APSS-1 Launch on RocketLab Electron - 20th November 2020

I’ve been able to obtain some initial information on APSS-1:

Frequency: 435.1 MHz
Datamode: FM-mode
Modulation Type: GMSK
Protocol: AX-25 Space Packet Protocol
Encoding: ECSS Telemetry & Telecommand Packet Utilization Standard (PUS)

It’s worth noting that this frequency appears to be uncoordinated, and overlaps with FalconSat-1.


Added in DB with temporary NORAD ID 99769.

They had a coordination request but it was never coordinated or declined.


Approximate TLE for this launch, assuming launch at the start of the window (2020-11-16T01:44:00). Thanks to @vk5qi for providing info and helping create this.

1 99769U          20321.07569444  .00000000  00000-0  50000-4 0    09
2 99769  97.3000  85.5000 0001454   0.0000 216.0000 15.21937999    07
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It is moved on 9th as @vk5qi noted at the chatroom. New TLE will be available soon. :slight_smile:

I’ve written up a guide on how to generate these TLEs here: https://gist.github.com/darksidelemm/60dd22c74ebe2e6d89bae9e6a845da5e

The TLE for a launch on the 19th at 01:44Z will be:

1 99998U 14900A   20324.07569444  .00000000  00000-0  50000-4 0    00
2 99998  97.3000  89.9569 0001454   0.0000 218.5000 15.21937999    06

The next guide I write will be how to fit the estimated TLE to radio observations (once we have some!).


Updated TLE for a 20th November 01:44Z Launch:

1 99998U 14900A   20325.07569444  .00000000  00000-0  50000-4 0    01
2 99998  97.3000  90.9426 0001454   0.0000 218.5000 15.21937999    00

If the launch slips, I’ll post new TLEs in this thread.


It looks like this sat somehow got moved into the ‘finished’ coordination list:

I wonder what happened there?

Also, I’ve been informed it will be start beaconing 45 minute after deployment, and will only be beaconing every 5 minutes initially. This will make doppler analysis difficult.

The first pass over NZ (when they can command a higher beacon rate) isn’t until about 13:16Z.

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Very interesting. Wonder if it got lost in paper work somewhere.

New TLE by @vk5qi for 2020-11-20 2:20 UTC.

1 99999U          20325.10069444  .00000000  00000-0  50000-4 0    07
2 99999  97.3536 100.0000 0001454   0.0000 218.5000 15.21937999    06

APSS-1 is now scheduled for the first 12h:


To station owners, have in mind that TLE set is probably going to change soon, so scheduling later than 12h may not be a good idea.

Here are the TLE we got after communicating with the team.

1 99999U          20325.17361111  .00030528  00000-0  13898-2 0 00000
2 99999 097.3667 113.5674 0013096 302.4434 111.9199 15.20662795000016

However this set shows a different orbit than the one we have calculated in our previous TLE and also it seems to be off by ~1h. Anyway, until we make clear what’s going on, we will continue to use the TLE we calculated.

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Unfortunately nothing heard yet from APSS-1.

After some adjustments and based on an object at around 400MHz that seems to be from this deployment we have made a small fix to our previous generated TLE set:

1 99769U          20325.13194444  .00000000  00000-0  50000-4 0    04
2 99769  97.3700  99.8400 0000726   0.0000  35.2405 15.20445498    04

Special thanks to @cgbsat and @vk5qi. Here is a related tweet:

Decode uploaded to SatNogs #99769 @ 2020-11-20 07:43:30 UTC was unfortunately just trash.

Nothing heard 435.100 on the first couple of passes over the U.S. East Coast.

-Scott, K4KDR


Some updates:

  1. Nothing heard from APSS-1
  2. Spacetrack has published “To Be Assigned” TLE sets (46929 - 46953)
  3. We have added an unknown satellite from this deployment in DB that transmits at 401.735MHz and it seems to fit OBJECT W(46949), so for now we follow this NORAD ID for this satellite in DB.
  4. For APSS-1 I’ve chosen randomly OBJECT Q(46943), currently TLE sets describe objects that are close enough, so picking one of them will not affect reception if the satellite transmits.
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So excited to think I might be getting decodes from APSS-1 until I saw U.S. call signs & realized it was FalconSat-3!

Will keep trying…

-Scott, K4KDR

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This is unfortunately going to be a common theme.
They should be easy enough to tell apart in the waterfall because FalconSat-3 transmits continuously, and APSS-1 doesn’t.

APSS-1 was meant to be beaconing every 5 minutes, but so far we’ve heard nothing. I suspect it might be DoA :frowning:

From Observation 3222370: APSS-1 (99769)

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