NASA engineers have produced a material that absorbs, on average, more than 99 percent of the ultraviolet, visible, infrared, and far-infrared light that hits it -- a development that promises to open new frontiers in space technology.
Engineers at NASA's Goddard Space Flight Center in Greenbelt, MD, developed the nanotech-based coating, a thin layer of multi-walled carbon nanotubes (tiny hollow tubes made of pure carbon about 10,000 times thinner than a strand of human hair). They are positioned vertically on various substrate materials, much like a shag rug. The team has grown the nanotubes on silicon, silicon nitride, titanium, and stainless steel -- materials commonly used in space-based scientific instruments.
Tests indicate that the material is especially useful for spaceflight applications where observing in multiple wavelength bands is important to scientific discovery. If used in detectors and other instrument components, the technology would allow scientists to gather measurements of objects so distant in the universe that astronomers no longer can see them in visible light. Earth scientists studying the oceans and atmosphere also would benefit. More than 90 percent of the light Earth-monitoring instruments gather comes from the atmosphere, overwhelming the faint signal they are trying to retrieve.
Black materials also serve an important function on spacecraft instruments, particularly infrared-sensing instruments. The blacker the material, the more heat it radiates away. In other words, super-black materials can be used on devices that remove heat from instruments and radiate it away to deep space. This cools the instruments to lower temperatures, where they are more sensitive to faint signals.
Click here to view a high-magnification image that shows the hollow carbon nanotubes.