Space Pen Capabilities and Design Overview

• Writes in zero gravity (used by astronauts)
• Functions underwater, extreme heat/cold, upside down
• Ingenious design keeps ink flowing toward tip regardless of orientation
• Nitrogen-pressurized ink system (unlike gravity-dependent ordinary ballpoints)
• Invented 1966, first space use: Apollo 7 astronauts

Writing Point Manufacturing Process

• Starts as 3/10 inch long stainless steel block
• Passes through 12+ machining operations
• Progressive shaping creates point
• Bore hole through tip forms pocket for carbide steel ball
• Final station: inserts ball, curves pocket edges inward
• Ball locked in position but can rotate to spread ink

Ink Cartridge (Refill) Assembly

• Empty brass tube base
• Assembly machine inserts white plastic "float" ball in back end
• Pumps in 0.5 grams of ink
• Float follows ink down tube, moves residual ink forward toward point
• Writing point inserted into opposite end
• End crimped to prevent writing point dislodging

Pressurization System

• Sealant applied to back end
• Nitrogen injected to pressurize refill
• Capped with hollow brass plug
• Nitrogen chosen as inert gas (doesn't harm tube/contents)
• Pressurized nitrogen forces ink flow

Quality Control and Finishing

• Each refill subjected to writing test
• Surface washed to remove machine lubricant/residues
• Company name and product information printed on refill

Cap Assembly (Select Models)

• Brass cap with clip attachment
• Clip stamped from spring steel
• Chrome-plated for corrosion resistance/aesthetics
• Machine drives clip teeth through cap wall
• Teeth curled back inside wall to lock clip position

Pen Body Assembly

• Two-part brass body construction
• Bottom part called "barrel"
• Brass reinforcement "nose tip" inserted at writing end
• End crimped, nose tip flared inside barrel (prevents slipping out)
• Chrome-plated brass body available

Final Assembly Process

• Barrel placed in foam holder
• Spring inserted for refill positioning
• Threaded brass connector added
• Silicone rubber O-ring placed on barrel top edge
• Refill inserted in barrel
• Connector inserted into top body half
• Electric motor threads parts together
• Cap placed open-side up in foam holder
• Pen inserted, O-ring holds cap in place

Product Variations

• Original space pen: push button on top (extend refill), side button (retract)
• Demonstration model: cutaway section shows inner workings
• All models write underwater, zero gravity, freezing cold, intense heat, upside down