RHESSI Pre-Launch Home Page - hardware, ground-system, and pre-launch information (note: this is a streamlined version of the SSL RHESSI Pre-Launch Site hosted at UCB)
Max Millennium - Program for coordinating solar flare research
Northrop Grumman (formerly Orbital Sciences) - they built the Pegasus launch vehicle
RHESSI Launched February 5, 2002 by a Pegasus XL rocket which was released from a L-1011 aircraft flying out of the Cape Canaveral AFS