By Aaron Harper

Communication is a fundamental part of intelligence; it is one of the things that makes us human.  It should come as no surprise that a foundational technology to mankind’s reach into space is his ability to communicate.  To communicate with a spacecraft, a specialized set of equipment is required.  It requires a computer, radio, antenna, and operator.  While this sounds fairly straightforward, space throws us a few curves.

The first issue is literally a curve…  the curvature of the earth and to a lesser degree the local terrain.  This is an issue because a spacecraft is only visible to any given spot on earth for a small part of it’s orbit.  It would really help to know in advance where the spacecraft will be at any given time in order to prepare for the communication.  As you would expect, this is possible with the application of mathematics

The second issue is that to remain in orbit, the spacecraft is moving at a fairly high velocity, and thus the time it is visible (called a window) can be quite short if it is in low earth orbit (LEO).  At a higher orbit, the craft remains visible for longer as it’s apparent motion is slower until you get to the geostationary altitude of 22,236 miles, when the apparent motion matches the earth’s rotation, making it stationary relative to a fixed point on the earth.

A third issue is the orientation of the spacecraft.  While it is generally safe to assume the business end of the antenna will be pointed at the surface of the earth, but what is up, down, left, and right makes a difference in standard antennas.  The craft will cross over different parts of the ground at different angles (skew), so a standard vertical or horizontally polarized antenna will require constant fiddling like the rabbit ears on an old TV.

The fourth issue relates to the apparent (relative) velocity of the spacecraft.  Like anything else in motion producing a waveform, the doppler shift applies.  As a train approaches the sound of the horn is higher than when it departs because the sound waves are compressed by the motion of the train relative to the listener (you).  The satellite, which is moving at a good clip relative to the ground station shifts the radio frequency as well, making tuning rather challenging.

The final issue is that radio signals become weaker as the distance increases (inverse-square law).  A very bright flashlight will be barely visible, if at all, on a distant mountain.  This is because as the light travels outward, less and less photons reach our eyes until it is below our ability to perceive it.  Spacecraft are a fairly long way away when in orbit, not to mention when they are visiting distant worlds, so receiving their signals becomes quite challenging.

Without solving these issues, stable radio communication with space assets is impossible.  Fortunately, these problems have already been solved for us, and it is these solutions working in concert that become a 21st century ground station.  Today a ground station designed to receive voice and data traffic from spacecraft such as ISS may be constructed using common components for under $200.00, not the millions it cost NASA.

A computer running software to predict a satellite pass is the first component of a ground station.  This will easily predict satellite passes, giving us the craft’s precise location in the sky at any given time, though it generally will not take terrain into account.  GPredict is a free, open source program that has an intuitive interface, displaying the data on a table or the view on a map or polar graph.  With some plug-ins, it also solves a few of the other issues as well.

The skew issue is solved by using circular polarization which only cares if the signal is sent with a right hand or left hand polarization (imagine a spiral from the spacecraft to the ground station), not which way the transmit and receive antennas are oriented.  This is a function of antenna design, and a bit of a “black art” compared to the rest of the solutions.  This brings us to a decision…  to point or not to point.

There are plenty of omnidirectional circular polarized antenna designs, but they have a weakness.  An antenna which points in all directions at once can only increase the signal (gain) by a factor of 8 as a theoretical maximum (+9dB), while antennas which focus on one direction (directional antennas) can go much higher, bringing in the weak signals.  The disadvantage is that the higher the antenna gain, the more directional the pattern, and the more precisely the antenna must be aimed.  This increases complexity, mass, and expense.  Always a tradeoff.

The ability to point a directional array, while technically optional for LEO spacecraft, is mandatory for anything in geostationary orbit or beyond.  The mechanism used to point the antenna or array of antennas are largely up to the imagination of the engineer, but they must be made to point accurately enough so that the spacecraft stays within the peak gain area (lobe) of the antenna and it is able to do so in high wind without damage.  Keep in mind that flat panel antennas as well as dishes make excellent sails on blustery days.

Now, wouldn’t it be nice if the prediction software such as GPredict were able to sent the direction of the spacecraft to the pointing assembly (Az-El mount)?  Most can!  In GPredict, a module called hamlib may be added which facilitates the communications between the computer running GPredict and equipment including Az-El mounts.  That said, for the sub-$200.00 ground station, an omnidirectional antenna will be used.
Since the position and velocity of the craft are known, the prediction software may be used to calculate the anticipated doppler shift during the satellite pass.  Using this information in GPredict, some radios may be tuned directly using the hamlib plugin.  This makes running a modern, well integrated ground station a relatively simple process.  As a spacecraft comes into view, simply select it on the software and the hamlib plugin will point the antenna and keep the radio in tune.  This solves all but the last issue in setting up a ground station, that of signal strength.

Major factors which contribute to the ability of a signal to reach from the transmitter to the receiver are the output power of the transmitter, the gain of the transmitter antenna, the distance (inverse square of the distance, as mentioned before), the gain of the receive antenna, and the sensitivity of the receiver.  Unless we designed it, we don’t have much control over the transmitter output power, antenna gain, or the distance (orbital altitude) of the spacecraft.  This leaves the receive antenna gain and receiver sensitivity as areas the builder of a ground station can optimize things.

Fortunately for us, modern radio receivers have really improved.  Back in the day, we were lucky to get a sensitivity figure of -84dB, but today a $20.00 USB dongle is capable of -114dB.  To put this into perspective, every 3dB difference essentially doubles the measurement in this logarithmic scale.  This means that the 30dB difference represents a real improvement of 2 to the 10th power, or 1024.  In English, a modern USB dongle receiver available on Ebay or Amazon is over 1000 times more sensitive than those used in the 60’s that communicated with our astronauts on the moon!

Sensitivity and low cost isn’t the only thing these receivers have going for them. those same receivers which had the 84dB sensitivity were capable of tuning only within a fairly narrow band (406 – 549 Mhz).  The dongle (a Realtek RTL2832u TV receiver) is capable of tuning 24MHZ to roughly 1850MHz by way of comparison.  Simply put, this dongle makes the bridge between a modern computer and an antenna, turning it into the ground station Apollo era engineers could only dream of.  The only wildcard is the antenna.

While there are many antenna designs, to keep the ground station simple and below $200.00, we must select the best omnidirectional solution instead of building (and paying for) an Az-El mount.  A little research has shown a simple design with excellent gain characteristics that can be built by a hobbyist; the “eggbeater” antenna.  As it’s name suggests, this antenna’s design looks like an eggbeater with two wire loops at 90 degrees to one another.  This antenna is circularly polarized, and has a gain of around 8dB.  Construction details are available at here.

This leaves one final component.  The operator is a person with the responsibility and/or interest to operate the ground station.  They have the knowledge of how the systems work, and get usable audio and/or data from the system.  While a license (FCC amateur radio, ham license) is not required for reception in the United States, local, homeowner association, and national regulations vary.  Check if in doubt.  That said, a ham license will be required for the next step: transmitting.

Transmitting voice and data is required for most use of space based assets and real communication.  This will be the subject of the next $200.00 project write up, and as said before, the use will require an FCC license.  A technician class ham radio license is quite easy to get, with no requirement to learn morse code.  The concepts you will learn in getting one will serve you well as an operator of a full fledged ground station.  Transmitting capability is an upgrade to the ground station that will take your equipment to the next level and will let you use space for your communication needs.  Stay tuned!

Our engineering process was largely created and refined during the course of that first test stand project, and is now being applied (and further refined) in the creation of our newest project – a satellite tracking Ground Station . One of the things that’s been most interesting to me to watch has been how certain pieces of a project are best developed. The first thing I noticed is that there is a lot of power in spinning up a forum post on a step in the design process and then letting the discussion take its own course. Using the ODE forums for the initial discussion has two main advantages that I see:

1. It gives everyone a chance to participate. If we hold a Google+ Hangout at 5PM EST in the U.S. to do the design of a widget from scratch, people in other U.S. timezones (or parts of the world) may very well not get a chance to participate. Posting a step of the design process on the forums and then leaving it for a day or two, or until the discussion runs its course, allows more people to give their input.
2. It gives everyone a chance to think. Sometimes you just need to sit on a thought for a day or two before your ideas really become clear. You might have even posted an idea to the forums earlier in a day, and then a better way of doing that thing, or a major flaw in your idea sends you right back to the forums to post a retraction or revision. Using this form of communication gives you that time to think.

In some cases, the forums are all you need to complete a step in our engineering process. For example, on the Ground Station project we were able to complete steps 1 through 3 of our engineering process without ever having a face-to-face meeting. In step 1 we answered the high level whys and hows of the project. Questions like “Why are we building this?” and “How is this going to be used?” are what we tackle here. Step 3 involves creating a diagram so that it’s easy to see all the parts of what we want to build and how they all fit together. Then step 2 of the engineering process, which involves creating requirements that use words like “must” and “shall”, naturally come out of step 1. Requirements create a measuring stick that helps us make sure a project is doing what it’s supposed to.

Now, all of that is not meant to give the idea that forums are the be-all and end-all of project communication. One you’ve had the initial discussions in the forums, we’ve found that it’s often best to do those “in person” meetings using tools like Google+ Hangouts to help solidify and finalize decisions. This seems to be especially important with things like mechanical, electrical, and software design which often are easier to finalize when discussed face to face. On our preliminary design for instance, which is where we come up with a rough idea of what parts we need for a project, we may start out in the forum to give everyone a chance to contribute, but then we hold a Hangout to finalize the preliminary design. We discuss in real-time what everyone has put forth in the forum and distill it all down to a plausible design.

We realize that our processes will continue to evolve and be refined as we continue our work to enable the human race’s journey to the stars. Each project we do brings with it new lessons and opportunities for growth both on a personal level, and an organizational one. We encourage you to join us as we grow towards completing our mission.

Credit Rob Sayer

Not everyone knows this, but my first degree is in theatre, specifically theatre lighting design.  Before I ever learned about differential equations, stress analysis, or lift-to-drag ratios, I studied color theory, script analysis, and worked lights for dozens of shows ranging from “A Christmas Carol” to “Evita“.

One of the secrets to making sure a play comes off without a hitch every single night for weeks, months, or even years on end is something called a dimmer check.  Before each performance (even if there was one earlier in the day), the lighting crew chases everyone out of the theatre, and one by one turns on the 50-500 lights over the stage to make sure everything is still working.  The crew checks to make sure the lights come on, that the color filter in front of the light has not faded or burned through, that the light is still pointed at the correct location on the stage.  And, believe it or not, for medium to large shows, there is almost always something that needs to be fixed before each and every performance.  Yes, even when the last performance was just a couple of hours ago.

This attention to detail, and insistence that every time the equipment is turned back on it should be tested, is an essential element to getting live performances right every single time.  It’s even more important when you have just changed something, whether it is to make a repair or an improvement.

I pride myself on how my experience in theatre influences the way I approach live events at Mach 30 and elsewhere.  I always insist on rehearsals, especially when technology is involved (we had two separate technical rehearsals for this year’s Yuri’s Night Party), and I do my own version of the dimmer check for any gear I plan to use during an event.

Mach 30 Hangouts happen each Thursday

But this week, I got cocky, and I made a change (to improve our Google+ page) without running through any tests afterwards, and this change broke our ability to host On-Air Hangouts (on a week when we had an important one scheduled).  #Oops.  Apparently, linking one’s YouTube channel to a Google+ Page causes some squirrelly behavior with On-Air Hangouts.  Behavior we did not notice until during and after this week’s OSHW Documentation Jam Round Table Hangout, which not only led us to starting twenty minutes late, it also appears to have prevented the video from becoming sync’ed over to our YouTube Channel (which is too bad, I think our panelists and guests had some really great things to say, and I am sorry we won’t be able to share them with the Open Source Hardware Community).

So, that’s the bad news.  Of course, the good news is no one died or was injured from my failure to properly test things.  But, Mach 30′s work is building to a day when people’s lives will be on the line, so it is important to recognize small failures so we can learn from them.  In this case, the lessons are

1. Remember to test everything associated with a system after making changes to the system (there is likely a balance of risk vs reward to be struck, but clearly the key features of a system should be checked when significant changes are made)
2. Mach 30 needs to identify the core features we are using Google+ for (such as On-Air Hangouts) and create a test plan (or dimmer check) to be run when changes are made to our Google+ infrastructure, either because Google upgrades a feature or because we turn on an existing one we had not been using.

And, in the mean time, I will look into trying to recover our lost hangout video, and schedule the already discussed second round table hangout (after I have fixed our YouTube settings).

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Mach 30′s Ground Station Antenna

For those who don’t know, Open Design Engine is Mach 30′s free project hosting site for open source hardware projects.  We use it to host all of our publicly available projects (aka those not covered by export controls) such as the Shepard Test Stand and GS-001 (our new ground station project).  It is also home to a number of very cool projects from other users, including Andrew Starr’s Scanning Tunnelling Microscope.

Over the last couple of months, volunteers at Mach 30 have been planning the next major release of Open Design Engine as part of the work to apply for the SpaceGAMBIT Call for Projects.  As this plan came together, the volunteer team leading this effort realized Mach 30 would continue to need external software development support.  Unfortunately for us (but very fortunately for them), Littlelines, our developer for the current version of Open Design Engine, has plenty of work lined up at the moment and is unavailable for our next round of work.  All is not lost, however.  After reaching out through the volunteer team’s professional network, Mach 30 has been introduced to Mutually Human Software.  I am very happy to report Mutually Human will be a great addition to the Open Design Engine team.  Not only are they a skilled Ruby on Rails shop (Rails is the toolchain which Open Design Engine is built on), but they also “get” open source hardware and the maker community.  So much so that they are sponsoring a local startup makerspace, GR Makers.

April also saw the completion of Mach 30′s application for funding from SpaceGAMBIT’s Call for Projects to support Open Design Engine development.  Our application includes work to completely overhall the user interface, improve the infrastructure to support git repositories (among other things), implement one or more revenue generation streams so Open Design Engine can become self-sufficient, and marketing Open Design Engine to grow its user base.  I encourage you to take a look at the application.  The team did a great job in planning this new version, and in preparing the document.

Finally, I have been getting ready for the Open Source Hardware Documentation Jam.  This three day long conference/hack-a-thon is all about what the Open Source Hardware community needs to easily publish, share, and reuse documentation for open source hardware projects.  I am very excited to be included in this event for Mach 30′s work on Open Design Engine, and I am looking forward to sharing what we have learned and where we are headed, as well as finding out what the community needs from sites like Open Design Engine.  Stay tuned for updates from the Documentation Jam, and for a follow up On-Air Hangout covering the lessons learned and the community’s path forward after the event.

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Starting last year, with a great deal of encouragement and support from our volunteers, Mach 30 celebrated Yuri’s Night with an online party.  Each year, we choose a theme and hold a space trivia contest, complete with prizes for our guests out in cyberspace.  As a distributed organization we find the online format gives our volunteers, partners, board members, and fans a chance to celebrate human spaceflight together without the need for a transporter.

We just held our 2013 party this weekend.  Check it out in the video above.  The theme was Rocket Science: Live!  During the party we demonstrated two of our open source spaceflight projects (the Shepard Test Stand and our first ground station prototype).  Both were a big hit with our guests including makers from Bucketworks and Club Cyberia, and students from John Mall High School.

From all of us at Mach 30, I want to thank our volunteers, guests, and partners who helped make this year’s party a huge success.  We had a blast!  And we can’t wait to celebrate fifty-three years!

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Donations

This is a great way to help us out, especially if you don’t have lots of free time to give. Whether it’s one dollar or a thousand, everything counts and it encourages us to know that we’re not alone in the mission to secure our spacefaring future.  Donate now and you can become a member of the 2013 Catalyst Club! Joining the Catalyst Club makes you eligible for some special perks that are our way of saying “Thank You”.

Advocacy

We need people to spread the word about our mission, and about the fact that space is worth striving for. We’ve even made business cards for you to make it easy to share Mach 30 with everyone.

Follow, Like, Add, Friend, +1, Circle, and Subscribe

Mach 30 is on Facebook, Google+, YouTube, and Twitter. Join us there! To get updates on our recent activities, subscribe to receive our monthly newsletter called The Launchpad. Here is the archive of past issues. If you trust us with your email, it will never be given to anyone else without your permission, ever. Period.

Event Planning

We love to do events like Yuri’s Night and the impromptu Curiosity landing party, and we’d love to do even more. We’ve even talked about holding some type of open source spaceflight conference. To make these events happen we need event planners and coordinators.

Documentation

It’s hard to keep up on project documentation, and we could always use more help on this. Documentation is not just about CAD drafts and engineering analyses. There’s a lot of documentation to be done, and things like operating manuals can be even better when they’re written by a non-engineer.

Legal Consultation

We’re in a critical time right now where we have to navigate the deep waters of export controls. We need legal counsel to help us through this, and even beyond export controls there’s the day-to-day legal issues that an organization like Mach 30 encounters.

Project Management

Not every Mach 30 project has to be technical in nature. For example, we’ve recently launched the Mach 30 Book Club which is designed to allow everyone to participate. Have a look at our Mach 30 Drawing Board to see if there are any projects which you’d be interested in starting and managing. If there aren’t any, why not propose your own?

Marketing

If you can market Mach 30 to a broader audience, we want your help too. The more people that know about us and support us, the larger our impact will be. Remember, the goal here is to move humankind to become a spacefaring civilization. We want everyone around the world to know about and support our mission.

Education

Mach 30 is focused on education and outreach as part of our mission. We love the idea of helping to train and inspire the next generation of explorers. If you’re a teacher who wants to introduce your students to rocket science in a safe and fun way, an educator who wants to develop school room curriculum for our hardware projects, or just someone who wants to help us reach students from age 5 to 105, we’re looking for you too.

Fundraising

This is an area that our current Board of Directors has found challenging. Not only can we not develop the cool spaceflight projects we want without money, we also can’t do things like travel to meet interesting people like you. Every dollar that you can help us raise allows us to build the relationships and infrastructure needed to complete our mission.

Testing and Feedback

Almost every project has users, but most of them never report anything back to the project managers. Are you an Open Design Engine user who’s noticed a bug? Did you build a Shepard Test Stand and notice a mistake in one of the drawings? Were you browsing the Mach 30 website and noticed a mispelling? It would be great to have your feedback.

Graphic Design

The Board of Directors is lucky to have it’s very own mercinary art ninja, Bekah McGrady, but she’s always on the lookout for help from other graphic designers. We like our projects to look as good as they work, and you can be a part of that. Can you help us design mission patches for each of our projects? How about helping us to create merit or skill badges for people to earn as they learn new skills? These are just a couple of the ideas that are being talked about that would need graphic design.

Gamification/Skills Advancement

Mach 30 wants to work with other organizations all around the world to create a skills advancement system that would allow people to be rewarded for the hands-on skills they learn. If you want to be part of this educational frontier and help us train the innovators of the future, we have a spot for you.

Insert Your Interest Here

Did I miss what you’re interested in? No problem, there’s a really good chance that you’ll fit right in somewhere at Mach 30. We’re looking for all skill levels and interests to help us accomplish our mission. Contact Us to let us know how you want to get involved.

So, still think that Mach 30 is just for engineers and rocket scientists? I’m an engineer by profession, and some would say by personality as well, and I can say that in my experience Mach 30 has a place for everyone who loves space and wants to go there someday. Come, join us and help shape the future.

Open Design Engine KickStarter Logo

We are very excited to announce the launch of the Open Design Engine (ODE) Public Beta. The road to get here ended up being a little longer than we expected, but we’re happy with the results. We could not have made this push to the finish without the help of Kevin Bouwkamp, Bryan Christian, and The School Factory, and we are grateful for their help in getting ODE safely off the launchpad. Self-registration for user accounts is now active, and we are ready for our next round of promotion for Open Design Engine. Please share this news on Twitter, Facebook, Google+, and your own personal blogs (be sure to link to this post).

If you have not signed up for an account yet, please do so. Then, start a project on ODE to document one of your own Open Source Hardware creations. Don’t have a project yet? No problem. You can start one, or join one of the projects already in progress. Mach 30 currently has two projects that are active on ODE, the Shepard Test Stand and the Far Horizons High Altitude Balloon (HAB) project. We’re always looking for help, so feel free to Contact Us to see how you can get involved.

And this is just the beginning. We are already actively improving the site. For example, within the last 2 weeks Kevin completed the funding plugin, allowing users to insert Kickstarter badges and PayPal buttons into any field which supports wiki-syntax. What this means for you is that you can ask for help to fund your projects right from your ODE project pages. Future plans include adding support for integrated git repositories and major improvements to the user interface. As always, watch the roadmap to keep up with our plans and progress.

Thanks to all of our supporters, backers, kickstarters, and volunteers. We are looking forward to growing Open Design Engine into a great site for hosting open source hardware projects. And remember, Makers, document what you make.

The group decided that they wanted to kick off this new project by reading the book X-teams: how to build teams that lead, innovate and succeed.  So here we go!  There’s a ton of great background on the drawing board page for the Mach 30 Book Club idea.  I’d suggest taking a quick glance through that so you know what to expect.

X-teams: How to build teams that lead, innovate, and succeed

We’ll start by discussing the Introduction to the book on Monday, November 26th. If you want to be part of the discussion you can add comments to this blog post, even if you don’t have an account. If you click in the “Leave a Reply” box below you’ll see options to post as your Twitter and Facebook logins too. We’re really looking forward to getting started with this book, and we hope you’ll join us. If you’re a part of teams in any way, this will be a great discussion.

So, grab a copy of the book, a comfy chair, a hot or cold beverage of your choice, and lets get started!

We also broadcast and record that hangout, so even if you can’t join us live, you can still stay in the loop.

If you’d rather not watch the whole meeting, or if you’d like to have easy access to the resources we discuss, you can access the meeting minutes here.

Bonus Video!

In addition to our usual reports hangout, we did a bonus on air hangout in September from the Open Hardware Summit.  If you missed it, you can catch up here.

And here are the videos and pictures previewed in the Open Hardware Summit hangout.

• Pictures
• Cool lighting project
• Keyglove interview
• Trilife interview

It’s not too late for feedback!

If you have questions or ideas we want to hear them.  Leave a comment below and a Mach 30 board member will answer as soon as we can.

We also broadcast and record that hangout, so even if you can’t join us live, you can still stay in the loop.

If you’d rather not watch the whole meeting, or if you’d like to have easy access to the resources we discuss, you can access the meeting minutes here.

It’s not too late for feedback!

If you have questions or ideas we want to hear them.  Leave a comment below and a Mach 30 board member will answer as soon as we can.