The document describes a project to design and test an extendable electrostatic gripper arm and reactive satellite simulator (RSS) to demonstrate the feasibility of using electroadhesion for satellite capture and manipulation. The gripper arm uses electroadhesion pads which provide mechanical simplicity over traditional docking mechanisms. An RSS with 5 degrees of freedom was also designed and tested to simulate tumbling satellites. Initial testing showed electroadhesion is a viable solution for capturing satellites not designed for docking and could help address issues like servicing and debris removal. Future work aims to refine the arm design and test different gripper pad configurations.

1. Universal Satellite Capture Arm and
Reactive Satellite Simulator
Jared Kepron1, Lindsey Marinello2, Colin Stelly3 Principal Investigator: Thomas Bryan; Marshall Space Flight Center, ES35
1Worcester Polytechnic Institute, 2Bryn Mawr College, 3Auburn University
Abstract
Docking mechanisms grant the ability to redirect or service satellites in
microgravity. This research explores an alternative method using electroadhesion
for target capture and manipulation. The key advantage of electroadhesion for
satellite capture lies in its mechanical simplicity and adhesive versatility. Whereas
traditional methods require the interaction of multiple interlocking parts for
successful capture, electroadhesion requires only a contact surface. This property
minimizes the possibility of inflicting undesired perturbations on the target.
Electroadhesion also enables new capabilities in handling and redirecting satellites
not previously designed for docking or capture, including space debris and
meteoroids. An extendable electrostatic gripper and target mock-up were designed
and built for testing in simulated microgravity conditions to determine the
feasibility of this system for spaceflight applications.
Background
Objective: Design, fabricate, and test a gripper arm and Reactive Satellite
Simulator (RSS) with integrated sensing capability forflat floortesting
I. Design, build, andtest an electrostatic gripper arm with sensing capability
 Extendable Spiralift boom supported by two scissor lift arms for structural
rigidity and constructed with lightweight material is chain-driven by two high
powered DCmotors running through a gearbox
 2 durable LEDDAR sensors detect rough geometry and target distance during
initial approach; Verisense sensor determines target rotation center and speed to
allow gripper to align and spin appropriately
 Touchscreen PLC GUI provides control using analog 3-axis joystick controller;
analog potentiometer input gives position feedback
II. Design, build, and test first-ever 5 DOFReactive Satellite Simulator (RSS)
or“Turtle”
 Spherical air bearing grants free rotation about stable center of gravity, while
angle-adjustable end plates allow testing of different rotation planes
 Aluminum shell provides mounting surface for various simulate materials
III. Frictionless Flat FloorTesting
 RSS approved for flat floor testing after necessary reconfiguration to ensure air
bearing stability
 Universal Satellite Capture Arm construction in progress, will conduct testing
with RSSupon completion
Methodology Conclusion
Future Research
Acknowledgements
 Most satellites are not designed for docking, servicing, and refueling
 Many high-value satellites become prematurely inoperable due to fuel depletion
 Current efforts at Goddard Space Flight Center to service satellites focus on
complex, customized mechanical docking mechanisms
Proposal: Tumbling satellites and orbital debris can be captured and stabilized
through the use of a Universal Satellite CaptureArm
The Challenge: Every satellite has its own unique physical features and
characteristics, a fact that presents significantdifficulties when designing a universal
capture mechanism
The Solution: ElectrostaticAdhesion
Why utilize electrostatic adhesion?
 Able to grip and release objects on command
 Able to flex and conform to different surfaces
 Fewer moving parts, increased reliability
 Electrostatic adhesion works on a wide variety of materials, reducing the
number of required end effectors
Modes of Manipulation
Material
 Refine arm design to reduce overall weight and size, and evaluate alternative
sensor placements
 Design and test arm configuration incorporating a second Spiralift boom
 Test gripper arm on RSS with differing rotation planes and applied nutation
 Evaluate and test alternative electrostatic pad geometries for increased grip
strength and flexibility
 Explore algorithmic approaches to satellite geometry and rotation rate detection
in order to achieve system automation
We would like to give our most sincere thanks to our mentor, Tom Bryan, for his
guidance and support throughout our project. We also extend our gratitude to
Charles Cowen and Thomas DeMatteis for supporting us in hardware acquisition
and machining, and in information technology support, respectively.
Finally, wegive our thanks to theAlabama, Massachusetts, and
Pennsylvania Space Grant Consortia as well as Marshall Space
Flight Center for making the 2015 RoboticsAcademy possible.(Goeser, Gonzalez, Leung, Miller. “Validation of Electroadhesion as a Docking Method for Spacecraft and Satellite Servicing”. 2014.)
Currently, space agencies and private industries around the world are losing
revenue and critical data as a result of their inability to efficiently service satellites.
Additionally, the rising threat of space debris looms without a clear solution.
Electrostatic adhesion is a demonstrated technology that allows for reliable and
efficient capture and manipulation of satellites. This technology could both extend
the mission lifetime of hundreds of existing satellites and ensure the safety and
longevity of thousands of missions to come. Our work validates that utilization of a
Universal Satellite Capture Arm is a viable solution for a secure space environment,
and a secure future of space exploration.
Electrogrip Gripper Pad
Reactive Satellite Simulator
Planar (Translational)
Air Bearings
Onboard Pressure
Regulators
Aluminum
“Shell” Frame
Angle-adjustable
End Plate
Spherical (Rotational)
Air Bearing
Rotation Inducing
Air Jets
Universal Satellite Capture Arm (Under Construction)
Azimuth and Elevation
Mounted at 30°
Base Plate with Extension
DC Motor and Gearbox
String Potentiometer
Extension Chain Drive
Spiralift Boom
Scissor Lift (x2) with
Sliding Mounts
End Effector Plate with
Stepper Motor, Belt Drive
Bearing and Slip
Ring Assembly
Cross Bar with LEDs for
Detection System
Electrostatic
Gripper Pad
Grabit Inc. Gripper Pad