NOAA Drops GOES-R Sensors

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, tellingprospective contractors the agency is not confident a brand new sensor suite can be developed on time and on budget, according to NOAA andindustry officials.

The Hyperspectral Environmental Suite (HES), formerly knownas the Advanced Baseline Sounder, would have taken detailed atmospheric measurements of temperature, pressure and humidity. U.S. weather forecastershad wanted the ability to feed this new data into computer models of theatmosphere to improve their ability to predict severe weather events,especially hurricanes. HES might also have included a coastal water imager tospot algae blooms that threaten commercial fisheries.

The sounder and the coastal imager "proved to be a littlebit too new" to develop for NOAA's next-generation Geostationary OperationalEnvironmental Satellite-R spacecraft, said Greg Withee, head of NOAA'ssatellite 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," Witheesaid.

The existing GOES weather satellites carry less sensitiveatmospheric sounders developed in the 1980s that profile the atmosphere in 19spectral bands compared to more than a thousand for the proposed HES hyperspectralsounder. The existing GOES satellites do not carry coastal water imagers. Witheesaid NOAA will replace the HES sounder on GOES-R with an updated version of theexisting sounder aboard GOES satellites.

However, other NOAA and NASA officials said the top-leveldecision to drop HES made it unclear whether the GOES-R satellites would carrya sounder at all. Withee disagreed saying, "We will have a sounder capability.... But something closer to continuity than the hyperspectral instrument wethought might have been possible when we started this."

NOAA will end the HES effort in December when formulationcontracts with three prospective contractors --- Ball Aerospace of Boulder,Colo.; ITT of Fort Wayne, Ind.; and BAE of Nashua, N.H. -- expire. Each companyhad received a $25 million contract via NASA to study HES concepts.

Industry officials were disappointed by the decision to dropthe sensor package. "We certainly think we had a good approach that was lowrisk," said Rajani Kuddapah, BAE's manager for its HES formulation study team.

Others said the decision is the latest in a series ofsatellite cuts that threaten U.S. leadership in space-based science. "It'sridiculous. It's gutting a major system and leaving the U.S. to fall behind theEuropeans in weather science," said one HES expert.

At the root of NOAA's decision was the agency's painfulexperience so far developing the National Polar-orbiting OperationalEnvironmental Satellite System (NPOESS), government and industry officialssaid. Before the decision was made to cut some instruments from NPOESS, itsprojected cost had nearly doubled to $13.8 billion due in part to problemsdeveloping another complicated sensor package, the Visible/Infrared ImagerRadiometer Suite.

NOAA managers feared that the complexity of HES might setthem on a similar course in the GOES-R effort, according to NOAA officials. OneNOAA official said the agency's tight budget and the NPOESS overruns, forced"tough decisions."

Withee said NPOESS "certainly brought us to attention interms of risk, and cost and complexity factors." He said he hopes research anddevelopment work would continue on HES, perhaps by NASA or the DefenseDepartment, 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 toextend capabilities that are currently found only on low Earth orbitingsatellites to its geosynchronous weather satellites. The most detailedatmospheric soundings currently come from the AIRS instrument on NASA's Aquaenvironmental satellite which follows a polar orbit. Coastal monitoring isperformed by another low Earth orbiter, the Sea-Viewing Wide Field of ViewSensor on Orbimage Corp's OrbView-2 satellite. HES was going to extend thosecapabilities to the GOES-R spacecraft.

Withee said the technical jump proved to be too great. "Justthe [spacecraft] geometry plagues you alone," he said. Infrared emissions andreflected light are weaker at geostationary orbits 35,000 kilometers aboveEarth than at low-Earth orbits of 800 kilometers. "Signal to noise is aproblem," he said. Sensors would require "bigger apertures" or openings tocapture more energy, he explained.

But modernizing the existing GOES sounder will not be easyeither. "There are some problems with that," said Dan Flanagan, NASA'sinstrument 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 wasdesigned for launch on a smaller launch vehicle with less vibration. "There arequestions about whether it would even survive launch," Flanagan said.