Title:  Fast Spectral Variability in GRS 1915+105

Object: GRS 1915+105
Exposure: 100 ks
Lead scientist: Neilsen
[ ] Primary or [ X] Backup
Constraints (none/easy/average) NONE (prefer uninterrupted if possible  
but not required)
[ ] TOO?

Brief description: Over the last 10 years, HETG observations of the  
bright, variable microquasar GRS 1915+105 have repeatedly provided  
major advances in our understanding of accretion and ejection  
processes in X-ray binaries (in terms of accretion disk behavior, jet  
physics, and accretion disk winds). While this important source  
remains in outburst, we ask for an additional 100 ks of HETG time to  
continue making new discoveries about black hole accretion physics. We  
do not seek a ToO because GRS 1915+105 is very reliably interesting,  
regardless of its behavior.