NASA harnesses the power of carbon nanotubes
Image: Carbon nanotube coating provides electrons for space probe analysis. [NASA]
NASA has released a stunning image of a new carbon nanotube coating that serves as an electron source for its concept mini-space probe.
The probe, designed to analyse the chemical properties of rocks and soil on asteroids and the Moon, uses the carbon nanotubes to provide the electrons needed to excite minerals contained in extraterrestrial samples.
The ultra-dark coating comprises arrays of multi-walled nanotubes, only 100 micron in diameter.
Electron microscopy images show the patterned nanotubes that would operate as electron emitters in a new instrument now being developed for analysing extraterrestrial samples, (right: a single emitter). [NASA]
To create these structures, John Hagopian and Lucy Lim from NASA first place a silicon wafer in a furnace.
As the furnace heats up, the substrate is bathed in a carbon feedstock gas to produce the thin coating of nanotubes.
Hagopian and Lim use this technique to generate carbon nanotubes in a grid pattern.
John Hagopian (left) collaborated with instrument scientist Lucy Lim to develop a new instrument that relies on carbon nanotubes to provide the electrons needed to excite minerals contained in an extraterrestrial sample. Larry Hess (right) patterns all the leads and patches where the catalyst for growing nanotubes is deposited. [NASA's Goddard Space Flight Center/Bill Hrybyk]
Circuits above and below the grids create an electrical field that activates the release of electrons contained within the carbon-nanotube arrays.
Under Lim’s space probe concept, the electron beams are accelerated through a stack of electrostatic lenses and focused on the extraterrestrial target.
“We would be able to choose which [carbon nanotube] bump to activate,” highlights Lim. “We would then be able to analyse different spots on the sample individually.”
Lim and colleagues believe they can demonstrate the nanotube-based electron probe within a couple years under the NASA-funded research effort.