Data collected since May 31, 2003 by the Enhanced Thematic Mapper on Landsat 7 appear to contain anomalies. The problems are consistent with a failure of the Scan Line Corrector (SLC) component which compensates for affects on the image data due to forward motion of the satellite along its orbit path.
An SLC problem may or may not be repairable through manipulation from the ground; the orbit height and path would probably make it impractical for a Space Shuttle visit even if the shuttles were flying at this time.
Check the official Landsat web site for the most recent information.
More information: USGS Landsat Project update page