The Domain of ESP

This table compares the domain of ESP to other scheduling domains. The domain of ESP is loosely called "space activity scheduling".

Space Activity Scheduling	Job-Shop Scheduling
Size
Many scarce resources Many bottlenecks Many activities with repetitions	Few resources Few bottlenecks Few activities with many repetitions
Oversubscription
Not all desired science in the schedule when the mission is launched Healthy to have a shopping list of things to do if equipment fails or the mission is extended	All orders must be filled
Scheduling Determinators
Some partial critical paths (critical threads) Many independent tasks which are related only by virtue of sharing common resources	Usually critical-path determined
Schedule Loading Strategy
Front loading desired because it maximizes- opportunities to - repair malfunctioning equipment correct never-tried- in-space procedures add repetitions science return if the mission is shortened	Just-in-time is popular approach minimizes inventory cost minimizes product handling
Time Window / Opportunity Constraints
Many activities must be done only during certain times; e.g., only over North Atlantic	Time windows usually not a constraint
Scheduling Objectives
Maximize amount of science collected Resource leveling has little or no value Schedule around bottlenecks	Maximize profits Minimize overtime (level peak resource usage) Determine equipment to purchase or number of workers to hire (bottleneck elimination)
There are several other scheduling domains: Airline scheduling where the objective is to position flight crews and planes while minimizing ferry flights. Planetary flyby missions where the objective is to sequence a set of observations. Earth-orbiting astronomy platforms where the objective is to minimize telescope slew time.