah_srogers · February 22, 2020, 3:27am

I just got a notification from T.S. Kelso that the satellites are now all on Celestrack! These can be found here, at the bottom of the list: https://celestrak.com/NORAD/elements/tle-new.txt
I’ve included them below for convenience

1998-067QZ              
1 45256U 98067QZ  20052.64799524  .00005438  00000-0  10401-3 0  9996
2 45256  51.6454 205.0862 0007426 286.1051  73.9120 15.49766047   386
1998-067RA              
1 45257U 98067RA  20052.64783822  .00004103  00000-0  80222-4 0  9998
2 45257  51.6506 205.0462 0012661 218.5462 141.4624 15.49824663   382
1998-067RB              
1 45258U 98067RB  20052.77678768  .00002742  00000-0  56311-4 0  9994
2 45258  51.6486 204.4335 0006150 357.8247   2.2596 15.49850210   374
1998-067RC              
1 45259U 98067RC  20052.38977371  .00386848  00000-0  62697-2 0  9998
2 45259  51.6447 206.3568 0020498 292.0461  67.8665 15.50647616   336
1998-067RD              
1 45260U 98067RD  20051.69921362  .02246026  00000-0  34712-1 0  9993
2 45260  51.6436 209.7990 0009749 310.9616 152.5509 15.49926336   246
1998-067RE              
1 45261U 98067RE  20050.47222222 -.00000460  00000-0  00000+0 0  9998
2 45261  51.6410 215.8687 0007855 275.8567 177.5811 15.50023155    40
1998-067RG              
1 45263U 98067RG  20052.84144132  .00021581  00000-0  38755-3 0  9994
2 45263  51.6438 204.1271 0007343 275.8091  84.1933 15.49796020   444
1998-067RH              
1 45264U 98067RH  20052.77709573  .00003346  00000-0  67291-4 0  9990
2 45264  51.6412 204.4504 0007484 297.3095  62.7131 15.49689443   406

sarah_srogers · February 22, 2020, 3:29am

based on the TLEs, this is where everything appears to be.

fredy · February 22, 2020, 7:28am

That’s totally fine for the stage we are, as we haven’t identified the satellites but try to follow TLE and check if the satellite signal matches.

sarah_srogers · February 22, 2020, 11:50am

Are the TLEs ever updated after they are posted? Or can we usually trust these for some time after they are released?

fredy · February 22, 2020, 11:56am

The TLEs are updated regularly and they are pretty accurate for at least 2-3 days for the satellites at that altitude.

sarah_srogers · February 22, 2020, 12:07pm

Ok. We just tracked the cubesat swarm using our ground station, but didn’t get anything on our frequency. It doesn’t look like other observations have picked up Phoenix’s beacon or QARMAN’s (unless I missed it). Given that, I I’m curious to know how it might be best to handle things from here. Should we just continue to cycle through the TLE list in the hope that we hear from our spacecraft?

slu_ssrl · February 22, 2020, 4:21pm

Since per these TLEs the swarm is not very phased out yet our approach will be to track the middle-most object. Since we cannot be certain that it is us yet, perhaps it’ll be closer than rotating or tracking the object leading or lagging the pack.

fredy · February 22, 2020, 4:33pm

That is the best option, at least for now that objects are close to each other according to TLE.

cgbsat · February 22, 2020, 4:50pm

There are quite a few Argus-02 observations that you have vetting as good. Please be aware that AZTECHSAT-1 is transmitting at a frequency only 10kHz higher than Argus-02, so all Argus-02 waterfalls will have signals from AZTECHSAT-1 on the right hand side. Given that these are modulated with 9k6 GFSK, those signals are wide and might trick you in believing that you see Argus-02. Be cautious with vetting these observations.

luckyjunknowitz · February 22, 2020, 5:56pm

In case anyone wants a slightly different perspective on things, feel free to use the Celestrak 3D viewer that T.S. has provided.

Furthermore, you can “hack the URL” submission to whittle down things to what you want.

For example, this URL, which T.S. has linked on his main page loads (and propagates… WebAssembly FTW!!)) the WHOLE catalog all at once (kind of braggin’ rights to be able to do that in a web context actually ):
https://celestrak.com/cesium/orbit-viz.php?tle=/pub/TLE/catalog.txt&satcat=/pub/satcat.txt&referenceFrame=1
which I admit is a little overwhelming graphically, and will take some time to turn on/off the things you might want to see.

Can we pare this down a bit ?
Sure. Pay attention to the “tle=/pub/TLE/catalog.txt” in the URL. You can change that, but you don’t have a view into the celestrak.com …/pub folder to know which “.txt” files to reference
What to do ?

Well, we know there are other direct links on the Celestrak site, so let’s use the ones that we DO know how to reference… like the one @sarah_srogers linked above:
https://celestrak.com/NORAD/elements/tle-new.txt

and build the full URL appropriatey, resulting in:

https://celestrak.com/cesium/orbit-viz.php?tle=https://celestrak.com/NORAD/elements/tle-new.txt

which is a MUCH smaller number of items to display, and if you use the menu system on the top left, turn on the catalog view, and make sure to scroll to the 3rd page of the list (it’s still a lengthy file) you can more easily highlight the items of the swarm…

Now, I don’t know if this URL “hack” (it’s not a real hack folks, just a proper use of a REST interface) works with .txt files located on other domains that aren’t Celestrak.com, and since I don’t have a handy short-list of TLE’s I care about located on a public URL at the moment, I cannot test the full extent of what’s possible, but if this 3D viewer approach for just the curated list of birds you care about works for you, I can chat with T.S. about making this kind of custom use more “formal”

but yeah, it works, and you get a pretty neat vantage on the spread of the swarm at the moment. As the new-tle.txt file gets updated (every few days) you can simply refresh this URL to watch the swarm drift apart.

slu_ssrl · February 22, 2020, 8:32pm

We are aware and have been in contact with the AzTechSat-1 team. We are keeping a list of passes that also ccaptured AzTechSat-1 (or exclusively them!)

fredy · February 23, 2020, 10:51am

Spacetrack has identified all 9 satellites from the deployment, however I have some concerns about this identification. For example we consistently receive QARMAN and we can see at the image bellow from ikhnos that if we follow identification of spacetrack (red line) it doesn’t follow the observed signal.

Some independent sources like PA0DLO also disagree.

One big notice is that 3 of 9 TLEs are less than 1 day old, 4 of 9 are 1+ dayss old, 1 of 9 is 2+ days old and 1 of 9 is 3+ days old (and it happens this 1 to be QARMAN). So, I leave a big question-mark on the identification and I’ll wait for newer TLEs to draw some safe conclusions.

s59mz · February 23, 2020, 6:25pm

Here’s one of my observation that I’m not sure if it is Argus-2 or Aztechsat-1.
https://network.satnogs.org/observations/1742995/
Can someone check, please.

slu_ssrl · February 23, 2020, 11:04pm

That’d be AzTechSat-1. For the record, AzTechSat-1 beacons every 60s, and Argus-02 goes back and forth between 45s bursts of telemetry and an ax.25 beacon every 30s.

fredy · February 24, 2020, 2:42am

From the latest TLE published from spacetrack:

QARMAN: OBJECT QZ(45256), OBJECT RC(45259), OBJECT RG(45263)(selected to follow in Network), OBJECT RH(45264)
From Observation 1740252 - OBJECT RG with red:

AZTECHSAT-1: OBJECT RD(45260), OBJECT RE(45261)(selected to follow in Network), OBJECT RF(45262)
From Observation 1741194 - OBJECT RE with red:

Finally changed Phoenix to follow OBJECT RD (45260)

fredy · February 26, 2020, 2:00am

AZTECHSAT-1: is still between OBJECT RD(45260)(less possible), OBJECT RE(45261)(still selected to follow in Network), OBJECT RF(45262).

QARMAN: OBJECT QZ(45256)(less possible), OBJECT RC(45259), OBJECT RG(45263)(still selected to follow in Network)

sarah_srogers · February 26, 2020, 4:28am

We have not heard from Phoenix using ID 45260, but we received an email from an operator who did hear something from the spacecraft while tracking 45260 this morning. That’s one packet heard since last Wednesday, so I can’t confirm this, but I’ll let you know if we receive anything else.

slu_ssrl · February 26, 2020, 4:22pm

We believe Argus-02 may actually be 45257.

Moreover, the HARP team believes they are object 45256.

fredy · February 26, 2020, 6:21pm

We track 45256 for HARP in Network and I’ve changed Argus-02 to follow 45257.
Any logic behind these selected NORAD IDs? Like deployment order or any reception?

I’ve also changed RadSat-U to follow 45262 following the suggestion from Observation 1740922: RadSat-U (99830).

slu_ssrl · February 26, 2020, 7:24pm

Out hypothesis is that the smaller spacecraft (i.e. Argus-02) may have drifted towards the front of the group due to the interaction of the differences in density and drag due to size. We may be wrong, but again it is a hypothesis.

This is supported by the fact that every time we (think we) have seen Argus-02 on fixed antennas (i.e. station 6 Apohamon) it seems to be in the beginning of passes, rather than in the middle or at the end. This could be explained by Argus-02 already having passed the highest point of the pass by the time the pass start to be recorded.

While the group is still close together and any satellite can be tracked to hear another, we believe our argument is still feasible.

Some passes that indicate such behavior are:
https://network.satnogs.org/observations/1720958/
https://network.satnogs.org/observations/1721025/
https://network.satnogs.org/observations/1732237/