Apollo Pintle Injector Sweatshirt

Design

To land on the Moon, the Lunar Module's descent engine had to throttle smoothly from full power down to a gentle hover. TRW solved it with a variable-area pintle injector. Oxidizer (nitrogen tetroxide) flowed down the centre and out past a fixed pintle as a ring of individual sprays. Fuel (Aerozine 50) left the faceplate as a thin cylindrical sheet, and the oxidizer sprays broke it up and mixed with it. A movable sleeve, linked to the flow control valves, changed the size of both openings at the same time, so the mixture stayed right at every thrust setting.

The engine throttled between 10% and 60% of its 10,500 lbf maximum, or ran at full thrust; the range between 65% and 92.5% was avoided to protect the nozzle. On Apollo 13 the same engine pushed the crippled spacecraft back towards Earth. The pintle injector design later went into SpaceX's Merlin engines.

This design shows the engine in half-section, with Detail A drawing out the injector: the fixed pintle, the movable sleeve and the two propellant paths.

Item

A classic sweatshirt refined for everyday wear. Built without side seams for a clean silhouette and reduced fabric waste, finished with a durable ribbed knit collar that keeps its shape over time. The fit is relaxed yet structured, designed for all-day comfort. Crafted from ethically grown US cotton and dyed with OEKO-TEX certified colors for a responsible footprint.

Care instructions

- Non-chlorine: bleach as needed
- Do not iron
- Do not dryclean
- Machine wash: cold (max 30C or 90F)
- Tumble dry: low heat