The National Polar-orbiting Operational Environmental Satellite System (NPOESS)

Over the last decade, the U.S. government has been merging the nation's military and civil operational meteorological satellite programs into a single, integrated, end-to-end satellite system capable of satisfying both civil and national security requirements for space-based remotely sensed environmental data. Convergence of these programs is the most significant change in U.S. operational remote sensing since the launching of the first weather satellite in April 1960, and marks a significant departure from eight previous attempts over the last 25 years to combine these separate programs.

For the first time, the U.S. government is taking an integrated approach to identifying and meeting the operational satellite needs of both the civil and national security communities. The joint program formed in 1994 by a Presidential Decision Directive is the National Polar-orbiting Operational Environmental Satellite System. The NPOESS program has provided more than $670 million in savings through Fiscal Year 2001, and it is expected to save $1.6 billion in acquisition and operational costs through the System Life Cycle of the program compared to the costs of continuing the previously planned upgrades to the separate satellite systems within the Department of Defense and the Department of Commerce.

The U.S. government has traditionally maintained two operational weather satellite systems, each with over a 40-year heritage of successful service: the National Oceanic and Atmospheric Administration’s Polar-orbiting Operational Environmental Satellite (POES), and DoD’s Defense Meteorological Satellite Program (DMSP). The POES and DMSP spacecraft have revolutionized the way in which we observe and predict the weather. With the development of NPOESS, we will evolve and expand our capabilities to observe, assess and predict the total Earth system—atmosphere, ocean, land and the space environment.

Recent changes in world political events and declining agency budgets prompted a re-examination of combining the two systems. In 1992, a National Space Council study recommended convergence of the two separate weather satellite systems. Following further recommendations contained in the National Performance Review and influenced by increased Congressional interest, NOAA, DoD and the National Aeronautics and Space Administration initiated studies in 1993 to determine how to converge the two systems. The completed study revealed that a converged system could reduce agency duplication and bureaucracy, substantially reduce costs, and satisfy both civil and military requirements for operational, space-based, remotely sensed environmental data. This tri-agency study formed the basis for the development of the Implementation Plan for a Converged Polar-orbiting Environmental Satellite System that was issued in conjunction with the 1994 Presidential Decision Directive.

On October 3, 1994, NOAA, DoD, and NASA created an Integrated Program Office to develop, manage, acquire, and operate NPOESS. The IPO is located organizationally within NOAA and is headed by a System Program Director who is responsible to the NPOESS Executive Committee. This Committee, which includes senior representatives from the three agencies, serves as a board of directors to ensure that the overall program plans meet the needs of the three participating agencies. Interagency efforts with NPOESS will result in the continuation of and improvements to the critical satellite measurements necessary to provide timely and accurate forecasts and warnings to the public and to conduct worldwide military operations.

The Integrated Program Office concept provides each of the participating agencies with lead responsibility for one of three primary functional areas. NOAA has overall responsibility for the converged system and is also responsible for satellite operations. NOAA is also the primary interface with the international and civil user communities. DoD is responsible for supporting the IPO for major systems acquisitions, including launch support. NASA has a primary responsibility for facilitating the development and incorporation of new cost-effective technologies into the converged system. Although each agency provides certain key personnel in their lead role, tri-agency work teams staff each functional division to maintain the integrated approach.

Early Convergence
As an early step in the convergence process and the first tangible result of the NPOESS effort, Satellite Control Authority for the existing DMSP satellites was transferred in May 1998 from the U.S. Air Force Space Command to the NPOESS Integrated Program Office. The command, control and communications functions for the DMSP satellites have been combined with the control for NOAA's POES satellites at NOAA’s Satellite Operations Control Center in Suitland, Md. The DMSP satellites are being “flown” by civilian personnel at the SOCC. This is the first time in the 40-year history of this DoD program that the DMSP satellites have not been flown by U.S. Air Force personnel. The transfer of DMSP operations was accomplished in less than four years, on budget, and allowed the USAF to close DMSP satellite operations control facilities at Fairchild Air Force Base, Washington, and Offutt Air Force Base, Nebraska, three months ahead of schedule. A backup satellite operations center, manned by USAF Reserve personnel, was established at Schriever Air Force Base, Colorado. This interagency team effort provided the U.S. government with new, state-of-the-technology satellite control equipment and has resulted in significant budgetary savings, as well as uninterrupted service to the end users.

On December 12, 1999, the U.S. Air Force successfully launched the first of the next block of military weather satellites, the DMSP Block 5D-3, aboard a Titan II rocket, from Vandenberg Air Force Base, California. A NOAA/USAF/contractor launch team at NOAA’s SOCC supported the launch of a DMSP satellite for the first time ever. DMSP, operated by NOAA, is used for strategic and tactical weather prediction to aid the U.S. military in planning operations at sea, on land and in the air. Equipped with a sophisticated sensor suite that can create visible and infrared images of cloud cover, the satellite collects specialized atmospheric and oceanic information, as well as data about the sun's effects on the Earth in all weather conditions. Control of the new DMSP spacecraft was transferred on December 23, 1999, to the NPOESS Integrated Program Office. A joint launch team operating from NOAA’s SOCC will support the next launch of a DMSP satellite in October 2002.

Later this decade, launch and operations of the remaining POES and DMSP spacecraft will cease. Instead, the converged NPOESS spacecraft will be launched beginning in early 2009, after NOAA and the USAF have both exhausted the satellites currently in the “pipeline.” Full operational capability of the NPOESS constellation is expected by 2013. Satellite operations for NPOESS will be conducted from Mission Management Centers located at NOAA’s SOCC and at Schriever Air Force Base.

Development of the Converged Polar-Orbiting Satellite System
The NPOESS development and acquisition plan is designed to make best use of production and existing POES and DMSP assets, to reduce risk on critical sensor payloads and algorithms, and to leverage civil, governmental, and international payload and spacecraft developments. The planned evolution from the current POES and DMSP programs to NPOESS will take place over several years. Currently the U.S. is operating two POES and two DMSP primary satellites. With the launch in 2005 of the first polar-orbiting Metop satellite by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), there will be one POES, one Metop, and two DMSP satellites in four orbital planes. The first converged NPOESS satellite must be available for launch by 2008 to back-up the last launches of the current DMSP and POES satellites.

The agencies participating in the NPOESS development have agreed upon a fully defined set of integrated operational requirements that will meet the needs of the nation's civil and military users for satellite data. The established requirements for 55 atmospheric, oceanic, terrestrial, climatic and solar-geophysical data products are guiding the development of advanced technology visible, infrared, and microwave imagers and sounders that will provide enhanced capabilities to users and improve the accuracy and timeliness of observations. The data that will be collected by the NPOESS suite of instruments fully encompass the Earth science disciplines. When operational, NPOESS will truly be an “environmental observing system,” not just an advanced “weather” satellite.

In 1997, the IPO initiated a robust sensor risk reduction effort that has been focused on early development of the critical sensor suites and algorithms necessary to support NPOESS. The IPO initially awarded competitive contracts to multiple industry partners for preliminary design concepts of these instruments. Depending upon the complexity of the instruments and the maturity of the competing designs, the IPO began awarding single contracts to industry for the follow-on development and fabrication of the instruments approximately two years into the sensor risk reduction effort.

Contracts were awarded to Ball Aerospace and Technologies Corporation of Boulder, Colo., in 1999 for the development and fabrication of an Ozone Mapping and Profiler Suite instrument to improve the accuracy of Earth's ozone measurements; to ITT Industries, ITT Aerospace/Communications Division of Ft. Wayne, Ind., in 2000 for the development and fabrication of a Cross-track Infrared Sounder to provide high spectral resolution measurements of the vertical distribution of temperature, moisture and pressure in the atmosphere; and to Saab Ericsson Space of Göteborg, Sweden in 1997 for the development and fabrication of a Global Positioning System Occultation Sensor to make primary measurements of electron density and profiles in the ionosphere and secondary measurements of tropospheric temperature and humidity profiles.

In 2000, a contract was awarded to Raytheon's Santa Barbara Remote Sensing Group of Santa Barbara, Calif., for the development and fabrication of a Visible/Infrared Imager Radiometer Suite to provide accurate, high spatial resolution measurements of atmospheric, oceanic and terrestrial parameters for use in short-term weather nowcasting and forecasting and in other oceanic and terrestrial applications. In 2001, a contract was awarded to Boeing Satellite Systems, Inc. of El Segundo, Calif., for the development and fabrication of a Conical-scanning Microwave Imager Sounder to deliver all-weather microwave measurements of ocean surface wind speed and direction, sea surface temperature, rain rate, the amount of water in clouds, soil moisture and atmospheric temperature and moisture profiles.

These critical NPOESS instruments will deliver higher resolution and more accurate atmospheric, oceanographic, terrestrial and solar-geophysical data to support improved accuracy in short-term weather forecasts and warnings and severe storm warnings, as well as serve the data continuity requirements of the climate community for improved climate prediction and assessment and environmental monitoring. Final design, prototype development and fabrication of these instruments are well underway, with delivery of the first flight units for three sensors scheduled for late 2004.

In 2000, the IPO initiated a Program Definition and Risk Reduction program to define the requirements for the NPOESS total system architecture, including space, ground processing, and command, control and communications components, as well as to develop specifications for sensor/spacecraft integration. Lockheed Martin Missiles and Space of Sunnyvale, Calif., and TRW Space and Electronics Group of Redondo Beach, Calif., have been working under contract to the IPO on this phase of the NPOESS development program. The IPO will conclude the PDRR phase by September 2002 with the award of a single prime contract for Shared System Performance Responsibility to accomplish the Acquisitions & Operations.

During A&O, the contractor will manage completion of development of the NPOESS sensor payloads; provide two satellite sensors (VIIRS and CrIS) and integration support to the joint IPO/NASA NPOESS Preparatory Project (NPP) mission; develop, deliver and support the Command, Control and Communication (C3) and Interface Data Processing (IDP) segments; develop, integrate, and deploy the NPOESS space segment; integrate the NPOESS space segment with the launch support segment; develop and deploy the NPOESS support system; develop, deploy and support the software portion of the NPOESS field terminals; conduct a progressive integration, test and acceptance program; and operate and maintain NPOESS through Initial Operational Capability (IOC), including on-going calibration and validation activities. During the later Production phase, the contractor will integrate and deploy additional satellites as needed through the program life. The A&O contractor will have responsibility for integrating, deploying, and operating NPOESS satellites in three polar orbits (0530, 0930, and 1330 Equatorial crossing times) to meet the tri-agency requirements for NPOESS over the 10-year operational life of the program (2008-2018).

Early Flight Testing
As a critical part of the NPOESS development strategy, early flight-testing of instruments is planned to reduce development risk and to demonstrate and validate global imaging and sounding instruments, algorithms and pre-operational ground systems prior to the first NPOESS flight in 2009. The joint DoD/IPO WindSat/Coriolis mission will be launched in early 2003 to provide a space-based test and demonstration of passive microwave polarimetric techniques to derive measurements of ocean surface wind speed and direction. This three-year mission will continue the development of improved microwave measurement capabilities from the Special Sensor Microwave Imager and Sounder on DMSP to CMIS on NPOESS.

The NPOESS Preparatory Project, a joint IPO/NASA mission that will be launched in early 2006, will carry three of the critical NPOESS sensors (VIIRS, CrIS, and the NASA-developed Advanced Technology Microwave Sounder-ATMS) to provide on-orbit testing and validation of sensors, algorithms and ground-based operations and data processing systems while the current operational POES and DMSP and the NASA Earth Observing System Terra and Aqua research satellite systems are still in place. In addition to the ATMS, NASA is providing the NPP spacecraft that is being built by Ball Aerospace and Technologies Corporation, as well as the launch vehicle. The IPO is responsible for the VIIRS and CrIS instruments, NPP spacecraft operations and ground processing systems.

The NPP mission will provide operational agencies early access to the next generation of operational sensors, thereby greatly reducing the risks incurred during the transition from POES and DMSP to NPOESS. NPP will demonstrate the utility of the improved imaging and radiometric data in short-term weather “nowcasting” and forecasting and in other oceanic and terrestrial applications, such as harmful algal blooms, volcanic ash and wildfire detection. In addition to serving as a valuable risk reduction and prototyping mission for the IPO and users of NPOESS data, NPP will provide continuity of the calibrated, validated and geo-located NASA EOS Terra and Aqua systematic global imaging and sounding observations for NASA Earth Science research. With a five-year design lifetime, NPP will provide data past the planned lifetime of EOS Terra and Aqua and provide a “bridge” to the operational NPOESS mission. NPP will extend the series of key measurements in support of long-term monitoring of climate change and of global biological productivity.

The current operational concept for NPOESS consists of a constellation of spacecraft flying at an altitude of 833 km in three sun-synchronous (98.7 degree inclination) orbital planes with equatorial nodal crossing times of 0530, 0930, and 1330 local solar time, respectively. The early morning (0530) and afternoon (1330) spacecraft will carry full complements of instruments. The mid-morning (0930) NPOESS-“Lite” spacecraft will carry a reduced complement of instruments, including VIIRS and CMIS that are required to meet the stringent U.S. horizontal resolution and data refresh requirements for all-weather imaging in this orbit. The IPO plans to continue cooperation with EUMETSAT for a Joint Polar System. While in a transition phase to a future international polar satellite program, the NPOESS-“Lite” spacecraft will complement EUMETSAT’s third Metop satellite flying in the 0930 orbit.

To meet U.S. requirements for the 55 geophysical parameters, the NPOESS Command, Control and Communications system will deliver global Stored Mission Data to four U.S. Operational Processing Centers for processing and distribution. NPOESS spacecraft will also simultaneously broadcast two types of real-time data to suitably equipped ground stations. The NPOESS High Rate Data broadcast will be a complete, full resolution data set containing all sensor data and auxiliary data necessary to generate all NPOESS Environmental Data Records and is intended to support users at regional hubs. The NPOESS Low Rate Data broadcast will be a subset of the full set of EDRs and is intended for U.S. and worldwide users of field terminals (land and ship-based, fixed and mobile environmental data receivers operated by DoD users and surface receivers operated by other U.S. government agencies, worldwide weather services and other international users). Future communications capabilities may allow other-than-direct data transmission to follow-on field terminal systems.

NPOESS will provide significantly improved operational capabilities and benefits to satisfy the nation’s critical civil and national security requirements for space-based, remotely sensed environmental data. The advanced technology visible, infrared and microwave imagers and sounders that are being developed for NPOESS will deliver higher spatial and temporal resolution atmospheric, oceanic, terrestrial and solar-geophysical data enabling more accurate short-term weather forecasts and severe storm warnings, as well as serving the data continuity requirements for improved global climate change assessment and prediction. The improved accuracy in atmospheric temperature and humidity soundings from these instruments, in combination with other observations expected to become available over the next ten years, will enable the current 3- to 5-day short-term weather forecasts to be improved from 70 to 80 percent to better than 90 percent and to be extended to 5 to 7 days with 80-percent accuracy.

NPOESS will also provide improved measurements and information about the space environment necessary to ensure reliable and safe operations of space-based and ground-based systems, as well as continue to provide surface data collection and search and rescue capabilities. The IPO, in cooperation with the POES and DMSP program offices, is also studying additional potential cost effective approaches to maximize user satisfaction during the transition to NPOESS, while guaranteeing continued uninterrupted satellite data services.

From a resource perspective, the convergence of these satellite systems has yielded more than $670 million in savings through Fiscal Year 2001. Additional savings will accrue throughout the life of the system. By combining the now separate civil and military missions into NPOESS, the total number of satellites required and their associated ground systems will be significantly reduced. Increased system performance capability over today's systems is also expected from the synergistic effects of combining the separate polar satellite programs, and through expeditious insertion of new technology.

Savings will accrue in the following primary areas

Development — Only one system development effort is required for NPOESS. Continuation of the DMSP and POES programs would have required two parallel satellite development efforts to design two new, independent systems (spacecraft, instruments, and ground command and control systems).

Number of satellites and launches — The previously planned follow-on programs to the current DMSP and POES programs were expected to require three U.S. satellites, each with a design life of about four years, in orbit at any given time to fulfill the separate operational missions over their operational lifetimes. As a result, eleven satellites were planned to be procured and launched. The NPOESS spacecraft are being designed for a nominal five to six years of on-orbit operations. Although the fully operational NPOESS constellation will also require satellites in three orbits, the expected increased longevity of the NPOESS spacecraft will require only six satellites over the comparable 10-year operational life of the program.

Ground Systems/Operations — “Early Convergence” of the DMSP and POES satellite operations occurred in 1998, by consolidating DMSP and POES operations at the NOAA SOCC in Suitland, Md., and establishing a backup satellite operations control facility at Schriever Air Force Base, Colorado. Relocation of DMSP operations to the same site as other NOAA satellite operations and closure of two DMSP satellite control facilities resulted in combined savings in FY 1996-FY 1998 of about $50 million. Additional annual savings of about $8 million in personnel costs have been realized through the reduction from nearly 250 USAF operators at the former DMSP operations centers to only about 50 civilian NOAA operators at the Suitland SOCC. Further cost savings will be realized as the existing DMSP and POES programs are more fully integrated during the transition to NPOESS.

Additional savings will also accrue throughout other phases of the program

European participation — The NPOESS program will continue and build upon international cooperation with the European Organisation for the Exploitation of Meteorological Satellites. The POES program plans to provide instruments for flight on the EUMETSAT Meteorological Observation Satellite Series (Metop-1, -2, -3) satellites and receive European instrumentation for flight on NOAA satellites as part of the Initial Joint Polar System. During the transition to a future international polar satellite program, the NPOESS-“Lite” spacecraft and EUMETSAT’s Metop-3 satellite will occupy the mid-morning orbit (0930) and provide complementary data from the advanced sounding and imaging instruments on each satellite. Use of data from EUMETSAT’s Metop satellite will increase the global coverage and refresh rate of the U.S. polar satellite system. In addition, the European meteorological community will receive valuable data from instruments on both the Metop and NPOESS series of satellites. Shared operation of NPOESS ground systems with EUMETSAT is also under consideration.

Capability — By combining the DMSP and POES programs, not only will the capabilities of the current systems be preserved, but the Integrated Program Office will be able to increase the total satellite system performance through synergism.

Management — NPOESS is managed under the tri-agency IPO. The government/contractor program management staff required to execute the program is approximately half of what would be required to manage two separate development offices under the old DMSP and POES programs. Furthermore, the IPO System Program Director can influence the utilization of existing DMSP and POES assets to achieve additional cost savings.

These approaches also include the optimization of the NPOESS acquisition to make best use of production and on-orbit assets, to reduce risk on critical sensor payloads and algorithms, and to provide satisfaction to users while better leveraging civil, governmental and international payload and spacecraft developments. The development of NPOESS represents a significant and exciting change in the way the United States acquires, manages and operates environmental satellites. The agencies and industrial partners who are designing and building NPOESS are well on their way to creating a system that will cost less, be more responsive to user demands and provide sustained, space-based measurements to better support joint program requirements. Data from NPOESS will improve the accuracy of weather forecasts to better support operational decisions, allow us to anticipate the weather so the war-fighter can exploit it and ensure that our humanitarian relief and rescue efforts are more responsive. The U.S. and international communities will continue to benefit from this new way of doing business well into the 21st century.

For more information contact Patricia Viets, NOAA NESDIS Public Affairs, Suitland, Md., (301) 457-5005.

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Updated August 2002