PICAXE is in Space

srnet

Senior Member
$50SAT (Eagle2) a PICAXE powered micro satellite was successfully launched from Dombarovsky Air Base in Russia this morning at 07:11.

It should have been deployed by now at an altitude of 600km.

As far as we know this is the lightest satellite ever to be put in earth orbit at circa 210g.

The closest pass to the UK based on preliminary orbital elements will be at 10:26 this morning, distance 1173km, then at 11:58, distance 911km.

It puts out a slow Morse beacon of call signs on 437.505Mhz about once per minute.

Further details can be found here;

https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8
 

bfgstew

Senior Member
Absolutely amazing @srnet, congrats on a succesful mission, shame I have no way off 'listening' to $50SAT, will look forward to later posts and see how it is progressing.

ATB

Stewart
 

bfgstew

Senior Member
@srnet

What is going to happen with $50SAT, is it going to stay in orbit and if so how long, or is it a short term deployment and comes hurtling back into Earth's atmosphere creating a spectacular fireball on re-entry?...............................:p
 

bfgstew

Senior Member
Enough time then for me to build a receiver to listen to it then..............LOL.

You all must be so thrilled, well done again on a great acheivement.
 

srnet

Senior Member
Enough time then for me to build a receiver to listen to it then..............LOL.
If you have a UHF handheld receiver (FM) tuned to 437.505Mhz and listen tomorrow at around 22:30, there is a pass directly over the UK, distance to satellite is a mere 512km.

The tuning will not be exactly 437.505Mhz, allow for Doppler shift, up to +8khz a few minutes before 22:30 and -8khz a few minutes after 22:30.

You all must be so thrilled, well done again on a great acheivement.
There were many doubters that it would be possible, using such an 'inadequate' processor and radio, but it was a once in a lifetime opportunity.
 

Technical

Technical Support
Staff member
Well done, PICAXE has already been used on every continent and now in space!

Any deep sea ROV builders out there?
 

MFB

Senior Member
Congratulations on a excellent job well done. Regarding the 'inadequate processor' I hope that Rev-Ed really make the most of the marketing opportunities offered by this project. Just think what a fuss there would be if a Raspberry Pi made it into space!
 

srnet

Senior Member
It was given the name $50SAT slightly tongue in cheek, as we though that would be around the cost, $50.

The cost of the high tech triple junction solar cells really blew that budget, but you could still build one for around $200.
 

bfgstew

Senior Member
Congratulations on a excellent job well done. Regarding the 'inadequate processor' I hope that Rev-Ed really make the most of the marketing opportunities offered by this project. Just think what a fuss there would be if a Raspberry Pi made it into space!
Pi in the sky..................................Pah
 

srnet

Senior Member
Pi in the sky..................................Pah
No chance.

There is not enough power available from the solar panels, the device really does need an idle current of 5ma or less.

And the Pi at 47sqcm is way too big, the two $50SAT PCBs were 16sqcm each (stacked) no room for anything bigger.
 

srnet

Senior Member
Regarding the 'inadequate processor' I hope that Rev-Ed really make the most of the marketing opportunities offered by this project
By no means do I think it was inadequate, ideal for the task really.

Simple easy to understand programs, and extremely reliable.

Quick and easy to write debug and test routines for development purposes.

Well capable of doing all that was asked of it.

There were only really two tricky bits, getting the delays right for the FSK RTTY, the bit time had to be very close and consistent at 10ms. And the FEC encoded data packet which a colleague did.
 

Hemi345

Senior Member
Congrats srnet!

Can you disclose what data you've received so far?

I heard on the news last night that there are over 13,000 satellites in orbit. :cool: One thing that I have always wondered about is how the new satellites that are deployed don't collide with one of the existing satellites... mainly for those that are not in geostationary orbit.
 

MartinM57

Moderator
Well done indeed :D

Do all the satellites go round in the same direction (I really am novice about all this stuff) so you only get rear-end collisions - but at a given height, aren't they all going the same speed anyway?

Disclaimer: I really have no clue what I'm talking about :)
 

Paix

Senior Member
My heartiest congratulations Srnet.

I'm way behind on all my projects . . . no change there then, so no AZ/EL or frequency tracking, but I will attempt a search tonight around 22.43Z

In the longer term, will you report the Norad Catalogue number here, when it is assigned. I believe that it is normally available some time after the launch.
The Funcube is 00312U, useful for extracting the latest TLE from Spacetrack.org

@Technical, I'm sure that the cost of a telephone call to SRNET and could produce some mutually worthwhile PR. Where is the telephone-number/email-address of the local/national newspaper/TV station when you need it?
 

srnet

Senior Member
Can you disclose what data you've received so far?
Very limited data at the moment, but I may not pick up the data telemetry, I dont have a high gain tracking antenna here.

Although with my Quadrafiler Helix Omni I did pick up the last resort comms, the FSK RTTY version of the data packet;

$$50SAT,128,,162,,,54,3,,21,140,87,,102,,3723,*70

Which basically tells me its cold in space, -13C (the 140 is the raw output from the 'readtemp' command) and the battery volts is 3.723V.

And charge is disabled, no solar charge current or voltage which there would not be until the temperature exceeds 0C, could be normal, the satellite was not long out of the dark when I picked it up.

Oh and idle current, 3ma, receive current 21ma, TX current 87ma, all normal.
 

srnet

Senior Member
In the longer term, will you report the Norad Catalogue number here, when it is assigned. I believe that it is normally available some time after the launch.
The Funcube is 00312U, useful for extracting the latest TLE from Spacetrack.org
I have just received an updated TLE, I will post it later in case there are any more revisions, they are a bit vague so soon after launch.

We are not entirely sure that Norad will be able to track it due to the extreme small size, so I may have the CIA knocking on the door asking about the 'undetectable satellite'.

Just heard from the Rome team that $50SAT has been heard by someone else.........
 

Paix

Senior Member
Interesting point to consider. Not only is there spacial separation to consider, but the frequency management that goes on at great length way before the launch date. Listening on a specific satellite frequency will often reveal that the one frequency is being used by a whole train of satellites which appear one after the other, a bit like London buses . . . All this has to to be planned.

A lot has to be said for Open Source projects, if only "ITAR exampt . . ." :)

I seem to recollect in the case of Delfi-C3 in 2008 that it was almost a week before the separation of the individual satellites allowed the owners to get a definite bead on their own bird from the pack, which at that time was only five or six, not quite as ambitious as this launch where the flock count is nearer twelve if I'm not mistaken?

I bet you are feeling like the proverbial dog with . . . today. Definitely reason for a satisfied smile, a cup of cocoa and your feet up. Probably figuring how many beers you can get bought for you tomorrow night down your local as you just happen to mention where your latest bit of micro controller wizardry has been placed . . .

In a few years time, your grand kids will reckon that you are just shooting a line . . . Father Christmas, yeah! Grandpa helped build a satellite . . . nah! Even more reason for lots of PR now.

Just a thought, do the CIA buy beers?
 

hippy

Technical Support
Staff member
$$50SAT,128,,162,,,54,3,,21,140,87,,102,,3723,*70

Which basically tells me its cold in space, -13C (the 140 is the raw output from the 'readtemp' command) and the battery volts is 3.723V ... Oh and idle current, 3ma, receive current 21ma, TX current 87ma, all normal.
You must have been tempted to add -

$50TXT,"All systems go. Beep"

A tremendous achievement you can rightly be proud of.
 

Dippy

Moderator
Well done srnet (and chums)!

You must be really proud.... in fact 'over the moon' (almost). :)

Congratulations!
 

srnet

Senior Member
Just had a report from the US that using a small 6 element yagi and a UHF handheld, fragments of the slow Morse callsign beacon were heard at a distance estimated to be at least 1900km
 

srnet

Senior Member
At this time the orbital predictions, coming in from various sources, are too different to used as reliable, it may take some time for them to settle down.

All I know at the moment is that in the UK, there should be a close pass starting around 23:00, so as $50SAT will be approaching you at 7.5Km/sec, start to listen on 437.505Mhz plus around 8khz (437.513 Mhz) to account for the approaching doppler.
 

Paix

Senior Member
The smart money among you might realise that most FM communication receivers are normally/often channelised and may not be quite as suitable as the transmitter modulation suggests.

If your rig is a multi-mode one then pop to USB and open up your receive bandwidth.

Without frequency tracking the signal will appear in the high audio, pass across the audio and when the tones are low it will drop into zero beat and low frequency at much the same time, so it is advisable that you DON'T use LSB

When you have detected the bird, start tracking it's frequency manually. It should be as advertised when overhead and then depart tracking towards the lower frequency. The greatest rate of frequency-change will occur nearest the overhead position.

Good Luck. G0PAi QAP
 

manuka

Senior Member
Pointer for those contemplating a DIY UHF receiver. Consider instead a Chinese Baofeng UV-5R VHF/UHF SDR transceiver, which is small, wide range (~140-170 MHz VHF & ~400-520MHz UHF) a great performer,feature rich & brilliant value. Yes - they're a transmitter too (4 Watts) so it's important that they're used RESPONSIBLY. You can usually land one from the likes of Radioddity for a near unbelievable ~US$50 ! Get the USB programming cable too,as they're best configured via free "Chirp" PC software-they've 128 memories (with alpha display). Manual setup is a pain in comparison.

I've yet to ponder schedules for NZ, but beacons from numerous past ham "OSCAR" (Orbital Satellite Carrying Amateur Radio") ventures have been receivable here with just a mere rubber duckie. Hence I fully expect to hear this bird's pass over with the likes of a simple tape measure Yagi.

Stan. (Ham ZL2APS -since 1967)
 

Paix

Senior Member
Not sure - 23.03Z nominal "HI HI" received fleetingly in Morse when listening USB on 437.511MHz, but nothing else and scanning/tracking down through to 437.4964 over the next six minutes revealed nothing except a QRM carrier at that frequency, which had been there earlier. Watch closed.

Icom IC-7000, Colinear and Mk I ears.
 

Hemi345

Senior Member
Very limited data at the moment, but I may not pick up the data telemetry, I dont have a high gain tracking antenna here.

Although with my Quadrafiler Helix Omni I did pick up the last resort comms, the FSK RTTY version of the data packet;

$$50SAT,128,,162,,,54,3,,21,140,87,,102,,3723,*70

Which basically tells me its cold in space, -13C (the 140 is the raw output from the 'readtemp' command) and the battery volts is 3.723V.

And charge is disabled, no solar charge current or voltage which there would not be until the temperature exceeds 0C, could be normal, the satellite was not long out of the dark when I picked it up.

Oh and idle current, 3ma, receive current 21ma, TX current 87ma, all normal.
:cool::cool::cool::cool:
 

srnet

Senior Member
Some details of the launch;

http://www.nasaspaceflight.com/2013/11/russian-dnepr-record-breaking-32-satellite-haul/

"The Eagle 1 and 2 PocketQubes, also known as BeakerSat-1 and $50SAT respectively, are the first two prototypes of the PocketQube standard.

Developed at Morehead State University in Kentucky by a team working under Professor Twiggs, the two spacecraft will perform technology demonstration missions. BeakerSat-1 is a 2.5-unit satellite, measuring 5 by 5 by 15 centimetres (2 x 2 x 6 in), while $50SAT is a smaller 1.5p satellite – with a length of 10 centimetres (4 in). BeakerSat-1 will test a passive deorbit system while $50SAT is geared towards investigating the use of off-the shelf components in satellites."
 

srnet

Senior Member
The smart money among you might realise that most FM communication receivers are normally/often channelised and may not be quite as suitable as the transmitter modulation suggests.
The FM Morse is not true FM as such its just the RFM22 switching between two carriers (what do you expect from a $5 tranciever!) so the receive quality is better if you can tune the receiver by small amounts, say 1khz.

However with the deviation used, 5khz, you have a good chance of receiving it, allowing for doppler, on your average UHF handheld with 5khz channels.
 

srnet

Senior Member
Not sure - 23.03Z nominal "HI HI" received fleetingly in Morse when listening USB on 437.511MHz, but nothing else and scanning/tracking down through to 437.4964 over the next six minutes revealed nothing except a QRM carrier at that frequency, which had been there earlier. Watch closed.
You do stand a better chance of hearing the Morse beacon in LSB\USB mode due to the greater sensitivity, and as mentioned elsewhere the 'FM' Morse is really just two FSK carriers.

The best way of picking it up is with a Funcube Dongle, you get a nice spectrum display and you can normally see the signals on screen before you can hear them.
 

Paix

Senior Member
I have to agree with you that a SDR with a waterfall or similar display is ideal as you can see the signal to track it.

I thought that Eagle2 would be eclipsed and so may be low on power at the time. I would estimate the Morse speed at around 18-20WPM, but the estimate was from a "HI HI" message which may or not have been from the right source, but it had Doppler on it. Morse tone frequency . . . couldn't start to guess, but less than 1kHz.

I'll get a TLE into Orbitron for a daytime look when I have a moment. Enjoy!
 

srnet

Senior Member
I would estimate the Morse speed at around 18-20WPM, but the estimate was from a "HI HI" message which may or not have been from the right source, but it had Doppler on it. Morse tone frequency . . . couldn't start to guess, but less than 1kHz.
Thanks for the report.

If you time the gaps between the transmissions of the slow Morse beacon you can determine the battery charge state.

With a fully charged battery (circa 3900mV) the slow Morse beacons are 60 seconds apart, although this can vary by up to 10 seconds depending on whether fast Morse or FSK RTTY is being sent.

So for a specified gap between Morse beacons the battery voltages are;

60 seconds battery is more than 3800mv
73 seconds battery is more than 3700mv
97 seconds battery is more than 3600mv
173 seconds battery is more than 3500mv
223 seconds battery is more than 3400mv
274 seconds battery is more than 3300mv
 

StigOfTheDump

Senior Member
srnet

This is all very exciting. More so than 1969 to me. I have ordered the radio recommended by manuka, but even though UK sourced, at 22:30 it will probably be farther away than your satellite.

Being a complete novice to these radio transmissions, I am struggling to understand exactly what I am expecting to hear. Could you post a sample transmission exactly as it will appear, with some indication of timing.
Morse I can figure out but I am a little confused by the WPM. Is this 20 words (slow) of approximately 5 characters per minute?
FSK RTTY seems a little bit more complicated. 5 bit characters preceded by a 0 and followed by a 1? The wikipedia listing I have found, shows the bits 5 & 4 before the bits 1, 2 & 3. Also it lists for MSB left and MSB right.
Is the exact same data transmitted 3 times over, in slow morse then fast morse then FSK RTTY for every cycle?

Thanks
 

srnet

Senior Member
See the first post, it points to a document that should explain all.

The FSK RTTY was added because for a given transmit power its is a very good performer and it allows for the simple transmission of ASCII type data that is easy to decode from the screen. Its a little tricky to use primarily because of the large amounts of doppler shift (+\-10khz) that the signal has because the satellite is traveling towards then away from you at 17,000mph.
 
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