The Capabilities of the Graphical Observation Scheduling System (GROSS) 
as Used by the ASTRO-2 Spacelab Mission

Shaun M. Phillips
shaun.phillips@msfc.nasa.gov
NASA/MSFC

Abstract
Scheduling astronomy observations for the ASTRO-1 mission proved to be an
intense, time-consuming task.  Numerous hours were spent during the mission
using a cumbersome process developed around a suite of programs to modify,
delete, and add observations to the existing schedule.  Two characteristics of
this process were limited data visibility and an awkward, outmoded user 
interface design. With the availability of graphics workstations the planners 
for ASTRO-2 saw the possibility of developing a new software tool that would
consolidate functionality from the original planning tools into a single
application providing a method for graphically building and maintaining
the observation schedule.  The new tool would replace several existing 
programs in the scheduling process, providing additional data visibility and 
new editing capabilities.  The development was a joint effort between a 
programmer and an experienced mission planner.  The programmer provided the 
new Graphical User Interface  (GUI), including the new editing capabilities 
and data representation; the mission planner contributed insight into the 
needs of the planners along with the needed expertise with the existing 
software.  This approach led to the creation of the Graphical Observation 
Scheduling System (GROSS) which binds a X-Windows/Motif GUI with existing 
orbital analysis software.

This paper elaborates on GROSS's functionality and editing capabilities.
Graphical and textual representations of the observation schedule provide
the information necessary to rapidly update the schedule.   The GROSS
environment consolidates the functionality of the previous process and 
supplies a GUI with many graphical editing capabilities, including click 
select, drag and drop, and resize for both individual activities and groups of 
activities.  The ease in editing provided by this approach greatly enhanced 
the efficiency of the ASTRO-2 mission planning process.