Part 3 — Capstone Evaluation of Alternative Concepts

This milestone in our Capstone project was the continuation and prototyping and narrowing down our design space by using a decision matrix.  While we've already begun prototyping, this matrix has helped us confirm our reassessment of which concepts would be best to explore after new information from our mentors.  In addition, we conducted a "progress update" demonstration for Open House night.

The Report

Open House Display

Progress Presentation

Core Concepts

Decision Matrix

Effectively the only "concept" important to this new milestone, a decision matrix is a useful engineering tool which allows engineers to make a quantitative decision out of a qualitative one.  The idea is that a group of criteria are defined which all potential concepts will be evaluated on; then, each of these criteria is given a weight which defines how important that criterion is considered.  Lastly, each concept is ranked on a scale of 1-10 for each criterion.  By multiplying each ranking by the weight of the criterion and summing the scaled ranks, each concept gets a numerical rating.  The concept with the highest numerical rating corresponds best with the needs and wants expressed through the criteria and their respective weights, and is therefore the concept which should be pursued.

Important Factors

There are some trends in what factors are important for an engineering product.  These are:

• Cost: The cheaper a product is, the more feasible it becomes and the more money can be made from it.  Keeping cost as low as possible while maintaining the same level of result is paramount.

• Simplicity: Keeping a project simple both facilitates construction and reduces cost.  Not only material cost but also manufacturing cost will be reduced through simplifying a project.  Additionally, a simpler mechanism is less likely to fail, increasing the reliability.

• Durability: In the same vein of reliability, durability is an important consideration, especially for applications like space travel.  A single mechanism which fails easily can ruin the entirety of a project, so ensuring that each component has high durability will prevent compounded risks.

Reflection

At this stage of the project, I am confident that we are on track to producing a working final product by the deadline.  Seeing that we have both ends of the project working — the electrolysis and the thruster — makes me sure that we will be able to build the missing piece in a timely manner.  For this presentation night, our communication was definitely a strong point.  Our exhibit was clean and the poster was easy to read, which made a positive impression on many of the people who we spoke with.  Our presentational skills were well-used and we all spoke fluently about the project.  Our collaboration was also strong for the presentation night; we shared the work very evenly.  For example, when I was absent my teammates worked diligently on the poster, and when I returned I worked extra to get the electrolysis system into a demonstrable state.

Since this stage of the project is somewhat unlike other pages on this site (it does not involve a 'final product' which we produced), this space will also be used to discuss future plans.  In the coming weeks, we aim to produce the piping section of the project, the piece which links together the thruster and the electrolysis.  There are a few areas of this to be considered.  One nice aspect of the design of said component is that because of our use of 3d printing we will be able to rapidly adapt the coupling design to the thruster component; we have already begun 3D modeling the new coupler design to replace the one we have currently 3D printed.  The rapid manufacturing process of 3D printing has been a valuable asset so far and I am sure it will continue to be so.  Another area is the containment system.  We will need to get pressure-regulatory equipment for the gas containment, and no member of our group has much experience in this area.  For this reason I believe that most of our time will be spent on implementing the piping system, which will be a learning experience.  Overall, I'm excited to see what the future holds for this project, as I'm sure it will be extraordinary.