History was made on July 20th 1969 as the first man walked on the moon, all thanks to the Apollo Program which changed the world we live in now in terms of technologies and engineering. The program was a huge accomplishment for engineering and due to its success, it resulted in a massive overhaul of new technologies and products coming into the world. Off the back of the Apollo Program, they stimulated multiple areas of technology (over 1,800 products, in fact), these include; the CAT scanner, computer microchip, cordless power tools, joysticks, and satellite television.
Here are some stats from the Saturn V rocket which went into space:
• The Saturn V rockets that launched Apollo 11 into space was 363 feet tall, weighed 6.2 million pounds and took 7.5 million pounds of thrust to get the Armstrong and his team off of Earth.
• 400,000 people are estimated to have worked on the program.
• It was a collaborative effort between Boeing, North American Aviation and Douglas Aircraft.
• It was an incredibly complex machine made from over 3 million parts.
However, what was the status of industrial metrology tools in 1969 to support the colossal development and manufacturing tasks of the Apollo Program?
“Renishaw was only established in 1973 after the invention of the touch-trigger probe during the Concorde engine development program at Rolls Royce in the early ’70s. Until this time the first coordinate measuring machines that had emerged were extremely primitive manual devices with only a limited digital readout and mechanical ‘hard’ probes. The laser tracker, prominent throughout aerospace manufacturing today, was not invented until 1987. The articulated portable arm CMM patent was filed in 1974.” (source: metrology.news)
Here’s an overview of the metrology landscape during that time:
Manual Vernier and Dial Calipers
- Prevalence: These were the most common handheld tools for dimensional measurement.
- Accuracy: Typically capable of ±0.05 mm (±0.002 inches) accuracy, depending on quality.
- Limitations: Measurements relied on operator skill for reading scales, making the process slower and prone to human error.
Mechanical Micrometers
- Use: Widely used for measuring small dimensions such as shaft diameters and thicknesses with high precision.
- Accuracy: Could achieve ±0.01 mm resolution but required careful handling and calibration.
- Drawbacks: No digital output; measurements were manually read from the scale.
Early Coordinate Measuring Machines (CMMs)
- Technology: The first CMMs appeared in the early 1950s but were very basic in 1969.
- Capabilities: Manual probing with limited digital readout; mainly used for inspecting critical aerospace components.
- Limitations: Slow, operator-dependent, and lacking automated data collection or advanced software.
Optical Comparators and Measuring Microscopes
- Function: Used for non-contact inspection of profiles and small features by projecting magnified images onto a screen.
- Precision: Could measure dimensions down to a few microns, useful for detailed quality checks.
- Limitations: Not suitable for large parts or complex 3D shapes.
Surface Plates and Height Gauges
- Role: Fundamental reference surfaces (granite plates) were used for layout, marking, and inspection tasks. Height gauges with dial indicators measured vertical dimensions.
- Accuracy: Depended on flatness of the surface plate and gauge quality; generally ±0.01 mm precision achievable.
Mechanical Gauges and Go/No-Go Gauges
- Purpose: Used extensively for fast, repeatable inspection of critical dimensions, especially for mass-produced parts.
- Advantage: Quick pass/fail decisions with minimal operator training.
- Drawbacks: Limited to specific dimensions, no quantitative measurement recorded.
Contrast with Modern Metrology Tools Available Today
- Digital Calipers and Micrometers: Offer improved accuracy (±0.02 mm or better), instant digital readouts, unit conversion, and data output for integration with quality control systems.
- Advanced CMMs: Now automated with motorised probe heads, tactile and non-contact sensors, and fully integrated software for complex 3D measurements. Accuracy often exceeds ±0.005 mm.
- Laser Trackers: Provide real-time, high-accuracy 3D positioning of large-scale components, essential in aerospace and automotive industries. Invented after Apollo, in the late 1980s.
- Portable Articulated Arms: Allow flexible, on-site 3D measurements with sub-millimetre accuracy and direct CAD integration. Patented in the 1970s but matured later.
- Vision Systems and 3D Scanners: Non-contact optical measurement tools using lasers or structured light, capable of rapidly digitising complex shapes and surfaces with micron-level precision.
In conclusion, all of today’s incredible advanced metrology tools and technologies were not available to support the development and manufacturing involved for the Apollo Program and getting a man to the moon. However, we celebrate the amazing achievement of those involved back in 1969 and we can only imagine how tough it was in achieving the precision which helped them complete the mission as a success.
