Lasers at NASA Langley

Lasers at NASA Langley

Scientists at NASA Langley Research Center have been researching and developing lasers for remote sensing (monitoring and measuring) of Earth's atmosphere since the technology was in its infancy. In recent years, they have incorporated lasers into atmospheric studies as part of NASA's Mission to Planet Earth program. The goal of this long-term global research is to study the interaction of all the environmental components -- air, water, land, life -- that make up the Earth system. While a variety of remote sensing techniques have been used, advances in laser technology are opening up new views of the Earth's atmosphere and placing the laser at the forefront of research tools.

In 1985, NASA Langley performed its first airborne laser mission: to study water vapor and the density of aerosols (small particles) in our atmosphere.

Less than 10 years later, in 1994, NASA Langley joined with industry to put an atmospheric laser sensor in space to probe the atmosphere. The Lidar In-Space Technology Experiment (LITE) was flown aboard the Space Shuttle Discovery (STS-64). During its 12-day mission, LITE measured the Earth's cloud cover and tracked aerosols in the atmosphere. The laser used on this mission was a component of a Lidar (LIght Detection And Ranging). Lidar is similar to radar, but instead of bouncing radio waves off its target, a lidar uses short pulses of laser light to bounce or reflect off particles -- even molecules -- in the atmosphere. The reflected light comes back to a telescope where it is collected and measured.

The LITE data is being analyzed and archived and has proven so effective in presenting a global picture of the Earth's atmosphere that NASA Langley scientists are now exploring the feasibility and potential advantages of using lidar instruments on satellites.

That same year NASA Langley accomplished another lidar mission. Flown on the high-altitude ER-2 aircraft, which is a modified U-2 spy plane, the Lidar Atmospheric Sensing Experiment (LASE) used the first tunable laser to function autonomously. The lidar used in this mission was designed to measure atmospheric elements which are typically hard to detect, such as water vapor and pollutants. This DIfferential Absorption Lidar (DIAL) uses two laser beams pulsed at different wavelengths, one tuned to a specific particle or gas which absorbs it, and one tuned to remain unabsorbed. By measuring the difference between the two beams as they come back to the telescope - one partially absorbed and one intact -- scientists can determine the amount of a particle or gas present.

NASA Langley's work in the development of laser technology has naturally found application in medicine and manufacturing. NASA Langley engineers were instrumental in the development of the diode pump laser which is currently state of the art because of its efficiency, reliability and long life. In response to an industrial need for such a laser, NASA Langley teamed with others to take the diode semi-conductor from being a lab curiosity to a product which industry has since commercialized.

NASA Langley also contributed greatly to the development of a more efficient laser for special medical applications, such as incisions and arterial repairs.