 Landsat 8 during ground testing | |
| Names | Landsat Data Continuity Mission |
|---|---|
| Mission type | Satellite imagery |
| Operator | NASA / USGS |
| COSPAR ID | 2013-008A |
| SATCATno. | 39084 |
| Website | [1] |
| Mission duration | 5 years (planned) 10 years (with fuel) Elapsed: 12 years, 8 months, 24 days |
| Spacecraft properties | |
| Spacecraft | Landsat 8 |
| Spacecraft type | LEOStar |
| Bus | LEOStar-3 |
| Manufacturer | Orbital Sciences (prime) Ball Aerospace (OLI) NASAGSFC (TIRS) |
| Launch mass | 2,623 kg (5,783 lb) |
| Dry mass | 1,512 kg (3,333 lb) |
| Start of mission | |
| Launch date | 11 February 2013, 18:02:00UTC |
| Rocket | Atlas V 401 (AV-035) |
| Launch site | Vandenberg,SLC-3E |
| Contractor | United Launch Alliance |
| Entered service | 30 May 2013 |
| Orbital parameters | |
| Reference system | Geocentric orbit[1] |
| Regime | Sun-synchronous orbit |
| Altitude | 705 km |
| Inclination | 98.22° |
| Period | 98.8 minutes |
| Instruments | |
| Operational Land Imager (OLI) Thermal Infrared Sensor (TIRS) | |
 Landsat Data Continuity Mission (LDCM) mission patch | |
Landsat 8 is an AmericanEarth observationsatellite launched on 11 February 2013. It is the eighth satellite in theLandsat program and the seventh to reach orbit successfully. Originally called theLandsat Data Continuity Mission (LDCM), it is a collaboration betweenNASA and theUnited States Geological Survey (USGS). NASAGoddard Space Flight Center inGreenbelt, Maryland, 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. It comprises the camera of theOperational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS), which can be used to studyEarth surface temperature and is used to study global warming.[2]
The satellite was built byOrbital Sciences Corporation, who served asprime contractor for the mission.[3] The spacecraft's instruments were constructed byBall Aerospace & Technologies and NASA's Goddard Space Flight Center (GSFC),[4] and its launch was contracted toUnited Launch Alliance (ULA).[5] During the first 108 days in orbit, LDCM underwent checkout and verification by NASA and on 30 May 2013 operations were transferred from NASA to the USGS when LDCM was officially renamed to Landsat 8.[6]
WithLandsat 5 retiring in early 2013, leaving Landsat 7 as the only on-orbit Landsat program satellite, Landsat 8 ensures the continued acquisition and availability of Landsat data utilizing a two-sensor payload, theOperational Land Imager (OLI) and the Thermal InfraRed Sensor (TIRS). Respectively, these two instruments collect image data for nine shortwave bands and two longwave thermal bands. The satellite was developed with a 5 years mission design life but was launched with enough fuel on board to provide for upwards of ten years of operations.
Landsat 8 consists of three key mission and science objectives:
Providing moderate-resolution imagery, from 15 metres to 100 metres, of Earth's land surface and polar regions, Landsat 8 operates in thevisible,near-infrared,short wave infrared, andthermal infrared spectrums. Landsat 8 captures more than 700 scenes a day, an increase from the 250 scenes a day onLandsat 7. The OLI and TIRS sensors will see improvedsignal to noise radiometric (SNR) performance, enabling 12-bit quantization of data allowing for more bits for better land-cover characterization.
Planned parameters for Landsat 8 standard products:[8]
The Landsat 8 spacecraft was built byOrbital Sciences Corporation, under contract to NASA, and uses Orbital's standardLEOStar-3 satellite bus. Orbital was responsible for the design and manufacture of the Landsat 8 spacecraft bus, the integration of the customer-furnished payload instruments, and full observatory testing, including environmental and EMI/EMC.[9] The spacecraft supplies power, orbit and attitude control, communications, and data storage for OLI and TIRS.
All components, except for the propulsion module, are mounted on the exterior of the primary structure. A single deployable solar array generates power for the spacecraft components and charges the spacecraft's 125ampere hournickel-hydrogen (Ni-H2) battery. A 3.14-terabit solid state data recorder provides data storage aboard the spacecraft and anX-band antenna transmits 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.[10]
Landsat 8'sOperational Land Imager (OLI) improves on past Landsat sensors and was built, under contract to NASA, byBall Aerospace & Technologies. OLI uses a technological approach demonstrated by the Advanced Land Imager sensor flown on NASA's experimentalEarth Observing-1 (EO-1) satellite. The OLI instrument uses apushbroom sensor instead ofwhiskbroom sensors that were utilized on earlier Landsat satellites. The pushbroom sensor aligns the imaging detector arrays along Landsat 8's focal plane allowing it to view across the entire swath, 185 km (115 mi) cross-track field of view, as opposed to sweeping across the field of view. With over 7000 detectors per spectral band, the pushbroom design results in increased sensitivity, fewer moving parts, and improved land surface information.
OLI collects data from nine spectral bands. Seven of the nine bands are consistent with theThematic Mapper (TM) andEnhanced 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 measure water quality and improve detection of high, thinclouds.
| Spectral Band | Description | Wavelength | Resolution |
|---|---|---|---|
| Band 1 | Coastal Aerosol | 0.43 - 0.45 μm | 30 m |
| Band 2 | Blue | 0.450 - 0.51 μm | 30 m |
| Band 3 | Green | 0.53 - 0.59 μm | 30 m |
| Band 4 | Red | 0.64 - 0.67 μm | 30 m |
| Band 5 | Near-Infrared | 0.85 - 0.88 μm | 30 m |
| Band 6 | SWIR 1 | 1.57 - 1.65 μm | 30 m |
| Band 7 | SWIR 2 | 2.11 - 2.29 μm | 30 m |
| Band 8 | Panchromatic (PAN) | 0.50 - 0.68 μm | 15 m |
| Band 9 | Cirrus | 1.36 - 1.38 μm | 30 m |
The Thermal InfraRed Sensor (TIRS), built by the NASAGoddard Space Flight Center, conducts thermal imaging and supports emerging applications such asevapotranspiration rate measurements for water management. The TIRS focal plane usesgallium arsenide (GaAs)Quantum Well Infrared Photodetector arrays (known as QWIPs) for detecting the infrared radiation — a first for the Landsat program. The TIRS data will be registered to OLI data to create radiometrically, geometrically, and terrain-corrected 12-bit Landsat 8 data products.[8] Like OLI, TIRS employs a pushbroom sensor design with a 185 km swath width. Data for two long wavelength infrared bands will be collected with TIRS. This provides data continuity with Landsat 7's single thermal infrared band and adds a second.
With TIRS being a late addition to the Landsat 8 satellite, the design life requirement was relaxed in order to expedite development of the sensor. As such, TIRS only has a three-year design life.
| Spectral Band | Description | Wavelength | Resolution |
|---|---|---|---|
| Band 10 | Thermal infrared 1 | 10.60 – 11.19 μm | 100 m |
| Band 11 | Thermal infrared 2 | 11.50 – 12.51 μm | 100 m |
The Landsat 8 ground system performs two main functions: command and control of the satellite and management of mission data sent from the satellite. Satellite command and control is provided by the Mission Operations Center atGoddard Space Flight Center (NASA). Commands are sent from theMission Operations Center to the satellite via a Ground Network Element (GNE). Mission data from the satellite is downlinked to receiving stations inSioux Falls, South Dakota, Gilmore Creek,Arkansas, andSvalbard, Norway. From there, the data is sent via the GNE to theUSGSCenter for Earth Resources Observation and Science (EROS) in Sioux Falls, where it is ingested into the Data Processing and Archive System.[12]
The original Landsat 8 plans called for NASA to purchase data meeting Landsat 8 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 theWhite HouseOffice of Science and Technology Policy (OSTP) directed Federal agencies to place Landsat-type sensors on theNational Polar-orbiting Operational Environmental Satellite System (NPOESS) platform. Following an evaluation of the technical complexity of this task, the strategy was adjusted and on 23 December 2005, the OSTP issued a memorandum directing NASA to implement the Landsat 8 in the form of a free-flyer spacecraft carrying an instrument referred to as theOperational Land Imager (OLI). In December 2009, a decision was made to add a thermal infrared sensor (TIRS) to the mission payload.[8] On 7 October 2022 the satellite was imaged on orbit byWorldView-3.[13]
The satellite was launched aboard anAtlas 401launch vehicle with an Extended Payload Fairing.[14] The launch took place at 18:02:00UTC on 11 February 2013, fromVandenberg Space Launch Complex 3 (SLC-3E) atVandenberg Air Force Base.[15] Seventy eight minutes and thirty seconds later, the spacecraft separated from the Atlas V upper stage, successfully completing the launch.[16]
First images from the spacecraft were collected on 18 March 2013.[17] Landsat 8 joinsLandsat 7 on-orbit, providing increased coverage of the Earth's surface.
On 19 December 2014, ground controllers detected anomalous current levels associated with the Scene Select Mirror (SSM) encoder electronics. The SSM electronics were turned off with the instrument pointed at nadir and TIRS data was acquired but not processed. On 3 March 2015, operators switched TIRS from the A side to B side electronics to deal with the issue with the A side encoder electronics. TIRS resumed normal operations on 4 March 2015, and nominal blackbody and deep space calibration data collection resumed on 7 March 2015.[18]
On 3 November 2015, the ability of TIRS to accurately measure the location of the Scene Select Mirror (SSM) was compromised and the encoder was powered off.[19] In April 2016, an algorithm was developed to compensate for the powered off encoder and data reporting resumed.[20] In addition to these problems, TIRS launched with a stray light anomaly that increases the reported temperature by up to 4 Kelvin in band 10 and up to 8 K in band 11. Eventually, it was determined that the anomaly was caused by out-of-field reflections bouncing off a metal alloy retaining ring mounted just above the third lens of the four-lens refractive TIRS telescope and onto the TIRS focal plane.[21][22] In January 2017, an algorithm was developed to estimate the amount of stray light and subtract it from the data, reducing the error down to about 1 K.[23]
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