  We report on extensive X-ray observations of the galactic superluminal motion
source GRS 1915+105 with the RXTE satellite over the last year. More than 130
RXTE pointings have been performed. GRS 1915+105 displays drastic X-ray
intensity variations on a variety of time scales ranging from sub-seconds to
days. In general, the intensity changes are accompanied by spectral changes on
the same timescale. Three types of bursts with typical durations between
10--100 sec have been identified which have drastically different spectral
properties and seem to occur in a fixed sequence. One of the most intense
bursts has a bolometric X-ray luminosity of about 5*10^39 erg/s during the 25
sec maximum-intensity part.
