List small or large improvments we can make to design, process, or operations, in reverse-chronological order.

SAC 2023

General

Successes:

• Test-flight timeline (even without test flight) made us do much less last-minute so IREC weeek was less stressful

• Same goes for integration tests well before IREC

Failures:

• Never weighed rocket

• Showed up to Tuesday saftey checks without fully-assembled rocket

Mitigations & ideas:

• Show up to saftey check fully assembled (sans energetics)

• Weigh the rocket in the field

• Assign a systems engineer

Structures

Failures:

• Long tube makes assembly very hard

• Tubes fill with dust when wind gusts

• Weathercock off rail

  • Low-ish TWR

  • Long railguides levered and caught on rail

• Winding improvements

  • Redesign and reprint filament holder end caps

  • Design a dowel/other holding system for the rollers

Mitigations & ideas:

• Aim for higher TWR

• Return to button rail guides

• Shorter/more open tubes

• Printed end caps for tubes

• Make long tubes before lengths are figured out (work in parallel)

Avionics

Successes:

• Sleds not wired together

• Crimping multiple conductors into one ferrule for bridging

• Huge Big Red Bee battery

• Batteries with protection circuits

• T-shaped and tapered key, easy to insert and stops in the right place

Failures:

• Glued nut stuck inside, could not remove avionics bay

• FSR judge didn’t like the massive battery and thin sled parts

  • it did break during flight

• Sleds were loose when not in a tube

• Big Red Bees are way too unreliable for a COTS part, we’ve had 4 failures in total

• BRB antenna smashed into nose cone bulkhead and could not transmit

• Upper end cap broke

Mitigations & ideas:

• Retain the sleds while outside a tube

• Impact test avionics bay

• Re-do FEA after all changes, new holes/slots mean new stress concentrations

• Think about assembly forces, not just flight forces

  • Better nut retention on the mounting bars

• Do smaller slots for wire pass or put them on the side of the sled (DO backplane sled, DON’T do COTS sled)

• Reduce the number of threaded connections, labor-intensive to Loctite everything

• Have spares for everything (backup Big Red Bees saved us)

• Tripod for the antenna holder on the stands

• Use rubber ducky (or other encased antenna) for everything sticking up

• GSW tracks “time of last update” and “time of last change” for GPS packets to check lock

Payload

Successes:

• Mounting electronics to side panels improved density and made assembly easier

• JST connectors worked well

• Good to buy batteries with protections

Failures:

• Line cutter immediately got cut

  • Alternate: Early main due to pressure spike

• Need to depanel payload in the field to plug things in

• Not enough venting

Mitigations & ideas:

• Put a switch on every battery

• Stronger line for line cutter

Recovery

Successes:

• Drogue streamer is easier to integrate, easier to see on descent/recovery, less snatch force

• Mini-Tamiya connectors worked and did not need to be zip tied. Very cheap and easy to use.

Failures:

• Needed to reach down 5’ of tube

• Main at apogee for TBD reasons

• Single-bay might be more complicated than worth, but not totally clear since we had >1’ of payload

• Booster coupler tube cut shock cord, load rating did not matter

• Couldn’t de-integrate fully because integration testing didn’t have us threadlock the charge caps or

Mitigations & ideas:

• Back to dual bay

• Higher TWR for less weathercocking

• Fully (dummy energetics) integration test! No exceptions

• Protect potential cut points (wrap more kevlar/other protection)

• Wrench flats on charge cups

Launch operations

• Weigh the rocket

• More radio training

Field recovery

• Land navigation training

• Require all recovery to be HAM licensed

• Earpiece microphones

• More radio training

• Make sure one person has cell reception (Verizon seems reliable)

• Timer to drink water