Team Vision for Final Demo and Handoff
Plans for this phase
- Testing
- Full System Creep Succeeded
- High Altitude Balloon Test - Anthony, Paul
- Time to Remove Succeeded
- P16103 Succeeded
- Thermal Testing Succeeded
- Logistics
- ImagineRIT Succeeded
- Submit to the Journal of Small Satellites - Anthony
- Finish SPEX Closeout - Full team
- Present to SPEX Group - Full team
- Re Re Re Order Ultem for Final Build Succeeded
Final Design
This iteration produced a CubeSat that is, or is very close to, our final product. It represents the most recent iteration of the design.New Ultem Parts
Stratasys agreed to re-print our parts with the correct design revision for free. These parts were received during this phase.Rail Fabrication
The left and right rails are the only machined part of this CubeSat design to the beauty of 3D printing. These rails though have complicated geometry and tight tolerances, so documentation is supplied for the complete fabrication of the rails. The document can be found here Link. It includes fabrication of the deployment switch, and a walk-through for the anodizing process.The Cubesat specification document has a condition that the rails can be either 6061 or 7071, but the rails have to be hard anodize. Due to the high quoted prices received ($300), and that it will not be going into a LV any time soon we determined that anodizing was not a good use of funds. Also the process of anodizing adds a thickness of ~0.0020-0.0024” which means the rails need to be machined under spec. See the rail fabrication document for documentation on how to get the rails anodized.
Test Results Summary
Bake Test
Test Plan
- Follow assembly procedure for normal CubeSat deployment test
- Place CubeSat in environmental chamber with temperature >40C
- Wait a minimum of 9 hours to allow CubeSat temperature to stabilize
- Remove CubeSat from chamber
- Trigger deployment of panels
- Verify successful deployment
- Perform visual inspection of all components for signs of damage
Results
Takeaways
- Measurements taken of deployment frame
- Heat controlled between 140deg F to 200deg F, approximately 60deg C to 80deg C
- Rail edge to rail edge change was approximately zero (tens of micromter variation).
- After swapping to a 14 lbs line and keeping for 7.5 hours, the system did not deploy
The system can withstand high temperatures and not prematurely deploy or deform. This includes the fishing line which experienced no discernible creep.
Freeze Test
To confirm performance at the minimum temperature requirement of -40C, the CubeSat was exposed to extreme cold through the use of dry ice in a small insulated container. Successful deployment was demonstrated.Test Plan
- Follow assembly procedure for normal CubeSat deployment test
- Place CubeSat in environmental chamber with temperature <-40C
- Wait a minimum of 30 minutes to allow CubeSat temperature to stabilize
- Trigger deployment through hot knife current
- Remove CubeSat from chamber
- Verify successful deployment
- Perform visual inspection of all components for signs of damage
Results
Freeze Test VideoThe CubeSat successfully deployed at a temperature below -40C. After inspection, no damage was found on the CubeSat structure from deployment at low temperature. The hot knife was severed during the test. It is unclear if this was due to a rapid temperature change or from tension from retention line release.
Takeaways
We are confident that our system will perform over the full designed temperature range.Vibration Test (P16103)
Our CubeSat structure, with the mass analog inside, was vibrated according to the expected vibration profile of the launch vehicle. The vibration profile has not been verified by P16103.Test Plan
Results
The CubeSat passed the test. No visible damage to the CubeSat was detected after vibration.Takeaways
This vibration test was only preliminary but it supports our belief that our CubeSat will survive the vibration of launch.Time to Remove Internals Test
To test our fulfillment of the customer requirement for easy removal of internals, we timed one of our members disassembling the CubeSat and removing the mass analog.Results
The internals were completely removed after 180 seconds (3 minutes, 0 seconds).Takeaways
We failed to meet the desired time to remove of 60 seconds. At this point in the design, we do not have the ability to significantly improve this time. We believe that a three minute disassemble time, though longer than requested, will not be more than a minor inconvenience to the operator. This is supported by the low importance (1 on a 1-3-9 scale) initially assigned to the requirement. We are comfortable with this and do not have any plans to change it.Deployment Test
A deployment test with the new fishing line, Ultem design and spring configuration was run. Only one hot knife was used to test the redundancy of the system.Test Plan
Results
The CubeSat passed the test. Deployment was immediate.Takeaways
14lb fishing line in conjunction with the updated wire path is sufficient to cause deployment. Larger springs are not needed.Risk and Problem Tracking
The use of 14lb fishing line in the design eliminates the problems we were having with deployment. The new line is strong enough to hold the panels in place and thin enough to slide easily out of it’s wire routing - even with the outdated hot plate design. Stratasys also sent us our current design revision for free this phase, closing out the problem of the wrong revision Ultem parts.
Due to the inherent risks of putting a satellite into orbit and the current lack of a thermal vacuum chamber at RIT, there are many high severity, low likelihood risks remaining that we are not able to reduce any further. Successful deployment tests on the final design have reduced the likelihood of a solar panel failing to deploy in orbit. We believe further deployment testing over the next week will eliminate this risk completely. Risks eliminated since the previous iteration of risk assessment are as follows: system is expensive to manufacture, design cannot be completed in required time frame, system will not be compact, budget will be too low, system mass will be too high, EM Radiation cause CubeSat to heat up too much, deploying panels dangerously alters flight dynamics and system cannot be disassembled easily. We expect further vibration testing over the coming week to eliminate the risk of the system being damaged by launch vibrations as well.
Bill of Materials
Below is our updated bill of materials. At this point, all of our parts have been ordered and received with the exception of some extra helicoils that were recently purchased. This B.O.M. reflects a change from 30lb to 14lb fishing line, the doubling of the amount of hinge springs used, the addition of Kapton tape and a helicoil installation tool, and the removal of acrylic as a solar panel mass analog. Not included in this table is approximately $150 spent on shipping parts that did not make it into the final design. This brings our total money spent to $350, well under our $1,500 limit.Engineering Requirements
At this stage, almost all of our engineering requirements have been met. We failed the requirement of 60s disassemble time but be believe that the 180s disassemble time that we have will not be a major problem for the CubeSat's operator. Surviving P16103's vibration test remains unfulfilled as their test is just now being finalized. We believe the requirement will be met next week.Technical Paper
Imagine RIT
Poster
Below is the poster that we will present at Imagine RIT. Our final MSD poster that we submit to be hung in the hallways will be in portrait landscape and have some minor updates based on events occurring over the next week.Staffing Plan
We have assigned each team member a period of Imagine RIT in which they will staff our exhibit.Anthony - setup and 9am-12pm
Paul - 2pm-3pm
Tristan - 12pm-3pm
Robert - 3pm-5pm and teardown
Standards Followed
The following standards were called on for the design and test of our CubeSat. The first two ensured that we would qualify for launch. The third ensured that we could interface with an arbitrary payload. The fourth ensured that our design had the proper strength.
• NASA LSP REQ 317 01 Revision B
• CubeSat Standard Revision 13
• Pumpkin PCB Standard
• ASTM D638-Tensile Testing (ULTEM Characterization)
Plans for Wrap-up
- Begin handoff, begin training, and finalizing an build design to the best of our abilities.
- Ensure 10 cycle test success
- HAB Test
Gannt Chart
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