SAN FRANCISCO — NASA and National Oceanic and Atmospheric Administration (NOAA) scientists preparing for the scheduled Oct. 27 launch of a satellite carrying the next generation of Earth observation sensors say those instruments are needed urgently to prevent gaps in the data records that reveal long-term global climate and weather patterns.
They remain concerned, however, that budget problems could delay the planned 2016 launch of the satellite’s twin, the first satellite in NOAA’s Joint Polar Satellite System.
NASA officials have delivered the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) to Vandenberg Air Force Base in California, where United Launch Alliance officials are preparing to launch it on a Delta 2 rocket. Since a series of technical troubles and ballooning costs led to the cancellation in 2010 of the NPOESS program, an effort to meet military and civil requirements with a single mission, NPP, which was once billed as an effort to reduce risk by testing new sensors, has become a critical piece of the U.S. government’s Earth observing campaign.
Many of the space-based sensors NASA and NOAA officials rely on to gather data on Earth and its atmosphere are well beyond their anticipated lifespan, leading to worries that the sensors will stop functioning before their replacements aboard NPP are fully operational, NASA and NOAA officials said. After NPP’s launch, government officials plan to spend approximately 18 months calibrating the spacecraft’s five instruments and validating the data they produce, said Andrew Carson, NPP program executive at NASA headquarters. As various data products become available, they will be fed into global climate models and made available to the public through NASA and NOAA websites, Carson added.
In spite of technical hurdles that plagued the NPP program and led to delays in its launch, which originally was slated for 2006, program managers said they are confident the spacecraft and its sensors will perform well in orbit. NPP will help scientists gather the same types of data captured by the current fleet of Earth observation satellites, allowing them to extend long-term records of changes in the Earth’s oceans, atmosphere, land, vegetation and ice. In addition, NPP’s new sensors will provide more detailed information than previous sensors could capture, including much higher resolution spectral imagery, said Scott Asbury, Joint Polar Satellite System program manager for Ball Aerospace &Technologies Corp. of Boulder, Colo. Ball Aerospace is the prime contractor for the NPP spacecraft, NPP’s Ozone Mapping and Profiler Suite (OMPS) and the first satellite in the Joint Polar Satellite System.
NOAA officials said two NPP instruments, the Cross-track Infrared Sounder (CrIS) built by ITT Geospatial Systems of Rochester, N.Y., and the Advanced Technology Microwave Sounder (ATMS) built by Northrop Grumman Electronic Systems of Linthicum, Md., will help the National Weather Service improve forecasting by providing detailed information on the distribution of heat and moisture in the atmosphere. “NPP will provide the satellite data we need to continue to improve forecasting,” said Mitch Goldberg, satellite meteorology and climatology division chief for NOAA’s National Environmental Satellite Data and Information Service.
The NPP mission was delayed due largely to the challenge of building five advanced space sensors. “The development of state-of-the-art sensors is always challenging,” Carson said.
That effort was made even more challenging by the makeup of the original NPOESS program. Before NPOESS was canceled in 2010, NASA’s NPP officials had to work through problems with NOAA, the Air Force Space and Missile Systems Center, Northrop Grumman and each instrument team. “If I needed to work on something, I had a pretty big loop to go around,” Carson said. “Since the reorganization, all the groups responsible for the NPP ground systems and flight systems live in the same building.”
Four NPP instruments include elements of currently deployed sensors and technology, but are based on new designs. Those instruments are: ATMS, CrIS, OMPS and the Visible Infrared Imager Radiometer Suite built by Raytheon Space and Airborne Systems of El Segundo, Calif. Only NPP’s Clouds and the Earth’s Radiant Energy System instrument from Northrop Grumman Aerospace Systems of Redondo Beach, Calif., is identical to an instrument currently flying on the Earth observing system spacecraft, Carson said.
While NASA and NOAA officials look forward to retrieving data from NPP, they said one satellite is not enough to ensure continuation of Earth observation data records. NPP’s successor, NOAA’s two-satellite Joint Polar Satellite System, also is needed to maintain those observations over the long term, Goldberg said.
NPP initially was designed to complete a five-year research mission. The spacecraft carries enough fuel to last seven years, said Scott Tennant, Ball Aerospace NPP program manager.
Launch of the first Joint Polar Satellite System satellite, currently set for 2016, remains essential, Goldberg said. Even that timeline is risky because once the Joint Polar Satellite System is launched, program officials will spend approximately one year verifying that the satellite and instruments are functioning properly before using its data in operational weather and climate models, he added.
That Joint Polar Satellite System schedule may be in jeopardy, however, because NOAA has struggled to obtain funding for the project, Asbury said. In early 2010, White House officials scrapped the NPOESS program and directed NOAA and Air Force officials to draft plans for separate polar-orbiting spacecraft to fulfill civil and military missions. NOAA’s plan relied on a large infusion of money in 2011. That money was not appropriated because Congress failed to pass spending bills for federal agencies and instead froze 2011 budgets at 2010 levels.
The first Joint Polar Satellite System satellite is expected to carry the same sensors as NPP with the exception of OMPS. The OMPS aboard NPP includes a set of instruments designed to peer directly down at the Earth to map the global distribution of ozone and to measure the vertical distribution of ozone in the stratosphere. OMPS also includes an instrument called a limb profiler to detect ozone in the lower stratosphere and the tropopause. The OMPS limb profiler is not scheduled to fly on the Joint Polar Satellite System. It was eliminated during the NPOESS program when officials were looking for ways to trim costs.
The Joint Polar Satellite System instruments are being modified, however, to extend their anticipated lifespan. “There were significant anomalies discovered during NPP instrument testing,” Carson said. Those anomalies will not prevent the instruments from functioning but could make them stop working earlier than planned. The Joint Polar Satellite System team has spent the last year and a half working to resolve those issues and extend the on-orbit life of the instruments, he added.
In contrast to NPP, Joint Polar Satellite System spacecraft will feature more advanced batteries, solar panels and a Ka-band antenna, Asbury said.
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