Volume 9, Number 6 • November/December 2001 • Small Business/SBIR

Small Business Flying High

Instruments on NASA satellites and aircraft will be collecting the data needed by scientists to answer some of the most challenging questions faced today concerning our atmosphere and the formation of stars and planets. One of those instruments is a passive radiometer, which measures infrared or heat radiation from the atmosphere or space as seen through a telescope. Scientists use this information in a number of ways. When looking at the Earth’s atmosphere, observations in infrared vision allow scientists to calculate the amount of several environmentally important gases, such as ozone and carbon monoxide. When looking toward interstellar space, this data allows scientists to estimate the quantities of important chemicals, such as water and carbon in the clouds of dust and gas that are believed to collapse to form solar systems such as our own.

Working under a NASA SBIR contract managed at the Jet Propulsion Laboratory, DeMaria ElectroOptics developed a compact, efficient near-infrared (2.5 Thz) laser that extends the observation range of passive radiometers. Observations made by earlier passive radiometers were limited to the longer wavelength range of the infrared spectrum. The new source from DeMaria ElectroOptics increased the observation range to shorter wavelengths. The stable signal from the laser is used in converting the observed infrared radiation to a lower frequency signal for measuring its intensity.

Scientists focus on the infrared range of the spectrum for two reasons. First, atoms and molecules emit infrared radiation even at the very cold temperatures of interstellar space. Thus, these gases, which are invisible to us through a regular telescope, are visible using an infrared telescope. Second, different atoms and molecules have their own characteristic signatures or particular wavelengths at which they emit infrared radiation. Therefore, infrared radiation can be used to estimate the amount of different chemicals in the interstellar medium or the Earth’s atmosphere.

Under another contract with the Jet Propulsion Laboratory, DeMaria ElectroOptics is providing a near-infrared laser for the Microwave Limb Sounder instrument that will be a part of the Earth-Observing System (EOS) AURA mission. With a launch date in June 2003, the AURA satellite, with four major scientific instruments, will map data on the Earth’s atmosphere on a global scale. With its near-infrared capability, the Microwave Limb Sounder will measure the OH concentration in the upper atmosphere—a key factor in ozone chemistry and understanding the cause of the hole in the ozone layer.

DeMaria ElectroOptics also supplied a near-infrared laser being used in the development of the radiometer that will fly on the SOFIA mission—an effort between NASA and the German space agency, DLR. In a joint effort, the agencies will fly a large infrared telescope on a Boeing 747 aircraft. At ground level, the atmosphere filters out most of the infrared radiation from space; however, most of the infrared radiation is observable at stratospheric altitudes. Observations made from the aircraft when flying in the stratosphere will support a comprehensive study of the processes that lead from cold clouds of gas and dust in the Interstellar Medium to the formation of stars and planetary systems. SOFIA will also examine the dust and gas in the vicinity of our Galactic Center, and search for the signature of a black hole. The first flight is scheduled for late 2002. Q

For more information, contact Bryon Jackson at the Jet Propulsion Laboratory, 818/354-1246, Bryon.L.Jackson@jpl.nasa.gov. Please mention you read about it in Innovation.

NASA Official: Jonathan Root • Web Design: Printing & Design Office, NASA Headquarters • Credits