Sprites data analysis

[Janos Tolgyesi]

Maybe you remember, at March 22, Cees Bassa and Tammo Jan Dijkema made a planar scan  with the Dwingeloo 25m radiotelescope, and they detected some transmissions of Sprites, and they recorded this in a big file. You can download this file from their site, https://charon.camras.nl/public/satellites/
The file size is 2.7 Gbyte, and the name is: KICKSAT_PI9CAM_2019-03-22T19:55:09_437.35MHz_500ksps_complex.raw
Based on this recording, Daniel Estevez now published his analyzis of this recorded data:
"Detecting the Sprites from KickSat-2"
https://destevez.net/2019/04/detecting-the-sprites-from-kicksat-2/#more-6350

It is a long paper with many interesting details.
Here I emphesised only some sentences:
- It is interesting note from him, at the time, when was the recording, "At that moment, the Sprites were up to 5 minutes ahead KickSat-2, due to their much higher drag to mass ratio. They all probably reentered a few days after this." this is corresponds to the predictions, published here.
- He extracted not complete-transmissions from some sprites, he noted "shorter transmissions probably indicate that the transmission failed due to lack of power. As soon as the transmission started, the bus voltage dropped and the transmission stopped. It is also interesting to note that despite the large number of sprites launched, only 4 of them have been successfully detected. This seems to indicate that the failure ratio of these Sprites is very high."
-" Only one of them was functioning normally, transmitting complete messages. The remaining Sprites showed transmissions shorter than a complete message. Since more than 100 Sprites were launched by KickSat-2, this seems to indicate a high failure rate"
We can add the note, this analysis based only on this 11 minutes long recording. If we have another recorded data, maybe this result will extended.
- An interesting aspect of this analysis, that is it very "computationally expensive", need a high-end configuration: "the correlation against the complete recording amounts to more than 2.8 thousand million FFTs of 2048 samples. The algorithm took nearly 58 hours to run in my i7-2620M CPU, using dask for parallelization. This means that my machine is doing 13800 FFTs per second.".

t.janos

[Janos Tolgyesi]

To evaluate the situation, there is another point of view:
https://twitter.com/ea4gpz/status/1117400713271959555

The recording at Dwingeloo  was saved in the file at 2019-03-22T19:55:09. I dont remember, what was the reentry predicition on sprites at this time...
and how did the orbit looks like out from the sunshining.

[Rob Fryer in San Diego]

Looks like excellent work here. 

I always suspected that my little 5 element yagi might be too weak. 

One thing that strikes me is that a super cap or battery might keep the transmit voltage from dropping 

longer and at least get some of the telemetry sent 

We used a coin battery when testing  Sprite transmission over very modest distances and 

that worked fine. 

Looking forward to KickSat-3 

I want to test an engineering Sprite with added GPS  

I know it is a power hog, heavy, big and clumsy and illegal 

but sure would be nice to have all that accurate nav info. 

Rob 

Verne San Diego KickSat Team 

Dont go too high or too fast and ordinary GPS 

actually is legal. 

[T G]

Thank you Janos, that's awesome.

Cheers

Terry

--
You received this message because you are subscribed to the Google Groups "KickSat-gs" group.
To unsubscribe from this group and stop receiving emails from it, send an email to kicksat-gs+...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[S marie Johnson]

Thanks for the wonderful info

Shelley 🚀

--
You received this message because you are subscribed to the Google Groups "KickSat-gs" group.
To unsubscribe from this group and stop receiving emails from it, send an email to kicksat-gs+...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

--

Shelley Manson RPN

SMJ Care Consulting

    Care4Me: Caring for Caregivers in Canada

    "...you'll be glad you did."    

              613-621-3104

[Michael Turner]

I'm wondering if the apparent high failure rate could be considered a
useful scientific result, if the cause of the failure can be
determined, and it turns out to be related to electromagnetic effects
at the release altitude. The unique geometry of Sprites as satellites
at that orbital altitude may have teased out some phenomena that
haven't been measured accurately before.

Regards,
Michael Turner
Executive Director
Project Persephone
1-25-33 Takadanobaba
Shinjuku-ku Tokyo 169-0075
Mobile: +81 (90) 5203-8682
tur...@projectpersephone.org

Understand - http://www.projectpersephone.org/
Join - http://www.facebook.com/groups/ProjectPersephone/
Donate - http://www.patreon.com/ProjectPersephone
Volunteer - https://github.com/ProjectPersephone

"Love does not consist in gazing at each other, but in looking outward
together in the same direction." -- Antoine de Saint-Exupéry

[Janos Tolgyesi]

This is another chance to observe in real flight the behaviour of a similar swarm of sprite-category satellites on orbit:
https://www.kickstarter.com/projects/ambasat/ambasat-1-an-educational-space-satellite-kit

> To unsubscribe from this group and stop receiving emails from it, send an email to kicks...@googlegroups.com.

[Michael Turner]

Some pretty iffy things I noted immediately about Ambasat-1's campaign:.

Launch provider is InterOrbital, the longest-running vaporware
orbital-launch company around. Highest altitude reached: 10,000 feet.

Claiming 250 km orbital altitude, equatorial orbit. InterOrbital
hasn't launched from anywhere, and only mentions polar orbits on its
website. On the other hand, Alcantara (Brazil) may be opening up, so I
guess it's not outside the realm of possibility.

Claimed open source, no repo link.

Claims of being able to get one now, no purchase link.

Regards,
Michael Turner
Executive Director
Project Persephone
1-25-33 Takadanobaba
Shinjuku-ku Tokyo 169-0075
Mobile: +81 (90) 5203-8682
tur...@projectpersephone.org

Understand - http://www.projectpersephone.org/
Join - http://www.facebook.com/groups/ProjectPersephone/
Donate - http://www.patreon.com/ProjectPersephone
Volunteer - https://github.com/ProjectPersephone

"Love does not consist in gazing at each other, but in looking outward
together in the same direction." -- Antoine de Saint-Exupéry

> To unsubscribe from this group and stop receiving emails from it, send an email to kicksat-gs+...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kicksat-gs/7b352684-5ce1-414a-a3fe-db822908b47a%40googlegroups.com.

[T G]

Hi team

It is a year now since our sprite satellites were in orbit and making history.  I read that some signals were received and some decoding experiments carried out.  So I'm wondering, now that 12 months have passed, what is known about the signals, what was received, who has been analysing signals and which sprites were successful in their attempt to get a signal to the ground?

Regards

Terry