Autonomous Drilling in Extreme Environments

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Autonomous Drillingin Extreme Environments

• Gregory A. Dorais
• NASA Ames Research Center

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Outline

• Background
• Motivation
• Challenges
• Current Efforts
• Candidate Architecture

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Background
Technical Areas
4
Background Deep-hole Drilling

• 200m holes regularly drilled in China in 1100s
  (In 1132, 4900 brine wells were registered in
  Sichuan province alone)
• Xinhai well drilled to 1001m in 1835
• First steam-powered drill rig is operational in
  1856
• 12,261m hole was drilled in the Kola peninsula,
  Russia, 1970 - 1989

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Background Deep-hole Drilling (cont.)

• Holes are generally either drilled or cored
• Holes can be lined or left unlined. Frequently
  holes are only lined where needed. Liners can be
  continuous or segmented.
• Motor can be located on the surface or near the
  bit.
• Hole diameter can be constant or reduce with
  depth.
• Holes can be straight or vary directionally
• Semi-autonomous directional drilling is current
  state-of-the art. Such drills can follow a
  horizontal stratum less than 1m thick.
• A variety of sensor measurements can be made
  while drilling or down-hole when drilling stops

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Drilling Down-hole Science Sensors
Gamma Ray (U,Th,K) Spontaneous Potential Sonic De
nsity Neutron (scatter) Photoelectric
Absorption Neutron Activation (inelastic
capture) Galvanic Resistivity (laterolog) Inducti
on Resistivity Nuclear Magnetic Resonance
(NMR) Dielectric Electrical Borehole
Image Acoustic Borehole Image Video Image
? - yes ? - dont know X - no
Open Hole (fluid filled) Open Hole (air
filled) Steel Cased Hole Fiberglass Cased Hole
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Presented by Quinn Passey, Exxon-Mobil, at Mars
Drilling Feasibility Workshop, D. Beaty, S.
Miller, Houston, TX, 2/27/2001
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Background Extreme Environments

• Characteristics
• Temperature, e.g., Eros varies -150 to 100C
• Pressure
• Gravity
• Radiation
• Stability
• Accessibility
• Uncertainty

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Background Autonomy Robotics

• Deep Space 1 spacecraft
• Launched 10/98
• Technologies Flight Validated
• Remote Agent Autonomous Control System
  Demonstration(model-based, goal-oriented),
  included
• Planner/Scheduler
• Mode Identification Recovery
• Reactive Executive
• Autonomous Navigation System

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Motivation

• Exploring Earths extremes doesnt appear to have
  been or will be a driver of autonomous drilling
  technology research (much less expensive to have
  people nearby drill site).
• Two primary drivers are
• Cost-efficient production holes, e.g., oil.
• Space exploration
• Moons Luna, Europa, Titan
• Planets Mars, Venus, Mercury
• Asteroids
• Comets

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Motivation (cont.)

• Space exploration includes
• Astrobiology organic molecules, extinct and
  extant life
• Geology composition, physical properties, and
  age of strata
• Climatology climate history and its effect on
  crust
• Lithospheric Rheology, e.g., volcanism, tectonics
• Search for resources, e.g., water, minerals

Graphic from Mars Drilling Feasibility Workshop,
Introduction, D. Beaty, S. Miller, Houston, TX,
2/27/2001
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Challenges

• Extreme is an relative term earth vs. space
  extremes. Unclear how much more difficult
  drilling in various space extreme environments
  is.
• Drill Platform mobility (multi-hole capability?)
• Small hole diameter (e.g., miniaturization of
  sensors)
• Low power and mass budgets (limits redundancy and
  backup resources equipment)
• Cuttings removal (dry?)
• Down-force application (weight-on-bit)
• Bottom Hole Assembly Cooling
• Bit control, localization, and telemetry
• Contamination of samples and hole walls
• Core removal and sample handling attempt to
  maintain core temperature and pressure

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Challenges (cont.)

• COTS autonomous control systems mostly limited to
  nominal operations
• Resource Management
• Low power, significantly varies during day and
  between days
• Limited consumables, e.g., bits
• Stuck Equipment
• Mechanical Failure
• Self-maintenance, condition-based
• Autonomous recovery
• Unknown material in strata (e.g., risk of
  pressurized/gaseous zones)
• Hole Instability
• Hole stabilization (e.g., liners)
• Cave-in removal

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Drilling Hole-diameter Analysis

• A commercial drilling contractor, if asked to
  drill a hole 5km deep in unknown terrain, would
• bring in at least 50 tons of equipment
• use a prime mover with at least 50 kW of power
• producing a hole averaging perhaps 20 cm in
  diameter.
• The volume of this hole would be at about 160
  cubic meters
• the energy delivered to the rock face would about
  50 Gj,
• equivalent to over 17 kW for 100 eight hour days
  of drilling.
• This is vastly more mass and power than can be
  landed on Mars in a near-term subsurface
  exploration mission.

Presented by Brian Wilcox, JPL, at Mars Drilling
Feasibility Workshop, D. Beaty, S. Miller,
Houston, TX, 2/27/2001
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Comparison of Technology Challenges for Mars
YearDepth
Key for Technology Challenge 1 Greatest 8
Least
2014 missions assume successful 2007 mission
Chart from Technology Breakout Session, Mars
Drilling Feasibility Workshop, D. Beaty, S.
Miller, Houston, TX, 2/27/2001
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2007 Smart Lander Mission Concept

• Conduct Significant
• Science
• Sub-surface drilling
• In-situ soil/rock analysis
• Atmospheric measurements

SURFACE MOBILITY

• Demonstrate Next-Generation
• Lander/Rover Capabilities
• Global access
• latitude range
• surface elevation
• rugged terrain
• Accurate/safe landing
• Go-to mobility
• Extended mission operations

GUIDED ENTRY

• Approach
• Strong, multi-
• disciplinary team
• NASA centers
• Industry
• Universities
• Early pre-project
• with extensive
• technology program

HAZARD DETECTION/AVOIDANCE
No strawman payload yet defined, examples of
possible experiments listed
ROBUST TOUCHDOWN SYSTEM
Presented by Sam Thurman, JPL, at Mars Drilling
Feasibility Workshop, D. Beaty, S. Miller,
Houston, TX, 2/27/2001
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2007 Smart Lander/Rover Concept
1st Generation EDL System
N
Note that lower 1/3 of image is often shadowed
2nd Generation EDL System
99 dispersions shown
NOTE grid squares are 10 ? 10 km

• Target Crater in Elysium Planitia
• 36.7 N Lat., 252.3 W Lon.
• 10 km diameter
• Contains gully features

• Go-to Rover Traverse Capability
• Target site chosen for safety
• Rover capability employed to reach
• surface features of interest

Presented by Sam Thurman, JPL, at Mars Drilling
Feasibility Workshop, D. Beaty, S. Miller,
Houston, TX, 2/27/2001
17
Pallet Landing System with Fixed Payload
Presented by Tom Rivellini, JPL, at Mars Drilling
Feasibility Workshop, D. Beaty, S. Miller,
Houston, TX, 2/27/2001
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Drill Concepts for 2007 Mission

• 2m drill on Rover (low risk, mobile)
• 20m Auger Drill (med. risk)
• 20-200m Coiled Tube Drill (med. risk)
• 300-500m Worm drill (high risk, no core samples)

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Sample Drill Algorithm
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Sensors for Drilling Control

• Weight-on-bit
• Rate-of-penetration
• Rotation Rate
• Bit Torque
• Temperature
• Bit Depth
• Core Length
• Bottom-Hole Assembly Lift Weight
• X, Y Translation
• 6-DOF Inertia
• Gas Pressure
• Multi-spectral Imager
• Gamma Ray
• Neutron/Density

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Candidate Architecture
On-board Control System
System Environment Models, Procedures,
Constraints, Heuristics
Drilling and Sample Analysis Experts
Declarative/ReactivePlanners
plan requests
Ground Control System
Communication Network
plans
Plan Runner
Plan/State Database
Communication Mgr.
Communication Mgr.
high-level commands
state/health
AdaptiveControllers
AdaptiveControllers
Autonomous Drilling Management System
Core Bore Hole Data Analysis System
low-level commands
Core Handling Module Sensors Actuators
State/Health Estimator
signals
Bottom Hole Assembly Sensors Actuators
signals
physics
physics
Resources, e.g., energy, consumables
Ground Operator
Principal Investigator
Hole Environment
Surface Environment
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Reference

• Report on the Mars Drilling Feasibility Workshop
  of February 27-28, 2001, Lunar and Planetary
  Institute, Houston, TX, eds. Dave Beaty and
  Sylvia Miller, JPL.