There are two case studies:
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A simplified specification of the Mars 2020 Entry-Descent Landing (EDL) scenario
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A simplified spacecraft-small body approach scenario (see below).
This case study is based on the following paper:
I. A. Nesnas, B. J. Hockman, S. Bandopadhyay, B. J. Morrell, D. P. Lubey, J. Villa, D. S. Bayard, A. Osmundson, B. Jarvis, M. Bersani, et al., “Autonomous exploration of small bodies toward greater autonomy for deep space missions,” Frontiers in Robotics and AI, p. 270, 2021.
The specifications were developed in two phases.
These notebooks focus on explaining the system task specifications and on analyzing their characteristics.
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Tasks from the power viewpoint perspective:
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Tasks from the science viewpoint perspective:
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Tasks from the navigation perspective:
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Tasks from the thermal perspective:
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Fusing viewpoints (power, science, navigation):
Instead of specifying and analyzing a point design, the idea is to vary the design and operational parameters.
The following Python functions use the Pacti contract algebra for
generating task scenario designs from variable hyperparameters.
See ./space_mission/generators.py
The following notebooks demonstrate design generation with an interactive chart of CPU utilization to assess the efficiency of parallelizing the algebraic operations involved.
There are two variants of these notebooks according to the length of the task scenarios generated (5 vs. 20 tasks).
See ./space_mission/analysis_results1-5steps.ipynb
See ./space_mission/analysis_results1-20steps.ipynb
Alternatively, one can parallelize design generation using a Python script:
See ./space_mission/hyper_scenarios.py
The following Python functions use the Pacti contract algebra for analyzing a task scenario against operational requirements with variable hyperparameters.
See ./space_mission/schedulability.py
The following notebooks demonstrate the schedulability analysis of a task scenario design against operational requirements with variable hyperparameters with an interactive chart of CPU utilization to assess the efficiency of parallelizing the algebraic operations involved.
There are two variants of these notebooks according to the length of the task scenarios analyzed (5 vs. 20 tasks).
See ./space_mission/schedulability_analysis_5steps.ipynb
See ./space_mission/schedulability_analysis_20steps.ipynb
Alternatively, one can parallelize schedulability analysis using a Python script:
See ./space_mission/hyper_requirements.py
Some of the 5-step task solutions:
See ./space_mission/analysis_results1-5steps.ipynb
Some of the 20-step task solutions:
See ./space_mission/analysis_results1-20steps.ipynb
Scatter plots of the 20-step task solutions:
See ./space_mission/analysis_results2.ipynb
(cs-space-mission1-3.11) nfr@nfr-desktop:/opt/local/github.pacti-org/cs-space-mission1$ /opt/local/github.pacti-org/cs-space-mission1/.venv/bin/python /opt/local/github.pacti-org/cs-space-mission1/space_mission/hyper_scenarios.py
100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 100/100 [00:09<00:00, 10.84it/s]
Generated 100 hyperparameter variations of the 5-step scenario in 9.372139930725098 seconds.
Running on AMD Ryzen Threadripper PRO 3955WX 16-Cores @ 3.8927 GHz with up to 32 threads.
Pacti compose,quotient,merge statistics:
compose invocation counts: (min: 0, max: 12, avg: 8.16, total: 816)
min/max compose contract size: (constraints: 6, variables: 3)/(constraints: 22, variables: 12)
no quotient operations
merge invocation counts: (min: 0, max: 10, avg: 6.8, total: 680)
min/max merge contract size: (constraints: 3, variables: 2)/(constraints: 44, variables: 23)
Pacti PolyhedralTermList statistics:
no contains_behavior operations
Pacti PolyhedralCompoundContract statistics:
no compound_merge operations
100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 100/100 [01:37<00:00, 1.02it/s]
Generated 100 hyperparameter variations of the 20-step scenario in 97.78417682647705 seconds.
Running on AMD Ryzen Threadripper PRO 3955WX 16-Cores @ 3.8927 GHz with up to 32 threads.
Pacti compose,quotient,merge statistics:
compose invocation counts: (min: 51, max: 51, avg: 51.0, total: 5100)
min/max compose contract size: (constraints: 6, variables: 3)/(constraints: 187, variables: 95)
no quotient operations
merge invocation counts: (min: 40, max: 40, avg: 40.0, total: 4000)
min/max merge contract size: (constraints: 3, variables: 2)/(constraints: 44, variables: 23)
Pacti PolyhedralTermList statistics:
no contains_behavior operations
Pacti PolyhedralCompoundContract statistics:
no compound_merge operations
(cs-space-mission1-3.11) nfr@nfr-desktop:/opt/local/github.pacti-org/cs-space-mission1$ /opt/local/github.pacti-org/cs-space-mission1/.venv/bin/python /opt/local/github.pacti-org/cs-space-mission1/space_mission/hyper_requirements.py
100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2000/2000 [00:22<00:00, 87.49it/s]
Found 70 admissible and 9930 non-admissible schedules out of 10000 combinations generated from 100 variations of operational requirements for each of the 100 scenarios.
Total time 23.014519691467285 seconds running on AMD Ryzen Threadripper PRO 3955WX 16-Cores @ 3.8927 GHz with up to 32 threads.
Pacti compose,quotient,merge statistics:
no compose operations
no quotient operations
merge invocation counts: (min: 9, max: 11, avg: 9.0543, total: 90543)
min/max merge contract size: (constraints: 1, variables: 1)/(constraints: 80, variables: 35)
Pacti PolyhedralTermList statistics:
no contains_behavior operations
Pacti PolyhedralCompoundContract statistics:
no compound_merge operations
100%|█████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████████| 2000/2000 [01:11<00:00, 27.83it/s]
Found 56 admissible and 9944 non-admissible schedules out of 10000 combinations generated from 100 variations of operational requirements for each of the 100 scenarios.
Total time 72.22614121437073 seconds running on AMD Ryzen Threadripper PRO 3955WX 16-Cores @ 3.8927 GHz with up to 32 threads.
Pacti compose,quotient,merge statistics:
no compose operations
no quotient operations
merge invocation counts: (min: 9, max: 11, avg: 9.0548, total: 90548)
min/max merge contract size: (constraints: 1, variables: 1)/(constraints: 255, variables: 125)
Pacti PolyhedralTermList statistics:
no contains_behavior operations
Pacti PolyhedralCompoundContract statistics:
no compound_merge operations