Mission description

GOES 12 is an American geosynchronous weather satellite that was launched by an Atlas 2A rocket from Cape Canaveral at 07:23 UT on 23 July 2001. The spacecraft carries an IR imager, a "sounder", and an X-ray imager. The IR imager is a Cassegrain telescope covering five wavelength channels, 0.55-0.75, 3.80-4.00, 6.50-7.00, 10.20-11.20, and 11.50-12.50 microns. It can provide images covering 3,000 km x 3,000 km every 41 seconds, by scanning the area in 16 square kilometer sections. The "sounder" is to provide vertical distribution of temperature, moisture and ozone, by passive monitoring in 18 depth-dependent wavelengths. (Long wave IR: 14.71, 14.37, 14.06, 13.64, 13.37, 12.66, and 12.02 microns. Medium wave IR: 11.03, 9.71, 7.43, 7.02, and 6.51 microns. Short wave IR: 4.57, 4.52, 4.45, 4.13, 3.98, and 3.74 microns. There is also another band at visible wavelength 0.7 microns, just to provide pictures of cloud tops.) The sounder covers an area of 3,000 km x 3,000 km in about 42 minutes. Another instrument package named SEM (Space Environment Monitor) monitors the energetic electrons and protons in the magnetosphere and the x-rays from the Sun. The above three have been carried on the earlier GOES missions, but GOES 12 carries also an X-ray imager providing an X-ray (about 0.1-1.0 nm wavelength) picture of the solar disk.

Detector description

The implemented data set consists of averaged SEM measurements.

The Space Environment Monitor (SEM) System on the GOES-NEXT series of geostationary meteorological satellites (GOES I through GOES M) is designed to provide direct real-time measurement of solar activity. The SEM consists of

1. a Magnetic Field Sensor;
2. a Solar X-Ray Sensor; and,
3. an Energetic Particle Sensor (EPS)/High Energy Proton and Alpha Detector (HEPAD).

The Magnetic Field Sensor (MFS) allows for the real-time determination of the magnitude and orientation of the magnetic field. Data is telemetered twice a second for magnetic fields having a magnitude of +/- 1000 nanotesla (nT).

The Solar X-Ray Sensor permits real-time determination of the solar x-ray emission in two spectral bands: 0.5-5 Å and 1-8 Å.

The EPS makes flux measurements of protons in the 0.8 to 500 MeV range. The HEPAD monitors protons in four energy ranges above 350 MeV and alpha particles in two energy ranges above 640 MeV/nucleon.