Communication With Earth
In normal operation the spacecraft transmits a continuous 200 kbit/s data stream of photographs and other measurements via the NASA Deep Space Network of ground stations. SOHO's data about solar activity are used to predict solar flares, so electrical grids and satellites can be protected from their damaging effects (mainly, solar flares may produce geomagnetic storms, which in turn produce geomagnetically induced current creating black-outs, etc.).
In 2003 ESA reported the failure of the antenna Y-axis stepper motor, necessary for pointing the high gain antenna and allowing the downlink of high rate data. At the time, it was thought that the antenna anomaly might cause two to three week data-blackouts every three months. However, ESA and NASA engineers managed to use SOHO's low gain antennas together with the larger 34 and 70 meter DSN ground stations and judicious use of SOHO's Solid State Recorder (SSR) to prevent total data loss, with only a slightly reduced data flow every three months.
Read more about this topic: Solar And Heliospheric Observatory
Famous quotes containing the words communication with and/or earth:
“The present war having so long cut off all communication with Great-Britain, we are not able to make a fair estimate of the state of science in that country. The spirit in which she wages war is the only sample before our eyes, and that does not seem the legitimate offspring either of science or of civilization.”
—Thomas Jefferson (1743–1826)
“It is true, there are the innocent pleasures of country life, and it is sometimes pleasant to make the earth yield her increase, and gather the fruits in their season; but the heroic spirit will not fail to dream of remoter retirements and more rugged paths. It will have its garden-plots and its parterres elsewhere than on the earth, and gather nuts and berries by the way for its subsistence, or orchard fruits with such heedlessness as berries.”
—Henry David Thoreau (1817–1862)