Improved Landsat 8 sensors to gather visible light and infrared data
NASA announced that its Landsat Data Continuity Mission (LDCM) blasted off at 1:02 p.m. EST Monday aboard an Atlas V rocket from Vandenberg Air Force Base. LDCM is the eighth in the Landsat series of satellites that have been continuously observing Earth's land surfaces since 1972.
NASA said the spacecraft carries two instruments, the Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS), both of which improve reliability, sensitivity, and data quality compared with previous Landsat instruments.
OLI, built by Ball Aerospace & Technologies Corp., will continue observations currently made by Landsat 7 in the visible, near infrared, and shortwave infrared portions of the spectrum. It also will take measurements in two new bands not covered by Landsat 7—one to observe high-altitude cirrus clouds and another to observe atmospheric aerosols as well as water quality in lakes and shallow coastal waters. NASA said OLI's new design has fewer moving parts than instruments on previous Landsat satellites. Ball said OLI’s 14-module detector array enables it to scan with what it described as “a push-broom method rather than the older sweeping method.” The OLI instrument provides 15-m panchromatic and 30-m multispectral spatial resolutions along a 185-km-wide swath—it can image the entire globe 16 days.
NASA said its Goddard Space Flight Center built the TIRS instrument; Ball Aerospace added that it supplied the TIRS cryocooler, which will chill the TIRS instrument’s infrared photo detectors to 40 K. NASA said TIRS will collect data on heat emitted from Earth's surface in two thermal bands, as compared with a single thermal band on previous Landsat satellites. NASA said the thermal-band observations are becoming increasingly vital to monitoring water consumption, especially in the arid western U.S.
You can find more information on ETM+ and OLI/TIRS spectral bands here.
“Landsat is a centerpiece of NASA's Earth Science program, and today's successful launch will extend the longest continuous data record of Earth's surface as seen from space,” NASA Administrator Charles Bolden said. “This data is a key tool for monitoring climate change and has led to the improvement of human and biodiversity health, energy and water management, urban planning, disaster recovery and agriculture monitoring — all resulting in incalculable benefits to the U.S. and world economy.”
LDCM will go through a three-month check-out phase, after which operational control will be transferred to the Department of the Interior's U.S. Geological Survey (USGS), and the satellite will be renamed Landsat 8.
NASA noted that advancements in computer power and the decision by USGS to allow free online access to the information have transformed the use of Landsat data in recent years.
Landsat is all about data. But Erin Coulehan at Slate notes that Landsat images have aesthetic value as well. She has posted some striking images from earlier Landsat missions.
NASA said Orbital Sciences Corp. built, integrated, and tested the spacecraft in Gilbert, AZ; USGS provided the LDCM ground system; and United Launch Alliance provided the Atlas V launch vehicle. NASA's Launch Services Program based at the agency's Kennedy Space Center managed the launch.