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

SAC24

General

• More testing overall

• Avoid Cessaroni

• Epoxying nuts into bolted connections

Structures

Successes

• Airframe “smoothness” did not detract from flight performance and apogee - exceeded expected apogee

  • Heat shrink tubing was an overall success!

• Revised fin support structure design performed well

• Overall easier and faster integration due to additional separation point

• Unless otherwise specified below, all other structural components performed well (bulkheads, fins, thrust plate, retainer, etc)

Failures

• Nose cone weights & tip were not properly secured and became detached - most likely upon impact(?) - and damaged avionics sled

• Shear pin holes became stripped due to repeated use, leading to issues with disintegration and shear pins falling out

• Several epoxy failures. Some of the damage may have occurred due to suspected hard impact, but improper surface preparation & alternative epoxy (Proline 4500 vs “rocket epoxy” G5000) likely contributed

• Uneven tube ODs, especially between CF and FG. Surprisingly little noticeable impact on flight performance, but aesthetically bad and problematic for simulations.

Mitigations

• Better surface preparation for epoxy joints + consider using G5000 again

• More attention given to making consistent tube ODs between CF and FG tubes

• Keep a better inventory of tube and coupler stock…

• Tensile testing epoxy joints

• Removable/replaceable rail guides

• Tighter nose tip protector

Recovery

Successes

• Integration of single bay system

• Main parachute and streamer deployed successfully

• Good separation and no shock cord getting cut

• Integration was faster than last year, but more room for improvement

• Gaff tape protected beacon antennas from separation and deployment forces

Failures

• No recovery points

• Beacons were not audible until within 20ft

• Went from 2 TD-2s to 1 after a failure mode was discovered mid integration

• Primary BP charge did not separate rocket

• Potential RRC3 not detecting apogee, need to follow up on

  • Delayed post apogee due to RRC3 apogee detection

Mitigations

• More heavily consider dual bay systems

• Integrate sabot and shock cord ahead of time

• Better manage beacon wiring to prevent snags

• Make beacons more accessible

• Measure BP charges ahead of time

• Shorten detonation time between primary and secondary charges

• Research effect of orientation and air speed on deployment tests

Avionics

Successes

• Screw Retention worked very well for retaining and working on sleds

• Screw cones worked wonderfully for guiding arming key

• Backplane antennas notches decreased assembly time

• Backplane did function before flight

• 18650 holder was very robust and did not fail in flight despite structure failure (backplane was still on)

• RRC3's detected boost and deployed nominally

Failures

• Structural failure during extreme loads (Impact?) led to the destruction of the sleds and damaging of electronics <- most of the bay would need to be replaced

• Battery fatigue/transportation voltage not accounted for leading to decrease run time

• Potato not easily serviceable in final assembly (Potato ran out of space as it was full of junk data by following day)

• Camera did not record flight due to seating of SD card

• GPS packets not received after boost (Possibly related to avionics structural failure)

Mitigations

• Make the structure of stiffer materials or change the end cap design

• Additional spares and dedicated transportation procedures

• Move Potato into avionic section and add usb C for easier linking

• (skill issue) -> better pre spaceport procedures for ensuring proper seating

• (skill issue) -> Better procedures for ground station/radio tower setup

Payload

Successes

• Grim worked very well, detecting launch, powering cameras, and collecting flight data

• Cameras proved incredibly valuable for validating reefing performance, as well as observing the state of OMEN after separation. Cameras should absolutely be present on both the 2025 payload and rocket.

• Reefing system survived flight and worked almost flawlessly in its reefed position, operating within 5.5% of the expected open area.

• In field integration time was down to <15 minutes after practice

• All data and systems survived flight, landing at a higher than anticipated speed, and being rained on for an hour.

• More of the sabot recovered than in previous years

Failures

• Short igniter leads caused piranhas to be ripped free of them and parachute was not disreefed 

• Static line to the parachute bag broke on separation (Assumed by In-Flight Footage), causing the parachute bag to separate later than desired, from centrifugal/aero forces. This delay caused roughly 7.5s of free fall after separation.

• Due to this free fall, shock forces were greatly increased, overloading the load cell and destroying the sensor.

• Poor venting for the secondary RRC3 caused strange altitude readings (Assumed by data consideration and observation of payload layout)

• Grim had some trouble running sensors at full speed (I think, someone who knows more should expand on this)

• Reefed parachute had more drag than expected, causing a slower decent velocity than expected (-46ft/s)

• Only one packet was received during flight (radiosonde on accent w/o data), and payload was located by another team on recovery (ie dumb luck). While it is unknown how much this is due to the ground ops vs transmission from the payload, more testing is absolutely necessary to ensure this never happens again.

• Sabot was not fully recovered, we some litterbugs fr

Mitigations

• More testing is needed for novel systems like the reefed parachute. Simple errors like the igniter leads being too short, or the extra drag the parachute made would have been discovered if a full test of the system was ever performed.

• More FOS consideration is needed for things like the load cell and the static line. There were already concerns that there was a case that the load cell could break, and while that didn’t happen, this case shows that our estimates for the loads we expect don’t take into account every case.

• More radio testing using ground hardware is essential.

• Sabot hinges were blasted apart, the kevlar loops kept it together, thus should be used on future flights. Additional kevlar loops in other parts of the sabot could certainly allow for full recovery.

• Use tensile tester to calibrate strain gauge systems

Analysis

Successes

• We had an accurate Openrocket model

• Flight sims for multiple wind cases

• 23rd overall in Barrowman award accuracy (451 ft, 3.85%) off our actual apogee

• First of its kind separation force calculation

• Tracked masses accurately throughout the year, weighed rocket at Spaceport

• Modular weight system for stability

• Legitimate proof of rocket’s stability during flight using simulations

• New, more in depth fin flutter calculations

Failures

• Predicted apogee didn’t factor in different launch angles

• Did not use tools that could have given us more points (CADWIND, RocketPy)

• Poor OpenRocket version control

• Overestimated weight gain from paint

• Likely overestimated surface roughness after paint

Mitigations

• Simulate flight for a wide range of launch angles

• Communicate to Pad Ops what the angle is supposed to be

• Recruit more people

• Tie Openrocket version control to project management software

• Use data from this year for a more accurate paint/epoxy estimate

• Weigh and track epoxy use

• Measure surface roughness of painted components

  • @Alan Grilley (RIT Student) check with tech labs

Field recovery

Successes

• We found both payload and rocket

• Semi consistent radio between teams and pits, teams could communicate with each other consistently

• Extendo pole and Jonathan's mini computer promising additions to field recovery

• Universal HAM licenses

• Well prepared team, no need to run out and buy camelbaks, hats, or other reco gear

Failures

• Beacons weren’t audible until really close

• Coordination of Rocket recovery team

• Ensuring recovery hardware (extendo pole and mini computer) work BEFORE you carry them an hour into the desert.

Mitigations

• Ensure beacons are in RF transparent sections

• Minimize chance of beacon wires getting tangled

• Separate team lead and MCC backpack roles on recovery teams

• Ensure recovery gear functions before leaving pits

Pad Operations

Successes

• Second trip to the pad went great. Everything went smoothly. All electronics were armed. Igniter went well, Jaden did it pretty much without help, FoR just watched.

• Mylar blanket did a good job at keeping the temp of the rocket down.

Failures

•  First trip to the pad did not go well. We were sent to pad A but they overbooked it so then had to go to D. We also were late because people were walking in front of cars (Poor Rob was yelling at them not to). By the time we got to our rail most teams were already vertical. FSR was nice but spoke quietly so it was hard to hear him and that added to stress. As well as other FSR did not think we needed to oil rail and was confused by the fact we were using motor oil. Overall things were rushed and this pad team was new so they required a bit of guidance which was not conducive to the time restraints.

•  Igniter needed a lot of assistance from FoR.

• Could not hear the Grim Reefer beeps - fairly certain it was not armed but had to leave it because of time constraint.

• ESRA told us 85 deg +/- 1 so we did 85 which is different then what they originally said.

• Not a horrible thing but we did walk pretty slow with the rocket.

• Member that is assigned 10 ft away from the rocket is not the most effective use of a body. Especially when they are new.

• We had trouble getting in contact with the ground station to see if we were getting packets.

• Radio sonde did get hot in rocket

Mitigations

• More practice: walking with the rocket, arming electronics, igniter wire and going over procedures. I think that would have made us more comfortable under high pressure situations on attempt 1.

• Clear list of procedures, I think these could have been better organized - the material was there but hard to navigate to on pad with a bunch of loose papers. Practice would have helped with this.

• Deciding pad team and lead BEFORE the week starts. (Mary) was pad lead but that wasn't decided until a day and a half before launch, or at least I was not told and I am CERTAIN of that. I also had a decent amount of other responsibilities to payload so it was tough to manage both of these and would have pivoted/delegated my payload responsibilities before the week if I knew I was pad lead. I would not say it is impossible to be heavily involved in pad and another team BUT I  would have run the payload team differently knowing I had other responsibilities. So the moral of the story; just communicate.

• Member that is assigned to stay 10 ft away: This person should be more than just a cameraman. Needs to help with getting things out of the bag when people need it. They need to be anticipating next steps and having supplies ready. They need to be a HAM to radio back to the ground station for packets. Should have the tape measure antenna. Preferably someone who is knowledgeable with APRS, GPS and radio things.

  • ESRA thing

  • Person needs to anticipate needs and know procedures

• Longer dowel for ignitor wire - we were told ours was short.

  • “Dowel came with motor” -Donovan, info from Sam FoR

• To help keep temp down damp towels work well (We did that for KONG)

• Overall; it helps to have an assertive lead and more than 1 person who is familiar with the process at IREC.

• Staple procedures

  • RIT Launch Bookbinders

Ground Operations (During launch, people who did this should add to it)

Successes

• Big pole with weather station was great

Failures

• Big pole antenna was unplugged? 

• Big pole cable was not the correct ohmage

• Backplane receiving antenna was not connected

Mitigations 

• Checklists

• RP-SMA ban

AirB&B/Living

Successes

• Nobody got COVID

• Towel holders stayed on the wall

• Food was good

• We left the place clean and got a positive review

Failures

• Tetherball is dangerous

• Overbought on food

Mitigations

• Practice tetherball

• Plan to eat out more nights

Conference Center/Poster Session

Successes

• Passed FSR on first try, the reviewers were impressed by some of our design choices

• Many people were interested in the ground station and avionics

Failures

• ESRA decided that we should all do our best sardine impressions so everything was crowded

Mitigations

• Figure out booth shifts early

Notes from Other Tech Reports

• We did a bunch of thermal analysis for our PETG boattail and put NONE of it in the report??????

• BYU uses dual bay

• Neither team Donovan looked at was concerned with rod speed

• Vacuum bag for tubes

  • Tried in previous years

• Paint booth autoclave

• BYU patented zero degree wind

• CFD the crap out of everything, ravenCFD

• BYU bolt force calculator?