Adaptive, Ground-Compatible Flight Software System
L. Petro, G. Miller, T. Krueger, R. Doxsey, V. Balzano, J. Barshinger
(STScI), N. Jedrich, M. Paulkovich, L. Dunham, J. Borden (Jackson &
Tull, Inc.) 

The development and operations budget for the Next Generation Space
Telescope (NGST) will be severely constrained in keeping with the
"faster, cheaper, better" philosophy.  A study by three government and
industry teams has concluded that the development and maintenance of
flight software is a significant component of the life-cycle cost of a
mission (Next Generation Space Telescope, ed. H.S. Stockman, 1997.) In
the past this cost has been driven by several factors: the limited
processing speed and memory of flight qualified onboard computers,
non-standard operating systems, and custom command and data handling
(C&DH) subsystem interfaces.  These costs can be reduced through the
application of advanced technology and an improved operating paradigm.
  We are engaged in a project, supported by a NASA STTR Phase I grant,
to design a Common Integrated Processor Environment (CIPE) flight
system model with an adaptive scheduler/executive (ASE). The CIPE will
utilize commercial operating systems, software, and network
technologies to provide commonality between ground and deployed
systems, enabling low cost development and migration of flight
software to orbit. The ASE will utilize time-independent, event-driven
commands to flexibly respond to activity failures.   Eventual
development will be simplified by employing an onboard file management
system.  Operation will be simplified by using a network packet
protocol for exchange of data between the onboard computer and
peripheral devices and processors.  A common application environment
will be used to expedite  the migration of processes from the ground
system to the flight system.  The preliminary results of this project
will be presented.