During the launch of Hermes II, it seems that the thermal and lower electronics DAQ units were in proper working order. There were some ECNs (engineering change notifications) to attend to this semester.
These ECNS act as a MUST DO to-do list for the semester. Past this items, there are a variety of longer term engineering goals for payload to consider.
OUR ECNs:
Add switchband switch for Payload DAQ
RE: Miske
Classification: Iterative Improvement
Description: For Hermes 2 the last thing we did was install the nose cone, driven by concerns about payload battery life. By adding a switch, co-located with the avionics switches, we enable the nose cone to be closed at any time without leaving a battery burning. This will reduce integration time and complexity.
Approval: Approved, need to coordinate with inner structures, as this will largely fall on them.
DAQ Feedback
RE: Shreeyam
Classification: Iterative Improvement
Description: Currently no feedback from the DAQ to show that it's turned on. Adding a pair of differently coloured LEDs around the switch would help provide clear feedback when the DAQ is operational.
Approval: If we can do this without a hardware revision. How many DAQS do we have left
Use the DAQ's onboard flash
RE: Shreeyam
Classification: Risk Mitigation
Description: Solid state storage is more robust than SD cards to external vibrations and impacts.
Approval: Approved. I think this does not require hardware revisions. We should confirm. Also Shreeyam has yeeted the country--who is really doing to do this?
LE Camera Arming
RE: Elena
Classification: Flight or Test Failure Resolution
Description:
(also part of inner structures subteam?)
On Hermes II, cameras were turned on by inserting a screwdriver through holes on the switchband to press buttons on the cameras themselves. During testing, this pressure caused the buttons to break, and these had to be fixed last-minute before launch. The mechanism continued to be unreliable, since you can easily change the mode of the camera or not turn it on by accident, and during launch one of the cameras wasn’t able to be turned on at all.
One way to mitigate this would be connecting the cameras to a Pyxida, possibly a new one in the LE section, so that we can get remote confirmation that cameras have been turned on.
Alternatively, we could connect the LE cameras to the LE DAQ so that all LE components are turned on by turning on the DAQ only. In this case, the DAQ would still need to be turned on manually, but we have added LEDs to the DAQ switch so it should be much easier to tell that it’s on. However, this option wouldn’t give us remote confirmation that cameras and DAQ are on.
Approval: I like the LE DAQ idea since it doesn’t change as much on the avionics side. I wonder if the solution is cameras that have better buttons. I think we should discuss this with Elena before approving it. Use BBC.
UART Comms to Pyxida From Payload DAQ
RE: Miske
Classification: Technology Demonstration
Description: We lost all the data from the nosecone DAQ. The months of hard work put into the device could have been at least partially saved by running a few more characters into the string which is sent by Pyxida from the DAQ over the UART protocol. We have already checked and know that there is room on the Pyxida system to add another UART line to either DAQ. Small circuit changes would need to take place but we could theoretically use the same exact boards that flew on Hermes II.
Approval: Need someone to build a model that this data will be plugged into. I think that all progress on the NC payload should be halted until someone can show how we will use the results of the thermocouple data to design the spaceshot. ---- On another note, this seems like a secondary need to other payload challenges. Especially if this will require a hardware revision, I think that this should not be worked on.
Improved Nosecone Thermocouple Mounting
RE: Diane and Miske
Classification: Risk Mitigation
Description: We are looking to use copper pads with isolated threading for placing the thermocouples in order to reduce the chances of a shorting incident as well as make the process of inserting thermocouples easier.
Approval: Is this for the nosecone tip? My comments on the need for an analysis plan (see 1.5) apply here. But I think this is a good change if it speeds up or improves manufacturing. I agree that some clarification is needed.
Remove the Load Cell from Lower Electronics
RE: Juan
Classification: Change for Commonality with Spaceshot or other Vehicle
Description: The pressure transducer will provide more data about motor performance that is key for transitioning towards the space shot. Using the same load cell flown this year adds significant mass, is not cost effective, and would not provide useful data on Hermes III given that the space shot will include different parachutes.
Approval: Approved.