34 AI MAGAZINE
Impact
We were able to produce several alternatives for long-
term planning so that enough communications
resources were available at the time of execution. (For
each alternative, we needed enough resources to han-
dle all communications. Each alternative was based
on differing execution paths.) We also were able to
deliver operations plans daily, even in the face of
changing procedures and changing resource avail-
ability. Together this contributed to the success of the
mission.
The overall affect of using ASPEN has been approximated by the flight director as a 26 percent reduction in the execution time of the mission, a 50 percent reduction in the daily staff required to produce
plans, and a 35 percent reduction in planning errors.
Note that by planning error, we mean errors made
by staff in terms of what plans should be executed
that day, not errors in the plans themselves. This
reduction was due to the high visibility of each plan
and ready inspectability by expert staff. In fact, not
a single misconfigured command was sent during
operations.
All of these savings resulted in an estimated overall cost reduction of $10.4 million, mostly due to the
reduction in execution time. Keeping in mind that
the total cost of development and operations for the
automated ground planning system was less than $1
million, this becomes a clear winner. Note that this
does not include any economies of scale (which are
normally associated with claims of automation
reducing cost) as each major experiment was performed only once.
Figure 6. The Planning Flow.
Long Range and Daily Planning.
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71 61 51 41 31 21 11
42 32 22 12 02 91 81
82 72 62 52
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
February 2007
Daily ( 1 day out from execution day)
; Scenario Planning
– Verify that the plan matches expectation
; Trajectory Planning
– Project accurate ST, illumination, and site visibilities
; Resource Planning
– Precise file information, exact contact times
– Align TDRSS and AFSCN resources to match contact times
– Project memory and energy envelopes, repair.
– Respond to lost/gained contacts, changes in procedures, changes in the daily plan
e sda u
0
Long-Term ( 24-7 days out from execution day)
; Scenario Planning
– Decide on the day for each scenario
– Might interact with Trajectory Planning
; Trajectory Planning
– Decide on actual spacecraft trajectory, illumination, and site visibilities
; Resource Planning
– Approx. file information, contact times
– Assign TDRSS and AFSCN resources to scenario
– Project memory and energy envelopes