Interface Control Document (ICD)
Reactivity Rocket Project · Year 10 · 4 weeks
Purpose of this document
The ICD is the single source of truth for what each team owes the others. If a team’s deliverable changes, the change is recorded here first, then flowed to the team charters. No sub-team works in isolation — every output has a documented consumer.
Engineering principle: interfaces are the hardest part of any integrated system. Define them on Day 1, freeze them at the Week 2 design review, only break them with a formal change record.
Test articles and their owners
| ID | Article | Owner team | Phase | Used in |
|---|---|---|---|---|
| TA-01 | Brass plumbing insurance rig | Manufacturing | 1 | W3L11 atmospheric LPG flame demo |
| TA-02-plastic | Trotec-cut plastic chamber form study | Manufacturing | 1 | W3L10 cold-flow + W3L11 atmospheric LPG flame at nozzle face |
| TA-03 | H₂O₂ / KMnO₄ rates rig (separating funnel + flask + gas collection) | Rocket Chemistry | 1 | W2L5 rates calibration (student work at 3-6%, teacher demo at 35%) |
| TA-04-copper | Vendor-built copper combustion chamber | Manufacturing (procurement) + Materials (specification) | 2-3 | Phase 3 off-site vendor burn |
| TA-05 | Titration apparatus | Rocket Chemistry | 1 | Standalone neutralisation lab |
| TA-06 | Water-bath calorimeter (beaker + K-type TC + Arduino) | Rocket Chemistry + Heat Exchanger | 1 | W3L9 ethanol + methane calorimetry |
TA-04 has two valid construction options that the Manufacturing team chooses between based on vendor quotes (see program overview):
- TA-04-H: monolithic 3D-printed copper chamber (Leap71 pattern)
- TA-04-L: laminated 2D+1 copper stack, vendor-brazed (1940s cavity-magnetron pattern)
Both are vendor-built, both are within the safety case, both are copper.
Mass budget — TA-04 copper combustion chamber
For the copper chamber (TA-04). Total mass affects the vendor’s fabrication quote and the test-cell mounting.
| Component | Owner | Target mass (g) | Tolerance (g) | Notes |
|---|---|---|---|---|
| Copper chamber body (both options) | Manufacturing + Materials | 800-1200 | ±100 | Cu density 8.96 g/cm³; volume from CAD |
| Vendor-supplied fittings (inlet, instrumentation) | Vendor | 50-100 | per vendor spec | Not in our design scope |
| Total chamber as delivered | 850-1300 | Within typical 5 kg load-cell range at vendor cell |
Mass budget — TA-02-plastic form study
| Component | Owner | Target mass (g) | Tolerance (g) | Notes |
|---|---|---|---|---|
| Trotec-cut plastic plates ×8 + assembly | Manufacturing | 200-300 | ±20 | PLA or acrylic, 3-4 mm |
| Brass fittings (gas inlet, mounting) | Manufacturing | 60-100 | ±10 | Common plumbing parts |
| Total form study | 260-400 | Same external envelope as TA-04 |
Geometry envelope — chamber cavity
Shared between TA-02-plastic and TA-04-copper. The plastic form study is the dimensional verification of the copper part before procurement.
| Dimension | Value | Owner | Consumer |
|---|---|---|---|
| Outer envelope | ø100 × 100 mm | Manufacturing | Materials, Comp Eng |
| Combustion cavity diameter | 30 mm | Manufacturing | Rocket Chemistry, Comp Eng |
| Chamber length (cavity) | 60 mm | Manufacturing | All |
| Nozzle throat diameter | 6 mm | Manufacturing | Comp Eng (sets thrust prediction) |
| Nozzle exit diameter | 12 mm | Manufacturing | Comp Eng (sets expansion ratio) |
| Wall thickness (copper) | 4-6 mm | Materials | Vendor (in spec) |
| TC port locations | 3 ports: inlet end, throat collar, exit cone | Heat Exchanger | Manufacturing (CAD), Vendor (drill spec) |
Thermal budget
Predicted by Comp Eng Rust simulation, measured at vendor test cell, reconciled by Heat Exchanger team.
| Quantity | Predicted (TBD by Rust) | Measured by | Target accuracy |
|---|---|---|---|
| Adiabatic flame temp (LPG / air) | ~1950 °C | (not measured) | — |
| Adiabatic flame temp (ethanol / O₂-enriched) | ~2400 °C | (not measured) | — |
| Chamber wall TC-1 peak (inlet end, cold) | TBD | Vendor TC | ±20 °C |
| Chamber wall TC-2 peak (throat region, hot) | TBD | Vendor TC | ±30 °C |
| Chamber wall TC-3 peak (exit cone) | TBD | Vendor TC | ±20 °C |
| Burn duration (single pulse) | 3-5 s | Vendor log | ±0.2 s |
| Peak chamber pressure | TBD (vendor-set) | Vendor pressure transducer | ±5% |
Gas / fluid interfaces
| Stream | Source | Flow rate | Phase | Owner |
|---|---|---|---|---|
| LPG (atmospheric, school demo + calorimetry) | Fume cupboard tap or 9 kg cylinder | ~0.5 L/min for flame demo; metered for calorimetry | 1 | Rocket Chemistry (run), Manufacturing (rig) |
| Ethanol (school calorimetry) | School lab stock | denatured ethanol burner | 1 | Rocket Chemistry |
| Air (atmospheric, entrained) | Fume cupboard | At injector | 1 | — (passive) |
| LPG or ethanol vapour (Phase 3) | Vendor supply | per vendor | 3 | Vendor |
| O₂ enrichment (Phase 3, if used) | Vendor cylinder | per vendor | 3 | Vendor |
| 3% H₂O₂ (student rates lab) | Drugstore-grade school stock | 50 mL aliquot per run | 1 | Rocket Chemistry (use), Lab tech (dispense) |
| 6% H₂O₂ (student rates lab) | Drugstore-grade school stock | 50 mL aliquot per run | 1 | Rocket Chemistry (use), Lab tech (dispense) |
| 35% H₂O₂ (teacher demonstration only) | School lab stock, oxidiser cabinet | 50 mL aliquot, one demonstration | 1 | Teacher (dispense and run) |
| KMnO₄ solution (catalyst) | Prepared at 0.05, 0.10, 0.20, 0.40 M | Drip via separating funnel | 1 | Rocket Chemistry |
| 1 M HCl (titration + Mg pop test) | School stock | 25 mL titration; 10 mL pop test | 1 | Rocket Chemistry |
| 1 M NaOH (titration) | School stock | per protocol | 1 | Rocket Chemistry |
| Phenolphthalein (titration indicator) | School stock | drops | 1 | Rocket Chemistry |
| Mg ribbon (pop test) | School stock | 5 mm piece per test | 1 | Rocket Chemistry |
Electrical interfaces
| Signal | From | To | Range | Owner |
|---|---|---|---|---|
| Load cell (school LPG demo) | HX711 amp on TA-01 brass rig | Arduino + laptop | 0-1 kg, 0.1 g | Heat Exchanger + Manufacturing |
| Chamber TC × 3 (Phase 3) | Vendor TCs inline on TA-04 | Vendor DAQ | 0-1200 °C | Vendor — output as CSV to Heat Exchanger |
| Chamber pressure (Phase 3) | Vendor transducer | Vendor DAQ | 0-2 MPa | Vendor |
| Video stream (Phase 3) | Vendor cell camera | Recorded MP4 + live stream link | — | Vendor |
Chemistry interfaces — the four reaction types and where they live
| Reaction type | Producer | Consumer | Phase |
|---|---|---|---|
| Synthesis (LPG + O₂ atmospheric, ethanol + O₂ atmospheric, calorimetry) | Rocket Chemistry runs calorimetry | Comp Eng (combustion efficiency factor), Heat Exchanger | 1 |
| Synthesis (ethanol or LPG + O₂ pressurised) | Vendor | Heat Exchanger reconciles | 3 |
| Decomposition (2 H₂O₂ → 2 H₂O + O₂, catalysed by KMnO₄) | Rocket Chemistry runs rates calibration; teacher runs 35% demo | Comp Eng (peroxide rate model + activation energy); Lab Report 1 | 1 |
| Displacement (Mg + 2HCl → MgCl₂ + H₂; galvanic series Cu/Zn/Fe in CuSO₄) | Rocket Chemistry (pop test); Materials (galvanic demo) | Lab Report 1 | 1 |
| Neutralisation (HCl + NaOH titration) | Rocket Chemistry | Lab Report 1 — conceptual link to exhaust-gas scrubbing | 1 |
| Rates (three calibration curves: [H₂O₂], [KMnO₄], T) | Rocket Chemistry | Comp Eng (rate model parameters + Arrhenius activation energy); Lab Report 1 | 1 |
Headline cross-team output: the stoichiometric worked answer (RC-D8)
Rocket Chemistry combines their calibration curves (from rates lab) and calorimetry (from W3L9) into a single numerical answer:
Given measured H₂O₂ decomposition rate at 35% and measured ethanol combustion efficiency, can a school-scale H₂O₂ rig in principle supply enough O₂ for a 0.5 g/min ethanol burn?
This is the project’s headline engineering output from the chemistry side. Manufacturing references it in the vendor RFQ (“here is the oxidiser demand for our design ethanol flow”). Comp Eng cross-checks it against the Rust prediction sheet’s stoichiometric panel.
Test sequence (Phase 3 sequencing — vendor’s protocol, observed by us)
The off-site vendor burn happens on the vendor’s protocol, in their test cell, under their licensed operation. Our role is design intent and data reconciliation, not test execution.
- Vendor accepts CAD + Materials specification + RFQ
- Vendor fabricates TA-04 (option H or L per Manufacturing team’s selection)
- Vendor pressure-test fabricated chamber per their standard (we don’t specify)
- Vendor instruments chamber to our requested TC and pressure locations
- Vendor runs hot fire (cold-flow first, then ignition) per their cell SOP
- Vendor delivers: telemetry CSV + MP4 video + burn-duration log
- Heat Exchanger team reconciles measured vs predicted; Lab Report 4
Students attend none of steps 1-6 in person. Steps 5-6 may be live-streamed; otherwise recorded video is provided.
Change control
| Date | Change | Reason | Approved by |
|---|---|---|---|
| 2026-05-08 | Initial draft | Program kickoff | Teacher |
| 2026-05-08 | v0.2: drop electrolysis + bolted steel laminate; add vendor copper TA-04 (H/L options); pivot from in-school combustion chamber to vendor pressurised burn; collapse safety case accordingly | Hard rule: no heat+pressure at school | Teacher |
Any team requesting an interface change opens a row in this table at the weekly standup. Changes after Week 2 design review require teacher approval and must be cross-flowed to all consumer teams.