Geostationary Operational Environmental Satellite

 

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The Geostationary Satellite system (GOES), operated by the United States National Environmental Satellite, Data, and Information Service (NESDIS), supports weather forecasting, severe storm tracking, and meteorology research. Spacecraft and ground-based elements of the system work together to provide a continuous stream of environmental data. The National Weather Service (NWS) uses the GOES system for its United States weather monitoring and forecasting operations, and scientific researchers use the data to better understand land, atmosphere, ocean, and climate interactions.

The GOES system uses geosynchronous satellites which—since the launch of SMS-1 in 1974—have been a basic element of U.S. weather monitoring and forecasting.

Satellites

Four GOES satellites are currently available for operational use:

• GOES-12 is designated GOES-South, currently located at 60°W .^[1]
• GOES 13 is designated GOES-East, currently located at 75°W. It was placed in orbit on 24 May 2006, underwent Post-Launch Testing through early 2007, then replaced GOES 12 as GOES-East.^[2]
• GOES 14 is currently in storage at 90°W. It was temporarily designated GOES-East due to technical difficulties with GOES-13, and moved toward the GOES-East location, but after resolution of the GOES-13 anomaly GOES 14 returned to storage.^[3] It was placed in orbit on 7 July 2009, underwent Post-Launch Testing until December 2009 and then was placed in on-orbit storage at 105° W.^[2]
• GOES 15 is designated GOES-West, currently located at 135°W over the Pacific Ocean.^[4]

Several GOES satellites are still in orbit, either inactive or re-purposed. GOES-3 is no longer used for weather operations, but is a critical part of the communication links between the United States and Amundsen-Scott South Pole Station. Geostationary satellites cannot ordinarily be seen at all from the poles, but they require station keeping fuel to keep them stationary over the equator. When station keeping fuel runs out, solar and lunar perturbations increase the satellite's inclination so that its ground track begins to describe a figure-8 in the north-south direction. This usually ends the satellite's primary mission. But when the inclination is high enough, the satellite may begin to rise above the polar horizons at the extremes of the figure-8, as is the case for GOES-3. A nine-meter dish was constructed at the station, and communication with the satellite is currently possible for about five hours per day. Data rates are around 2.048 Mbit/s bi-directional under optimum conditions.

GOES-8 (GOES-East when it was in operation) is in a parking orbit, currently drifting about 4°W daily.^[5] It was decommissioned on April 1, 2003, and deactivated on May 5, 2004, after the failure of its propulsion system.^[6]

Weather data was lost for 13 days from GOES-12 on December 4, 2007 when it performed a standard station-keeping maneuver. GOES-11 initially took "full disk" images to cover the lost data until a contingency plan could be implemented.^[7] On December 5, 2007, GOES-10 was moved from South America operations to temporarily replace GOES-12 as the GOES-EAST operational satellite.^[8] On 9 December, communication with GOES-10 was also temporarily lost, but communication was resumed via a backup antenna.^[9] GOES-12 was successfully reactivated and moved back to normal operation following a thrust maneuver on 17 December.^[10] The trouble was traced to a leaking thruster valve, which pushed the satellite incorrectly. Emergency procedures were executed to cut off the valve, and a redundant thruster was activated to restore the location of the satellite.^[11]

GOES-10 was decommissioned on December 2, 2009 and was boosted to a graveyard orbit. It no longer had the fuel for required maneuvers to keep it on station.^[12] It joins GOES 8 and 9 which are already in graveyard orbits. With the cessation of GOES-10's duties, GOES-13 has replaced GOES-12 as "GOES-East". GOES-12 was then moved to 60° W and resume South American duties for GOES-10.

GOES-11 had a partial failure 6 Dec 2011, was decommissioned on 16 Dec 2011 and was boosted into a graveyard orbit. GOES 15 was moved to 135° W as GOES West.

GOES-13 is currently out of service due to technical difficulties.^[13] It was previously designated GOES-East, and is currently located at 75°W. It provided most of the U.S. weather information.^[14]

Purpose

Designed to operate to geostationary orbit, 35,790 km (22,240 statute miles) above the earth, thereby remaining stationary with respect to a point on the ground, the advanced GOES I–M spacecraft continuously view the continental United States, neighboring environs of the Pacific and Atlantic Oceans, and Central, South America and southern Canada. The three-axis, body-stabilized spacecraft design enables the sensors to "stare" at the earth and thus more frequently image clouds, monitor earth's surface temperature and water vapour fields, and sound the atmosphere for its vertical thermal and vapor structures. Thus the evolution of atmospheric phenomena can be followed, ensuring real-time coverage of short-lived dynamic events, especially severe local storms and tropical cyclones—two meteorological events that directly affect public safety, protection of property, and ultimately, economic health and development. The importance of this capability has been exemplified during hurricanes Hugo (1989) and Andrew (1992).

The GOES I–M series of spacecraft are the principal observational platforms for covering such dynamic weather events and the near-earth space environment for the 1990s and into the 21st century. These advanced spacecraft enhance the capability of the GOES system to continuously observe and measure meteorological phenomena in real time, providing the meteorological community and atmospheric scientists greatly improved observational and measurement data of the Western Hemisphere. In addition to short-term weather forecasting and space environmental monitoring, these enhanced operational services also improve support for atmospheric science research, numerical weather prediction models, and environmental sensor design and development. Data is received via the NOAA Command and Data Acquisition ground station at Wallops Island, Virginia^[15] The GOES satellites are controlled from the Satellite Operations Control Center (SOCC) located in Suitland, Maryland. During significant weather or other events the normal schedules can be altered to provide coverage requested by the National Weather Service and other agencies.

GOES spacecraft also provide a platform for the Solar X-Ray Imager (SXI), and space environment monitoring (SEM) instruments. The SEM measures in situ the effect of the sun on the near-earth solar-terrestrial electromagnetic environment, providing real-time data to the Space Environment Services Center (SESC). The SESC, as the nation’s “space weather” service, receives, monitors, and interprets a wide variety of solar-terrestrial data, and issues reports, alerts and forecasts for special events such as solar flares or geomagnetic storms. This information is important to the operation of military and civilian radio wave and satellite communication and navigation systems, as well as electric power networks, and to the mission of geophysical explorers, Shuttle and Space Station astronauts, high-altitude aviators, and scientific researchers. The SXI provides high-cadence monitoring of large scale solar structures to supports SESC's monitoring mission. However, the SXI unit on GOES-12 has been rendered inoperable from malfunctions, and the unit on GOES-13 was damaged by a solar flare in 2006.

Payload

The main mission is carried out by the primary payload instruments, the Imager and the Sounder. The Imager is a multichannel instrument that senses infrared radiant energy and visible reflected solar energy from the Earth's surface and atmosphere. The Sounder provides data for vertical atmospheric temperature and moisture profiles, surface and cloud top temperature, and ozone distribution.

Other instruments on board the spacecraft are the ground-based meteorological platform data collection and relay, and the space environment monitor. The latter consists of a magnetometer, an X-ray sensor, a high energy proton and alpha detector, and an energetic particles sensor, all used for in-situ surveying of the near-earth space environment. Satellites numbered 12 and greater also carry a solar x-ray imager (SXI) used for two-dimensional imaging of the Sun. The GOES 13-15 series also have a sun-pointed extreme ultraviolet sensor.

In addition, the GOES satellites carry Emergency Position-Indicating Radio Beacon (EPIRB) and Emergency Locator Transmitter (ELT) receivers, which are used for search-and-rescue purposes by the U.S. Air Force Rescue Coordination Center.

Satellite designations

Before being launched, GOES satellites are designated by letters (-A, -B, -C...). Once a GOES satellite is launched successfully, it is redesignated with a number (-1, -2, -3...). So, GOES-A to GOES-F became GOES-1 to GOES-6. Because GOES-G was a launch failure, it never received a number. Since then, GOES-H to GOES-P became GOES-7 to GOES-15.

The procurement, design and manufacturing of GOES is overseen by NASA, while all operations of the satellites once in orbit are done by NOAA. GOES spacecraft have been manufactured by Boeing (GOES D-H and N–P) and Space Systems/Loral (A–C and I–M). The two current GOES series (I-M and N-P) are documented in the "GOES I–M Databook" and "GOES N Series Databook". The future GOES series (GOES-R) is being built by Lockheed Martin.

GOES-13 (which was designated GOES-N prior to orbiting) was launched by a Delta IV rocket from Space Launch Complex 37B at Cape Canaveral Air Force Station in Florida at 22:11 GMT May 24, 2006.^[17] The launch of GOES-O was delayed several times due to various issues.^[18][19] GOES-O was launched Saturday, June 27, 2009 at 6:51 p.m. EDT from Florida's Cape Canaveral Air Force Station at Space Launch Complex 37 piggybacking on a Delta IV rocket.^[20] The GOES-O satellite is a part of the GOES-N Series, and was renamed as GOES-14 once it successfully arrived on orbit. GOES-14 is in on-orbit storage, and will be able to be activated for duty if another GOES satellite is decommissioned.^[21] GOES-P launched successfully on March 4, 2010 at 18:57 EST.^[22][23] Boeing would have built and launched a GOES-Q only if either GOES-O or GOES-P failed to be delivered on-orbit in good working order.

In October 2006, NOAA repositioned GOES-10 (originally GOES-K) over the Amazon region, to provide full-time coverage for South American countries. Although NOAA currently sends images to South America, the frequency drops from 30-minutes to 3 hours whenever a storm occurs in North America, which is roughly 40% of the time during the hurricane season.^[24] In 2010, NOAA assigned GOES-12 to observing South America, although it has expended its fuel and several science systems have failed.

In addition, because GOES satellites have only been equipped with infrared sounders. This limits GOES to where its soundings will only work in cloud free areas.^[25]

Future

The GOES-R series of spacecraft is in the development phase.^[26] The first GOES-R series satellite is scheduled for launch in fiscal year 2015^[27] and is expected to remain operational through December 2027.^[28] The proposed instrument package for the series initially included: the Advanced Baseline Imager (ABI); the Hyperspectral Environmental Suite (HES); the Space Environment In-Situ Suite (SEISS), which includes two Magnetospheric Particle Sensors (MPS-HI and MPS-LO), an Energetic Heavy Ion Sensor (EHIS), and a Solar and Galactic Proton Sensor (SGPS); the Solar Imaging Suite (SIS), which includes the Solar Ultraviolet Imager (SUVI), the Solar X-Ray Sensor (XRS), and the Extreme Ultraviolet Sensor (EUVS); the Geostationary Lightning Mapper (GLM); and the Magnetometer.^[29][30]

In September 2006 the Hyperspectral Environmental Suite (HES) was canceled and the planned number of satellites was reduced from 4 to 2 by NOAA due to concerns about cost overruns. The planned delivery schedule was also slowed down in order to reduce costs. The expected cost is $7.69 billion—a $670 million increase from the prior $7 billion estimate.^[26]

The contract for the constructing the satellites themselves, as well as the magnetometer system, SUVI and GLM, was awarded to Lockheed Martin. The award was challenged by Boeing, who lost the bid; however, the protest was subsequently dismissed. The ABI will be delivered by ITT Exelis. The SEISS will be delivered by Assurance Technology Corporation. XRS and EUVS will be combined into the Extreme Ultra Violet and X-Ray Irradiance Sensors (EXIS) which will be delivered by the Laboratory for Atmospheric and Space Physics of the University of Colorado.

The contract for the ground system (including data processing) was awarded to a team led by the Weather Systems division of Harris Corporation, including subcontracts to Boeing, Atmospheric and Environmental Research (AER), Honeywell, Carr Astronautics, Wyle Laboratories, and Ares.

History and status of GOES satellites

Main article: List of GOES satellites

• GOES 1, launched on October 16, 1975, decommissioned
• GOES 2, launched on June 16, 1977, decommissioned
• GOES 3, launched on June 16, 1978, used as a communications relay for the South Pole research station.
• GOES 4, launched on September 9, 1980, decommissioned
• GOES 5, launched on May 22, 1981, deactivated on July 18, 1990
• GOES 6, launched on April 28, 1983, decommissioned
• GOES-G, launched on May 3, 1986, failed to orbit
• GOES 7, launched April 28, 1987, used as a communications satellite by Peacesat
• GOES 8, launched on April 13, 1994, decommissioned
• GOES 9, launched on May 23, 1995, decommissioned on June 15, 2007
• GOES 10, launched on April 25, 1997, decommissioned on December 2, 2009
• GOES 11, launched on May 3, 2000, decommissioned on December 16, 2011
• GOES 12, launched on July 23, 2001, providing coverage for South America^[2]
• GOES 13, launched on May 24, 2006, in operation as GOES East, returned to operations 18 Oct 2012 after an anomaly
• GOES 14, launched on June 27, 2009, standby spacecraft, located at 90 degrees W as of Dec 2012^[2]
• GOES 15, launched on March 4, 2010, in operation as GOES West starting December 14, 2011^[2]
• GOES-R, scheduled for launch in 2015
• GOES S, scheduled for launch in 2017

The entire wiki link can be found at:  http://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite