What are the most significant risks that could jeopardize the success of the project? How are these risks being managed? What contingency plans are ready?
The most significant risk this week emerged from the PCB manufacturing process: the USB connector specified in our design is not rated for the reflow soldering temperatures required during board assembly. The connector has a maximum temperature rating of 260°C, but our lead-free reflow profile peaks at 245-250°C, creating an unacceptable safety margin that risks damaging the connector’s plastic housing during assembly. We managed this by identifying a pin-compatible high-temperature replacement connector (rated to 280°C), updating the PCB design with minimal footprint adjustments, and resubmitting to the manufacturer with fast-tracked review to minimize additional delays.
However, we have positive news that significantly reduces our integration risk: Mars successfully got the imaging code working this week and demonstrated seamless data recovery from test drives. The complete data recovery pipeline is now functional end-to-end, including error correction and data block reconstruction. This major breakthrough means software development is actually ahead of our internal milestones, eliminating the previous risk of software delays impacting integration.
Hardware integration risk remains centered on verifying VBUS power-cycling performance and USB signal integrity with the new connector. Mars has prepared comprehensive validation procedures including impedance verification for the USB differential pairs with the replacement connector. Our contingency plan includes tunable parameters in the power cycling circuit if adjustments are needed during bring-up.
Component availability risk is well-managed. Standard parts have been inventoried with 100% BOM match. The high-temperature USB connector and remaining long-lead components (MOSFETs and replacement redriver) align with our revised November 19th PCB delivery schedule.
Were any changes made to the existing design of the system (requirements, block diagram, system spec, etc)? Why was this change necessary, what costs does the change incur, and how will these costs be mitigated going forward?
We made one critical hardware change this week: replacing the USB connector with a high-temperature rated alternative. This change was necessary because the original connector’s temperature rating (260°C max) was incompatible with our lead-free reflow soldering process (245-250°C peak), which the PCB manufacturer identified during their design review before fabrication began. Using the original connector would risk plastic housing damage during assembly, potentially causing mechanical failure or compromised electrical connections.
The replacement connector is pin-compatible and maintains the same impedance specifications for USB differential pairs, requiring only minimal PCB footprint adjustments. Costs include an additional 5-day schedule delay (PCB delivery now November 19th instead of November 14th), revised fabrication charges, and approximately 6 hours of engineering time for redesign and verification.
We’re mitigating these costs through several approaches: the manufacturer fast-tracked our revised design through their review process to minimize additional delays; since the imaging and data recovery software is now fully functional, we’re expanding our software test suite using simulated hardware responses to validate edge cases without waiting for physical boards; and we’ve optimized our bring-up procedures to parallelize signal integrity measurements, potentially recovering 1-2 days during validation.
We are having a revised board that is just the 2 usb connectors being made first to confirm that in assembly those don’t get damaged. those will get delivered before anything else.
Provide an updated schedule if changes have occurred.
Revised schedule accounting for the USB connector issue and incorporating the software development breakthrough:
Weeks 5-6 (current): Board redesign completed with high-temperature USB connector, new PCB fabrication in progress. Major software milestone achieved – imaging code fully functional with successful data recovery demonstrations. Software development now ahead of schedule.
Weeks 7-8 (upcoming): PCB delivery November 19th, board assembly and bring-up with new connector. Signal integrity validation focusing on USB differential pair impedance with replacement connector. VBUS power cycling characterization. Software team expanding test coverage and edge case handling while hardware is in fabrication.
Weeks 9-10: System integration with functional software stack, initial recovery testing with failed drives across multiple failure modes, throughput optimization, user interface refinement.
Week 11: Cross-vendor drive compatibility validation, performance measurements, success rate analysis across different drive failure types.
Week 12: Final demonstration preparation, comprehensive documentation, demo video production, poster completion.
The critical path now runs through hardware validation and integration testing. Software development is no longer blocking, having achieved the major milestone of functional end-to-end data recovery. The 5-day hardware delay is partially offset by accelerated software readiness.
Progress summary and demonstrations
Hardware Progress: Mars managed the USB connector crisis by identifying the temperature rating incompatibility during manufacturer review, sourcing a high-temperature replacement (280°C rated), updating the PCB design while maintaining signal integrity requirements, and expediting the revised fabrication. Standard components have been inventoried with 100% BOM match. The testing and bring-up plan has been finalized with detailed procedures for USB signal integrity verification with the new connector. Hardware interface specifications are complete. We are considering producing one test board with just USB connectors to verify USB 3 SuperSpeed compliance before full system bring-up, which could also serve as a demo backup platform.
Software Progress: Major breakthrough this week – Mars successfully got the imaging code working and demonstrated seamless data recovery from test drives. Mars redid the software architecture entirely, and will work to get Apollo to update the documentation.
Integration: The team has updated hardware-software interface documentation to reflect the connector change and revised timeline. With software now functional and hardware expected November 19th, we’re well-positioned for rapid integration testing. The primary focus is preparing comprehensive bring-up procedures to validate the new USB connector’s signal integrity and leveraging the fabrication period to expand software test coverage and optimize the data recovery algorithms.