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Chips in Space - The Building of an Amateur Satellite

Chips in Space: Lessons learned (Part 1)

Steve Bible

9/17/2011 1:00 PM EDT

Project management teaches us to do a post-mortem review at the end of every project, to muse about the things that did and didn’t go right. If things went right, they are called “best practices.” If they did not go as planned or we overlooked something, we call them “lessons learned.” A polite way of saying, we goofed and we promise not to do that again (we hope).

Canvassing the team, I have collated several of the many lessons learned during this project, along with a couple of my favorite quotes on the subject. I will present these lessons over the next two posts, in the hopes that there will be something relevant that you can apply…
Learn from experience. Make new and more exciting mistakes each time!
-    Kimberly Wiefling, Scrappy Project Management
Smart people learn from experience; wise people learn from the experience of others.
-    Dr. Ichak Adizes
The first lesson we learned, which became all too apparent in surveying the team for this post:  designate a scribe, someone whose job it is to chronicle the project, maintain a list of decisions of why we did or did not do something, and be the keeper of history. This should be a team member’s sole job, not a collateral duty. We did not know going into this project how long it would last (four long years!). Nor did we realize that volunteers would come and go (but we should have!). Time and time again, we would discuss something only to scratch our heads trying to remember what was previously discussed and decided. The scribe can also ensure that everything gets documented and keep a list of lessons learned as the project progresses, not months after it was completed and memories fade.

Designate a project manager, and have everyone agree to follow him or her. Leading volunteers is a little like herding cats, but having too many cooks in the kitchen spoils the broth. For a project like this one, it is very hard to nail down the requirements from the beginning. As things are learned, designs will change. Expect change! Lots of it! Having a clear project goal is a must to keep everyone on task and on track.


Bob Davis (KF4KSS) filling silver-zinc battery

On the mechanical front, Bob Schwerdlin (WG9L) and Bob Davis (KF4KSS) learned a few things. They found that holding weekly Saturday-morning meetings using Skype voice calls was informative and allowed the mechanical group to bang around ideas and gain insights into the project. They also used Yugma for online desktop sharing and presentations, where everyone can see and exchange graphic details and allow each other to take control of the other’s desktop for information exchange. In a nutshell, communications are very important, both voice and video. There’s a lot of information and ideas to exchange. It is important that everyone is thinking and working from the same sheet of music.

On the deployment of ARISSat-1, during EVA 29 on August 3, 2011, we were treated with a first-person view of ARISSat-1 from the helmet cameras on the cosmonauts. During the design of ARISSat-1, we knew it would be deployed during an EVA, and we knew we had to make the handling and operation easy for the cosmonauts. We saw that the handles on the edges of the satellite were easy for them to grip. But, we could also see that the satellite was being bumped as they worked to unwrap and tether it for deployment. Those watching live and commenting in blogs and bulletin boards were bemoaning the rough handling of the satellite by the cosmonauts. But the reality is that it’s our responsibility to make the satellite robust and easy for them to handle. ARISSat-1 did well during its deployment and has been operational for more than six weeks now—a testament to its construction. For subsequent satellites, however, we need to study and come up with improved designs and methods for the deployment.


Maximum peak power tracker heatsinks, machined and ready for installation

With the shift of the satellite-in-a-suit to a satellite-in-a-space-frame, we needed to devote more time to the thermal aspects. Dick Jansson (KD1K), our resident thermal expert, said:
“Perhaps the biggest problem was the rather small size of some of the electronics, which were conceived and implemented with little thermal design input in the conception. As a result, we were forced to apply Band-Aid cures in the form of localized internal heat sinking, in some of the modules where there was little room for such treatments.”


Temperature sensors, prepped and ready for installation
We are seeing the results of our thermal design in the telemetry stream. Temperatures are warmer than we anticipated. This is an area we need to improve on next time.  With that thought, Jerry Zdenek (N9YTK) mentioned, “You'll always want more temperature-sensor points than you originally plan for.   Add extras; you'll use them.”

Next week, I will share the rest of the team’s lessons learned.

- Steve Bible (73 DE N7HPR)

ARISSat-1 Official Web Site

The Radio Amateur Satellite Corporation

Read the earlier Chips in Space blog posts, here.




Sanjib.Acharya

9/18/2011 1:13 AM EDT

Hi Steve, thank you for sharing the lessons learned. Surely it helps us in getting wiser :).
Documenting the minutes of every meeting is a tough job but if it is done, surely it helps a lot later, saves lot of time for not re-doing the same discussions.
Any lessons learned from: ARISat-I worked fine even after one antenna was found broken? :)

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ttt3

9/18/2011 11:27 AM EDT

I thought there would be at least a mention of the battery that didn't work? That sounded pretty embarrassing to me.

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David Ashton

9/18/2011 6:28 PM EDT

Steve did cover this pretty well in response to my questions in an earlier entry:

http://www.eetimes.com/electronics-blogs/chips-in-space/4219183/Chips-in-Space--Let-s-look-inside-ARISSat-1--part-2-

But I would agree such an early battery failure is not good.

Steve, any comments on the antenna failure pre-deployment? Would you do anything differently there? That said, I have worked with the type of antenna you describe and they are usually pretty rugged.

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Frank Eory

9/20/2011 5:04 PM EDT

The idea of a scribe is a good one, and I agree it is not a collateral duty. Unfortunately, most project teams don't have the luxury of dedicating a resource solely to that task.

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docdivakar

9/21/2011 2:40 PM EDT

@Frank Eory: to add a little more, in the teams I managed/led, the project manager was also the scribe and didn't miss any design review or concept meetings. We made efficient use of mind maps that captured all ideas, comments, inputs in a clear and structured way.

MP Divakar

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Steve Bible

9/20/2011 10:37 PM EDT

Concerning the uplink antenna, if you saw it in person you'd see that it is a very robust design. We are still trying to figure it out. Personally, I don't think we'll ever know what happened to the antenna. Thankfully the uplink works.

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Steve Bible

9/20/2011 10:38 PM EDT

Concerning the battery, as David mentioned, I did cover the failure, but as to the lesson learned, I do write about it in Part 2 of Lessons Learned (stay tuned).

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