This illustration depicts the GOES spacecraft. Credit: Boeing

GOES-O is the second spacecraft to be launched in the new GOES N Series of geostationary environmental weather satellites. Developed by NASA for the National Oceanic and Atmospheric Administration (NOAA), the GOES satellites continuously provide observations of 60 percent of the Earth including the continental U.S., providing weather monitoring and forecast operations, as well as a continuous and reliable stream of environmental information and severe weather warnings.

The GOES environmental satellites are key in helping meteorologists observe and predict local weather events, including thunderstorms, tornadoes, fog, flash floods, and severe weather. In addition, GOES satellites are able to monitor dust storms, volcanic eruptions and forest fires. Plus, the satellites support the search and rescue satellite aided system (SARSAT). GOES-O data will add to the global climate change databases of knowledge, embracing many civil and government forecasting organizations that work to benefit people everywhere and help save lives.

Each GOES satellite carries two major instruments: an Imager and a Sounder. Together they provide 2 valuable features. One feature is a is a flexible scanner that offers small-scale area imaging allowing meteorologists to take pictures of local weather trouble spots. This allows them to improve short-term forecasts over local areas. The second feature, simultaneous and independent imaging and sounding, is designed to allow weather forecasters to use multiple measurements of weather phenomena to increase the accuracy of their forecasts.

These instruments acquire high-resolution visible and infrared data, as well as temperature and moisture profiles of the atmosphere. They continuously transmit data to ground terminals where it is processed for rebroadcast to primary weather service offices in the U.S. and around the world, including the global research community.

GOES-O is scheduled to launch in the summer of 2009 on board a Boeing Delta IV (4,2) Expendable Launch Vehicle from the Space Launch Complex (SLC 37) at Cape Canaveral Air Force Station, Fla.

The NASA-NOAA Partnership

In 1983, NASA signed an agreement with the NOAA to design and build a new generation of environmental satellites. These satellites would carry instruments designed to operate as never before, taking near continuous observations of Earth. NASA and NOAA have worked jointly to perfect, develop and complete the GOES program, begun in 1975 with the launch of the GOES-1 satellite. The two agencies have been actively engaged in a cooperative program ever since, and will continue the GOES series with the launch of the GOES-O satellite.

NOAA manages the overall GOES Program and establishes requirements, provides funding, distributes environmental data for the U.S., and determines the need for satellite replacement.

NASA teams with NOAA to acquire and manage the study, design and development of each of the GOES spacecraft. NASA's Goddard Space Flight Center (GSFC) in Greenbelt, Md., is responsible for the construction, integration and verification testing of the spacecraft, instruments and unique ground equipment. Working as a team, NOAA and NASA design, develop, install and integrate the ground system needed to acquire, process, and disseminate the data from the sensors on the GOES satellites.

NASA's GSFC is responsible for the procurement of the GOES satellites for NOAA including final testing in Florida and the initial on-orbit checkout. NOAA is responsible for satellite operation, data distribution and management of the program. Boeing Launch Systems will conduct the commercial launch of GOES-O with a Federal Aviation Administration (FAA) launch license. Boeing is responsible for the Delta IV launch vehicle processing, the integration of the GOES-O spacecraft with the Boeing Delta IV and the launch countdown activities.

Design and Operations

The GOES N Series will provide scientists with continuous, dependable, timely and high-quality observations of the Earth and its environment. The instruments on board the satellites measure the Earth's emitted and reflected radiation from which atmospheric temperatures, winds, moisture and cloud cover can be derived.

The GOES satellites operate in geosynchronous orbit 22,236 miles above the Earth and, because their orbital velocity matches the rotation of the Earth, they appear to remain stationary in the sky. The GOES satellites have a three-axis body stabilized spacecraft design which enables the satellite to "stare" at the Earth and provide images of clouds, relay data about the Earth's surface temperature and water vapor fields, and to continuously sound the atmosphere for vertical thermal and water vapor profiles.

The system provides long-range weather forecasting, ensuring that non-visible data, for any region of the Earth, is no more than six hours old. It serves the central and eastern Pacific Ocean; North, Central, and South America; and the central and western Atlantic Ocean. Pacific coverage includes Hawaii and the Gulf of Alaska. Two satellites accomplish this, GOES west located at 135 degrees west longitude and GOES East at 75 degrees west longitude. NOAA's Command and Data acquisition station located in Wallops, Va., supports the interface to both satellites. The NOAA Satellite Operations Control Center in Suitland, Md. provides spacecraft scheduling, health and safety monitoring and engineering analyses. Processed data are received at the National Weather Service's National Centers for Environmental Prediction in Camp Springs, Md., and NWS forecast offices across the U.S.

The GOES N Series has several capabilities not on previous GOES satellites. These capabilities include the Weather Facsimile service changing from an analog to a digital Low Rate Information Transmission format; expanded measurements for the space environment monitoring instruments; a new dedicated channel for the Emergency Managers Weather Information Network service; and most importantly, a more stable platform for supporting improved Imager, Sounder, and SXI instruments.

GOES-O will carry the government furnished ITT Space Systems Division built Imager and Sounder instruments to provide regular measurements of the Earth's atmosphere, cloud cover, ocean temperatures and land surfaces. An advanced attitude control system using star trackers and an optical bench onto which the Imager and Sounder are mounted will provide enhanced instrument-pointing ability. These enhancements improve image navigation and registration to better locate severe storms and other events important to NOAA. NASA's GSFC and the NOAA's National Environmental Satellite, Data and Information Service (NESDIS) have set a higher standard of accuracy for the GOES N Series, including data pixel location to approximately two kilometers from geosynchronous orbit of 22,300 miles above the Earth's surface.

GOES-O will also carry a government furnished Solar X-ray Imager (SXI) built by Lockheed Martin Advanced Technology Center in Palo Alto, Calif. Carried for the first time by GOES-M launched in 2001, the SXI will monitor solar weather conditions, including the dynamic environment of energetic particles, solar wind streams and coronal mass ejections emanating from the sun. This data will allow forecasters to issue alerts of "space weather" conditions that may interfere with ground and space systems.

Another instrument package onboard GOES-O will be the Space Environment Monitor (SEM). SEM consists of three instrument groups including an Energetic Particle Sensor package, two magnetometer sensors, and a Solar X-Ray Sensor with an Extreme Ultraviolet Sensor. The units will perform in situ measurements of the magnetic and particle environments as well as remote measurement of the integrated X-ray emission and the extreme ultraviolet spectra of the sun.

The Energetic Particle Sensor and the Solar X-Ray Sensor with an Extreme Ultraviolet Sensor were built by Assurance Technology Corporation, Carlisle, Mass., and the two magnetometers were built by Science Applications International Corporation, Columbia, Md.

The GOES system currently consists of GOES-12, operating as GOES East in the eastern part of the constellation at 75 degrees west longitude, and GOES-11, operating as GOES West at 135 degrees west longitude. GOES-13 is in an on-orbit storage mode nominally located at 105 West longitude.

In addition to relaying information about the Earth's climate and atmosphere, the GOES satellites provide instantaneous relay of distress signals from people, aircraft, or marine vessels to the search and rescue ground stations of the Search and Rescue Satellite Aided Tracking (SARSAT) System. A dedicated search and rescue transponder on board GOES is designed to detect emergency distress signals originating from Earth-based sources. These unique identification signals are normally combined with signals received by NOAA's Polar Operational Environmental Satellite system and relayed to a search and rescue ground terminal. The combined data are used to perform effective search and rescue operations.

GOES System in Weather Forecasting

The GOES system is a basic element of U.S. weather monitoring and forecast operations and is a key component of NOAA's National Weather Service modernization program. Spacecraft and ground-based systems work together to accomplish the GOES mission of providing weather imagery and quantitative sounding data that form a continuous and reliable stream of environmental information for weather forecasting and related services.

The GOES satellites provide weather imagery and atmospheric sounding information for improved weather services, particularly for the timely forecasting of life-and property-threatening severe storms. The GOES N Series will aid activities ranging from severe storm warnings to resource management and advances in science. GOES-O data will add to the global community of knowledge, embracing many civil and government environmental forecasting organizations that work to benefit people everywhere and help save lives.

Commercial weather groups, universities, the Department of Defense, NASA and the global research community also use GOES data products. Other users of these products can also be found in air and ground traffic control, ship navigation and agricultural sectors.

The GOES satellites are given a letter designation while under construction on the ground and are renamed with a numerical designation after successful launch and orbit-raising. The satellites are built in alphabetical order, but are not necessarily launched in this same order.

GOES-O will be renamed GOES-14 upon reaching orbit where it will be stored until needed.

GOES-N Series Enhancements Over Previous GOES

• An improved Image Navigation and Registration (INR) system will use star trackers to provide precision image navigation and registration information for use with the Imaging and Sounding data products. This will improve knowledge by at least 50 percent of exactly where severe weather events are located (3 km accuracy now becomes 1.5 km). A stable optical bench has been provided to isolate the thermal deformations of the spacecraft from the Imager and Sounder instruments.
  
  
• The power subsystem has been improved so that operations during eclipse periods can be sustained. Outages due to solar intrusion Keep Out Zones (KOZ) will also be minimized because thermal shields have been added to the secondary mirror structure elements for the Imager and Sounder instruments. Over 600 more images and sounding sequences should be accomplished per year. Spacecraft design reduces solar loading on the radiant cooler and patch (no solar sail) so lower detector temperatures should reduce noise.
  
  
• The Satellite design lifetime has been improved from 7 to 10 years, and the expected propellant lifetime has been increased to 14 years.
  
  
• The Space Environmental Monitoring instruments have been increased and there are expanded measurement capabilities for charged particles.
  
  
• A data product improvement has been developed for digital Low Rate Information Transmission (LRIT) for distribution of data Products that were previously distributed in an analog WEFAX format. The LRIT system permits the transmission of data products consistent with the World Meteorological Organization (WMO) and allows the distribution of more National Weather Service (NWS) information at a higher data rate.
  
  
• The Data Collection System (DCS) has been enhanced with the addition of 300 and 1200 bps Data Collection Platforms (DCPs) and a higher power satellite transponder so that more DCPs can use the link at the same time.
  
  
• A dedicated transponder is being provided to support the Emergency Manager's Weather Information Network (EMWIN) service.
  
  
• The communications services have been tailored to comply with modern national and international requirements.
  
  
• The command data rate has been increased to 2,000 bps, as compared to a data rate of 250 bps for the previous generation of GOES satellites. The telemetry data rate has been improved to provide data at either 4,000 or 1,000 bps, as compared to the 2,000 bps data rate on the previous generation.
  
  
• A new Solar X-Ray Imager (SXI) developed by the Lockheed Martin Advanced Technology Center. SXI improvements include:
  
  
  • A back illuminated CCD (no high voltage)
  • Increased dynamic range
    
    
  • Improved charge collection efficiency (charge spreading/blurring)
    
    
  • Image jitter correction using the High Accuracy sun Sensor
    
    
  • Automatic flare event detection and more sequence capability
    
    
  • Multiple image exposure and downlink capability each minute
    
    
  • Flexibility of programmable memory for imaging