Controlled Autonomous Proximity Technology with flUx pinning & Reconfiguration Experiments

CAPTURE:

David Bayard, Laura Jones, and Swati Mohan

Jet Propulsion LaboratoryCalifornia Institute of Technology

Copyright 2014, California Institute of Technology. Government sponsorship acknowledgedClearance URS 248323, CL#14-5000, valid for U.S. and foreign release

• To advance an end-to-end autonomous rendezvous, docking, and reconfiguration

capability to TRL 7 using small satellites

CAPTURE Objective

docking

rendezvous

reconfiguration

Demonstrate GNC algorithms and capabilities for autonomous rendezvous of a chaser to a target to within 10cm from 5km

Mature the technology for a passively-stable capture and docking maneuver using flux-pinned interfaces

Demonstrate reconfiguration of the control system to achieve consistent control performance through changing configurations

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CAPTURE Core Technologies

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CAPTURE Rendezvous Technology

• Precision 6 DOF close-proximity G&C• Developed at JPL for ST6• Inspection/circumnavigation• Autonomous rendezvous & docking

guidance• Vision-based spacecraft-relative

navigation• Real-time image-based feedback

• 12 DOF state estimation using inertial/relative measurements

• IMU, sun sensor, star tracker, camera, flash lidar

• Autonomous operations with minimal ground intervention

Rendezvous & Docking

Circumnavigation

Reconfiguration

Flux Pinning: • Equilibrium is set below

critical temperature (~88K)

• Passive 6 DOF stability in a nonlinear potential well

• Natural stiffness and damping in up to 6 DOF

• Close proximity (~10s cm)

Cryocooled Superconductor Disk

Flux-Pinned Interface (FPI)

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CAPTURE Docking Technology

Docking with FPIs: • Passive physics-based

trajectory from solid-state mechanism

• Impact attenuation

• Misalignment Correction

• Electromagnet control

Magnet Array

Cryocooled Superconductor Disk

Flux-Pinned Interface (FPI)

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CAPTURE Docking Technology

Magnet Array

Flux-Pinned Passively Stable “Potential Well”

Spectrum of reconfiguration methods based on a-priori information assumed

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CAPTURE Reconfiguration Technology

Parameterized Control System

Complete No Information

Gain Scheduled (TRL 9)

Reference

Online Model Calculation New Technology (TRL 5)

Outer loop to monitor configuration

No info about target or attachment needed prior to dockingBeneficial when - New target for existing

chaser- Autonomy decides on

order of assembly- Minimizes ground

development and testing for multi-target missions

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Mission Demonstration

+V-Bar

+R-Bar

Formation Flying (~100 m)

Circumnavigation (~20m)(Football orbit)

Autonomous Mission Elements• Formation Flying• Circumnavigation• Close-Proximity Inspection• Approach/Closing• Docking with Flux Pinning• Control Reconfiguration

Close-Proximity Inspection (~5m)

Approach(Forced V-bar)

Docking with Flux Pinning

Start Experiment(Co-elliptic)

Reconfiguration

Importance to NASA/JPL

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– Relative sizing between Chaser and Target are relevant– Docking requirements commensurate with Orbiting Sample capture– Realistic starting approach distance (~ 5 km)– Coordinated relative sensing (Flash Lidar and Camera)

Mars Sample Capture

– Demo level of autonomy that is useful for assembly far from Earth– AR&D algorithms with plume impingement assessed– Show control Chaser alone and Chaser+Target to equivalent accuracy– Soft capture, beneficial to telescope applications, demonstrated

Telescope Assembly On Orbit

On-Orbit Servicing– Soft capture tech to dock and move Targets without physical contact– Show control Chaser alone and Chaser+Target to equivalent accuracy