The Cardboard Adapter | Cathy Mcmasters

Mission Brief

Date: April 11–17, 1970
Crew: Lovell, Swigert, Haise
Failure Mode: Oxygen Tank 2 explosion, forcing abandonment of Lunar Module ascent.
Critical Constraint: Square lithium hydroxide canisters (Command Module) incompatible with round ports (Lunar Module).

Source: Wikidata Q182252

I. Geometric Specification

The adapter solved a dimensional mismatch between two systems designed for different vessels. The solution required three components: a coupling sleeve, a flow distributor, and a seal.

Component	Material	Dimensions	Tolerance
Canister Sleeve	PVC Pipe Segment	ID: 7.6 cm (3")	±0.5 mm
Flow Interface	Plastic Bag (Polyethylene)	Diameter: 15.2 cm	N/A (Flexible)
Sealant	Suit Gloves + Magazine Pages	Thickness: 1.2 mm	Compression Fit
Strut Assembly	Cardboard Flight Manual Covers	Length: 20.3 cm	Rigid Fold

II. Chemical Stoichiometry

The adapter was merely the conduit; the reaction was the salvation. Lithium hydroxide scrubbed carbon dioxide from the cabin atmosphere via irreversible precipitation.

2 LiOH(s) + CO₂(g) ⟶ Li₂CO₃(s) + H₂O(l)

Input: 2 moles LiOH (48 g/mol × 2 = 96 g) per 1 mole CO₂ (44 g)
Output: Solid lithium carbonate precipitate + liquid water vapor
Capacity: Each canister contained approximately 15 kg LiOH, capable of scrubbing ~6.8 kg CO₂
Crew Load: 3 astronauts × 1 kg CO₂/day = 3 kg CO₂/day critical throughput

III. Verification Protocol

Ground control simulated the construction using identical materials. The flight manual covers provided structural rigidity; the plastic bag ensured gas permeability while maintaining pressure differential.

Result: Successful integration. The adapter reduced cabin CO₂ levels from lethal 7,000 ppm to safe operating range within 4 hours.