Landsat 8

Landsat Data Continuity Mission is an American Earth observation satellite launched in 2013. It is the eighth satellite in the Landsat program; the seventh to reach orbit successfully. The Landsat Data Continuity Mission is a collaboration between NASA and the United States Geological Survey (USGS). NASA Goddard Space Flight Center provided development, mission systems engineering, and acquisition of the launch vehicle while the USGS provided for development of the ground systems and will conduct on-going mission operations.

The satellite was built by Orbital Sciences Corporation, who served as prime contractor for the mission. The spacecraft's instruments were constructed by Ball Aerospace and NASA's Goddard Space Flight Center,and its launch was contracted to United Launch Alliance. During the first approximately 100 days in orbit, LDCM will undergo checkout and verification by NASA. Once complete, LDCM will be handed over to the USGS and officially renamed Landsat 8.

Launch

Landsat Data Continuity Mission launches atop an Atlas V

The satellite was launched aboard an Atlas V 401 carrier rocket with an Extended Payload Fairing. The launch took place at 18:02 UTC (10:02 PST) on 11 February 2013, from Space Launch Complex 3E at Vandenberg Air Force Base. Seventy eight minutes and thirty seconds later, the spacecraft separated from the upper stage of its carrier rocket, successfully completing the launch.

LDCM joins Landsat 7 on-orbit, providing increased coverage of the Earth's surface.

History

The original LDCM plans called for NASA to purchase data meeting LDCM specifications from a commercially owned and operated satellite system; however, after an evaluation of proposals received from industry, NASA cancelled the Request for Proposals in September 2003. In August 2004, a memorandum from the White House Office of Science and Technology Policy (OSTP) directed Federal agencies to place Landsat-type sensors on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) platform. Following an evaluation of the technical complexity of this task, the strategy was adjusted and on December 23, 2005, the OSTP issued a memorandum directing NASA to implement the LDCM in the form of a free-flyer spacecraft carrying an instrument referred to as the Operational Land Imager (OLI). In December 2009, a decision was made to add a thermal infrared sensor (TIRS) to the mission payload.

First images from the spacecraft were collected on March 18, 2013.

Mission Overview

With Landsat 5 retiring in early 2013, leaving Landsat 7 as the only on-orbit Landsat program satellite, the Landsat Data Continuity Mission will ensure the continued acquisition and availability of Landsat data utilizing a two-sensor payload, the Operational Land Imager (OLI) and the Thermal InfraRed Sensor (TIRS). Respectively, these two instruments will collect image data for nine shortwave bands and two longwave thermal bands. The satellite has been developed with a 5.25 years mission design life however has enough fuel onboard to provide for upwards of ten years of operations.

The Landsat Data Continuity Mission consists of three key mission and science objectives:

• Collect and archive medium resolution (30-meter spatial resolution) multispectral image data affording seasonal coverage of the global landmasses for a period of no less than 5 years;
• Ensure that LDCM data are sufficiently consistent with data from the earlier Landsat missions in terms of acquisition geometry, calibration, coverage characteristics, spectral characteristics, output product quality, and data availability to permit studies of landcover and land-use change over time;
• Distribute LDCM data products to the general public on a nondiscriminatory basis at no cost to the user.

Technical Details

First image from the Landsat Data Continuity Mission (LDCM). The area is Fort Collins, Colorado, USA and the image is shown in natural color using the Operational Land Imager (OLI) spectral bands 2 (blue), 3 (green), and 4 (red).

First image from the Landsat Data Continuity Mission (LDCM). The area is Fort Collins, Colorado, USA and the image is from the Operational Land Imager (OLI) spectral bands 3 (green), 5 (near infrared), and 7 (short wave infrared 2) displayed as blue, green and red, respectively.

Providing moderate-resolution imagery, from 15 meters to 100 meters, of Earth’s land surface and polar regions, LDCM will operate in the visible, near-infrared, short wave infrared, and thermal infrared spectrums. LDCM will capture approximately 400 scenes a day, an increase from the 250 scenes a day on Landsat 7. The OLI and TIRS sensors will see improved signal to noise (SNR) radiometric performance, enabling 12-bit quantization of data allowing for more bits for better land cover characterization.

Planned parameters for Landsat Data Continuity Mission standard products

• Product type: Level 1T (terrain corrected)
• Output format: GeoTIFF
• Pixel size: 15 meters/30 meters/100 meters (panchromatic/multispectral/thermal)
• Map projection: UTM (Polar Stereographic for Antarctica)
• Datum: WGS 84
• Orientation: North-up (map)
• Resampling: Cubic convolution
• Accuracy:
  • OLI: 12 meters circular error, 90-percent confidence
  • TIRS: 41 meters circular error, 90-percent confidence

Spacecraft

The LDCM spacecraft is being built by Orbital Sciences Corporation, under contract to NASA, and will utilize Orbital's standard LEOStar-3 satellite bus. Orbital is responsible for the design and manufacture of the LDCM spacecraft bus, the integration of the customer-furnished payload instruments, and full observatory testing, including environmental and EMI/EMC. The spacecraft will supply power, orbit and attitude control, communications, and data storage for OLI and TIRS.

All components, except for the propulsion module, will be mounted on the exterior of the primary structure. A deployable solar array will generate power for the spacecraft components and will charge the spacecraft’s 125 amp-hour nickelhydrogen (Ni-H2) battery. A 3.14-terabit solid state data recorder will provide data storage aboard the spacecraft and a X-band antenna will transmit OLI and TIRS data either in real time or played back from the data recorder. The OLI and TIRS are mounted on an optical bench at the forward end of the spacecraft.

Operational Land Imager

LDCM’s Operational Land Imager (OLI) improves on past Landsat sensors and is being built, under contract to NASA, by Ball Aerospace. OLI uses a technological approach demonstrated by the Advanced Land Imager sensor flown on NASA’s experimental EO-1 satellite. The OLI instrument will employ the use of a pushbroom sensor, compared to the use of whiskbroom sensors that were utilized on earlier Landsat satellites. The use of a pushbroom sensor will align the imaging detector arrays along LDCM's focal plane allowing it to view across the entire swath, 115 miles (185 kilometers) cross-track field of view, as opposed to sweeping across the field of view. With over 7,000 detectors per spectral band, the pushbroom design will result in increased sensitivity, less moving parts, and improved land surface information.

OLI will collect data from nine spectral bands. Seven of the nine bands will be consistent with the Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) sensors found on earlier Landsat satellites, providing for compatibility with the historical Landsat data, while also improving measurement capabilities. Two new spectral bands, a deep blue coastal / aerosol band and a shortwave-infrared cirrus band, will be collected allowing scientists to mesure water quality and improve detection of high, thin clouds.

 

OLI Spectral Bands

Spectral Band	Wavelength	Resolution
Band 1 - Coastal / Aerosol	0.433 - 0.453 µm	30 m
Band 2 - Blue	0.450 - 0.515 µm	30 m
Band 3 - Green	0.525 - 0.600 µm	30 m
Band 4 - Red	0.630 - 0.680 µm	30 m
Band 5 - Near Infrared	0.845 - 0.885 µm	30 m
Band 6 - Short Wavelength Infrared	1.560 - 1.660 µm	30 m
Band 7 - Short Wavelength Infrared	2.100 - 2.300 µm	30 m
Band 8 - Panchromatic	0.500 - 0.680 µm	15 m
Band 9 - Cirrus	1.360 - 1.390 µm	30 m

Thermal InfraRed Sensor

Thermal Infrared Sensor Design

The Thermal InfraRed Sensor (TIRS) was built by the NASA Goddard Space Flight Center and will allow for thermal imaging in addition to support emerging applications such as evapotranspiration rate measurements for water management. The TIRS data will be registered to OLI data to create radiometrically, geometrically and terrain-corrected 12-bit LDCM data products. The TIRS sensor will also employ, as does the OLI sensor, the use of a pushbroom sensor design in addition to a 185 kilometer cross-track field of view. Data for two long wavelength infrared bands will be collected with TIRS however TIRS only provides Landsat data continuity with one band, Band 10. With TIRS being a late addition to the LDCM satellite, the design life has been relaxed in order to expedite development of the sensor. As such, TIRS only has a three-year design life.

TIRS Spectral Bands

Spectral Band	Wavelength	Resolution
Band 10 - Long Wavelength Infrared	10.30 - 11.30 µm	100 m
Band 11 - Long Wavelength Infrared	11.50 - 12.50 µm	100 m

See also

• Landsat program
   

External links

• NASA's Landsat Website
• USGS Landsat Website
• NASA's Landsat Data Continuity Mission Website
• EarthNow! Landsat Image Viewer