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Landsat 7
Landsat 7
is the seventh satellite of the Landsat program. Launched on April 15, 1999, Landsat 7's primary goal is to refresh the global archive of satellite photos, providing up-to-date and cloud-free images. The Landsat Program is managed and operated by the USGS, and data from Landsat 7
Landsat 7
is collected and distributed by the USGS. The NASA World Wind
World Wind
project allows 3D images from Landsat 7
Landsat 7
and other sources to be freely navigated and viewed from any angle. The satellite's companion, Earth Observing-1, trailed by one minute and followed the same orbital characteristics, but in 2011 its fuel was depleted and EO-1's orbit began to degrade.[2] Landsat 7
Landsat 7
was built by Lockheed Martin Space Systems Company. In 2016, NASA
NASA
announced plans to attempt the first ever refueling of a live satellite by refueling Landsat 7
Landsat 7
in 2020.[3]

Contents

1 Satellite specifications 2 Main features 3 Scan Line Corrector failure 4 Satellite imagery 5 See also 6 References 7 External links

Satellite specifications[edit]

The effect of the SLC on ETM+ scans.

Landsat 7
Landsat 7
was designed to last for five years, and has the capacity to collect and transmit up to 532 images per day. It is in a polar, sun-synchronous orbit, meaning it scans across the entire earth's surface. With an altitude of 705 kilometers +/- 5 kilometers, it takes 232 orbits, or 16 days, to do so. The satellite weighs 1973 kg, is 4.04 m long, and 2.74 m in diameter. Unlike its predecessors, Landsat 7
Landsat 7
has a solid state memory of 378 gigabits (roughly 100 images). The main instrument on board Landsat 7
Landsat 7
is the Enhanced Thematic Mapper Plus (ETM+). Main features[edit]

A panchromatic band with "15 m (49 ft)" spatial resolution (band 8) Visible (reflected light) bands in the spectrum of blue, green, red, near-infrared (NIR), and mid-infrared (MIR) with 30 m (98 ft) spatial resolution (bands 1-5, 7) A thermal infrared channel with 60 m spatial resolution (band 6) Full aperture, 5% absolute radiometric calibration

Scan Line Corrector failure[edit] On May 31, 2003 the Scan Line Corrector (SLC) in the ETM+ instrument failed. The SLC consists of a pair of small mirrors that rotate about an axis in tandem with the motion of the main ETM+ scan mirror. The purpose of the SLC is to compensate for the forward motion (along-track) of the spacecraft so that the resulting scans are aligned parallel to each other. Without the effects of the SLC, the instrument images the Earth in a "zig-zag" fashion, resulting in some areas that are imaged twice and others that are not imaged at all. The net effect is that approximately 22% of the data in a Landsat 7
Landsat 7
scene is missing when acquired without a functional SLC. Following the SLC failure, an Anomaly Response Team (ART) was assembled, consisting of representatives from the USGS, NASA, and Hughes Santa Barbara Remote Sensing (the manufacturer of the ETM+ instrument). The team assembled a list of possible failure scenarios, most of which pointed at a mechanical problem with the SLC itself. Since there is no backup SLC, a mechanical failure would indicate that the problem was permanent. However, the team was unable to rule out the possibility of an electrical failure, though such a possibility was deemed remote. Nevertheless, on September 3, 2003, USGS
USGS
director Charles G. Groat
Charles G. Groat
authorized the Landsat project to reconfigure the ETM+ instrument and various other subsystems on board Landsat 7
Landsat 7
to use the spacecraft's redundant ("Side-B") electrical harness. With this authorization, the USGS
USGS
flight operations team at the NASA Goddard Space Flight Center
Goddard Space Flight Center
uploaded a series of commands to the spacecraft, instructing it to operate using the redundant electrical harness. This operation was successful, and on September 5, 2003, the ETM+ instrument was turned on and acquired data that was sent to the Landsat ground system at EROS outside Sioux Falls, South Dakota. It was immediately apparent that the migration to the Side-B electrical harness had not fixed the problem with the SLC. Following this, the instrument was reconfigured again to use its primary electrical harness. The subsequent conclusion of the ART was that the SLC problem was mechanical and permanent in nature. Landsat 7
Landsat 7
continues to acquire data in this mode. Data products are available with the missing data optionally filled in using other Landsat 7
Landsat 7
data selected by the user. In 2013, Landsat 7
Landsat 7
was joined by Landsat 8. Satellite imagery[edit]

False color
False color
IR image of Washington DC, taken by Landsat 7.

In August 1998, NASA
NASA
contracted EarthSat to produce Landsat GeoCover (Geocover 2000 in NASA
NASA
World Wind) — a positionally accurate orthorectified Landsat Thematic Mapper and Multispectral Scanner imagery covering the majority of the Earth's land mass. The contract was part of the NASA
NASA
Scientific Data Purchase which was administrated through NASA's John C. Stennis Space Center. GeoCover was later enhanced to EarthSat NaturalVue, a simulated natural color Landsat 7 derived c. year 2000, orthorectified, mosaicked and color balanced digital image dataset. Other commercial simulated true color 15-meter global imagery products built from the NASA
NASA
Landsat 7
Landsat 7
imagery include TerraColor from Earthstar Geographics, TruEarth (found in Google Earth and Google Maps) from TerraMetrics, BrightEarth from ComputaMaps, simulated natural color from Atlogis and a product of i-cubed used in World Wind. Largest parts of the earth surface displayed on web mapping services like Google Maps/Google Earth, MSN Maps or Yahoo Maps are based on enhanced and color balanced Landsat 7
Landsat 7
imagery. See also[edit]

Spaceflight portal

Google Earth NASA
NASA
World Wind Virtual globe UNIFORM-1

References[edit]

^ a b c d e "LANDSAT 7 Satellite details 1999-020A NORAD 25682". N2YO. 25 January 2015. Retrieved 25 January 2015.  ^ EO-1 Phase F Report ^ "NASA's Restore-L Mission to Refuel Landsat 7, Demonstrate Crosscutting Technologies". 23 June 2016. Retrieved 21 December 2017. 

External links[edit]

NASA's Landsat 7
Landsat 7
Website Landsat 7
Landsat 7
Science Data Users Handbook The USGS' Landsat Website " Landsat 7
Landsat 7
Media Kit". Boeing. Archived from the original on 1999-05-08.  NASA's World Wind
World Wind
Project

List of Landsat layers available in World Wind

NASA
NASA
Applied Sciences Directorate website for free viewing/download of Landsat GeoCover band 742 mosaics University of Maryland Global Land Cover Facility for free viewing/download of individual Landsat images, GeoCover mosaics, and other earth imagery data Harris GLOBE15 - Harris Corporation Geospatial website (includes 15m global data set details) EarthSat's NaturalVue 2000: Global natural color satellite imagery coverage (resolution 15 m), based on Landsat 7
Landsat 7
data acquired between 1999 and 2001 TerraColor.Net - TerraColor 15m imagery website TruEarth 15m imagery website ICEDS Webserver, a free WMS compliant webserver, serving a variety of Geographic data including Landsat images Atlogis Maps and Atlogis Meta-Maps: Online-Viewer for Landsat 5
Landsat 5
and Landsat 7
Landsat 7
Natural Color Mosaic CEOS MIM Database Landsat 7
Landsat 7
Entry

v t e

Landsat program

Landsat 1 2 3 4 5 6 7 8 9

v t e

Orbital meteorological and remote sensing systems

Concepts

Earth observation satellite Geographic information system
Geographic information system
(GIS) Weather satellite

Current projects

Earth Observing System (EOS)

GPM TRMM Landsat 7 QuikSCAT Terra ACRIMSAT NMP/EO-1 Jason-1 OSTM/Jason-2 Jason-3 Meteor 3M-1/Sage III GRACE Aqua SORCE Aura CloudSat CALIPSO NPOESS Megha-Tropiques SARAL IRS ESSP Aquarius Landsat 8 SMAP JPSS NISAR ICESat-2 Weather System Follow-on Microwave

A-train satellites

Aqua Aura CALIPSO CloudSat GCOM-W1 (Shizuku) OCO-2

Copernicus programme

Sentinel-1 Sentinel-2 Sentinel-3 Sentinel-4 Sentinel-5 Precursor Sentinel-5

Geostationary meteorological satellites

Elektro-L Fengyun-2 GOES INSAT Meteosat Himawari-8

Other satellites

CBERS COSMO-SkyMed DMSP DMC EROS Fengyun-3 GOSAT (Ibuki) Landsat MetOp Meteor POES RADARSAT-2 RapidEye Resurs-P SMOS SPOT TerraSAR-X THEOS

Former projects

Completed

ADEOS (Midori) ADEOS II
ADEOS II
(Midori 2) COSMIC (FORMOSAT-3) Envisat ERS FORMOSAT-1 FORMOSAT-2 Geosat GMS (Himawari) ICESat IKONOS JERS-1 (Fuyo-1) Nimbus PARASOL QuickBird RADARSAT-1 Seasat SeaWiFS TIROS TOPEX/Poseidon UARS Vanguard

Failed

OCO Glory

Cancelled

NMP/EO-3

v t e

← 1998  ·  Orbital launches in 1999  ·  2000 →

Mars Polar Lander
Mars Polar Lander
ROCSAT-1 Stardust Globalstar 23 · Globalstar 36 · Globalstar 38 · Globalstar 40 Telstar 6 JCSAT-6 Soyuz TM-29
Soyuz TM-29
ARGOS · Ørsted · SUNSAT Arabsat 3A · Skynet 4E
Skynet 4E
Globus No.15 Wide Field Infrared Explorer Globalstar 23 · Globalstar 37 · Globalstar 41 · Globalstar 46 AsiaSat 3S
AsiaSat 3S
DemoSat Progress M-41 · Sputnik 99
Sputnik 99
INSAT-2E
INSAT-2E
USA-142 Eutelsat W3 Globalstar 19 · Globalstar 42 · Globalstar 44 · Globalstar 45 Landsat 7
Landsat 7
UoSAT-12 Ikonos-1 ABRIXAS · Megsat-0 USA-143 Orion 3 Feng Yun 1C · Shijian 5 TERRIERS · MUBLCOM
MUBLCOM
Nimiq 1 USA-144 Oceansat-1 · Kitsat-3 · DLR-Tubsat STS-96
STS-96
(Starshine 1) Globalstar 25 · Globalstar 47 · Globalstar 49 · Globalstar 52 Iridium 14A · Iridium 21A Astra 1H
Astra 1H
QuikSCAT
QuikSCAT
FUSE Gran' No.45 Molniya 3-50 Globalstar 30 · Globalstar 32 · Globalstar 35 · Globalstar 51 Progress M-42 Okean-O No.1 STS-93
STS-93
(Chandra) Globalstar 26 · Globalstar 28 · Globalstar 43 · Globalstar 48 Telkom 1 · Globalstar 24 · Globalstar 27 · Globalstar 53 · Globalstar 54 Kosmos 2365 Kosmos 2366 Koreasat 3 Yamal-101 · Yamal-102 Foton 12 Globalstar 33 · Globalstar 50 · Globalstar 55 · Globalstar 58 EchoStar V Ikonos 2 Telstar 7 LMI-1 Resurs F-1M USA-145
USA-145
DirecTV-1R CBERS-1 · SACI-1 Globalstar 31 · Globalstar 56 · Globalstar 57 · Globalstar 59 Orion 2 Ekspress A1 GE-4 MTSAT-1 Shenzhou 1 Globalstar 29 · Globalstar 34 · Globalstar 39 · Globalstar 61 USA-146 Hélios 1B · Clémentine Orbcomm FM30 · Orbcomm FM31 · Orbcomm FM32 · Orbcomm FM33 · Orbcomm FM34 · Orbcomm FM35 · Orbcomm FM36 XMM-Newton
XMM-Newton
SACI-2 USA-147 Terra STS-103
STS-103
Arirang-1 · ACRIMSAT · Millennial Galaxy 11 Kosmos 2367 Kosmos 2368

Payloads are separated by bullets ( · ), launches by pipes ( ). Manned flights are indicated in bold text. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are de

.