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AIAA RS6-2008-1003

6th Responsive Space Conference Los Angeles, CA, April 28–May 1, 2008

ORS Mission Utility and Measures of Effectiveness
Unclassified Crown Copyright/MOD

James R. Wertz

April 29, 2008
4740 West 147th Street Hawthorne, CA 90250 Phone: (310) 219-2700 FAX: 310-219-2710 E-mail: web:


• • • • • •

Introduction toMission Utility and Measures of Effectiveness (MoEs) The Need for Mission Utility Analysis MoEs that Don’t Work MoEs for ORS Quantifying MoEs Example: The Hawaii Disaster


Introduction to Mission Utility

A performance assessment measures how well the system meets its quantitative goals and requirements
– Engineering oriented

Mission Utility is the quantitative expression of howwell the system meets its overall mission objectives
– User oriented — what will it do for the warfighter or the victim? Provide feedback for the mission design Provide quantitative information for the decision-making community • Should we buy an ORSSat or buy more UAVs? The space system doesn’t matter — the warfighter doesn’t care about “how,” only “what” the system can do for them They don’twant another piece of equipment that will serve mostly as something to put under the wheels of the truck when it gets stuck The issue is, What can Responsive Space do for the warfighter or for people who need help Ultimately, ORS is not about launch systems or spacecraft. It’s about what we can do to help the warfighter or the cop in New Orleans, at low cost, by tomorrow morning (or, better, thisafternoon). That’s what Mission Utility is intended to measure.

Two distinct objectives of utility analysis
– –

Critical Mission Utility lessons from the RS5 Warfigher panel:
– – –

The Need for Mission Utility Analysis for ORS

A key issue in the ORS debate is whether and to what extent Responsive Space systems have sufficient utility to warrant the funding requiredto implement them
– – Traditionally, Measures of Effectiveness (MoEs) = Figures of Merit (FoMs) have been used to quantify performance, which can then be compared to the cost Some initial attempts to use more traditional MoEs for ORS have resulted in confusing and misleading results

ORS Mission Utility is particularly challenging
– – – Traditional missions have a constant long-termpurpose • Example: Provide 0.25 m resolution images anywhere on Earth within 48 hours ORS missions are intended to respond to dynamic world events • Example: Provide appropriate coverage of hurricane Katrina and its aftermath This makes it hard to assess Mission Utility • How do we measure utility for future events that are unpredictable?

What we know is that unanticipated events will occur
–Will we be as prepared as possible for the next hurricane Katrina, tsunami, or biological, chemical, nuclear, or non-nuclear attack on a major world city?

Demonstrating and quantifying Mission Utility is key to funding ORS missions in a severely constrained budget environment and to funding the right ORS missions.

Lessons Learned: MoEs that Don’t Work

I was involved some time agowith designing a small constellation that needed frequent, but not continuous, coverage
– – – – We decided to use the Average Gap Duration (AGD) as our primary MoE and created a small program to calculate the average gap statistics We created a 4-satellite constellation that had an AGD of approximately 60 min, which we believed was a bit longer than would work well for the application We nexttried a 6-satellite constellation, which we re-optimized to provide the best coverage possible For 6 satellites the AGD went to about 90 min • It seemed to us that the customer was unlikely to be delighted with this result • We reviewed our calculations with some care and found that they were correct • Here’s what happened: – With 4 satellites, we had lots of gaps, some long and some short – With 6...
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