Getting Started with a Space Project

This is a blog post I wrote for the STEMN website

How The OzQube-1 Project Began

Background

When you see all the awesome projects on the Internet, social media or even the news, you get caught up in the amazement and wonder of what the project is or has achieved. People sometimes forget that they all had to start somewhere. They were all just an idea in someone's mind, and at some point, that idea needed to emerge into the physical world. I wanted to share the background of my project with the STEMN community, and to give readers some tips on getting started.

In case you're not familiar with my project, it's called "OzQube-1" . It's a tiny PocketQubesatellite that I'm building it in my back shed. Although to be fair, just the development and assembly of the prototype has been in the back shed! Its mission is to capture images of Australia from space, and transmit those images back down to earth to anyone that wants to listen. It's made news on ABC Radio here in Australia, one of the leading Science news websites Phys.Org , and even a prime time Current Affairs TV show - Today Tonight .

But how did I get started? Why did I decide to do this particular project? Lets go back a few years.....

If you're reading this, then I'm probably safe to assume that you've heard of the Mars Science Laboratory, also known as "Curiosity." It was the first space mission that I'd really taken an interest in. I couldn't tell you exactly when I got that space bug, but the it was somewhere between the launch and when it landed on Mars, a little over 3 years ago in August 2012. By the time Curiosity had landed, I was well and truly on my way to being a space nerd. I had become so excited about things that I even got my colleagues at work to watch the live stream for the landing! Following that event, one of my colleagues would regularly ask me "How's your mate on Mars?", at which point I'd update him on the latest images or discoveries. 

Not content with one space mission, I subscribed to a popular internet forum that deals with all things space, to get my fix of information for missions both old and new. The Internet has made information on all types of space missions much more accessible, yet many of the hands-on details and know-how surrounding these missions still remained  locked up by government agencies, under the belief that the transfer of knowledge relating to satellite systems needed to be regulated just like the trafficking of arms. One area, however, contained an abundance of reference material - Cubesats. By 2013, the Cubesats had been in orbit for more than 10 years. Various Universities (Colleges), companies and government organisations had launched a number of satellites based on the Cubesat form factor, specifically for research and scientific benefits. This has resulted in a large number of papers and theses being written, detailing the cubesat subsystems, operational performance and mission details. This was a goldmine for a space information junkie like myself! But at this point, I was not considering starting a project of my own.

In late July 2013, a company called Planetary Resources started a Kickstarter campaign to fund a space telescope that would be publicly accessible, and have a second camera and a screen onboard. The screen would be used to display a selfie that people uploaded via the web, and the second camera would capture an image of  the earth with their image in the foreground. Here was a company that really wanted people to get involved in space exploration, so I became a supporter of the campaign, and began to follow their progress.

Not long after the Planetary Resources Kickstarter, another space related campaign started. This one had an interesting title - "Want to build a satellite but dont have a NASA sized budget?". The campaign was part of the launch of a new online store that supplied structures for a new type of satellite called a "PocketQube". This was the first time I had heard of a PocketQube. Even though these satellites were designed to be more affordable that Cubesats, the structures on offer as part of the campaign were still something that you'd only consider if you were serious about building a satellite. They're not something that you'd buy just for interests sake (they were about $500AUD). But the potential for the electronics inside it was something that appealed to me. Not only had I been getting obsessed with space, I'd started to listen to a podcast called "The Amp Hour" during my daily commute, and was keen to learn about how to use electronics design tools to make custom circuit boards. Still, a satellite seemed a bit too complex. I had recently made my first RC quad-copter, and was thinking about giving the controller an upgrade with GPS etc, ready to turn it into a proper drone.

Very soon after the PocketQube Shop campaign, the first 4 PocketQube satellites werelaunched into orbit. One of the PocketQubes was called $50Sat. It was designed and built with the name in mind, although I found out subsequently that the cost to make it was more like $250. It used commodity components and it took advantage of low cost electronic prototyping. The creators of the satellite had made a lot of the details of their project available on the internet, so I learnt that it was fairly easy to listen to the telemetry being transmitted. I ended up buying the required equipment, which was one of those USB TV tuner dongles, along with a modest antenna and a cable or 2. I was then able to receive the telemetry from this satellite while sitting in my lounge room (My wife thinks I look quite amusing waving an antenna around in the air, waiting to hear the alien sounding transmissions.) But still, I wasn't thinking about making my own satellite

I kept in touch with the person behind the PocketQube Shop - Tom Walkinshaw. We traded emails and discussed things like the need for a standardized circuit board and backplane connector to make up the stack inside the PocketQubes. He put me in touch with a group of enthusiasts around the world, and together we managed to arrive at some kind of consensus - the PQ60 standard. Throughout this process, I really wanted to keep the hobbyist - i.e. myself - in mind so that the specifications wouldn't  exceed the skill level or affordability that comes with doing things at the hobbyist level. I had started to use some EDA tools (like Eagle) to make sure I could route the traces on the circuit board to and from the main connector. 

It was around this time that I had come to the realization that I believed that I could build myself a satellite. All I needed to do was work out exactly what to put in it, how to get it all working together, then actually build it..... Sounds simple!

How to get started

So we're finally at the point where I stopped just thinking about making a satellite. It was time to start creating something. It was time to start the project. Little did I realise that I had already started. Here are my steps or tips to starting a space project.

The first step to getting started is passion. Passion is the thing that inspired you in the first place, and it is the thing that keeps you going. It drives you to learn about things that you haven't done before, and to pick up the pieces when you make mistakes. There are often other motivations for doing a space project, but to stick with it and see it through, you have to be passionate.

What happens next? I know this is going to sound pretty out there, but the next step is to actually start.... It's time to take all those thoughts that have been swirling round your head and get them out into some kind of coordinated order. You've heard of "back of the envelope" calculations? Well, put them onto a proper piece of paper! (or spreadsheet.....unless you're old school!) Create yourself a high level concept and work out the key components. See if you can create a single page summary of the project. You don't need to know all the details yet, you just need to understand what the aim of the project is and what is it going to do. 

From this point, you should be able to break down the project into smaller chunks. Think of  your main project as a collection of smaller projects, each one with a specific purpose. This is where you start looking at the resources that you have, have access to, or need to obtain. What parts are you able to complete yourself? Who are your team members? What skills can they contribute? It's around this point where you do the old feasibility analysis. Based on all the information you've gathered and the breakdown you've worked out, is the project achievable? Do you need to just focus on some of the smaller projects? Sometimes, the smaller projects are just as important in their own right. It would be better to complete a smaller project than have an unfinished bigger one.

Once you've got your long list of smaller projects, it's time to start getting into the nitty gritty and start the technical side of things. You know - hard facts and numbers, creating technical designs and making actual hardware. That sort of thing. Its up to you how this part is managed. Big projects may need proper Project Management. Small ones may just be worked on in your spare time. That's up to you, and that's well past the scope of this blog post!

So......Summary?

If the above was a little long-winded, here's a short summary for you to end on.

You've got to want to do something (you wouldn't be reading this if you didnt!) 

Be passionate about the project. Know what you want to achieve.

Get the high level plans onto paper, or computer. Summarize the project.

Break it down into smaller, manageable chunks.

Start something amazing!

I hope that this post helps at least one of you out there. It may not work for all of you, but it is how I see things through what I've experienced creating my own space project. Please leave me feedback in the comments, and follow my project here on STEMN, or on Twitter andFacebook . If you want to help get my project into space, please consider donating via myGoFundMe campaign

Backyard Shed In the Media

After presenting at the Australian Cubesat Workshop in April, the news about OzQube-1 had started to spread! It was picked up on by a local journalist who made contact with me. He said that he'd like to write an article for a newsletter that he publishes (Tiros Space Information), and that he also writes for the US based SatMagazine.
We did the interview, and he took a few photos. The results are here:
http://www.satmagazine.com/story.php?number=1481898241

Following the appearance in the newsletter, I was contacted by another journalist who was representing ScienceNetwork Western Australia (SNWA). SNWA is produced by Scitech, the state’s science and technology centre and supported by the WA Government’s Office of Science via the Department of the Premier and Cabinet. So it's kind of a big deal here in Western Australia.

The article hit the website on 15th June 2015
 "DIY satellite launches from backyard shed to lower orbit"
The media reach from this was unexpected! The article was aggregated by Phys.org - http://phys.org/news/2015-06-diy-satellite-backyard-orbit.html

And to top it off, the "Inside Cover" editorial in the only daily Perth based newspaper - The West Australian, picked up on it. Here's what page 2 of the paper looks like:

As a bonus, the resident cartoonist - Dean Alston, drew a  cartoon with a humorous take on backyard launches!

I had always wanted to try and inspire others with my project, so hopefully this media coverage will help with that goal. The humble backyard shed is where many great things can start!

OzQube-1 CDH Design Complete

I had joked on social media that the CDH had passed the KDR - The Kitchen Design Review. For those not in the know, this is a play on the name of the Critical Design Review (CDR) phase often used in aerospace. In my case, I was being very literal - I reviewed the design in the kitchen! I have settled on a final design for the first revision of the OzQube1 CDH ( Command and Data Handling) board. This is the brains of the satellite. It co-ordinates the recording of data from the various sensors including the camera and the transmission and reception of data from the radio. So what's inside?

The OzQube-1 CDH

The brains of OzQube-1 starts with an Atmel ATmega328P Microcontroller. This is the same microcontroller used in many Arduino boards, and is closest in design to the Arduino Pro Mini 3.3V . It is an 8-bit microcontroller that runs at a leisurely 8 MHz. It has a "massive" 2 Kilobytes of SRAM, and 32 Kilobytes of flash memory. So it's a long way from something like your mobile phone or your computer.

In order to store the image data coming from the camera, a Micro-SD card is also incorporated onto the board. The Micro-SD can also be used to store telemetry data if required.

The next piece is the 9-axis motion tracking IC from Invensense - The MPU-9250. It contains a 3-axis Gyroscope, a 3-axis Accelerometer and 3-axis Compass. This is used to determine the satellites orientation, and the measure the strength of the earth's magnetic field. 

The next critical piece is the RTC (Real Time Clock). This, as the name suggests, is a clock. It can measure time more accurately that the microcontroller can, and uses a lot less power doing it. Unfortunately, because a satellite needs to have all power removed until it is deployed from the launch vehicle, it isn't possible to set the time in advance. It will only start counting once it has been deployed. It is possible to set the time remotely, but as there's no GPS onboard OzQube-1, the time will only be an approximation.

The RTC provides another very useful function, which is a countdown timer. The RTC can alert the microcontroller once a specific period has passed. It is important to do this external to the microcontroller, as microcontroller can sometimes get a bit "distracted" performing other tasks, leading to incorrect time measurements.

The remainder of the CDH is the local power supply arrangement. This includes a Watchdog Timer, which will reset the microcontroller if it hasn't toggled one of its inputs within a specified time. The electronics of the CDH are all 3.3V, but the EPS and Battery have a few different outputs. The EPS provides a regulated 3.3V for the CDH. This is the primary power source. If, for some reason, the 3.3V circuit fails, the CDH has its own circuit to take the battery voltage and regulate it down to the 3.3V required. This isn't as efficient as the EPS, but allows a bit of fault tolerance. Controlling all this is a small control circuit that will automatically switch and prioritise the power source.

Expansion

The main limit I found was the number of pins available on the microcontroller. The TQFP package of the ATmega328P has 32 pins. While I've managed to squeeze all the functionality into this design, I haven't stuck to the full PQ60 design specification. I'm not able to connect all the GPIO pins on the backplane to the microcontroller. 

One possibility is to replace the ATmega328P with another in the Atmel family - the ATmega1284P. This is the same architecture, but has 44 pins, 4 times the flash memory capacity and 8 times the SRAM capacity. It can also be configured to use the Arduino development environment, so it can be programmed the same way. 

Future satellites could use a different microcontroller architecture, but for OzQube-1 I wanted to stick to something that people are familiar with.

Basic PocketQube Power Supply

After posting a couple of pictures on Twitter of the small power supply I'd built for PocketQubes, I thought I'd give a bit more detail in a blog post.

Even though I'm building a different EPS (electrical power system) for my PocketQube "OzQube-1", I wanted a small power supply that could power the satellite while I am testing it.
I had a few requirements:

1. It needs to be able to be powered from a plug pack (wall wart) or from an external battery pack. 
2. It has to fit into the PocketQube PQ60 form factor
3. It needs to output 3.3V and 5V
4. It needs to have a similar current capacity to the real spacecraft EPS
5. Cheap

There is actually a very common thing that already fulfils most of these requirements - the humble breadboard power supply! The main issue is that they don't fit inside a PocketQube.

Fortunately, I have a prototyping solution that's already in the PQ60 PocketQube form factor - ProtoQube.

All that's needed now is a few components.

If you look at a breadboard power supply, they often have a DC jack, and a USB input. The problem with USB is that there's often a 500mA current limit. This wasn't going to work for me, so I opted for a 2 pin screw terminal input. 

Another issue with a breadboard power supply is the the voltage regulators. These are often SOT-223 surface mount parts. This is ok for a custom made power supply, but ProtoQube has a grid of holes, so a through hole regulator is needed. In order to keep the component count down, I went with fixed value voltage regulators. There are many on the market, so I went with some that were readily available - the ST Micro LD1117V50 and LD1117V33. These just need a single bypass capacitor on the input and output, and are capable of 800mA current.

Finishing off the power supply are some pin headers for each rail, and a LED indicator to show when power is connected. I also added a diode on the input for reverse polarity protection. Here's the schematic to show how it's all connected:

Assembling the power supply just requires some additional solid core wire, and the components arranged like you see in the pictures.

All that's needed now is to solder on the Hirose FX8C backplane connector, and some female pin header sockets so I can connect the power supply output to the rest of the stack!

OzQube-1 Presentation at Australian Cubesat Workshop

Late last year, the Australian Centre for Space Engineering Research (ACSER) announced that they were going to run a workshop titled "Launching Cubesats for and from Australia" in early 2015.

Yessss! Finally a smallsat event in Australia that I can attend, even if it is a 5 hour plane flight away.

After a suggestion from a Twitter follower ( Thanks @AusAndgie7 !) I made contact with the organisers to discuss the possibility of me doing a presentation about OzQube-1. As my email was sent between Christmas and New Years, the uni staff were on holidays and didn't reply straight away. But once they were back from their break, I got a reply saying that I was more than welcome to present! Now I just had to wait for further details as they arranged their schedules.

A few days ago, all the speakers received the draft schedule, and it looks like I'm on just before Tom from the PocketQube Shop, who is going to do his talk remotely via video conference. Each speaker in the "Missions" section has a  7.5 minute slot, including questions, so I'll have to make sure I don't spoil Tom's talk! Not to mention that this is the first time I've talked about OzQube-1 to a large audience, so hopefully I do ok. I don't want to have it turn into "7.5 minutes of terror"!

So if anyone that is interested in PocketQubes or Cubesats, and can make it to Sydney for April 1st, 2015, make sure you reserve a seat ( they're free). I'll be there all day, so come up and say "Hi!"

Cool PocketQube Infographic!

The PocketQube Shop and the DIY Space Exploration website have teamed up to create this fantastic PocketQube infographic.

Courtesy of: DIY Space Exploration

PocketQube Radio Ramblings (#2)

I have just come across a new product that might be interesting to all the PocketQube builders out there (or anyone who is interested in small RF links in general).

It is a new module from a company called "Nice RF" . This is different to HopeRF , so it seems that competition is alive and well in Shenzhen, China!

The module is the RF4463F30 .

If the part number looks familiar to those in the know, it is because it is based on the Silicon Labs Si4463 Wireless IC. The difference with this module is the F30 on the end of the part number....(Sorry, had to go there :-) ) Whereas the Si4463 is rated at +20dBm output, this module adds a power amplifier to boost the output to +30dBm! That's right, one whole watt! The module costs around $18USD, and is selling on AliExpress

Now HopeRF have a similar module , the RFM23BP, based on the Si4463's predecessor, the Si4432. This module can be purchased for around $9USD from places such as Anarduino

Remember, the Si4432 is the IC inside the venerable RFM22B, as used in $50Sat, which has now been continuously operating in space for more than 6 months! While the RFM22B has an output of +20dBm, the RFM23BP has an output of +30dBm. The RFM23BP also requires a 5V supply ( but supposedly works down to 3.3V)

To work out the differences between the RFM23BP and the RF4463F30, we'll need to dig into the datasheets. Now at the moment, the datasheet for the RF4463F30 is a little sparse, so I'll have to wait til my in-depth queries are answered by their tech support people. But on the surface, the differences are as follows:

Max Data Rate: 256kbps (RFM23BP), 1000kbps (RF4463F30)
Receive mode sensitivity: -120dBm (RFM23BP), -126dBm(RF4463F30)
Note the higher sensitivity of the RF4463F30 is based on a lower bit rate and smaller frequency deviation.
Receive mode current: 25mA (RFM23BP), 10-13.5mA (RF4463F30) - which seems to have 2 different sensitivity modes - High and Low
Transmit mode current (max power): 550mA (RFM23BP), 540mA (RF4463F30)
Size: 33mmx18mm(RFM23BP), 38mmx20mm(RF4463F30)

Now as the RF4463F30 is based on the Si4463, all the software commands that apply to the Si4463 can be used on the RF4463F30. Bearing in mind that 2 of the GPIO pins are used internally in the module for antenna switching functions.

So is this new module worth double the cost of the RFM23BP? Remembering we're talking about wireless modules that cost under $20 each, but it depends on your scenario. If you need to have (relatively) high power, both modules fit the bill, with similar power output and power usage. The newcomer seems to use less on the receive side, but if you want lower power usage for receiving, you may want to get the regular Si4463 module without the high power option, as the sensitivity is the same. The HopeRF module uses a register based firmware, whereas the Si4463 uses a new API approach.

I think some testing may be in order to really understand how the modules perform.

Other Modules

Looking at the NiceRF website, they have a few other modules that use either the Si4432 or the Si4463 Wireless IC's. Another of interest is the RF4432F27  . Looks like a +27dBm version of the RFM22B. Max TX current is 350mA @ 5V ( in case 500mA is too high)

They also have some test or demo boards with built-in Microcontroller and LCD. 

All in all, it looks like there are now a few more options for ready made radio modules for PocketQube's!

EPS Info for nanosats

Some more useful info for PocketQube builders relating to the ST SPV1040 IC. Turn out that it is being used in the US AMSAT Fox-1 Cubesat, CUBESTAR cubesat, NTNU Test Satellite ( NUTS), ESTCube-1 , and probably several others. If you read all the papers and articles about these, you should get a good idea about system designs.

This means the list of useful candidates is:

Linear Technology LTC3105
ST Microelectronics SPV1040
Spansion MB39C831QN
Texas Instruments BQ25504

They all have different features and limitations, so you'll need to look at the datasheets to make sure it's right for your project.

Receiving Telemetry from Satellites - DIY Style

Why would you want to?

I'm sure everyone could appreciate the reasons for satellite operators to receive the signals or transmissions from their own satellites, but why do people want to receive signals from other peoples's satellites? I'm not talking about the signals of the Satellite TV stations. I'm talking about the morse code, and other encoded data transmitted from many nanosatellites currently in orbit. 

I call it Citizen Science. And because it doesn't take a whole lot of gear to get it happening.

Alot of Cubesats and PocketQubes are from organisations that don't have the global communications networks like NASA or ESA. They are often based in a single location in a single country. Consider how often a satellite will pass within range of that location. At the altitude most nanosatellites orbit the earth, they only have line-of-sight contact with the groundstation for about 9 minutes or so.  Nanosatellites also have a limited speed that they can transfer data at. If that organisation could only transfer data from the satellite when it is in range of that single ground station, the total amount of data transferred would be very low. The satellite would have to store information from its many orbits, then try and dump all the data when it is in range. 

Now imagine if that satellite operator had ground stations spread all the way round the world. The measurements taken by the instruments onboard could be downloaded much more often. It the information was then collated, it would be much more useful.

An example at the moment is the PocketQube $50SAT. This little satellite transmits in the UHF band, at 437.505Mhz. The transmitter is only 100mw, which is pretty low compared to most small satellites. They have published a document in their dropbox account that describes how to receive their telemetry. Each transmission contains the actual realtime readings from various spacecraft sensors. If no-one receives the transmission, that info is lost. Anyone with the right gear can receive these signals and help the $50SAT team with their measurements.

Aren't HAM radio's expensive?

Good ones are, but we're going to use some modern tech that is cheap, and then you can either buy or build an antenna to your liking. It all depends on how you want to use it.

What do I need to do?

We'll use $50Sat as an example. The published communications guide contains alot of info, but before you get to that, you'll need about 5 things. A USB DVB-T Dongle, an adapter, an antenna cable, an antenna, and a computer to install a few pieces of software on.

USB DVB-T Dongle.
Often found on eBay. Search for RTL2832U or E4000. Or go to http://sdr.osmocom.org/trac/wiki/rtl-sdr to get a list of compatible dongles. I used one like this

Antenna adapter.
 Depending on the type of dongle you purchased, you'll need to adapt the antenna connector to one more readily used for the frequencies we're interested in. Also on eBay. The connector I had was an MCX connector, so I got an MCX male to SMA Female adapter.

Cable.
Now this depends on what type of antenna you're going to use as well. I'll assume for now, you're going to wave something round the lounge room, until you work out exactly how to consistently receive the transmissions. So you'll need a cable anywhere from 1-3M. The type if cable can vary. Use RG59 for short lengths, or something like LMR200 for lower cable loss. SMA Male connector on one end, and the other end will depend on your antenna. Usually it'll be an N Male. Mine was purchased with the antenna. I went with 3M of LMR200 cable.

Antenna.
There are many books on the subject. You could either make or buy one, depending on how keen you are. I went with a custom tuned 4 element Yagi from an Australian supplier called ZCG Scalar. The model is the Y404 . I requested the tuning for a center frequency of 437Mhz. RRP for this antenna was $199.
Here's a British Interplanetary Society article showing a few other options they are using for receiving signals from KickSats.
Computer
First, you'll need some software to use with the SDR dongle. 2 that I use are SDR# and HDSDR . SDR# has a guide on how to install the required drivers on Windows. The HDSDR site has instructions for specifics to their software.
Basically, don't let windows detect and install a driver. Click cancel to check online etc. Then run the Zadig software to associate the proper driver with the Bulk-In Interface 0. Don't worry about Interface 1.
Then put the correct dll files into the program file folder.
Like I said, just follow the instructions for the software you're going to use. You may want to read the user guides for each bit of software to become familiar with how they operate and how you set the tuning frequencies etc.

Next, you'll need to find out where the satellites are! You can do this with a program called Orbitron. Once again, read the manual for how to use it. You'll need to get the latest TLE's for the satellites from Celestrak. Orbitron has this function built in. TLE's are also known as Two Line Elements. They describe the orbital characteristics of a satellite. Load the Cubesat.txt TLE file, then select Eagle 2 from the list. This is the alternative name for $50SAT. Once selected, it will show you the current location of the satellite!
Now set your home location, then run the prediction setup and enter the required parameters. Go to the Prediction tab then press Predict. It will show you when the satellite will be in range next.

Receiving signals from space!!!!

Once you've got the hang of Orbitron and the SDR software, you're ready to track down the satellite. When Orbitron says the satellite will be in range, start the SDR software and configure it to record the raw input signal RF. This file gets big very quick!

Select LSB , and set the tuning frequency just below the frequency of $50SAT ( 437.495 ish) The exact figure doesn't matter as the dongle isn't 100% accurate, and you can adjust later.

Watch the waterfall around where you've set the tuning frequency, and with any luck, you'll see the telltale blips leading up to the RTTY transmission. You can set the tuning frequency just above the signal, so that the highlighted area covers the radio signal. The RTTY looks like 2 parallel lines running at an angle up the screen. Here's an HDSDR screenshot.

Now you can either keep recording while the satellite is in range, or move to the next step.

Decoding It!

Now here's the very low tech bit. You'll need a 3.5mm Stereo to 3.5mm Stereo cable, long enough to connect your microphone jack to the headphone jack.
Open the sound mixer on your computer and go to the input settings. Turn off any microphone boost checkboxes, and set the volume down just under 1 segment. Plug in the cable.
In HDSDR, open the WAV file you created earlier ( usually in MY Docs / HDSDR). Loop through the file and set the tuning frequency so that the whole transmission is contained within the highlighted area, then go back to just before the transmission starts, then pause the playback. Open a sound recording program, such as the built in Windows Sound Recorder. Hit record, then unpause the HDSDR playback. Look at the sound recorder to see if the audio level as high or low enough. You want it high enough so that the volume is good, but no clipping or distortion. ( Remember to unplug the headphone plug to hear the playback!!!)
If the levels are good, save the file as 48Khz , 16 bit mono audio. ( Must be mono)
Then, as described in the $50SAT comms document, you'll need another bit of software called "fldigi".
Setup the software as described in the document. One thing that isn't mentioned in the document is some settings that are visible in the latest version of the software. At the bottom left of the screen are 2 boxes with arrows either side - "Upper Signal" and "Signal Range". I set these to -28 and 17 respectively, but this can vary depending on the volume level of the output file.
Select File > Audio > Playback, then select the file you created with Sound Recorder. It should start a waterfall display down the bottom of the screen. If you've setup the software correctly, you should be able to click in the centre of the rtty transmission, and the red bars go over the red part of the waterfall plot.
If the signal is right, you should start seeing the telemetry being decoded in the top window!
You may need to manually click the centre frequency "up the slope" to get it to decode different sections of the file, in case the Auto Frequency Correction doesn't work.

Voila! You're now receiving and decoding data from a satellite.

If you validate the data correctly, submit it to the $50SAT team to add to the other reports that people are making. Hopefully you'll get a warm fuzzy feeling that you've helped someone, and a sense of achievement that you've built a functional ground station!

PocketQube Radio Ramblings

As PocketQube's are pretty new on the space scene, there isn't much in the way of  COTS hardware available. You can now purchase the bus structures and ground integration jigs from PocketQube Shop , but it takes a few more components to get a fully functioning satellite!

One important area to consider is comms. How am I going to communicate with the satellite, and how is it going to communicate with the ground? For now I'll just talk about the space to ground segment hardware. I won't include discussions about licensing as that's for another time.  The spacecraft is going to need a radio and an antenna, along with sufficient power to enable the signal to reach the ground.

Out of the 4 PQ "veterans" in space, at least 2 ($50Sat and T-LogoQube) are known to have used the HopeRF RFM22B radio module. This is a tiny 16x16mm RF tranceiver module, that is capable of +20dBm output (That's 100mW for those that haven't googled it yet), in the UHF frequency range. It is based on the Silicon Labs Si4432 Radio IC. Despite the seemingly limited power output, some of the data types can be detected almost horizon to horizon - approx 2900km range! Data packets can also be decoded at up to 900km with just a 10db gain Yagi and a LNA. Not bad for a sub $25 radio module!!!!!
Compare this to Cubesat Radio systems that cost well over $5000. GomSpace sell one for 8000 EUR with a 3W transmitter. Clyde-Space have one for $8600 , with 500mW to 2W RF output.

There's a thread on the DIYsats forum here about this and other HopeRF radio modules.

So where to from here?

So the RFM22B is a proven performer for PocketQubes. Its low power requirements make it a good choice, but it does have some limitations. The data rate used by $50Sat is 1kbps. This is fine if your payload isn't very data intensive. But what are the alternatives? Here's a few areas I am looking into.

HopeRF make another module  - RFM23BP. This is similar to the RFM22B, except the power output is 500mW. The higher power should allow higher data rates. The issue with this module is the higher electrical power requirements, which can affect how the PQ power subsystem is designed.

Still on the HopeRF parts list is the RFM69HCW. This module appears similar in specification to the RFM22B, but is based on the Silicon Labs Si4463 module. Now Silicon Labs state that the Si4432 shouldn't be used for new designs, although I don't think they intended their parts to be used in space! The Si4463/RFM69HCW uses an new API style approach to programming. While touted as being simpler and more efficient, testing from the $50Sat team has so far proved otherwise.

Silicon Labs also state that a low cost external FET can be used to boost the output to 27dBm/500mW.

Testing would need to be conducted to validate this approach.

Another HopeRF product is the RFM26W . While similar again, it is described as a device that "operates as a time division duplexing (TDD) transceiver where the device alternately transmits and receives data packets."

On to the RFM96W and the RFM98W. These are based on Semtech IC's, probably the SX1276 . These have the capability of using a patented LoRa modem, which can potentially increase the devices sensitivity, and therefore link budget. Further investigation is required as this ic has duty cycle limits, and whether the LoRa function works when the radio isn't configured for spread spectrum usage.

Then there's the HM-TRP. These are possibly most commonly used in the 3D Robotics Wireless Data Module. These also have 100mW/20dBm output, but operate as a simple transparent FSK transceiver - meaning that you just feed it UART data and it converts it to RF.

Another option could be to use a FEM ( Front End Module) in conjunction with the RFM22B. RFMD make a module - RFFM6403 . This is a 1W Power amplifier, but it can also operate in Bypass mode if required. It can also be a LNA for the receiver. This part is brand new and is available now in a reel, or later in March if you need single items. Definitely worth evaluating.

Other alternatives are pre-made modules from Radiometrix. They have some compact VHF / UHF transceivers. ( maybe not as cheap as $25 though).

Then there's 2.4ghz modules........ I haven't looked that far into this, but given my intention to use a USB SDR Dongle as a groundstation, that's out of their frequency range ( although I did find an interesting article recently using some cheap hardware as a down-converter. See here for info)

Conclusion

The only conclusion so far is that I really need to get my Amateur radio license and start doing some testing! I've purchased some of the HopeRF modules for testing, and have made the rookie mistake of buying the bare modules, sans breakout board. Half pitch pins don't fit in normal breadboards!

Fortunately bare breakout boards for the RFM22B are available from Modtronics in Australia. Others should take my advice and get populated boards such as those from Modtronics or from Sparkfun in USA. 

As for the other modules, if you have any skills in KiCad, you can design a basic breakout and get the boards manufactured relatively cheaply from places such as Seeedstudio or Itead Studio. 

I'll let you know how I get along!

How do I start to build a PocketQube?

So, you think the idea of building your own Sputnik seems pretty cool. I don't know if it's a good pick-up line at parties, but as far as personal achievement goes, it's up there. But where to start?

Disclaimer: I'm not an expert, or even qualified to give financial advice...This post is just to give potential people or teams a place to start and spur imagination and further exploration.

Back to the story. If you've got to the point of thinking that you're capable of building a satellite, you probably got at least some knowledge about what's involved. Yes? No ? I'm not going to write this "Choose your own Adventure" style, so I'll start with some basics.

You've got as far as deciding on a form factor for the satellite. PocketQube. Now, what size PocketQube are you going to build? If you know anything about getting things into space, it's not exactly cheap, and the cost is based on mass. The bigger the chassis, the larger the mass. So a 1P PocketQube is the smallest in the range, and you can go up from there, generally in .5P increments, up to 2.5P. PocketQube Shop can provide a range of off-the-shelf hardware. Or you can build it from scratch like Wren . Depends on the skills you or your team possess. You just need to ensure it complies with the PocketQube Standards.

Next. Subsystems.

There's a few critical systems you'll need to have. While they can be separate, and often are in cubesats, they may need to be integrated for a PocketQube. But as far as design goes you'll need to think about the following:
Power ( Generation and storage)
Command and Data Handling ( CDH)
Attitude Determination and Control Subsystem ( ADCS)
Communication
Payload
Thermal
Structure
Software

Now you're going to have to "hit the books", both literally and metaphorically. Each subsystem can be considered a specialist area, and there are many books on each one. Pocketqube's haven't been around for a while, so there's nothing currently written that's specific to the platform.
At the cheaper end of the scale ( less than $8), there are general books such as "DIY Satellite Platforms" by Sandy Antunes. The other end of the scale has textbooks like the "Handbook of Satellite Applications" that costs $850.
Or you could use the internet. The Cubesat standard has gone through the same progression that the PocketQube standard will undoubtedly go through. There are presentations from Cubesat Developers Workshops  . There are peer-reviewed publications . There are hundreds of PhD Thesis that can be Googled.

At the end of the day, you'll need to apply what you learn and build your satellite. There's not yet a complete turnkey COTS solution for Pocketqubes, so you'll have to roll up your sleeves! You'll need to understand each of the subsystems and devise a way to integrate them all. You'll learn things like "Link Budget" and that Lithium Polymer batteries won't charge in temperatures below 0C, and many other intricacies of building a satellite.

Testing. Do what the $50Sat team did and breadboard your satellite. At early stages, you don't need to have the final circuit board designed. You don't need the space rated solar cells for testing your control and radio code. When you get close to finalising these things, make 1 or more engineering models so you can test mechanical systems like antenna deployment.

There's definitely alot to learn if you're an amateur like me, but it's achievable. The cost of the hardware isn't exorbitant, and you just need the dedication and enthusiasm ( ok, and aptitude) to build your own satellite.

What or Who is OzQube-1?

OzQube-1 is the name for a pico-satellite that is proposed to be designed and built as a DIY project, by a space enthusiast. It is going to be based on the PocketQube form factor. This means that it is very small as far as satellites go ( as small as 5cm³), and will not use expensive hardware.

Inspiration for this satellite came from Kickstarter, where I contributed to a project called Pocketqubeshop.com. This project showed me that it was possible to build a satellite for less than the cost of a TV. ( Launching it is another thing I'll go into another time). The Kickstarter campaign coincided with the first launch of several satellites using the Pocketqube form factor. The highlight for me was the $50sat , or Eagle2. This is a Pocketqube that was built for around $250 in parts* ( the original plan was for $50, but they opted for higher cost solar cells). This little bird has proven to be a solid, reliable platform, providing radio telemetry to radio amateurs around the world. It was a collaborative education project between Professor Bob Twiggs, ( the inventor of the cubesat and Pocketqube standards), Morehead State University in USA, and 3 radio amateurs. Have a look at the links page for more on $50sat.

It is the intention that OzQube-1 follows a similar path. The beacon and basic telemetry will be using the amateur radio bands, with an aim to make it accessible to anyone with a USB Software Defined Radio (aka USB DVB-T dongle from eBay) , some free software, and an antenna.

Now I am not an engineer, or someone that has had previous experience with building hardware for space. I'm currently an IT Professional, but I am definitely an amateur when it comes to the other skill areas required for building this craft, so I'll be learning a lot along the way. I have tinkered a bit with various mechanical and electronic systems, so I'm not completely in the dark about the challenge that lies ahead.

In addition to the amateur radio part of the craft, I've yet to formalise a plan for the main onboard computer that will function as the Command and Data Handling System, or any potential payload. I'll have more in future posts!

Naming the Baby

Like with a newborn, a name is something that parents approach in different ways. Some go through the pregnancy trying to decide on a name they like. Some have a name picked out in advance, well before conception. Some wait till the baby is born before they decide on a name.

Having never been involved with the build of an actual satellite before, I was not sure what to do. I've only just decided to build a proof of concept "engineering model" PocketQube. I'm not sure what it's purpose is yet. I'm not even sure if it's something I'm capable of building. I don't know if I'll have the resources to progress the idea past a certain point.

BUT, I'll give it a shot! So while I'm formulating a plan for this endeavour, I thought it would be better if I gave it a name, so that my obsession can have a focus. ( plus it gives my wife a specific thing to refer to, rather than call me Space Geek)

I've experienced naming children, so surely this couldn't be too far removed?

So what does one do in this day and age? Well.... I emailed people and Googled names.
Being a relatively new standard, there aren't many birds flying yet, so there's not alot of risk in having the same name as an existing PocketQube. I looked at names of CubeSat's. I looked at Australia's involvement in the space industry ( didn't have to look far, but it eliminated Aussat from the list of potential names)

After all that, I wanted something simple, that referred to 2 things - Australia and PocketQubes.

The result:

OzQube-1

(Because it could be the first of many!)