Electron "It's Business Time" Launch this weekend - Irvine 01 Amateur Payload

The launch window for the next Electron launch “It’s Business Time” opens this weekend on the 11th of November.
Onboard are a range of small sats, including the ‘Irvine 01’ cubesat, which has a 9.6k FSK downlink on 437.8 MHz.

There’s also Fleet-Space’s ‘Proxima 1/2’ sats, which were developed in my hometown of Adelaide, South Australia. These are commercial satellites, and from analysis of licensing of Fleet Space’s ground station, I expect them to have a down-link on 400.625 MHz. I don’t expect these to be added to the SatNOGS db due to their commercial nature. Given my close proximity to their ground station, I’ll be best placed to investigate the downlink from these sats.

Unfortunately I have’t yet seen a preliminary TLE for this launch. Hopefully something becomes available closer to the launch date (though that’s not far off!). Also, given Rocketlab’s history of repeated launch holds and delays, any TLEs will have to be treated with caution!

Mark VK5QI

Irvine-01 Info: https://space.skyrocket.de/doc_sdat/irvine-01.htm
Irvine-01 Frequency Coordination: http://www.amsatuk.me.uk/iaru/finished_detail.php?serialnum=504
FleetSpace Ground Station: https://web.acma.gov.au/rrl//site_search.site_lookup?pSITE_ID=10010120


Through Scott VE7TIL I got an ECEF state vector from the Irvine communications team. This state vector yields this TLE:

1 70001U 18599A 18315.16151858 .00000000 00000-0 00000-0 0 06
2 70001 85.1214 90.1577 0000000 268.3772 134.4415 15.20781546 06

This assumes an on time launch at 2018-11-11T03:00:00.

The IRVINE01 release is planned for 52m35s after launch. Solar panel deploy is planned 35m10s after release, antenna deploy 45m36s after release and the radio is activated 91m after release.

They report that IRVINE01 will transmit “IRV1” as Morse code about every 41 seconds. Call sign is WI2XPH.

The IRVINE01 communications team will start tracking only 14 hours after launch, while first pass over SatNOGS stations with the radio active occurs over Australia, about 3h10m after launch. Stations in the US and Europe will have visibility later.


How do make this TLE load up nicely in gpredict? It won’t seem to accept it in a file, i.e. like:

1 70001U 18599A 18315.16151858 .00000000 00000-0 00000-0 0 06
2 70001 85.1214 90.1577 0000000 268.3772 134.4415 15.20781546 06

Also, what happens if the launch is delayed (as is likely, given what happened with the last Rocketlab launch)? How would we generate an appropriate TLE if we know the new launch time?

The problem is probably due to the eccentricity being zero. This is due to my code having trouble converging for orbits with small eccentricities.

Does this TLE work with gpredict?

1 70002U 18599A 18315.16151858 .00000000 00000-0 00000-0 0 07
2 70002 85.1205 90.1568 0012705 292.5520 107.9249 15.20792276 04

This TLE was made by having GMAT propagate the orbit for 12000 seconds and then using the J2000 XYZ positions to fit an orbit to them. This approach is a bit elaborate, but tools from my sattools repository are tried and tested.

As for a delayed launch, you can use launchtle tool from sattools. A git clone and make launchtle should work without having to install all the sattools dependencies. This tool takes an input TLE and launchtime and then corrects the epoch of the TLE for the new launch time, and adjusts the right ascension of the ascending node for how much it would have changed between the old and new launch time.

You’d use it like this: launchtle -c irvine.txt -i 70002 -t 2018-11-11T03:00:00 -T 2018-11-11T05:00:00 -I 70003 to use the 70002 TLE in irvine.txt, which has a 2018-11-11T03:00:00 launch time, to correct it for a new launch time at 2018-11-11T05:00:00 and store it with a new identifier (70003 in this case).

1 70002U 18599A   18315.16151858  .00000000  00000-0  00000-0 0    07
2 70002  85.1205  90.1568 0012705 292.5520 107.9249 15.20792276    04

This works fine for me (I’ve also fixed some missing spaces).
I’ve also added it in network and scheduled a couple of observations.

Thanks @cgbsat!

PS It seems that the problem with the spaces is coming from using “quote” instead of the “preformatted text” which is the “</>” button.

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Ah, good point. Should’ve checked that.

As there are changes in launch time, we are going to use different TLE by generating them with @cgbsat way described above.

For now launch has been moved not earlier than 3:50 UTC… still waiting before adding new TLE for other announcements of changed launch time.

After adding the new TLE, I’ll remove and reschedule the already scheduled observations as they will not have any meaning with such a change.

The first observations will use these TLE:

1 70004U 14900A   18315.19803478  .00000000  00000-0  00000-0 0    06
2 70004  85.1205 103.3386 0012705 292.5520 107.9249 15.20792276    01

This launch was quite on time, nevertheless I re-implemented launchtle in python (as a small exercise to get used to TLEs/orbital calculations), see this jupyter notebook TLE_delayed_launch.ipynb.


Some updates on this:

The launch and deployment was successful. We have scheduled several observations, unfortunately the signal, if the cubesat transmits continuously, is very weak.

There are some reports on twitter that have seen the satellite and we have only 3 good observations out of 70 that managed to capture it. Two of them were from @csete’s stations which don’t use gr-satnogs scripts and one from @DL4PD’s station that uses gr-satnogs scripts.

I have scheduled a couple more observations (with >30 degrees max elevation) for the next hours.