PocketQube Workshop presentation slides released

OzQube-1 LogoIn March Stuart McAndrew gave a presentation on OzQube-1 a tiny PocketQube satellite which aims to transmit images of the Earth from space.

OzQube-1 will be just 5x5x5 cm (1P) in size and the aim is to keep the hardware costs down to under $1,000. The satellite structure is being developed by Jo Hinchliffe MW6CYK.

Stuart’s talk titled ‘Building a Satellite from Scratch: The DIY Engineering behind OzQube-1’ describes some of the challenges he’s faced in building his own low-cost satellite.

Watch OzQube-1 Presentation at TU Delft PocketQube Workshop

Download all the workshop presentation slides including OzQube-1 from

Delfi Space hosted the PocketQube satellite workshop at the Delft University of Technology on March 24, 2017 http://www.delfispace.nl/pocketqube-workshop

Stuart McAndrew OzQube-1

Jo Hinchliffe MW6CYK

Video of $50SAT ham radio satellite talk

Yaesu handheld and $50SAT 1.5U PocketQube

Yaesu handheld and $50SAT 1.5U PocketQube

The story behind $50SAT, a new approach to amateur satellite design which became the world’s smallest operational satellite, built for £125 in a garden shed.

On Saturday, August 6, Stuart Robinson GW7HPW gave a presentation on the amateur radio satellite $50SAT to the Electromagnetic Field event EMF 2016 in Guildford.

Talk Description: If you are building an Amateur satellite the simple choice would be to assemble a device with all the latest satisfyingly advanced and complex tech. The $50SAT team made a decision to go against convention and produce a design with the minimum of components.

$50SAT was the first of a new class of satellite pioneered by Professor Bob Twiggs KE6QMD; the PocketQubes, designed to be small and light so they would be cheap to launch. $50SAT was launched in November 2013 using a Dnepr rocket from Dombarovsky Air Base in Russia and remained working in orbit for 20 months, the team had only expected it to last for a month at best.

Watch The story behind $50SAT

$50SAT http://www.50dollarsat.info/

$50Sat Eagle2 PocketQube

$50SAT Falls Silent  http://www.dk3wn.info/p/?cat=143

UK and Malta University Satellite Collaboration

Mock-up showing typical size of a PocketQube satellite

Mock-up showing typical size of a PocketQube satellite

The UK’s University of Birmingham, the University of Malta, the Malta Amateur Radio League (MARL) and the Italian Astrodynamics company, GAUSS Srl are collaborating on a project to send a PocketQube satellite with an amateur radio payload into space.

The Times of Malta newspaper reports:

The 5x5x5 cm device, referred to as a PocketQube pico-satellite, will be launched in 2018 into a sun-synchronous low earth orbit (LEO) and will be used to validate on-board equipment that will study the properties the Earth’s ionosphere.

This project will pave the way for a swarm of eight such satellites that will spread over a large geographical area and hence gain better coverage of changeable ionospheric conditions which affect radio communications.

The collaboration has brought together two Maltese post graduate engineering students – Darren Cachia in Malta and Jonathan Osairiis Camilleri (Ozzy), a Ph.D. student at the University of Birmingham – who have joined efforts and are developing the satellite platform and the scientific payload respectively.

The mission is expected to last about 18 months and will relay information back to Earth that will be accessible to anyone owning a simple ham radio set. Information will be made available in due course to allow schools and interested individuals to participate using inexpensive equipment.

Read the Time of Malta story at

Read the Independent newspaper story at

Martin Sweeting G3YJO gave a presentation to the University of Birmingham titled: Keeping Satellites in Space – Where Science and Engineering Meet

Malta Amateur Radio League (MARL) http://www.9h1mrl.org/

$50SAT Falls Silent

Yaesu handheld and $50SAT 1.5U PocketQube

Yaesu handheld and $50SAT 1.5U PocketQube

The $50SAT amateur radio spacecraft ,which measures just 5x5x7.5 cm and weighs only 210 grams, has ceased transmitting after nearly 20 months in space.

Michael Kirkhart, KD8QBA, writes:

Tuesday, July 21, 2015 marked the 20 month anniversary of the launch of $50SAT/MO-76/Eagle2, and unfortunately, it appears to have gone silent.  The last time I heard it was on Sunday, July 19, 2015, 08:42 UTC from Anton’s (ZR6AIC) WebSDR.  A screenshot of the WebSDR while $50SAT was transmitting RTTY, a screenshot of gpredict showing its location during the transmission, and the captured RTTY audio are up on the Dropbox; they are accessible via the following URL:


Unfortunately, there was a fade starting in the middle of the capture, so I was only able to do a partial decode:
2015-07-19,08:42,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15719,,,84,3,,22,?,?,?,?,?,?,*? (NO CHECKSUM – MISSING DATA)

Has anyone else has heard $50SAT since July 19?  If so, please let us know.

The likely cause of failure was a near complete loss of solar power.  Looking at the last 5 complete RTTY telemetry messages, the amount of solar power being generated was very low:

2015-06-21,08:23,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15688,,,82,3,,22,16,78,,3435,1572,3319,*4A  (3435 mV, 0 mA, 0 mW)
2015-06-22,08:15,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15689,,,81,3,,21,15,78,4,3536,1573,3339,*7D (3536 mV, 4 mA, 14 mW)
2015-06-22,08:20,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15689,,,84,3,,22,17,78,3,3556,1573,3339,*78 (3556 mV, 3 mA, 11 mW)
2015-07-07,08:25,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15706,,,84,3,,22,18,78,1,3475,1590,3319,*7C (3475 mV, 1 mA, 3 mW)
2015-07-09,08:07,KG43,ZR6AIC/KD8QBA,$50SAT,,2990,15708,,,81,3,,22,15,78,3,3516,1592,3319,*7E (3516 mV, 3 mA, 11 mW)

Moreover, when looking at the Battery Voltage/MPPT Current chart, the last set of MPPT (solar) current measurements are well below the trendline, which itself has a negative slope:


Because $50SAT will not transmit if the battery voltage is below 3300 mV, we do not know if it is completely dead or the battery voltage is almost always too low to enable the transmitter.

$50SAT Boards

$50SAT Boards

Our best guess as to what happened is the solar cells have been slowly damaged due to sputtering.  All the high energy particles from the solar wind can effectively “sandblast” the satellite, and since our cells had no protective cover glass, this will cause the surface to slowly become diffused, and thus cause the output of the cells to drop.  We knew this would happen.  What we did not know is $50SAT would operate long enough where this would become a problem; our bets were on the battery failing first.  Since many other CubeSats used the same Spectrolab TASC cells as we did, we are curious about how long it took for the solar output to degrade on these other satellites.  If any of them are reading this post, we would love to hear from you!

We are now in the “how long will it stay in orbit?” phase of the mission.  Thanks to James DeYoung, N8OQ, we have a de-orbit prediction of May of 2017.  From July 6, 2015 to August 28, 2015, the orbital decay rate was about 0.79 km/week.  Earlier this year, it was about 1.2 km/week.  As of August 28, 2015, apogee was at 554 km, and perigee was at 525 km.  We will continue to monitor the TLEs from Celestrak and periodically update the “Orbital-Analysis” folder on the Dropbox.

We would like to extend a very big THANK YOU to the worldwide amateur satellite community!  You helped make our mission a resounding success!  We were able to determine it was possible to make a satellite this small which could generate and store its own power as well as have two-way radio communication capability.  We were able to do this using commercially available parts, including a $10 Li-Ion camera battery, a $10 ISM band radio, and a microcontroller programmed in interpreted BASIC.  We look forward to seeing what the next generation of PocketQubes can do.


The $50SAT/MO-76/Eagle-2 team:

Howie DeFelice, AB2S
Stuart Robinson, GW7HPW
Michael Kirkhart, KD8QBA
Professor Robert Twiggs, KE6QMD

$50SAT 19 Months in Space https://amsat-uk.org/2015/06/30/50dollarsat-19-months-in-space/

New UK CubeSat Regulations Proposed

AO-73 (FUNcube-1) - Image credit Wouter Weggelaar PA3WEG

AO-73 (FUNcube-1) – Image credit Wouter Weggelaar PA3WEG

The UK Space Agency has conducted a review to evaluate how its regulatory approach might be tailored for CubeSat systems, they require responses to the proposals by September 1.

The UK’s Outer Space Act 1986 places a significant burden on small educational satellites such as CubeSats and other formats with the builders facing charges of up to £65,000 each year for insurance. These charges stop educational organisations building and launching CubeSats putting the UK at a significant disadvantage.

The UK Space Agency says:

Recognising the common aspects of such missions, there is an opportunity for the UK Space Agency to exploit a range of pre-determined technical assessments and associated likely regulatory outcomes for a range of likely CubeSat systems, presented in the form of a traffic light system.

The outcome of the internal review conducted by the UK Space Agency is a series of recommendations. The UK Space Agency invites responses from the space community on these proposals.

Comments on the recommendations and associated observations/suggestions relating to the regulation of CubeSats should be sent to Ryan King (ryan.king@ukspaceagency.bis.gsi.gov.uk) by September 1, 2015.

Submissions will be duly considered by the UK Space Agency and reflected accordingly in future implementation plans to address the regulation of CubeSats.

The two documents can be downloaded from

It is suggested those in the UK with an interest in small satellites, be it CubeSat, PocketQube or the other formats, provide feedback to Ryan King to help ensure the future regulatory environment does not place any undue restrictions on small satellite developers.

See the UK CubeSat Forum at http://www.cubesatforum.org.uk/

$50SAT 19 months in Space and still working

Yaesu handheld and $50SAT 1.5U PocketQube

Yaesu handheld and $50SAT 1.5U PocketQube

Michael Kirkhart KD8QBA provides an update on the $50SAT amateur radio spacecraft which measures just 5x5x7.5 cm.

Sunday, June 21, 2015 marked the 19 month anniversary of the launch of $50SAT/MO-76/Eagle-2.  The good news is it still operating.  The bad news is the power situation has been degrading, with an apparent step change on or near May 12, 2015, followed by another on Tuesday, June 23, 2015.  The last full telemetry capture made here in EN82 land was on Wednesday, May 27, 2015, and the last time it was heard was on Friday, June 6, 2015.  I continued to attempt to listen for it for another week or so, and heard nothing.  Has anybody heard it since then?

At this point, I have been monitoring it using Anton’s (ZR6AIC) WebSDR as it makes daytime passes over South Africa.  These occur between 7:30 and 9:00 UTC, which translates to 3:30 and 5:00 AM here in EN82 land.  This is tough, as I am not a morning person.  Sometimes, however, you have to do these things; helping build a satellite might be a once-in-a-lifetime event.  During these passes, where it has already spent a significant amount of time in sunlight, the battery voltage is below 3400 mV.  Is the battery going bad?  While it is certainly possible the battery has suffered from some loss of charge capacity, one has to remember it is does not generate energy; it merely stores it.  Since it is the solar power system that generates the power used by the satellite and stored in the battery, could the drop in battery voltage be due to a degradation in solar power generation?

Back around May 12, I noticed the MPPT (solar) current readings were typically less than 10 mA.  This much lower than it should be.  To better understand what might be going on, a new chart was added to the telemetry spreadsheet which shows both the battery voltage and the MPPT (solar) current (with the zero readings removed), each with its own linear regression line.  This chart can be seen from the following URL:


Notice how the MPPT current trend line has been sloping downward, similar to that of the battery voltage.  Moreover, starting 2 weeks before June 4, 2015 (each X axis division on the chart represents 2 weeks time), each reading has been at or below the trend line.

A more striking comparison can be seen by doing the following:
1. Zoom in of the Battery-Voltage-MPPT-Current-Chart to show the 4 week interval starting May 7, 2015, and ending June 4, 2015
(see https://www.dropbox.com/sh/l3919wtfiywk2gf/AACdQtySHZW3kVl7UMgSrxfHa/Telemetry-analysis/Battery-Voltage-MPPT-Current-Comparison-2015-05/Battery-Voltage-MPPT-Current-2015-05.pdf )
2. Zoom in of the Battery-Voltage-MPPT-Current-Chart to show the 4 week interval starting May 8, 2014, and ending June 5, 2014
(see https://www.dropbox.com/sh/l3919wtfiywk2gf/AACracUWkivilfsKGBUFkmDXa/Telemetry-analysis/Battery-Voltage-MPPT-Current-Comparison-2015-05/Battery-Voltage-MPPT-Current-2014-05.pdf )

$50SAT Boards

$50SAT Boards

In comparing these charts, it is clear both the battery voltage and the MPPT current were significantly lower this year that during the same period last year.  On June 5, 2014, the trend line value for battery voltage was about 3610 mV, and for MPPT current was about 30 mA.  One year later (June 4, 2015), the trend line value for battery voltage was about 3380 mV, and for MMPT current was about 14 mA.  Therefore, while it is likely the battery has suffered some loss of capacity, it appears the low battery voltage is due to low solar power output.  There are many possible reasons for this, including:

* Solar cell damage due to sputtering: since there was no protective covering on the solar cells, impacts from high energy particles can damage the cells, causing a drop in output.

* Solar cell damage due to thermal cycling:  We know from telemetry data the interior of the satellite cycle between +30 degrees C and -30 degrees C each orbit.  It is likely the exterior temperatures experienced higher extremes, and this periodic thermal cycling may have caused the solar cells to fracture, thus leading to a drop in output.

* Short circuit failure of one or more of the diodes which isolate each MPP tracker output, which can cause an inactive MPP tracker (one whose corresponding solar panel is not facing the sun) to load an active one (one whose corresponding solar panel is facing the sun).

Because of the limited amount of telemetry gathered, it may not be possible to determine the exact cause.  If the solar output power continues to drop, the battery voltage may never get above the 3300 mV threshold needed to enable the transmitter, at which point we will lose the ability to monitor its status.  Even if this does happen, however, we never really thought it would last this long.  We would have been happy if it just worked, and really happy if it lasted a month or two.  19 months – this is way beyond what any of us expected!

As of June 25, 2015, the orbit has decayed by about 73 km since launch.  Since April 21, 2015, it has been decaying at a rate of about 1 km per week.  Apogee is now at 561 km, and perigee is at 529 km.

The following are the TLEs from 2015-06-25:

1 39436U 13066W   15176.16386703  .00013608  00000-0  90105-3 0  9991
2 39436  97.7444 252.3622 0022818  80.2035 280.1767 15.07230510 86697

Again, if anyone wants to make an attempt at predicting when it will de-orbit, here is some useful information:

Average cross-sectional area = 0.014252 m^2
Mass = 210 g
Area/mass ratio = 0.06787 m^2/kg

From the 2015-06-25 TLEs:
Semi-major axis: 6922.8 km
Eccentricity: 0.0022818
Apogee: 560.6
Perigee: 529.0

As always, please post any telemetry, or for that matter, any reception reports to the Yahoo discussion group.  We would especially like to encourage our friends in the southern hemisphere to listen for $50SAT/MO-76/Eagle-2.  We really appreciate everyone who has provided reception reports and telemetry as well as access to their WebSDRs.  To date, we have 3,098 individual error-free telemetry captures, and the vast majority of these did not come from Stuart, Howie, or I.

73 Michael Kirkhart KD8QBA
$50SAT/MO-76/Eagle-2 team

$50SAT is one of the smallest amateur radio satellites ever launched at 5x5x7.5 cm and weighs only 210 grams. Transmitter power is just 100 mW on 437.505 MHz (+/-9 kHz Doppler shift) FM CW/RTTY. It uses the low cost Hope RFM22B single chip radio and PICaxe 40X2 processor.

$50SAT has been a collaborative education project between Professor Bob Twiggs, KE6QMD, Morehead State University and three other radio amateurs, Howie DeFelice, AB2S, Michael Kirkhart, KD8QBA, and Stuart Robinson, GW7HPW.

Further information in the $50SAT Dropbox https://www.dropbox.com/sh/l3919wtfiywk2gf/-HxyXNsIr8

There is a discussion group for $50SAT http://groups.yahoo.com/groups/50dollarsat/

50DollarSat http://www.50dollarsat.info/