ELaNa 38 from ISS - 2022-01-26 (GASPACS and other satellites)

I was extremely pleased to get an enthusiastic response from Jack, KJ7RSW, when I inquired about the GASPACS Satellite (Utah State University) which I believe is slated for deployment from the ISS in the not too distant future.

GASPACS | Projects | GAS | Physics | USU

So far I have been able to confirm that this satellite will downlink on 437.365 MHz with a 9k6 2GFSK modulation scheme. And of particular interest, in addition to telemetry there are plans to downlink images! (I have already tested their SSDV-based image decoder & it works perfectly! – I’m so glad that someone is using SSDV)

Other than to bring this interesting satellite to everyone’s attention, I also wanted to start this thread so that I could share the link with Jack. He is very interested in doing what is necessary for SatNogs to be equipped with the proper code to decode this unique modulation.

I’m sure that those familiar with integrating decoders into SatNogs will be a big help with this.

Hopefully more to follow!

-Scott, K4KDR


Thanks for opening a thread about it. There were a couple other satellite that are going to be deployed from ISS in the same launch, here is a list from Gunter’s page:

Light 1
GT 1?

We’ll need to find info about them and add them in DB before the deployment :slight_smile:

I didn’t yet check if there is downlink documentation available! If anyone has hints: they are welcome!

TARGIT - IARU Sat Coordinator

GASPACS - IARU Sat Coordinator

GT 1 - IARU Sat Coordinator

Coordination Declined…
FEES 2 - IARU Sat Coordinator

I couldn’t find any other ones in the IARU lists but it could be that have different names that were used. (Or they just aren’t using amateur freqs since most of the other ones seem to be purely scientific / agency ran in nature.)


Thanks Scott for starting this thread! Here is a webpage we’ve put together that should contain all of the communications information for GASPACS. If there’s anything missing or confusing, let me know. We will be updating the webpage with information on our ground station equipment, and some software we’ve developed that may help with decoding. GASPACS CubeSat Communications Information | GASPACS-Comms-Info

We would like to make a SATNOGS decoder for GASPACS, but don’t have any experience with it. If someone could point us in the right direction, that’d be great!


Welcome! Glad you are still updating the Project’s documentation - very interesting!

From previous testing, or perhaps even now from an engineering spare that you might have on-hand, would it be possible to share a ‘Sample’ file of the satellite’s downlink? That would be very helpful so that we can test our various reception setups before GASPACS is even deployed.

An audio file is fine or even an I/Q file if that’s the only thing available.


-Scott, K4KDR

1 Like


Sure thing - we have an engineering spare that we’ve been testing our comms with. We’ll work on recording a sample of the downlink. We’ll try to get one of each packet type.

-Jack, KJ7RSW

1 Like

We just received a time for the upcoming GASPACS deployment (and the other satellites on that day)!

We are still planning to get those sample packets recorded - we ran into some major issues with our ground station and had to take the whole thing apart!

1 Like

Great news on the deployment schedule - thanks for sharing!

We will certainly be listening and of course please get in touch if there is anything specific that we can do to assist.

I’ve uploaded a wav file containing IQ data for the GASPACS AX.25 beacon. It has been successfully decoded by PE0SAT using gr_satellites. More info available in the AX.25 Packet Structure section of our site.

Also, we created a Twitter where we will post updates about the satellite! https://twitter.com/GASPACS_CubeSat


Many thanks for uploading more information & a sample file.

I was able to play the I/Q file and save an audio version for experimentation. I see that PE0SAT just posted a link to his audio file as well - thanks Jan!

Thank you and best of luck with the deployment!

-Scott, K4KDR

1 Like
Satellite Temporary NORAD ID Deployment Time(UTC)
GASPACS 99430 10:20
FEES-2 99431 10:20
PATCOOL 99432 10:30
DAILI 99433 12:00
TARGIT 99434 12:10

That’s interesting: there is no AX.25 packet structure other than the “hello world” message - telemetry is not transmitted in AX.25. Is that still correct?

I’ve set up a simple dashboard that just shows stations / SIDS submitter data for GASPACS. Unfortunately, the telemetry beacon is only sent upon telecommand and is not easily decoded due to a proprietary header from the transceiver manufacturer. We may add support for it later, but right now it’s not a priority. The dashboard is showing FalconSat-3 data for testing, but I’ll change this over before deployment.


Sorry for the noise, please ignore these pics. I just needed to post these images so I can hotlink them on the dashboard.


Deployment delayed for 26th of Jan:

@usugas is the deployment for tomorrow still valid? Are the satellites going to be deployed at the same time as it was announced some days ago?

This is correct, it was bit of an oversight on our part to not put useful information in the beacon

1 Like

We haven’t had any updates on when the deployment will happen, all we know is that it might happen sometime tomorrow (1/26). We will post the deployment time on the GASPACS twitter when we know.


per GASPACS twitter account just now:

Updated GASPACS deployment: 12:00 UTC (5:00 am MST) Wednesday 1/26/22!


Cool! I’m going to enable GASPACS and the rest for scheduling. I’m going to assume that the schedule is similar to the previous one so:

Satellite Temporary NORAD ID Deployment Time(UTC)
GASPACS 99430 12:00
FEES-2 99431 12:00
PATCOOL 99432 12:10
DAILI 99433 13:30
TARGIT 99434 13:40