This week, our team finalized a few specific concepts to pursue based on our research. One of the most promising is a multistage opening system designed to control how the structure breaks down during re-entry. The idea is to use staged geometric changes that respond to altitude, temperature, vibration, or time, to maximize heat flux and ensure an even rate of demise.
We envision three stages:
- Initial stage: The system remains closed as it first encounters re-entry conditions.
- Second stage: At a predetermined trigger (altitude, temperature, vibration, or time), wings or flaps deploy to increase the exposed surface area, enhancing heat flux.
- Final stage: The structure reconfigures into a specific geometry that both reorients the system and distributes heating more evenly, maintaining maximum heat transfer/flux and ensuring complete demise.
On Monday, we met with our liaisons at Honeywell. We reviewed the Product Design Specification (PDS) with them and addressed any concerns they had. We have now updated the PDS to reflect their critiques. We clarified the distinction between active and passive approaches to satellite demise. A passive system relies on natural re-entry forces (mostly heat generated by the atmosphere) to initiate structural failure without expending additional energy. An active system, on the other hand, uses sensors and actuators. This requires stored energy, such as batteries, to trigger the decomposition process. We compiled a list of system requirements and constraints:
- Weight considerations: The system does not need to be strictly minimized in mass; instead, additional sensor-related components should remain within 15% of the total system weight
- Vibration and shock: The design must meet random vibration and shock requirements (R10 level), ensuring it is robust enough to survive launch conditions. We will revisit what these requirements mean in detail at the next meeting.
- Power: A rough estimate of power requirements is still to be determined.
We were reminded to include references to source documents (like the European Space Agency’s casualty risk statistics) in our appendix. This will strengthen the traceability and credibility of our design decisions.
Our tentative Preliminary Design Review (PDR) is scheduled for Tuesday, October 14th. All team members will need to submit site-visit forms and provide proof of U.S. citizenship. We are planning to follow up with the university regarding proper documentation.
In the upcoming week, we will finalize power requirement estimates, research and prepare a discussion on vibration/shock testing rationale, and submit site visit documentation in preparation for the PDR.
On Tuesday, we met with Dr. Lind and discussed Nichrome (nickel-chrome alloy) as an approach for the prototype. Nichrome is known for its high resistivity and ability to withstand elevated temperatures, which makes it a strong candidate for components that may experience extreme heating during re-entry.
Dr. Lind highlighted that Nichrome’s durability and controlled heating properties could make it an effective material for testing passive demise concepts. Its ability to generate and tolerate heat without melting too quickly may allow us to simulate or accelerate certain failure mechanisms in a controlled manner. This opens possibilities for integrating Nichrome into the design as part of a targeted trigger of a subsystem within the prototype.
The conversation also emphasized the importance of comparing Nichrome’s properties, like melting point, oxidation resistance, and weight implications, against other potential materials. This evaluation will help determine whether Nichrome can provide both functional reliability and alignment with the overall system requirements discussed earlier with Honeywell.
Going forward, we would like to conduct further research on Nichrome’s performance in aerospace or high-temperature applications, compare its material properties with alternatives to assess tradeoffs, and begin considering how Nichrome could be incorporated into prototype testing for re-entry scenarios.