Killswitch - spacecraft-design-lab-2019/documentation GitHub Wiki
Requirements
- PQ-Mech-12: shall use at least two kill switches to keep the PocketQube offline in deployer
- PQ-Mech-13: kill switches shall make contact witht the deployer rail or with another PocketQube (see figure 6)
- PQ-Mech-14: kill switches shall be located only on the Z-axis; placement options (see figure 6):
- in the lateral side of the satellite within 20mm from the Z-faces and touching the deployment rails
- aligned with the backplate in the Z-face and in contact and in contact with the PocketQube below or the pusher plate
PQ-Mech-15: kill switches shall not obstruct ejection of the satellite from the deployer
Notes
- SPST-NC circuit (Single-Pole Single-Throw Normally Closed)
- Suggestions: Lever or wheel type if on sides of rails, pin type if on forward or rearward ends?
- Min. 4.2V DC voltage capability (battery max)
- Min. 2A DC current capability (update with total battery array capability once known)
Green Location Options
| Style | Part No. | Dimensions (mm) | Current Rating (DC) | Voltage Rating (DC) | Price |
|---|---|---|---|---|---|
| Roller | OMRON D2F-L2-A | 12.8 x 5.8 x 13 (16.5) | 2A | 30V | $4.02 |
| Roller | OMRON D2F-L2-A1 | 12.8 x 5.8 x 13 (16.5) | 2A | 30V | $4.02 |
- Smallest roller switch option capable of needed power throughput found so far
- A & A1 are left- and right-angled terminal versions of same switch, to make mounting to either side of satellite easier
- Boards need vias to accept switch terminals; through-holes or threaded holes for switch thru-hole mounts
- Datasheet here
- Need to test or get more info on vacuum compatibility, offgassing
- Just buy some and stick them in the bell jar to see if anything happens?
Blue Location Options
| Style | Part No. | Dimensions (mm) | Capacity Rating | Voltage Rating |
|---|---|---|---|---|
| Lever | ESE-18R63D | 4.8 x 4.0 x 1.2 | 10mA | 5V |
| Lever | JJDVDUJ314NCPMRTR | 4.2 x 3.6 x 1.2 | 1mA | 5V |
| Push | JJMH0UG200NCNMRTR | 5.7 x 4 x 2 | 100mA | 12V |
Current Choice
The plan is to use the roller option listed in the "Green Location Options" table above. These kill switches will lie on top of the bottom board below the battery compartment. The rollers will slide along the rails of the pod. This will prevent the kill switches from taking up surface area space from solar cells on the bottom board.
UPDATE [10/28]: Alba Orbital suggests we use kill switches on the bottom of the bottom board instead of the top. This would reduce area for the Solar Panels on the bottom surface of the pocket cube. Decide where we want to put these.