SWAS Spacecraft Pages
[ 1 ]
[ 2 ]
[ 3 ]
[ 4 ]
Observing in Earth orbit
The spacecraft will typically point the science instrument at 3-5 targets
per orbit. Target selection is constrained so that the solar arrays always
face within 15 degress of the Sun, except during eclipse. Each week an
observational timeline consisting of science targets and navigational
guide stars is generated at the SWAS Science Operations Center in Cambridge,
Massachusetts. Using this timeline, the spacecraft, without ground
intervention, will "nod" from an on-source target position to an off-source
instrument calibration position up to three degrees away in under 15 seconds.
This nodding occurs approximately every 40 seconds.
The observed data are stored in the spacecraft memory and are periodically
sent to a ground station. Within 24 hours of receipt at the ground station,
these data are received at the SWAS Science Operations Center. There, the
science content of the data is analyzed and new astronomical targets are
selected for observation.