KickSat-2

[Zac Manchester]

Hi Everyone,

First, a huge thanks to all of you for your efforts. I very much appreciate all you've done, and I hope you've had fun!

I'm already starting work on KickSat-2  and I'd like to have your input. I'm already planning on using different radios and aiming for a very robust uplink to avoid the problems we had this time. Any other suggestions? What kind of data would you like to see in the telemetry? Should we consider a different modulation, packet format, etc. for the beacon? Any comments are welcome.

Best,

Zac

[arcanum]

Hi Zac,

A great first attempt, thanks for letting us play, even if I didn't get a decode....

I realise there are power budget issues with running a receiver long term, however you could run it pulsed mode as you do with Tx, using the Tx burst as a synchronisation mark, some seconds after the Tx burst to allow for propagation delays, the spacecraft receiver is turned on, only for a few ms, if it detects a carrier then it stays on and brings up the demodulator system in time to receive the message. The receive operation does not need to be after every Tx burst of course. A few ms of operation every 30S should give a very low power receiver system though.

Just a thought....

Ian W.

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[daniela daniela]

Can the uplink radio receiver be on while mainboard is off, in the Phonesat platform? 

[John]

Zac,

One comment:
If you are planning to use a PRN sequence code for kicksat2 and plan on
using the cc430 again, it appeared that the cc430 transmitter could only
send bit sequences that were multiples of 8.
So the original SLCE 640-bit code would have met that requirement, but
(guessing) due to license or patent issues, could not be used.
The 511-bit gold codes had to be padded to 512-bits, so their
correlation properties were degraded somewhat.
Also, only some of the 513 512-bit codes were balanced with respect to
one/zero count.
That balance, ideally, one would like to have for ac-coupled signal chains.
So gold codes may not be the best way to go with this hardware.

But, what code to use? Are SLCE codes permanently out of consideration?
If so, perhaps we can get the group to discuss options.

John

[Zac Manchester]

Thanks Ian. I'm looking into different radios right now that have much lower power requirements than the MHX2420 we had this time around. I'll likely be doing everything in the 70cm band next time. Having the receiver in the spacecraft listening as often as possible is definitely key. I really like this idea.

- Zac

[Zac Manchester]

Hi John,

You're exactly right - the CC430 can only transmit a byte at a time. Another consideration is that doing FFT stuff in the receiver gets much more expensive for lengths that are not powers of 2. I originally started out with Gold codes, then switched to the SLCE codes for exactly the reasons you cite. It turned out that they performed worse than the padded Gold codes in practice, so I switched back. I'm considering trying to develop a code family with a length that is a multiple of eight with a genetic algorithm or other brute force optimization approach, probably seeding it with Gold codes to start it off.

- Zac

[Дмитрий Пашков]

Zac, leave the format as a beacon and was 1k2 AFSK. Very comfortable and no problems in decoding. Many devices support this protocol. This portable and transportable and fixed stations. Just do a little bit more power at the lighthouse. Can be further reduced periud lighthouse to 1 minute. It was hard to pick up the signal, and many who are not familiar with the principles of data from the satellite signal is generally not able to. You can count on me as a ground station

[Rick Mann]

Is power really so constrained you can send a packet every second? Is part of the problem a lack of area for PV because you need open bays from which to deploy sprites? What about pop-out panels and magnetorquers? Too expensive?

On May 15, 2014, at 01:12 , Дмитрий Пашков <r4uab....@gmail.com> wrote:

> Zac, leave the format as a beacon and was 1k2 AFSK. Very comfortable and no problems in decoding. Many devices support this protocol. This portable and transportable and fixed stations. Just do a little bit more power at the lighthouse. Can be further reduced periud lighthouse to 1 minute. It was hard to pick up the signal, and many who are not familiar with the principles of data from the satellite signal is generally not able to. You can count on me as a ground station
>

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Rick

[Zac Manchester]

Is power really so constrained you can send a packet every second? Is part of the problem a lack of area for PV because you need open bays from which to deploy sprites? What about pop-out panels and magnetorquers? Too expensive?

Power really is constrained. We could probably transmit more often than every 2.5 minutes, but not as often as once per second. Deployable solar panels complicate everything and are very non-trivial to do right. If the solar panel deployment doesn't work, then the mission is over. Since our primary goal is deploying the Sprites, it makes sense to keep the bus as simple as possible and not introduce extra risk.

[Zac Manchester]

Zac, leave the format as a beacon and was 1k2 AFSK. Very comfortable and no problems in decoding. Many devices support this protocol. This portable and transportable and fixed stations. Just do a little bit more power at the lighthouse. Can be further reduced periud lighthouse to 1 minute. It was hard to pick up the signal, and many who are not familiar with the principles of data from the satellite signal is generally not able to. You can count on me as a ground station

Thanks. We're looking into different radios now. There's always trades to make between TX power and beacon frequency etc. I'll post more info as we figure things out.

- Zac 

[Andy Thomas]

If you could maintain the protocol of 9k6 or 1k2 then many more amateurs would be able to receive it using conventional narrow band receivers. If you rely on SDR then all kinds of new issues arrive.

andy G0SFJ

[Dave Webb KB1PVH]

I would suggest 1k2 over 9k6 because with the 1k2 you can just go from speaker out on any radio and plug it directly into the soundcard on computer, but with 9k6 you would need a discriminator tap which isn't factory on some radios.

Dave-KB1PVH

Sent from my Verizon Wireless Droid RAZR

[Юрий Мироненко]

If for some reason long deployment timer will be needed next time, then we definitely need test sprite.

You see: even catching KickSat's signal is not easy task. With Sprites, it will be even harder - signal is much weaker - and you even don't know - maybe your ground station is not configured correctly, maybe your sprite flies away from KickSat and out of antenna focus, maybe it is not lightened just now.

So, why not activate one of the sprites with the kicksat? Then, while waiting for deployment timer, people can try to catch this test Sprite signal. And when it will be time for deployment, receivers will be configured, tested and ready.

четверг, 15 мая 2014 г., 2:25:59 UTC+4 пользователь Zac Manchester написал:

[Zac Manchester]

Yes! This is a very good idea.

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[Rick Mann]

I used my dev kit sprite to verify my ground station worked. It might not have had the noise floor necessary to pick up the sprite in orbit, but it did work from a couple blocks away with houses and trees in between.

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[Jay Payne]

If I may ask a few different types of questions.   

1.  Are you going to use a KickStarter project to fund KickSat-2?       

2.  Was the Kickstarter funding sufficient to really meet your KickSat needs?

Thanks

--J

[Zac Manchester]

1.  Are you going to use a KickStarter project to fund KickSat-2?       

I'm trying to avoid doing another round of fundraising due to the huge amount of time/work involved. We built 3 of all of the major components of KickSat the first time around, so we have enough spare parts to build KickSat2 with minimal extra cost.

 

2.  Was the Kickstarter funding sufficient to really meet your KickSat needs?

Yes, we were able to build everything with the money raised on Kickstarter. Keep in mind that money only covered component/material purchases, not labor or launch costs.

 

[Julian Priest]

Hi Zac,

first I just wanted to say a big thank you for the whole kicksat project
- it has been a great learning experience for me personally and I've had
only positive feedback from the hundreds of people who have come into
contact with it despite the ups and downs.

I did a total of 17 events around the project in the end, some as part
of an artwork, some explanatory for technical audiences and some as way
of introducing school kids to space stuff. At the second launch attempt
for instance a whole class of school kids turned up at Whanganui
observatory, munched donuts and I gave a talk about orbits and gravity
as well as the project. Basically none of those events would have been
possible without your project so just wanted to say a big thank you for
the opportunity.

I'd also love to take part in Kicksat-2 and would still like to get to
fly a version of my code so do let me know how plans develop. It sounds
like you have the physical side of KickSat sorted with the spares. What
are the launch possibilities looking like? I noticed ESA has a similar
educational Cubesat prgrame to ENLA so might be worth looking there as well.

hope all well,

cheers

/julian

[Zac Manchester]

Thanks Julian. I'll have more news in the next few weeks.

Best,

Zac

[Michael Turner]

On the Sprite side, I'm interested in flying gravitational biology
experiments with (necessarily) tiny extremophile ecosystems hosted on
biosensor chips. If two Sprites, or a Sprite that can separate into
two tethered pieces, require special treatment in the deployer, it
would be good to start working on it soon. With hundreds of Sprites
pre-rotated by a KickSat II magnetorquer, a range of gravities might
be achieved.



Regards,
Michael Turner
Executive Director
Project Persephone
K-1 bldg 3F
7-2-6 Nishishinjuku
Shinjuku-ku Tokyo 160-0023
Tel: +81 (3) 6890-1140
Fax: +81 (3) 6890-1158
Mobile: +81 (90) 5203-8682
tur...@projectpersephone.org
http://www.projectpersephone.org/

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

[Michael Turner]

"I'm trying to avoid doing another round of fundraising due to the
huge amount of time/work involved."

For KickSat I, the video you did was perfect. It sold me, anyway.

Would you consider farming out the fundraising effort this time? A
crowdfunding promo video done with your approval over every element?
When you started, you had little material to work with. Now, there are
lots of photos, and I'm sure Julian has more.

You might need more money if you can't get another ELaNa slot.

I know a former EE who now does entertainment video production. He'd
love to be involved, I'm sure.

Regards,
Michael Turner
Executive Director
Project Persephone
K-1 bldg 3F
7-2-6 Nishishinjuku
Shinjuku-ku Tokyo 160-0023
Tel: +81 (3) 6890-1140
Fax: +81 (3) 6890-1158
Mobile: +81 (90) 5203-8682
tur...@projectpersephone.org
http://www.projectpersephone.org/

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