A sensor designed to be the eyes of a future asteroid-tracking mission has passed a critical test.
The Near Earth Object Camera (NEOCam) sensor is a new infrared-light detector to improve the performance and efficiency of the next generation of space-based asteroid-hunting telescopes. It is the result of a long-term collaboration between the University of Rochester, USA, and the Jet Propulsion Laboratory (JPL), together with Teledyne Imaging Sensors.
A paper on the NEOCam sensor test will be published in an upcoming issue of the Journal of Optical Engineering.
'The NEOCam sensor will increase our ability to detect hazardous asteroids near the Earth and improve our understanding of threatening objects,' said William Forrest, professor of astronomy at the University of Rochester. The NASA-funded NEOCam space mission will also search for the most favourable destinations for future exploration by humans or robotic missions.
Asteroids do not emit visible light, they reflect it. When searching for near-Earth objects with optical telescopes (using visible light) the data collected can be deceiving because – depending on how reflective the object is – a small, light-coloured space rock can look the same as a big, dark one.
Asteroids do, however, always emit infrared radiation. 'We can learn more about asteroids when we look at them with infrared light,' explained Amy Mainzer, an author on the paper and principal investigator for NASA's NEOWISE and NEOCam missions at the JPL in Pasadena, California.
'When you observe a space rock with infrared, you are seeing its thermal emissions, which can better define the asteroid's size as well as tell you something about composition.'
Asteroids emit most of their radiation at infrared wavelengths near about 10µm, which humans perceive as heat. There is also relatively less radiation from stars and galaxies at these wavelengths, which simplifies detection of faint moving objects.
The NEOCam sensor is made of mercury, cadmium, and tellurium. Forrest and his colleague Judith Pipher started working on sensors from this combination of materials nearly 20 years ago, when they saw the potential they offered for higher operating temperatures.
