NOAA-N Prime is the latest in the Advanced TIROS-N (ATN) satellite series. All have been designed and built for the National Aeronautics and Space Administration (NASA) by Lockheed Martin since the first Television and Infrared Observational Satellite (TIROS) weather satellite launch in April 1960. NASA manages the spacecraft’s launch and the National Oceanic and Atmospheric Administration (NOAA) operates the satellite once in space. Over many years of service, the TIROS satellites have earned the reputation as the workhorses of the Civil Space Earth-imaging inventory.
A constellation consists of two POES satellites circling the planet in nearly north-south orbits. As the Earth rotates, the entire globe, one swath at a time rolls into view of the satellites’ instruments. The satellites provide measurements of reflected solar and radiated thermal energy from land, sea, clouds and the atmosphere in the visible, microwave and infrared spectrum, atmospheric soundings of temperature and humidity, measurements of global sea surface temperature, aerosol distribution data, ozone concentration data, soil moisture data, and measurements of orbital proton and electron flux. Additionally, POES satellites collect data from remote platforms, relay search and rescue data, and also provide direct broadcast of environmental data worldwide. Data from the spacecraft support a broad range of environmental monitoring applications including weather analysis and forecasting, climate research and prediction, ocean dynamics research, volcanic eruption monitoring and forest fire detection. Together these data comprise irreplaceable inputs to the numerical weather forecast model and are vital to medium and long-range forecasting. Separately or in combination, the data are utilized to produce sea-surface temperature maps, ice condition charts, vegetation maps and other forecasting and management tools.
The NOAA-N Prime spacecraft is 13.75 feet long by 6.2 feet in diameter, and weighs 3,130 pounds at liftoff. Its solar array has 180.6 square feet of surface area and generates 833 watts at a zero degree sun angle. The instruments onboard NOAA-N Prime were provided by NASA and NOAA, and include the Advanced Very High Resolution Radiometer (AVHRR/3), the High Resolution Infrared Radiation Sounder (HIRS/4), the Advanced Microwave Sounding Unit A (AMSU-A), the EUMETSAT-supplied Microwave Humidity Sounder (MHS), the Solar Backscatter Ultraviolet Spectral Radiometer/2 (SBUV/2), the Space Environment Monitor/2 (SEM/2) and the Advanced Data Collection System (DCS/2). In addition, NOAA-N Prime carries two search and rescue instruments, the Search and Rescue Repeater (SARR) and the Search and Rescue Processor (SARP) that are used internationally for locating ships, aircraft, and people in distress. The use of satellites in search and rescue has been instrumental in saving more than 24,500 lives since the inception of the Search and Rescue Satellite-Aided Tracking (SARSAT) system.
Spacecraft launch site processing at VAFB included end-to-end testing with the Satellite Operations Control Center in Suitland, Maryland, final spacecraft electrical testing and spacecraft inspections. The NOAA-N Prime spacecraft was launched from the Western Range Space Launch Complex-2 at Vandenberg Air Force Base, by a two-stage United Launch Alliance Delta II 7320-10C space launch vehicle. NASA‘s Goddard Space Flight Center, in Greenbelt, Maryland, is responsible for the procurement, development, launch services, and verification of the spacecraft, instruments, and unique ground equipment. Following spacecraft launch, Goddard is responsible for satellite health and safety during a comprehensive on-orbit verification period that lasts 45 days. Following satellite checkout, NASA turns operational control over to NOAA. NOAA will operate the satellite from the Satellite Operations Control Center along with the nation’s other environmental satellites.
The NOAA-N Prime satellite operates in a circular, near-polar orbit of 464 nautical miles above the Earth with an inclination angle of 98.73 degrees to the equator. Its orbital period — the time it takes to complete one orbit of the Earth — is approximately 102.14 minutes. The NOAA-N Prime orbit is Sun-synchronous, rotating eastward about the Earth’s polar axis 0.968 degrees each day, approximately the same rate and direction as the Earth’s average daily rotation about the sun. The rotation keeps the satellite in a constant position with reference to the sun for constant scene illumination throughout the year.
(Photos: NOAA-N Prime being built and tested, courtesy of Lockheed Martin)
