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Middeck Active Control Experiment-II (MACE-II)
06.27.08

Overview | Description | Applications | Operations | Results | Publications | Images

Experiment/Payload Overview

Brief Summary

Tested self-reliant, adaptive technologies that can detect problems with ISS hardware and correct those problems as needed. These technologies decreased the effects of vibration in ISS allowing engineers to design future spacecraft and facilities with lightweight, inexpensive materials without sacrificing the stability demanded by sensitive payloads.

Principal Investigator

  • R. Rory Ninneman, Air Force Research Laboratory, Albuquerque, NM

    • Co-Investigator(s)/Collaborator(s)

  • David W. Miller, Ph.D., Massachusetts Institute of Technology, Cambridge, MA

    • Payload Developer


    Air Force Research Laboratory, Albuquerque, NM
    Langley Research Center, Hampton, VA
    United States Department of Defense Space Test Program, Johnson Space Center, Houston, TX

    Sponsoring Agency

    National Aeronautics and Space Administration (NASA)

    Expeditions Assigned

    |1|2|

    Previous ISS Missions

    STS-67 (MACE-I)

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    Experiment/Payload Description

    Research Summary

    • As experimentation takes place on the ISS, one prominent goal is to develop the next generation of smart spacecraft, able to make decisions and solve problems without human intervention.


    • The launching of a spacecraft subjects it to vibrations. The most severe oscillations are felt at the cones at the top of the rocket. And even though they may not be catastrophic to the craft itself, these vibrations can damage the vehicle's instrumentation during the ride into orbit.


    • MACE-II examined the performance of controlled payloads performing pointing and tracking tasks on the multibody platform and tested models for satellite control of the station's sensors and actuators.

    Description

    The Middeck Active Control Experiment-II (MACE-II) will allow engineers to design future spacecraft and facilities with lightweight, inexpensive structures and materials without sacrificing the stability demanded by sensitive payloads. MACE-II, the first hands-on experiment on board station, consists of two basic parts designed to detect and compensate for vibrations. The multi-body platform (MBP) test article, which is the structure undergoing tests, has four 1-inch-diameter struts connected to five nodes. It is loosely tethered in the aisle between racks during operations and is stowed between operations. The entire platform has 20 separate sensors that monitor vibration. The experiment support module (ESM) is a self-contained computer with a power interface to the EXPRESS rack and an umbilical connection to the MBP.

    During experiments scientists used a gimbal on the MBP to create a disturbance at one end of the platform. The ESM detected these movements and, using an adaptable set of algorithms, calculated the opposing forces to be applied at the opposite gimbal, thereby stabilizing the platform. The algorithms could be adapted to changes due to moving parts, variations in temperature, and normal wear and tear on mechanical systems.

    A collaborating team at MIT planned to study how control systems such as that used for MACE-II can be applied to hardware and systems that change over time, such as telescopes, antennas, and robotic arms that must be moved to perform specific duties.

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    Applications

    Space Applications

    MACE-II also tested self-reliant, adaptive technologies that could detect problems with ISS hardware and correct those problems as needed. This would reduce the amount of crew and ground-based personnel time required to monitor and repair Station hardware. This technique is also critical for control of large flexible structures that must perform precision pointing and tracking missions.

    Earth Applications

    Autonomous adaptive control technology demonstrated by MACE-II can be used in any vehicle that must negotiate turbulent airstreams and atmospheric changes. It can be used to develop smart, problem-solving auto pilots for commercial jets or better guidance and pointing systems for military aircraft.

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    Operations

    Operational Requirements

    Bill Shepherd, who operated MACE-II during Expedition 1, and Susan Helms, who took over the operation for Expedition 2, received preliminary training at Johnson Space Center and additional computer-based training while on Station. Power for MACE-II was supplied by EXPRESS rack.

    Operational Protocols

    MACE-II operations were carried out in twelve 4- to 8-hour sessions. Data downlink and control uplink occurred between sessions. On July 30, 2001, the Expedition 2 crew deactivated and stowed MACE-II for its return on STS-105.

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    Results/More Information

    MACE-II provided data autonomously (no human intervention or prior knowledge of the system), decreasing the effects of vibration in moving structures in space. Algorithms were developed to control mechanical systems in real time using only information from on-board sensors and actuators to respond to changes in the system. The system was able to reduce unwanted vibrations without human intervention once it was turned on. These algorithms were able to "adapt" whenever they sensed changes in vibration or the loss of a sensor or actuator.

    Fourteen test protocols were completed during Expedition 1, and an additional 62 test protocols were completed during Expedition 2. The MACE-II unit, which was returned on shuttle flight STS-105, successfully completed all its experiment objectives associated with the AFRL Science Team while on station. On orbit they demonstrated a decrease in vibration by a factor of ten while the system was under control. They then showed that their system could adapt to failure of a primary actuator on the system and still decrease vibration by a factor of six.

    However, due to data downlink constraints, the MIT Science Team was unable to meet its science objectives. The MIT team required downlink of specific on-orbit tests to build its control algorithms. By the time data were provided to the university, there was insufficient time to uplink the commands to run the critical experiments.

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    Related Web Sites
  • NASA Fact Sheet
  • Middeck Active Control Experiment

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    Publications

    Results Publications
    • Ninneman R, Founds D, Davis L, Greeley S, King J. Middeck Active Control Experiment Reflight (MACE II) Program: Adventures in Space. AIAA Space 2003 Conference and Exhibition, Long Beach, CA. 2003 ;AIAA 2003-6243.
    • Davis L. Economical and Reliable Adaptive Disturbance Cancellation. AFRL-VS-TR-2002-1118. Sep, 2002 ;Vol. I - II: Pt. 1-3 (DoD Clearance is needed to view this paper).

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    Related Publications
    • Blaurock C, Kenney S, Miller D, Yung J. Nonlinear Modeling and Control for the Middeck Active Control Experiment Reflight. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4589. 1999
    • Hyland D, Scharf D. Adaptive Nueral Control for MACE II. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4588. 1999
    • Denoyer K, Sharp T, Shelly S. Robust Line-of-Sight Stability and Jitter Compensation Using Spatio-Temporal-Flitering Based Control. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4587. 1999
    • Davis L, Greeley S, Hyland D, King J. Autonomous System Identification and Control of MACE II Using the Frequency Domain Expert Algorithm. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4586. 1999
    • Leo D, McEver M. Adaptive Low-Authority Control Algorithms for Precision Space Structures. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4585. 1999
    • Ninneman R, Denoyer K. Middeck Active Control Experiment Reflight (MACE II) Program. AIAA Space Technology Conference and Exposition, Albuquerque, NM. Sep 28 - 30, ;AIAA 1999-4584. 1999
    • Ninneman R. Middeck Active Control Experiment Reflight (MACE II) Program: Lessoned Learned. AIAA Space 2000 Conference and Exposition, Long Beach, CA. Sep 19 - 21, ;AIAA 2000-5092. 2000
    • Ninneman R. Demonstration of Adaptive Structural Control in Space: Middeck Active Control Experiment Reflight (MACE II) Program. 51st International Astronautics Congress, Rio de Janeiro, Brazil. ;IAF-00-I.04.03. 2000
    • Davis L, Greeley S, King J, Ninneman R. In Flight Autonomous System Identification and Control of MACE II Using the Frequency Domain Expert Algorithm. Conference and Exhibit on International Space Station Utilization, Cape Canaveral, FL. Oct 15 - 18, ;AIAA-2001-4641. 2001

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    Images

    imageNASA Image: ISS002E6721 - Susan Helms, Expedition 2 flight engineer, works with MACE-II, which is shown "floating" in the microgravity environment of ISS.
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    imageNASA Image: ISS01E5216 - MACE-II hardware on board ISS during Expedition 1.
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    Information Provided and Updated by the ISS Program Scientist's Office
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