v1.0 - SEP Step 1 - Ask Questions

Added by Jeremy Wright almost 11 years ago

This covers the "Requirements Definition" item in the more formal Systems Engineering Process (SEP) here: https://opendesignengine.net/boards/4/topics/8 .

The following are some questions that can help define the requirements for this project. Please post your proposed answers to any or all of the questions below.

Q1. Why are we making this?
Q2. Who is this for?
Q3. How will this be used?
Q4. What features does it need to have (now)?
Q5. What features does it need to have (later)?
Q6. What are the legacy requirements?
Q7. Who's going to build this?
Q8. How many do we want to make?
Q9. What is the budget?
Q10. What is the timeline?
Q11. What waste products will be produced by the manufacture and/or operation of this?


Replies (17)

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

Here are some answers I would give based on what I currently know.

Q1. Why are we making this?

A1. To gain experience in the open design and development of test stands (and other equipment), test ODE (Open Design Engine), and to provide a marketing, outreach, and educational tool.

Q2. Who is this for?

A2. It is hoped that the design and development process will be helpful to any and all who have an interest in test stands, and the finished stand will be used by Mach 30 and its partners.

Q3. How will this be used?

A3. The final test stand will be used for verification of typical motor performance metrics such as thrust and exhaust temperature. These metrics will be compared against benchmark values provided in the Estes motor documentation: http://estes.aptinet.com/images/page%2033.pdf The test stand will also be used to do demonstrations at various conferences and educational events.

Q4. What features does it need to have (now)?

A4. The test stand needs to:
-Be easily set up and torn down for demonstration purposes.
-Be easy to package for shipment to any event at which it will be used.
-Provide a stable base on which to test model rocket motors.
-Be as safe to operate as possible.
-Accomodate Estes rocket motor sizes A through E.
-Provide the ability to measure thrust and exhaust temperature while keeping an accurate timestamp for each data point.

Q5. What features does it need to have (later)?

A5. Version 2.0 of the test stand will be a separate design that will add support for commercial high-power model rocket motors (above E), and high and low speed video capture.

Q6. What are the legacy requirements?

A6. This is a first generation test stand, so there are no legacy requirements to remain compatible with previous Mach 30 designs.

Q7. Who's going to build this?

A7. It is assumed that volunteers within the Mach 30 community will build this test stand. The designs will be open so that other individuals and groups may choose to build their own as well.

Q8. How many do we want to make?

A8. One.

Q9. What is the budget?

A9. $200

Q10. What is the timeline?

A10. An original timeline of 3 months was proposed, but the timeline will be completely dependent on the invlovement of the Mach 30 community.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by J. Simmons almost 11 years ago

Jeremy, I think you have done a great job with your answers. In many ways I could just give a thumbs up and say let's move on. But, I want to get some practice integrating comments and alternative answers here, so in the spirit of "going around the room", I am going to answer the questions myself here.

Q1. Why are we making this?

A1. The Shepard Test Stand is the first step toward developing an open source test stand for flight capable rocket engines. It's focus on low power, commercially available amateur rocket motors is intended to provide a safe first experience for both designers (low power and low cost lead to little penalty for failing to mean design goals the first time around) and operators (low power leads to lower cost if accidentally misused during early training). Additionally, as one of Mach 30's earliest open source hardware projects, it will give us practical experience in open source hardware development and managing projects on ODE. Finally, we have received interest in performing live demonstrations of the test stand as part of educational and outreach activities, so it is expected the test stand will become an educational and marketing tool.

Q2. Who is this for?

A2. The Shepard Test Stand is for anyone wanting to learn about measuring the performance of rockets. This includes open source spaceflight designers who will design and build future test stands (at Mach 30 or elsewhere), Mach 30 operators who will use future test stands in other Mach 30 projects, students and educators who want to bring rocket engineering into the classroom, and anyone else interested in how rockets are tested.

Q3. How will this be used?

A3. The final test stand will be used for verification of typical motor performance metrics such as thrust and exhaust temperature. These metrics will be compared against benchmark values provided in the Estes motor documentation: http://estes.aptinet.com/images/page%2033.pdf The test stand will also be used to do demonstrations at various conferences and educational events.

A3a. Additionally, the test stand (or a related version) can be used as the first introduction to rocket testing and operation procedures for Mach 30 volunteers interested in test and operation of rockets.

Q4. What features does it need to have (now)?

A4. The test stand needs to:
-Be easily set up and torn down for demonstration purposes.
-Be easy to package for shipment to any event at which it will be used.
-Provide a stable base on which to test model rocket motors.
-Be as safe to operate as possible.
-Accommodate Estes rocket motor sizes A through E.
-Provide the ability to measure thrust and exhaust temperature while keeping an accurate timestamp for each data point.

A4a. I would adjust the safety requirement to read:
-Conform to NAR safety rules for the operation of model rockets (for example, using "non-metal parts" for all components directly interfacing with the motor to reduce the risk from shrapnel)

Q5. What features does it need to have (later)?

A5. Once we have enough experience with Estes class motors, I think the logical progression in scale of test stands (most of which I expect to be implemented as separate projects, spread out over a significant period of time) is

  1. high power commercial solid motors
  2. small hybrid motors (on the thrust scale of high power commercial solid motors)
  3. larger thrust hybrid motors
  4. small liquid engines
  5. medium liquid engines
  6. large liquid engines

In terms of other features to add to the test stands, those could include:

  • video capture of the tests (high and low speed, from multiple angles)
  • integrated ignition systems (so the test management software can control the entire test)
  • additional measurements
  • higher fidelity measurements

Q6. What are the legacy requirements?

A6. This is the first project of its kind at Mach 30, there are no existing projects it must interface with. However, if the system includes desktop control software (and I expect it will), that software should run on all three major PC platforms (MS Windows, Mac OS X, and Linux). Additionally, it should use standard connections back to the control software (for example, USB, Ethernet, or similar connections).

Q7. Who's going to build this?

A7. It is assumed that volunteers within the Mach 30 community will build this test stand. The designs will be open so that other individuals and groups may choose to build their own as well.

I have nothing else to add to this answer.

Q8. How many do we want to make?

A8. One (for now). If the design proves particularly valuable as a teaching or training tool, we may revisit this decision. If highly successful, it is not outside the realm of possibility to consider offering it (or a related design) as a kit for others to assemble.

Q9. What is the budget?

A9. $200, firm. If there is a conflict between function and budget, for this iteration, budget should trump. Our goal is not to make the perfect test stand, it is to make the first prototype of a test stand and see what we can learn from that experience (both about test stands, and about our processes). We can always go back and do another iteration to meet the design requirements if needed. Holding to a firm budget minimizes the amount of time spent trying to make it perfect (once you are out of money, you have to wrap up the project, successful or not). Even a "unsuccessful" prototype will teach us important lessons to apply moving forward.

Q10. What is the timeline?

A10. The goal is to complete the project within three months of formal launch as an exercise of agile design. However, given the project is also an experiment in open source hardware development and is all volunteer based, we need to recognize the need to be flexible in this requirement.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Greg Moran almost 11 years ago

I cannot adequately explain how satisfied I am with the initial discussions regarding the Open design practices for the Shepherd test stand. This level of detail is exactly what I had envisioned for the early prototype development. The critical test however comes from the results of teh process and our ability to use it to actually do what we've set out to do. Anyway... Here are my thoughts and comments about the Step 1: asking questions.
Q&A 1: I Agree
Q&A 2: I Agree
Q&A 3: I agree
Q&A 4: I agree
A4a: I disagree. I think the application of the NAR safety code for operations of model rockets does not apply to the design and operations of rocket motor test stands. While there are some parts of this rule set are reasonable i don't think that the entire code can be applied in broad strokes. A rocket test stand is not designed to fly, however this code was developed for flight operations of rockets. We need to better define the intent of the safety requirement for this project.
Q&A 5: I agree
Q&A 6: I agree
Q&A 7: I would add that the intent is to simplify the design such that ANYONE, without necessarily a technical education in rocketry, propulsion, or engineering, would be able to build and operate a Shepherd test stand.
Q&A 8: I agree
Q&A 9: I'm not really sure why the arbitrary number of $200 is important. J and I have already talked about this and it turns out that I'm not invested enough to pursue the discussion farther. I don't know that sticking to a $200 budget at the expense of a successful project is very valuable, but agree that we should continue to work our way through the process and see what comes out the other end.
Q&A 10: I agree

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

Q4. What features does it need to have (now)?

A4a. I would adjust the safety requirement to read:
-Conform to NAR safety rules for the operation of model rockets (for example, using "non-metal parts" for all components directly interfacing with the motor to reduce the risk from shrapnel)

A4a: I disagree. I think the application of the NAR safety code for operations of model rockets does not apply to the design and operations of rocket motor test stands. While there are some parts of this rule set are reasonable i don't think that the entire code can be applied in broad strokes. A rocket test stand is not designed to fly, however this code was developed for flight operations of rockets. We need to better define the intent of the safety requirement for this project.

Maybe it would be a good idea to spin this off into a separate forum topic? I researched examples of amateur test stand safety procedures a little bit last night, but haven't had time to filter the steps out that apply to this project yet. When I do it would be nice to have a place where we can discuss them.

Q8. How many do we want to make?

A8. One (for now). If the design proves particularly valuable as a teaching or training tool, we may revisit this decision. If highly successful, it is not outside the realm of possibility to consider offering it (or a related design) as a kit for others to assemble.

I would suggest giving some serious consideration to making the kit option a definite part of this answer. In my view, the design requirements for making the stand easy to ship and set up at conferences are not that far off from the requirements for a kit design.

Q9. What is the budget?

A9. $200, firm. If there is a conflict between function and budget, for this iteration, budget should trump. Our goal is not to make the perfect test stand, it is to make the first prototype of a test stand and see what we can learn from that experience (both about test stands, and about our processes). We can always go back and do another iteration to meet the design requirements if needed. Holding to a firm budget minimizes the amount of time spent trying to make it perfect (once you are out of money, you have to wrap up the project, successful or not). Even a "unsuccessful" prototype will teach us important lessons to apply moving forward.

Q&A 9: I'm not really sure why the arbitrary number of $200 is important. J and I have already talked about this and it turns out that I'm not invested enough to pursue the discussion farther. I don't know that sticking to a $200 budget at the expense of a successful project is very valuable, but agree that we should continue to work our way through the process and see what comes out the other end.

It might be a good idea to document the reasoning behind the $200 figure for future users/contributors in the "Initial budget discussion" forum topic, or somewhere else appropriate.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by J. Simmons almost 11 years ago

So it looks to me like we have three open topics we are still working on answering, plus a possible additional question about disposal (based on the converstation about the SEP).

  1. How to develop safety requirements? - I would like to amend my previous answer regarding safety to be Where appropriate, conform to NAR safety rules for the operation of model rockets (for example, using "non-metal parts" for all components directly interfacing with the motor to reduce the risk from shrapnel). My thought is the Shepard test stand should be something that NAR can endorse both educationally and as it relates to safety. And I agree, I think we need a separate forum thread to discuss the safety issues in greater detail.
  2. Kit option and how it relates to who will use the test stand - I really like the idea of ultimately developing a kit version of the Shepard Test Stand. I think the educational opportunites alone are worth pursuing this (which also supports the idea that this should be something anyone could start out with). Having just wrapped up another project (that is needs some attention in the documentation department), I am realizing that the first iteration is not necessarily something that will be ready to make into a kit. So, I imagine we may find ourselves completing this version of the test stand, and then saying to ourselves "if we made these changes, I bet we could turn this into a super awesome kit." This would then probably drive another design iteration (and a new version of the same project - vs working on upgrade capabilities on a new project). This makes me wonder about how some of these questions relate to the ultimate goals (here things like having a test stand for training/education/marketing/kits) vs the current versions goals (get a first cut at a design, test it and learn from it, etc).
  3. Budget - I am realising that there may be some more of the project level vs version level issues here. As I think about this more, I see that on a budget front, I am thinking about the current version being developed, not necessarily the entire project. by holding to a firm budget (that happens to be very small), we ensure the design cycle will be short because the budget helps constrain the features. The idea is it is better to get a design cycle done that we can learn from than to let a project drag on without product to show for its work. This is all based on my interpretation of Dan Ward's FIST principles (sorry the link to the book is dead, so I can't point you at it right now) and some reflection on the way the Wright Brothers worked. I will totally admit, these concepts need their own testing, but I think this is a good place to start on that testing.

TL;DR - Let's start a new safety discussion thread where we are mindful of NAR rules, but make adjustments as necessary. And let's talk about calrifying the answers to the questions between the long range goals (an Estes Test Stand kit) and the first prototype of the test stand.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

If you look at the list at the top of this thread, you'll see that I've added a question 11. This deals with disposal so that we can keep it in mind throughout the engineering process.

Q11. What waste products will be produced by the manufacture and/or operation of this?

Here are a few links that I based my answer on. The first one includes "SECTION 13 - DISPOSAL CONSIDERATION" for Estes motors.
http://www2.estesrockets.com/pdf/MSDS-Estes%20Engines.pdf
http://www.apogeerockets.com/MSDS/Quest/MSDS_Quest%20Model%20Rocket%20Motor.pdf
http://en.allexperts.com/q/Model-Rocketry-2312/Disposing-Old-Motors.htm

A11. Spent Estes motors will be a waste product of the operation of this test stand, and any residual materials should be treated as hazardous. Disposal of these motors should conform to all local, state, and federal guidelines. Estes motors are based on black powder propellant, so any motors that do not fire properly or are damaged can be disposed of in an ordinary manner by first soaking them in water until the casing unwraps and the propellant falls apart.

Let's start a new safety discussion thread where we are mindful of NAR rules, but make adjustments as necessary.

Done. You can find it here

My thought is the Shepard test stand should be something that NAR can endorse both educationally and as it relates to safety.

Should we send NAR an email to see if they would like to be involved in the safety discussion? Maybe we can at least send them our agreed-upon safety guidelines to see if they would endorse them?

And let's talk about calrifying the answers to the questions between the long range goals (an Estes Test Stand kit) and the first prototype of the test stand.

This will take some thought on my part. I'm not quite sure where ease of shipment and setup for conferences ends and where kits begin. Maybe there should just be a version 1.5 of the stand who's primary requirement is to be a kit version of version 1.0? I guess an important question to ask even before worrying about the kits would be if there's a market for them. There's no need to spend the resources on a kit if nobody wants one.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by J. Simmons almost 11 years ago

Great stuff. I need some time to chew on the third item as well. I just wanted to point out an observation about the various threads I saw running through the discussion. And, I think the question of big project goals vs goals for first prototype may also illuminate some of the questions around the budget. I think I am going to make another pass at my answers to the questions this weekend to see if I can tease out the differences in my mind and get them written down.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

I took another look at our proposed answers for this step, and I think that we can go ahead and accept a few of them. There is a wiki requirements page holding these questions and answers.

I propose that we accept J's answers for questions 1, 2, 3, 6, and 10. I feel that they cover my answers and then add more detail and clarity. I think that I can easily clean up and combine the answers to question 4, but I wanted to tackle the low hanging fruit tonight. I've included each question and the finalized answer that I'm proposing below for ease of review. Please note that I made some minor edits that I don't believe change J's intended meaning. If there are no objections, I will set these answers as being the accepted ones.

Also, I was looking into cleaning up the Shepard wiki which requires creating new pages, but I can't get it to work. Clicking on the "Start page" link doesn't do it, so I guess I'm missing something. Any ideas on what to try would be appreciated.

Q1. Why are we making this?

A1. The Shepard Test Stand is the first step toward developing an open source test stand for flight capable rocket engines. It's focus on low power, commercially available amateur rocket motors is intended to provide a safe first experience for both designers (low power and low cost lead to little penalty for failing to mean design goals the first time around) and operators (low power leads to lower cost if accidentally misused during early training). Additionally, as one of Mach 30's earliest open source hardware projects, it will give us practical experience in open source hardware development and managing projects on ODE. Finally, we have received interest in performing live demonstrations of the test stand as part of educational and outreach activities, so it is expected the test stand will become an educational and marketing tool.

Q2. Who is this for?

A2. The Shepard Test Stand is for anyone wanting to learn about measuring the performance of rocket motors. This includes open source spaceflight designers who will design and build future test stands (at Mach 30 or elsewhere), Mach 30 operators who will use future test stands in other Mach 30 projects, students and educators who want to bring rocket engineering into the classroom, and anyone else interested in how rockets are tested.

Q3. How will this be used?

A3. The final test stand will be used for verification of typical motor performance metrics such as thrust and exhaust temperature. These metrics will be compared against benchmark values provided in the Estes motor documentation . The test stand will also be used to do demonstrations at various conferences and educational events.

Q6. What are the legacy requirements?

A6. This is the first project of its kind at Mach 30, there are no existing projects it must interface with. However, if the system includes desktop control software, that software should run on all three major PC platforms (MS Windows, Mac OS X, and Linux). Additionally, it should use standard connections back to the control software (for example, USB, Ethernet, or similar connections).

Q10. What is the timeline?

A10. The goal is to complete the project within three months of formal launch as an exercise of agile design. However, given the project is also an experiment in open source hardware development and is all volunteer based, we need to recognize the need to be flexible in this requirement.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

And here is question 4 and the combined answer.

Q4. What features does it need to have (now)?

A4. The test stand needs to:
  1. Be easily set up and torn down for demonstration purposes.
  2. Be easy to package for shipment to any event at which it will be used.
  3. Provide a stable base on which to test model rocket motors.
  4. Where appropriate, conform to NAR safety rules for the operation of model rockets (for example, using "non-metal parts" for all components directly interfacing with the motor to reduce the risk from shrapnel). The Shepard test stand should be something that NAR can endorse (if desired) both educationally and as it relates to safety.
  5. Accommodate Estes rocket motor sizes A through E.
  6. Provide the ability to measure thrust and exhaust temperature while keeping an accurate timestamp for each data point.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Greg Moran almost 11 years ago

I concur with 1, 2, 3, 6, and 10. I do not agree to the Q4 answer part 4. My specific objection is to the example used from the NAR safety code. I do not think that it makes sense to limit ourselves to non-metal components for the motor interface. This consideration applies to rocketsthat fly, but not test stands.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

I concur with 1, 2, 3, 6, and 10.

It sounds like I can safely finalize 1, 2, 3, 6, and 10 then.

I do not agree to the Q4 answer part 4. My specific objection is to the example used from the NAR safety code. I do not think that it makes sense to limit ourselves to non-metal components for the motor interface. This consideration applies to rocketsthat fly, but not test stands.

On Q4 - I took J's example to mean that there's a risk of shrapnel being thrown by a motor explosion no matter whether it comes from rocket fins, or from motor mount straps on a test stand. Granted, the explosive forces we'd be dealing with in the A through E motors should not be enough to break copper/aluminum/steel motor mounts, but I think the spirit of the original concern addressed in the NAR guidelines is there. I tend to agree though that we should not rule out metal parts, and Ben Barnett has echoed this sentiment in the safety procedures topic. I would expect that using a "non-metal" material that's too "lightweight" could add to the danger of a motor coming loose from it's mount(s) and hitting an operator/observer during a misfire or explosion. I'm wondering if the shielding that we've mentioned over in the safety discussion offers us a good route for compromise on this. This issue might also be resolved if we can get some NAR input on our safety guidelines, and that is being worked on.

This is a great discussion, and I think we're making good progress.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright almost 11 years ago

I got a chance to take another look at the questions and saw a couple more that seem pretty much done.

Q7. Who's going to build this?

A7. It is assumed that volunteers within the Mach 30 community will build this test stand. The designs will be open so that ANYONE, without necessarily a technical education in rocketry, propulsion, or engineering, would be able to build and operate a Shepard test stand.

Q8. How many do we want to make?

A8. One (for now). If the design proves particularly valuable as a teaching or training tool, we may revisit this decision. If highly successful, it is not outside the realm of possibility to consider offering it (or a related design) as a kit for others to assemble.

If there are no objections, I'll finalize these questions in order to spend our time on the more challenging ones during Thursday's hangout.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Greg Moran almost 11 years ago

I concur with 7 and 8! Talk to every one on Thursday.
Respect,
-greg

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright over 10 years ago

Based on the discussion during the hangout, I tried to put finalized answers to a 3 of the last 4 questions. Let me know what you think. If we can finalize these we'll only have question 4 left.

Q5. What features does it need to have (later)?

A5a. Version 2.0
  • High and low speed video capture of the tests from multiple angles.
  • Integrated ignition system so the test management software can control the entire test.
  • Additional measurements.
  • Higher resolution measurements.
A5b. Beyond Version 2.0
  • High power commercial solid motors.
  • Small hybrid motors (on the thrust scale of high power commercial solid motors).
  • Larger thrust hybrid motors.
  • Small liquid engines.
  • Medium liquid engines.
  • Large liquid engines.

Q9. What is the budget?

A9. $200, firm. If there is a conflict between function and budget, for this iteration, budget should trump. Our goal is not to make the perfect test stand, it is to make the first prototype of a test stand and see what we can learn from that experience (both about test stands, and about our processes). We can always go back and do another iteration to meet the design requirements if needed. Holding to a firm budget minimizes the amount of time spent trying to make it perfect (once you are out of money, you have to wrap up the project, successful or not). Even a "unsuccessful" prototype will teach us important lessons to apply moving forward. This budget does not include "consumables" such as motors, nor tools, but the $200 cost for the stand itself keeps the basic project affordable if standard tools found in hackerspaces can be used. Any manufacturing that has to be hired out to a third party will be taken out of the $200 budget, and should be avoided to keep this project more practical for those same hackerspaces.

Q11. What waste products will be produced by the manufacture and/or operation of this?

A11. Spent Estes motors will be a waste product of the operation of this test stand, and any residual materials should be treated as hazardous. Disposal of these motors should conform to all local, state, and federal guidelines. Estes motors are based on black powder propellant, so any motors that do not fire properly or are damaged can be disposed of in an ordinary manner by first soaking them in water until the casing unwraps and the propellant falls apart. Possible electronic waste items may include batteries from the ignition control box, and circuit boards. These must also be disposed of according to all local, state, and federal guidelines. If the frame of the test stand is damaged beyond repair during operation, proper disposal/recycling guidelines must be followed for the materials used in its construction.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright over 10 years ago

I've updated the "Initial Questions" wiki document to reflect the fact that we have an agreed direction for the safety requirements (last answer for question #4).

https://opendesignengine.net/projects/shepard-ts/wiki/Initial_Questions_v1_0

If there's no objection, I'm going to add something like "Gelled: 2012-05-01" below the "Draft: 2012-03-05" line to reflect the state of the document. For anyone who hasn't been in on the "gelled" vs "frozen" conversations, "gelled" means that a step in the Systems Engineering Process is closed except for any critical issues that are brought to the team's attention. Any new ideas are still welcomed, but will be moved to the discussion areas for future Shepard versions. The term "frozen" will mean that the topic has progressed to the point where no new input (even critical issues) will be accepted. We have yet to decide if any Shepard version will ever get to the point where a new critical issue would not be accepted. My feeling is that we'll always document something that's critical somehow.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by J. Simmons over 10 years ago

Concur. Thanks for making sure we closed out this step.

RE: v1.0 - SEP Step 1 - Ask Questions - Added by Jeremy Wright over 10 years ago

Per the requirements document discussion, I took the drafted date off of this step's wiki doc and moved the gelled date to the bottom.

(1-17/17)