Integrated System Build & Test
Team Vision for Integrated System Build & Test Phase
- We tested the deployment
- Manufactured Cubesat panels
- We assembled the power system
Test Results SummaryA summary of all tests can be found here.
The full scale booms were tested for deployment. The progression can be seen in the pictures below. The full deployment took one hour and eight minutes. The sail was extended successfully two times.
A problem was encountered when the sails were extended without an aid to prop them up. A deployment test was started that ended up stalling out in which the booms were not level with the table and started to sag. The sagging was concluded to be the result of the failure. The purpose of this boom is to be deployed in space where there is no gravity to drag the booms down so it is not considered an issue.
Sail Folding TestWe folded the sails and put them in a vacuum bag.
The sail was folded using the method below.
At this point, the hinges have sprung open and are now locked in the open position. In order to fold them back up, pressure must be applied to the center of the linkages wher the spring is.
This image shows the actuation motion of the spring hinges. The spring is forcing the linkages into the straight position, as shown in the previous image.
In the second picture, the deployment cover is pictured with the sensors wired up. This cover may have to change, because after redesigning the boom deployment spool, the sensors had to be mounted below the deployment cover. This would not have been an issue on the old design, but with the top circular plate on the spool, it is now hitting the sensors. A redesign will need to be completed.
Custom BaseboardThe custom baseboard had arrived and has been assembled and tested. This board incorporates:
- msp430fr5969 microcontroller
- Power Regulation
- Battery Charging
A hurdle was encountered during the assembly and test of this subsystem, which did not allow the microcontroller to power on. This design flaw was fixed with a minor rework on the board.
Due to this design flaw, as well as some minor layout changes, a second version of the baseboard will be ordered and assembled before the handoff to the customer.
Sensor and Motor DaughterboardA second board was designed and ordered to break out:
- Connectors for the sensors
- Signal conditioning for the sensors
- Bidirectional H-Bridge motor driver
- Nichrome driver
- Prototype area for further development by the next team, without the need for another board
Risk and Problem TrackingThe Risk Management document has been update through out this semester. This semester due to the issues with deployment, not getting the solar sail to deploy is our highest risk. From the last design review the risk is smaller since we got the deployment working but something could still go wrong. Our updated design should help reduce the risk. Other risks
- Not being able to fold the sail small enough
- Solar panels don't deploy
- Nichrome wire doesn't cut the fishing line
Since we faced some problems with the deployment we updated the problem tracking document which can also be seen below.
PV Array Alternative Selection StudyThe Simulink architecture, showcased in the last review, is still in progress pending completion of a rough prototype of the CubeSat. However, significant progress was made with the PV array selection study. To reiterate, the decision was made to not source solar arrays for the CubeSat during this phase of the project. This was due to a lack of funding, or more specifically a lack of time to source proper funding, as well as a few technical uncertainties. To mitigate this decision, this study was undertaken to provide the teams of future project phases general knowledge of space grade solar cells, and a specific model recommended for them to source.
The in progress IEEE formatted study can be found here. Essentially it sources multiple alternatives from local SMEs and NASA studies. It then rates these alternatives against set criteria by averaging the ratings of multiple subjective stakeholders. The criteria themselves are also weighted by the stakeholders based on subjective importance. The average of the ratings and average weighted criteria are then combined to produce a holistic numerical representation of each alternative.
Snapshots of the outline and the stakeholder survey supporting this study are also found below.
Scheduling and Budgeting
Currently, the team has $385 left in the current budget. An exhaustive list of all purchases made across MSDI and MSDII can be found here. The graph below also shows the progressive cumulative total remaining of the team's budget across MSDI and MSDII.
The three graphs below cumulatively represent the schedule progression in order across all design reviews so far during MSDII. The red line represents the current review date, and where we expected to be during that particular review by now. Overall the tasking has taken longer than anticipated at every review, and the extension of most action items is due to the testing process. The integration and test phase is notorious for it's unpredictability and hindrance of project timelines, as testing often requires adjudications and further repetitions.
Plans for next phaseFor the next phase, in three weeks, we plan to have all the parts machined. The electronics will be assembled as well. This will allow for full systems tests.
- Sail deployment test
- Finish Machining
- Update Schedule
- System Arch./Design Doc.
- PV Array Alternative Selection Study
- Continue to assist with machining
- Solder and test power/control board
- Develop wire harnessing for sensors, motors, and nichrome wire
- Sail deployment test
- Work on poster
- Work on paper
- Update test plans
- Update Risks
- Update edge page
- Test ADC with Boom Sensors
- Create Ground Software
- Code Watchdog Timer
- Create RTC Functions for Additional Safety Checks