---
type: meeting
date: 2026-01-02
attendees:
  - "[[Sarah Chen]]"
  - "[[Marcus Johnson]]"
  - "[[Elena Rodriguez]]"
  - "[[James Park]]"
  - "[[David Kim]]"
tags:
  - meeting
  - sprint-planning
---
# [[2026-01-02 Sprint Planning]]

## [[Meeting Info]]

**[[Date]]**: [[January 2]], 2026
**Time**: 14:00-15:30
**[[Location]]**: [[Conference Room]] A
**Facilitator**: [[Sarah Chen]]

**Attendees**:
- [[Sarah Chen]] ([[Chief Engineer]])
- [[Marcus Johnson]] ([[Propulsion Lead]])
- [[Elena Rodriguez]] ([[Avionics Lead]])
- [[James Park]] ([[Structures Lead]])
- [[David Kim]] ([[Senior Propulsion Engineer]])

## Agenda

1. [[Test 3]] [[Results Review]] (120-[[Second Burn]])
2. [[Test 4]] planning ([[Restart Test]], [[Jan 15]])
3. [[Avionics System]] [[Integration Status]]
4. [[Structures System]] fabrication update
5. [[Sprint Goals]] ([[Jan 2]]-15)
6. [[Risk Review]]

## [[Test 3]] [[Results]] Review

**Presenter**: [[David Kim]]

**[[Summary]]**:
- ✅ **[[Test]] 3 fully successful** (120-second burn [[Completed]] Jan 2, 2026)
- [[All]] [[Performance]] objectives met:
  - Thrust: 44.2 kN (98% of 45 kN [[Target]])
  - ISP: 287s (99% of 290s target)
  - [[Chamber Pressure]]: 8.2 MPa ([[Stable]] throughout)
  - [[Thermal Performance]]: 595°C steady-state (well [[Below 650]]°C limit)

**[[Key Findings]]**:
- [[Cooling System]] performed excellently (no hotspots, uniform temperatures)
- [[Turbopump]] smooth operation (32,100 RPM, no vibration)
- [[Ignition Sequence]] repeatable (435ms delay, consistent with [[Tests 1]]-2)
- No degradation over 120s burn (validates endurance for flight)

**Post-[[Test Inspection]]**:
- [[Engine Condition]] [[Excellent]] (minimal [[Carbon]] deposits)
- All subsystems nominal (no wear, no damage)
- [[Cleared]] for [[Test 4]] (restart test)

**[[Action Items]]**:
- [ ] [[David Kim]]: [[Complete Test]] 3 analysis [[Report]] by [[Jan 5]] 📅 2026-01-05
- [ ] [[Marcus Johnson]]: [[Review Test]] [[Data]], approve [[Test 4]] proceed decision 📅 2026-01-03

**Discussion**:

[[Sarah Chen]]: "Excellent work on Test 3. [[Three]] successful tests in a row gives us [[High]] confidence in the [[Propulsion System]]. The [[Thermal Margin]] is particularly encouraging - 55°C below the limit means we [[Have]] headroom for off-nominal conditions."

[[Marcus Johnson]]: "Agreed. The consistency across all three tests is remarkable. [[Ignition Delay]] variation is [[Only]] 30ms (420-450ms range), which [[Shows]] our [[Ignition Sequence]] is very repeatable. I'm confident we're [[Ready]] for Test 4."

[[David Kim]]: "[[One]] minor observation: we're seeing a consistent 4% shortfall in chamber pressure (8.2 MPa vs 8.5 MPa target). [[Root Cause]] is the [[Mixture Ratio]] being slightly low (2.38:1 vs 2.4:1 target). We can adjust LOX [[Flow Rate]] for Test 4 to hit the target."

[[Sarah Chen]]: "Is that adjustment necessary for Test 4, or can we defer to flight?"

[[Marcus Johnson]]: "I'd recommend making the adjustment for Test 4. The restart test is our [[Last]] chance to validate performance before integrated [[Testing]]. If we adjust [[Now]] and [[See]] 8.5 MPa, we'll have more confidence in the flight configuration."

[[Sarah Chen]]: "Agreed. Make the [[LOX Flow]] adjustment for Test 4. Document the change in the [[Test Plan]]."

**Decision**: Adjust LOX flow [[Rate]] for Test 4 to achieve 2.4:1 mixture ratio target

## Test 4 Planning

**Presenter**: [[Marcus Johnson]]

**[[Test Objectives]]**:
- Validate [[Engine]] cold restart [[After]] coast [[Phase]]
- Simulate landing burn [[Scenario]] (5-minute shutdown, restart, 20s burn)
- Confirm propellant [[Ullage Management]] works in flight-like conditions

**[[Test Sequence]]**:
1. Initial burn: 30s (establish baseline performance)
2. Shutdown: Execute standard [[Shutdown Sequence]]
3. Coast phase: 5 minutes (engine cold, propellants settle)
4. Ullage burn: 2s GN2 thruster (settle propellants, simulate microgravity)
5. Restart: Execute [[Ignition Sequence]] (cold start)
6. Second burn: 20s (landing [[Burn Duration]])

**[[Success Criteria]]**:
- Clean restart ignition (<1s delay)
- Stable combustion on second burn
- Thrust/ISP within 5% of initial burn
- No cavitation or [[Turbopump]] issues

**Schedule**:
- Test date: [[January 15]], 2026 (13 days from now)
- Test stand booking confirmed
- Propellants ordered (delivery [[Jan 12]])

**Risks**:
- **[[LOX Boiloff]] during coast**: [[Expect 2]]-5% loss, mitigated by [[Loading]] extra 10 kg
- **Turbopump cold restart**: May require longer spin-up, adjusted [[Gas Generator]] flow
- **[[Propellant Ullage]]**: Capillary vanes in [[Fuel Tanks]] tested, [[Should]] work

**[[Action]] Items**:
- [ ] [[Marcus Johnson]]: [[Finalize Test]] 4 procedure document 📅 2026-01-08
- [ ] [[David Kim]]: Coordinate with [[Test Facility]] for Jan 15 slot 📅 2026-01-05
- [ ] [[Marcus Johnson]]: Order extra LOX for boiloff margin 📅 2026-01-06

**Discussion**:

[[Elena Rodriguez]]: "[[Are]] we instrumenting the ullage [[System]] for Test 4? It [[Would]] be valuable to see how the capillary vanes perform during the coast phase."

[[Marcus Johnson]]: "[[Yes]], we're adding 4 [[Pressure Sensors]] in the fuel tank ullage space to monitor pressure distribution. We'll see if the ullage burn [[Successfully]] settles the propellants before restart."

[[Sarah Chen]]: "[[What]]'s the abort [[Criteria]] if restart fails?"

[[David Kim]]: "If we [[Don]]'t see ignition within 2 seconds of the restart [[Command]], we'll abort and purge. The test is designed to be [[Safe]] - we can always try again if needed."

[[Sarah Chen]]: "[[Good]]. [[This]] is the last major propulsion test before [[Integrated Vehicle Testing]]. Make sure we [[Get]] all the data we [[Need]]."

## [[Avionics System Integration Status]]

**Presenter**: [[Elena Rodriguez]]

**[[Hardware Status]]**:
- ✅ Triple-[[Redundant]] [[Flight Computer]] boards delivered ([[Dec 2025]])
- ✅ [[CAN Bus]] wiring harness [[Complete]]
- 🔄 Sensor [[Integration]] ongoing (IMU, GPS, pressure sensors)
- ⏳ [[Telemetry]] system pending ([[Ground]] stations setup)

**[[Software Status]]**:
- ✅ [[Autopilot Software]] [[Core]] loops complete (guidance, navigation, control)
- ✅ [[Voting]] logic [[Implemented]] and tested (fault [[Injection]] tests passed)
- 🔄 [[Landing Algorithm]] integration ([[Powered Descent Guidance]])
- 🔄 [[Engine Controller]] CAN interface (90% complete)

**[[Hardware]]-in-[[Loop Testing]]**:
- 47 simulated flights completed (96% success rate)
- 2 failures: [[Both]] sensor failures correctly handled by redundancy
- [[Remaining 53]] flights [[Scheduled]] for Jan-[[May 2026]]

**Challenges**:
- **CAN bus timing**: [[Some]] messages have 5-10ms jitter
  - Root cause: [[Linux]] scheduling latency (PREEMPT_RT kernel tuning needed)
  - Impact: Minor, [[Control Loop]] still stable
  - Fix: Kernel parameter tuning [[In Progress]]
- **GPS acquisition time**: 30s cold start (longer than desired)
  - Root cause: [[GPS Receiver]] firmware
  - Impact: Low (warm start <5s, adequate for flight)
  - Mitigation: Pre-flight GPS power-on during countdown

**Action Items**:
- [ ] [[Elena Rodriguez]]: Tune PREEMPT_RT kernel for CAN bus timing 📅 2026-01-10
- [ ] [[Elena Rodriguez]]: Complete [[Engine Controller]] CAN interface 📅 2026-01-12
- [ ] [[Elena Rodriguez]]: Schedule [[Landing Algorithm]] HIL [[Validation]] 📅 2026-01-20

**Discussion**:

[[Sarah Chen]]: "[[The 96]]% success rate in HIL is excellent. That gives us confidence in the [[Flight Software]] before we go to integrated vehicle testing."

[[Elena Rodriguez]]: "Thanks. The [[Two]] failures were actually good [[Learning]] - we caught a bug in the [[Sensor Fusion]] code that wouldn't have been [[Found]] without [[Fault Injection Testing]]. The triple redundancy worked as designed."

[[Marcus Johnson]]: "What's the [[Status]] on the [[Engine Controller]] CAN interface? We'll need that [[Working]] for Test 4 if we want to test the [[Full]] command chain."

[[Elena Rodriguez]]: "We're 90% there. The [[Basic]] commands (ignition, shutdown, throttle) are working. Still implementing the TVC gimbal commands, [[But]] that's [[Not]] needed for Test 4. We'll have it complete by Jan 12."

[[Sarah Chen]]: "Make sure we test the full command chain in HIL before Test 4. I don't want any surprises at the test stand."

[[Elena Rodriguez]]: "Agreed. We'll [[Run]] a full mission sim with the [[Engine Controller]] in the loop [[Next]] week."

## [[Structures System Fabrication Update]]

**Presenter**: [[James Park]]

**[[Airframe Design]] Status**:
- ✅ [[Primary Structure]] fabrication complete ([[Aluminum 2219]])
- ✅ Friction stir welding complete (all joints inspected)
- 🔄 Thrust structure assembly ongoing (engine mount)
- ⏳ [[Landing Legs]] fabrication (delivery expected [[Jan 20]])

**[[Stage Separation System]]**:
- ✅ Pyrotechnic [[Separation]] mechanism delivered
- ✅ Test jig fabrication complete
- ⏳ [[Separation Test]] scheduled ([[Feb 2026]])

**[[Landing System]]**:
- 🔄 Landing leg fabrication (4 legs, crush core shock absorbers)
- 🔄 Deployment mechanism testing (pneumatic actuators)
- ⏳ Full vehicle load test pending (after legs delivered)

**Schedule**:
- Airframe complete: Jan 15, 2026 (on schedule)
- Landing legs delivered: Jan 20, 2026 (on schedule)
- Integrated vehicle assembly: [[Feb 1]], 2026 (on schedule)

**Action Items**:
- [ ] [[James Park]]: Complete thrust structure assembly 📅 2026-01-15
- [ ] [[James Park]]: Inspect landing leg delivery (Jan 20) 📅 2026-01-20
- [ ] [[James Park]]: Coordinate integrated assembly schedule 📅 2026-01-25

**Discussion**:

[[Sarah Chen]]: "Structures is on schedule, which is great. The landing legs are the [[Critical Path]] item - any [[Risk]] of delay?"

[[James Park]]: "Low risk. The supplier has [[Built]] similar legs for other projects. We're in weekly contact with them, and [[They]]'re [[On Track]] for Jan 20 delivery. We'll inspect them immediately and start deployment testing."

[[Marcus Johnson]]: "Will the thrust structure be ready for integrated testing in June?"

[[James Park]]: "Yes, thrust structure will be complete by Jan 15. We'll mate the engine to the airframe in February, which gives us plenty of time for integrated testing in June."

[[Sarah Chen]]: "Good. Let's make sure we coordinate the engine/airframe integration carefully. That's a critical interface."

## [[Sprint]] Goals (Jan 2-15)

[[Propulsion System]] ([[Marcus Johnson]]):
- ✅ Test 3 analysis complete
- ⏳ Test 4 preparation (procedure, propellants, instrumentation)
- ⏳ Test 4 [[Execution]] (Jan 15)

[[Avionics System]] ([[Elena Rodriguez]]):
- ⏳ Complete [[Engine Controller]] CAN interface
- ⏳ Tune PREEMPT_RT kernel for CAN timing
- ⏳ Continue HIL testing (target 70/100 flights complete)

[[Structures System]] ([[James Park]]):
- ⏳ Complete thrust structure assembly
- ⏳ Landing leg delivery and inspection
- ⏳ Plan integrated vehicle assembly

[[GNC System]] ([[Elena Rodriguez]]):
- ⏳ [[Landing Algorithm]] HIL validation
- ⏳ [[Trajectory Optimization]] testing
- ⏳ Sensor fusion tuning

**[[Team Consensus]]**: All sprint goals achievable, no blockers [[Identified]]

## Risk Review

[[Sarah Chen]]: "Let's review the [[Top]] risks from the [[Risk Register]]."

**R-015: [[Software Qualification Timeline]]** (Score: 9, MEDIUM)
- [[Current Status]]: Flight [[Software]] 85% complete
- [[Code Review]] 80% complete
- On [[Track]] for Feb 2026 qualification

**R-021: [[Hot Fire Anomaly]]** (Score: 9, MEDIUM)
- [[Current]] status: 3/3 tests successful to date
- Test 4 is highest risk (restart test, new procedure)
- Mitigation: Conservative test plan, extra instrumentation

**R-022: [[Environmental Test Failure]]** (Score: 6, LOW-MEDIUM)
- Current status: Component-level testing passed
- Full vehicle [[Environmental Testing]] in Jun-[[Aug 2026]]
- Mitigation: Component pre-qualification, thermal margins

**[[New Risks]]**:
- [[None]] identified this sprint

**[[Retired Risks]]**:
- R-024: [[First Hot Fire Failure]] (retired after [[Test 1]] success)

**Discussion**:

[[Sarah Chen]]: "R-021 is our highest [[Active]] risk. Test 4 is the [[Most]] complex test yet. Let's make sure we're conservative with the test plan."

[[Marcus Johnson]]: "Agreed. We're adding extra instrumentation on the ullage system and [[Turbopump Restart]]. If we see anything anomalous during the initial burn or coast phase, we'll abort before attempting restart."

[[Elena Rodriguez]]: "R-015 is on track. The software qualification review is scheduled for [[Feb 15]], and we should be ready. The HIL testing is giving us confidence that the software is robust."

[[Sarah Chen]]: "Good. No new risks this sprint, which is a positive [[Sign]]. Keep up the good work, everyone."

## [[Action Items Summary]]

[[Marcus Johnson]] (Propulsion):
- [ ] Review Test 3 data, approve Test 4 proceed decision 📅 2026-01-03
- [ ] Adjust LOX flow rate for Test 4 (mixture ratio 2.4:1) 📅 2026-01-06
- [ ] Order extra LOX for boiloff margin 📅 2026-01-06
- [ ] Finalize Test 4 procedure document 📅 2026-01-08

[[David Kim]] ([[Test Engineering]]):
- [ ] Complete Test 3 analysis report 📅 2026-01-05
- [ ] Coordinate with test facility for Jan 15 slot 📅 2026-01-05

[[Elena Rodriguez]] (Avionics):
- [ ] Tune PREEMPT_RT kernel for CAN bus timing 📅 2026-01-10
- [ ] Complete [[Engine Controller]] CAN interface 📅 2026-01-12
- [ ] Schedule [[Landing Algorithm]] HIL validation 📅 2026-01-20

[[James Park]] (Structures):
- [ ] Complete thrust structure assembly 📅 2026-01-15
- [ ] Inspect landing leg delivery 📅 2026-01-20
- [ ] Coordinate integrated assembly schedule 📅 2026-01-25

## [[Next Meeting]]

**[[Sprint Review]]**: January 15, 2026 (post-Test 4)
**Location**: Conference Room A
**Time**: 14:00-15:00

**Agenda**:
- Test 4 results review
- Sprint retrospective
- Next [[Sprint Planning]] ([[Jan 16]]-30)

## [[Related Notes]]

[[Test Documentation]]:
- [[Engine Hot Fire Results]] - Test 3 [[Detailed Results]]
- [[Test Campaign Overview]] - Master test schedule
- [[ADR-004 Test Campaign]] - Test [[Strategy]]

[[Systems]]:
- [[Propulsion System]] - Test 4 planning
- [[Avionics System]] - HIL status
- [[Structures System]] - [[Fabrication Status]]
- [[GNC System]] - [[Landing Algorithm]]

[[Program Management]]:
- [[Project Roadmap]] - Sprint goals and schedule
- [[Risk Register]] - Risk review
- [[Team Roster]] - Attendees

[[Team]]:
- [[Sarah Chen]] - Meeting facilitator
- [[Marcus Johnson]] - Propulsion updates
- [[Elena Rodriguez]] - Avionics updates
- [[James Park]] - Structures updates
- [[David Kim]] - Test [[Engineering]]

---

*[[Meeting Notes]] by [[Sarah Chen]] - 2026-01-02*
*Next meeting: 2026-01-15 Sprint Review*
