P16102: RIT-SPEX Structure
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Integrated System Build & Test

Table of Contents

Team Vision for Integrated System Build & Test Phase

Prototype III

In this phase, a new prototype was built. This prototype represents the most recent 3-D printed design changes. This prototype also, for the first time, includes machined aluminum rails - a requirement for the final CubeSat. This prototype includes a mass analog as well, which will be necessary for later vibration testing. The plastic used in this version is still ABS as the new Ultem parts have not yet arrived. This prototype is useful for new fit and deployment tests that do not require Ultem.
Prototype III (3/16/16)

Prototype III (3/16/16)

Assembly Process

The new prototype was assembled in a more streamlined manner than the previous prototype. The key to assembly was assembling the hot plate - NiChrome - restraining line structure before attaching the subsystem to the rest of the CubeSat. We found this to be much easier than assembling those components while the restraining line was tensioned to the deployable side panels.
Individually assembled Hot Plate (3/16/16)

Individually assembled Hot Plate (3/16/16)

Ultem Printing

We recently reached out to Stratasys to get a status update. According to their distributor, our parts are being processed now, and should arrive over spring break. When we receive the parts, final assembly will begin.

Mass Analog

For P16103's vibration test to be as informative as possible to us, our CubeSat requires an internal mass analog. This will simulate the mass of all the internal components. We created an analog by 3-D printing a structure that fits within our CubeSat structure. The internal structure had a cylinder drilled out of it and a metal cylinder inserted to increase overall mass. The target mass for an internal of this nature is 950g but due to the relatively unknown mass of the fasteners that we will use, this number has some leeway. The internal we manufactured has a mass of 735g. This discrepancy leaves room for fasteners to come in heavier than expected. If when the design and fasteners are finalized and the internal mass is still too low, more mass can be added by packing the internal with sawdust.

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Mass Analog (3/15/16)

Mass Analog (3/15/16)

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Mass Analog (3/15/16)

Mass Analog (3/15/16)

Design Changes

Hot Plate

Upon initial testing of our full CubeSat deployment system, we encountered some issues with the design of the wire path. Several deployment failures were caused by the retention line being pinched by tight corners in its path. In response to this issue, we redesigned the wire path to remove all tight corners, and chose a thinner fishing line that was less rigid.

Deployable Backer Panel

When we attempted to prepare for the deployment testing, we had some difficulty assembling the retention line onto the deployable panels. To improve this aspect of our design, we integrated small indents to accommodate the retention line knot more easily.

Test Results Summary

Table Top Deploy II

Last phase, we tested a table top deployment of the CubeSat. In that test, it was revealed that the restraining line became stuck in its routing path and wouldn't always come lose when cut. As a result, design changes to the routing path were made, as detailed in the previous phase's edge page. During the current phase, a new table top deployment rest was run to see if the design changes were effective in allowing reliable deployment. This test involves deploying a prototype CubeSat in a lab ambient setting. The NiChrome hot knife's ability to cut the restraining line, the springs' ability to deploy the panels and the ability of one hot knife cut to free both panels were all tested. ER5 - Time from command to deploy, is tested.

Test Plan

Table Top Test Plan(2/23/16)

Table Top Test Plan(2/23/16)

Videos of Test

Table Top Deploy with New Hot Plate

Table Top Deploy with Thin Fishing Line

Results

Takeaways

Vacuum Testing

Vacuum Testing for Offgassing

Vacuum Testing for Offgassing

Risk and Problem Tracking

The highest priority risk we were addressing this phase was the potential failure of the solar panels to deploy. Table Top Deploy Test II, which was run with minor design changes from Table Top Deploy Test I, showed a deployment mechanism that was improved but still not reliable. As a result, as detailed above, several more design changes were made. A test of this new system will be required before the likelihood of a failed deployment decreases. All other risks have remained at largely the same level over the past phase.
Updated Risk Assessment(3/16/16)

Updated Risk Assessment(3/16/16)

As we have progressed through this phase, our status on several problems has progressed. We have recieved confirmation from Stratasys that we can get free printed Ultem from them. We have machined a pin for use in the deployment sensor. We have also experienced a second semi-failed deployment test. In addition, many ordinary risks have been delt with, as cataloged below.

Updated Problem Tracking(3/16/16)

Updated Problem Tracking(3/16/16)

Bill of Materials

Below is our current Bill of Materials. The BOM has been updated to reflect the aquisition of new, thinner fishing line for use with the hot knife. It also reflects Stratasys's assurance that we will receive free Ultem parts from them.
Updated BOM (3/16/16)

Updated BOM (3/16/16)

Imagine RIT

In order to make sure we were staying on track to complete our final goals, we began to really look ahead to the Imagine RIT presentation this phase. This mainly included beginning to work on a poster.

Poster

Below is our progress on the poster so far. Much of it is template material and even what we put in ourselves is subject to change over the coming weeks. We will work off of this design from now until Imagine.
Updated Poster (3/15/16)

Updated Poster (3/15/16)

Plans for next phase

Gaant Chart

MSD Plan(Updated 2/24/16)

MSD Plan(Updated 2/24/16)


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