Did you know that the path to the stars is paved with…gold? It’s true. Gold is an essential material in spacecraft design, found in every NASA vessel ever launched, and with good reason. As a protector, reflector, collector and connector, gold is unrivaled. Without gold, the moon would remain out of reach. Let’s examine this versatile metal, one of mankind’s ancient discoveries and yet so vital to modern aerospace technology.
Heavy, malleable and workable, gold can be manipulated into any shape imaginable. One ounce of gold can be drawn into a wire 60 mi. long or hammered into a film thin enough to allow sunlight to pass through. With its high melting point (1948°F), gold and gold alloys excel as braze compounds and coatings. Unlike copper and silver, gold resists rust and corrosion, making it a highly reliable conductor for electronic circuitry. In aerospace, gold’s greatest attribute is its ability to reflect radiation, and thus dispel heat.
Cosmic and solar radiation is everywhere. Luckily for us, earth’s electromagnetic field combines with atmospheric conditions to prevent virtually 100% of this radiation from reaching the surface. But at 6000 miles high, earth’s atmosphere ends, and the protection vanishes. Our closest celestial destinations — the Moon and Mars — lack both an atmosphere and a magnetic field and offer no natural barriers to radiation. Without a means of thermal control, any spacecraft would become a cinder moments after launch.
Radiation batters a spacecraft in the form of rays, electromagnetic waves or particles. This direct action transfers heat, similar to the action of a microwave oven. Non-ionizing radiation consists of ultraviolet, visible and infrared rays, while ionizing radiation is comprised of X-rays and gamma rays. While all radiation is problematic in space, ionizing radiation presents the more serious hazard because it can penetrate through a spacecraft — and the skin of an astronaut. According to NASA, “Ionizing radiation is like an atomic-scale cannonball that blasts through material, leaving significant damage behind.”
Prolonged exposure to ionizing radiation can increase the risk of cancer and cause injury or death. NASA carefully studies the levels and effects of radiation exposure on its astronauts. As a result, safety for both vessel and crew is paramount to the planning of every space mission, and “an ounce of prevention” becomes a creed.
As seen in the movie Apollo 13, the slightest mishap in space is potentially catastrophic. With no space garages handy, the spacecraft and its equipment must be built for unerring operation beyond the limits of the mission. Every component, every material used must be dependable, reliable, and capable of withstanding the rigors of space. Enter gold. As an aerospace building block, gold delivers the ruggedness, reliability and stamina worthy of an astronaut to combat the formidable challenges of heat and radiation in space.
Astronauts cloak themselves in gold protection. Their spacesuits contain thin integral gold layers to reflect solar heat. Polycarbonate helmet visors are electroplated with a gold microfilm coating that protects their eyes by filtering IR rays while permitting sunlight through without glare.
Spacecraft from satellites to manned rockets to space shuttles bear gilded “armor” as well.
Gold coatings on panels act as heat and radiation shields by reflecting or deflecting solar and cosmic radiation, critical to stabilizing the temperature of the vessel and protecting the crew.
Gold circuitry does not corrode and resists heat and static electricity.
As a lubricant, gold film between moving parts performs unfailingly in space where organic lubricants would falter. Gold molecules slip past each other under force, creating a unique “oiling” effect.
Exterior gold plating doubles as a data collector. When assayed before and after a mission, the gold reveals the nature of the particles that struck it during flight.
Camera and telescope mirrors integrate gold layers (see sidebar) because gold’s excellent IR reflectance helps to create ultra-high-resolution images.
Space shuttles incorporated gold in their fuel cells to aid the electrochemical propulsion process.
Perhaps our ancestors discovered gold at about the same time they first gazed at the moon. Did they ever dream that this shiny yellow ore would one day help us to get there? We can only wonder. One fact is certain: Whatever the space mission, look at the details and you’ll strike gold.