After battling instrument delays, NASA’s Npoess Preparatory Project (NPP) satellite has emerged from its last major prelaunch hurdle, a two-month-long thermal vacuum test, and is on track for an Oct. 25 liftoff from Vandenberg AFB, Calif.

The 13.5-ft. tall, 4,700-lb. satellite is based on Ball Aerospace’s BCP 2000 bus and includes five weather and remote sensing instruments. It is to be launched on a medium-lift United Launch Alliance Delta II 7920-10 configuration rocket into a Sun-synchronous “afternoon” orbit with an ascending node at 1:30 p.m. that is inclined 98.7 deg. and 824 km (512 mi.) high.

NPP Project Manager Ken Schwer of NASA’s Goddard Space Flight Center calls the mission a “new undertaking” for the space agency that combines improved weather forecasting with a continuation of data collections from global Earth observation missions that date back three decades.

Forecasts

In addition to contributing to the daily and 10-day weather forecasts that television watchers are accustomed to, NPP’s instrument suite will be able to study events such as volcanic eruptions and forest fires, says NPP Project Scientist James Gleason of Goddard. And NPP’s instruments will continue long-term studies of climatic changes, such as changes in stratospheric ozone distribution, that affect crops and human health. The instruments will measure the Earth’s radiative balance, a major issue in climate change, and provide thermal images of long-term weather phenomena such as persistent heat waves or storm systems that spawn destructive weather patterns.

The instrument suite includes the Advanced Technology Microwave (ATMS) sounder from Northrop Grumman that profiles atmospheric temperatures and moisture levels used for weather forecasting; the Visible Infrared Imaging Radiometer System (Viirs) from Raytheon that collects measurements of clouds, aerosols, ocean color, surface temperature, fires and the Earth’s albedo; the Ozone Mapping and Profiler Suite (OMPS) from Ball that continues data collection on Earth’s protective ozone layer; the Cross-track Infrared Sounder (CrIS) from ITT used in water vapor and temperature studies for long-term weather forecasting; and the Clouds and the Earth’s Radiant Energy System (Ceres) from NASA Langley Research Center used to measure Earth’s energy balance for global climate change studies.

Raytheon also developed NPP’s ground system. The satellite’s daily data dumps will be collected by Norway’s Svalbard ground station. The National Oceanic and Atmospheric Administration’s (NOAA) new meteorological weather center in Suitland, Md., will manage distribution of the data to civil agencies and university researchers.

NPP was always planned as pathfinder for the joint civil/military National Polar-Orbiting Environmental Satellite System (Npoess). Npoess was finally killed last year following years of delays, bureaucratic infighting and cost overruns associated with the technology challenges on the Viirs and CrIS instruments. NOAA and the Defense Department since have gone their separate ways.

Pathfinder Project

Now, NPP is a transitional platform for the next-generation of civil weather/climate satellites. Ball is to use its BCP bus for NOAA’s Joint Polar Satellite System.

Despite the collapse of the Npoess concept, both the Defense Department and NOAA will use data from NPP. The defense follow-on to the DMSP program, known as the Defense Weather Satellite System, is still being defined, but it will use Raytheon’s Viirs instrument.

The overall cost of the NPP program is $1.5 billion, a figure that includes costs buried in the Npoess program. The spacecraft, launch and operations budget is $864 million, according to Gleason. NPP is the last mission scheduled for the Delta II, and the direct launch cost is $90 million, he says.