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Currently Playing: CubeSat Standard Read-Through: Electrical Specifications (Part 2 of 2)

Join the Discord: https://discord.gg/yeusgM75ys In this episode we finish our read-through of the CubeSat Design Specification (CDS) document by looking at the electrical specs (mostly deployment switch requirements) and some operational specs like (a first glance at the RF spectrum licensing ordeal to come). This video is for you if you have just started learning about CubeSats or if you don't usually read a lot of technical docs and want to prepare for hands-on #cubesat development. *Dev kit shop will be up in late 2025 / early 26* – get pinged: https://forms.gle/5a2UZdfcyUmFjTZd8 ## 🛰️ Support This Project If you are looking for a way to support this channel, leave a tip or become a member :) - Channel Memberships: https://www.youtube.com/channel/UCLf9aKlW-TbC8zbrl0OvKLQ/join - Patreon: https://patreon.com/buildacubesat - Ko-fi: https://ko-fi.com/buildacubesat - PayPal: https://tinyurl.com/bac-paypal-donation *Summary* - CubeSat needs to be electrically inert (except for a battery protection circuit and a real time clock (RTC) that may be powered) until it is deployed. - RTC frequency shall be less than 320 kHz and it shall draw less than 10 mA. - This is done with 2 mechanisms: The remove before flight (RBF) feature and 1 or more deployment switches (number depending on LP requirements). - Deployment switches are momentary switches that are actuated using spring loaded plungers that protrude through the Z+ faces of the rails. As the CubeSat is deployed, the switch may actuate and activate power to the system. - Deployment switch actuation needs to reset the deployment timers. - Deployment timers are used to delay the activation of the RF system and deployables after the CubeSat has left the dispenser in order for it to gain some distance to the spacecraft. - Deployables like antennas can be activated 30 minutes after deployment of the CubeSat. - The RF system can be activated 45 minutes after deployment. - The CubeSat itself may power up and boot directly after deployment. - Umbilical Connectors (aka. power and data cables that need to be accessible on the ground) as well as the RBF feature should all be on the same side. Check LP specs for this. - Use a battery protection system / battery management system (BPS / BMS) for charging and discharging. Duh. - Only use UL-listed: https://en.wikipedia.org/wiki/UL_%28safety_organization%29) batteries. - RF systems and deployables need at least 3 independent inhibits. TBD what exactly counts as an inhibit. Deployment timers are not inhibits. - Testing and dispensers will be discussed in a future video. *Timestamps* 00:00 Intro 00:35 Remove Before Flight Feature 01:15 Deployment Switch 03:30 Real Time Clock 04:50 Umbilical Connectors 06:30 Battery Protection Feature 07:43 Inhibits for RF and Deployables 08:30 Operational Specs: RF Licensing 11:26 Deployment Sequence 12:39 Testing (will be discussed in a future video) 14:03 Quick look at dispensers *Repo Links* CDS Mechanical Specs Notes (stuff that needs more investigating, etc.): https://codeberg.org/buildacubesat-project/bac-docs/src/branch/main/content/s01e04/CDS-electrical-notes.md CDS with my highlighting: https://codeberg.org/buildacubesat-project/bac-docs/src/branch/main/content/s01e03/CDS+REV14_1+2022-02-09-annotated.pdf *Links* Cal Poly: CubeSat Design Specification (CP-CDS-R14.1): https://www.cubesat.org/s/CDS-REV14_1-2022-02-09.pdf Cal Poly: CubeSat Interface and Fit-Check Procedures (CIFP): https://www.cubesat.org/s/CP-CIFP-20W-Public-Version.pdf *Credits* 1. RBF Feature (Nano Satellite “ITF-2”): https://www.jstage.jst.go.jp/article/tastj/17/2/17_17.253/_pdf/-char/en 2. Deployment Switch (Nano Satellite “ITF-2”): https://www.jstage.jst.go.jp/article/tastj/17/2/17_17.253/_pdf/-char/en Get in touch: https://buildacubesat.space Need a friendly, a non-corporate GitHub/Gitlab alternative? Check out https://codeberg.org/ #buildacubesat #episode #s01e04