The U.S. National Oceanic and Atmospheric Administration (NOAA) has decided to drop plans for the development of a new instrument package for the next generation of geostationary weather satellites, telling prospective contractors the agency is not confident a brand new sensor suite can be developed on time and on budget, according to NOAA and industry officials.
The Hyperspectral Environmental Suite (HES), formerly known as the Advanced Baseline Sounder, would have taken detailed atmospheric measurements of temperature, pressure and humidity. U.S. weather forecasters had wanted the ability to feed this new data into computer models of the atmosphere to improve their ability to predict severe weather events, especially hurricanes. HES might also have included a coastal water imager to spot algae blooms that threaten commercial fisheries.
The sounder and the coastal imager "proved to be a little bit too new" to develop for NOAA's next-generation Geostationary Operational Environmental Satellite-R spacecraft, said Greg Withee, head of NOAA's satellite and information services. "They need to be built and tested by an R & D [research and development] space agency like NASA or the Air Force or [Defense Department] components before we would actually fly them," Withee said.
The existing GOES weather satellites carry less sensitive atmospheric sounders developed in the 1980s that profile the atmosphere in 19 spectral bands compared to more than a thousand for the proposed HES hyperspectral sounder. The existing GOES satellites do not carry coastal water imagers. Withee said NOAA will replace the HES sounder on GOES-R with an updated version of the existing sounder aboard GOES satellites.
However, other NOAA and NASA officials said the top-level decision to drop HES made it unclear whether the GOES-R satellites would carry a sounder at all. Withee disagreed saying, "We will have a sounder capability. ... But something closer to continuity than the hyperspectral instrument we thought might have been possible when we started this."
NOAA will end the HES effort in December when formulation contracts with three prospective contractors --- Ball Aerospace of Boulder, Colo.; ITT of Fort Wayne, Ind.; and BAE of Nashua, N.H. -- expire. Each company had received a $25 million contract via NASA to study HES concepts.
Industry officials were disappointed by the decision to drop the sensor package. "We certainly think we had a good approach that was low risk," said Rajani Kuddapah, BAE's manager for its HES formulation study team.
Others said the decision is the latest in a series of satellite cuts that threaten U.S. leadership in space-based science. "It's ridiculous. It's gutting a major system and leaving the U.S. to fall behind the Europeans in weather science," said one HES expert.
At the root of NOAA's decision was the agency's painful experience so far developing the National Polar-orbiting Operational Environmental Satellite System (NPOESS), government and industry officials said. Before the decision was made to cut some instruments from NPOESS, its projected cost had nearly doubled to $13.8 billion due in part to problems developing another complicated sensor package, the Visible/Infrared Imager Radiometer Suite.
NOAA managers feared that the complexity of HES might set them on a similar course in the GOES-R effort, according to NOAA officials. One NOAA official said the agency's tight budget and the NPOESS overruns, forced "tough decisions."
Withee said NPOESS "certainly brought us to attention in terms of risk, and cost and complexity factors." He said he hopes research and development work would continue on HES, perhaps by NASA or the Defense Department, so that a version might eventually be ready for launch on GOES satellites.
For now, the HES decision marks the end of NOAA's plan to extend capabilities that are currently found only on low Earth orbiting satellites to its geosynchronous weather satellites. The most detailed atmospheric soundings currently come from the AIRS instrument on NASA's Aqua environmental satellite which follows a polar orbit. Coastal monitoring is performed by another low Earth orbiter, the Sea-Viewing Wide Field of View Sensor on Orbimage Corp's OrbView-2 satellite. HES was going to extend those capabilities to the GOES-R spacecraft.
Withee said the technical jump proved to be too great. "Just the [spacecraft] geometry plagues you alone," he said. Infrared emissions and reflected light are weaker at geostationary orbits 35,000 kilometers above Earth than at low-Earth orbits of 800 kilometers. "Signal to noise is a problem," he said. Sensors would require "bigger apertures" or openings to capture more energy, he explained.
But modernizing the existing GOES sounder will not be easy either. "There are some problems with that," said Dan Flanagan, NASA's instrument manager for GOES-R at Goddard Spaceflight Center in Greenbelt, Md. The existing sounder would not fit on GOES-R as it is currently designed, and it was designed for launch on a smaller launch vehicle with less vibration. "There are questions about whether it would even survive launch," Flanagan said.