Microgravity Acceleration Measurement System (MAMS) - 11.02.17

Summary | Overview | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Microgravity Acceleration Measurement System (MAMS) studies the small forces, or vibrations and accelerations, on the International Space Station (ISS) that result from the operation of hardware, crew activities, dockings and maneuvering. Results are used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station.
Science Results for Everyone Don't rock the boat. Hardware operation, crew activities, visiting vehicle docking and maneuvering all cause small vibrations on the International Space Station (ISS) that can affect sensitive experiments. For the ISS to function well as a low-gravity environment for experiments, researchers must measure such disturbances and assess their effect. The Microgravity Acceleration Management System (MAMS) does just that. MAMS data revealed short-term vibrations that analysts connected to movement of the Ku-band antenna (used to transmit science data and video to Earth). MAMS data is also being analyzed for correlation of the motion of air bubbles in water with vibrations, and the system is collecting data during major mission events such as Soyuz and Progress docking.

The following content was provided by William Foster, and is maintained in a database by the ISS Program Science Office.
Facility Details


Facility Manager(s)
William Foster, Glenn Research Center, Cleveland, OH, United States

Facility Representative(s)
Information Pending

ZIN Technologies Incorporated, Cleveland, OH, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

ISS Expedition Duration
November 2000 - December 2002; November 2002 - May 2003; April 2003 - March 2015; September 2017 - February 2018

Expeditions Assigned

Previous Missions
MAMS has been operating on ISS since Expedition 2.

Information Pending

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Facility Description

Facility Overview

  • Microgravity Acceleration Measurement System (MAMS) measures vibratory and quasi-steady acceleration within the United States Laboratory Module on the International Space Station(ISS).

  • Vibrations exist on the ISS from a variety of sources, such as equipment operation, life-support systems, crew activities, aerodynamic drag, gravity gradient, rotational effects and the vehicle structural resonance frequencies.

  • The quasi-steady acceleration is caused by forces from aerodynamic drag, gravity gradient effects, centripetal (rotational) motion, spacecraft propulsion, and vehicle orientation control actions.

  • Two sensors, the Orbital Acceleration Research Experiment (OARE) Sensor Subsystem (OSS) and the High Resolution Accelerometer Package (HiRAP), monitor these disturbances. The OARE OSS measures low range frequency (up to 1 Hz). The HiRAP characterizes the ISS vibratory environment from 0.01 Hz to 100 Hz.

Changes in acceleration and moving mechanical parts cause small vibrations to move through the Station's structure. These disturbances occur within the frequency range of 0.01 to 300 Hz. Microgravity Acceleration Measurement System (MAMS) is one of two experiments onboard that measures and records the vibrations. The Space Acceleration Measurement System-II (SAMS-II) measures vibrations from vehicle acceleration, systems operations, and crew movements. MAMS complements this data by recording accelerations caused by aerodynamic drag and ISS movements caused by small attitude adjustments, gravity gradient, and the venting of water. These quasi-steady state accelerations occur in the frequency range below 1 Hz. MAMS consists of a low-frequency triaxial accelerometer, the Miniature Electro-Static Accelerometer (MESA), a high-frequency accelerometer, the High-Resolution Accelerometer Package (HiRAP), and associated computer, power, and signal processing subsystems contained within a Double Middeck Locker enclosure.

MESA consists of a hollow, cylindrical flanged mass, two X-axis forcing electrodes, an outer cylindrical proofmass carrier with Y- and Z-axis electrodes, and control electronics enclosed in a protective case. Static electricity forces the sensor proofmass to remain centered between the electrodes. The "sensed" acceleration is proportional to the voltage needed to keep the sensor centered.

MESA is mounted on a Bias Calibration Table Assembly (BCTA), a mechanism allowing on-orbit calibration. Calibration is used to remove electronic bias from the "sensed" acceleration.

Currently MAMS is only operated during special events such as an International Space Station (ISS) reboost and spacecraft dockings.

Crew time is required for transfer to EXPRESS Rack 1, lockers 3 and 4, activation and deactivation, and movement of hardware to alternate locations. Otherwise, MAMS operates automatically. Electrical power is controlled through a circuit breaker in the front panel.

MAMS measures subtle accelerations that affect only certain types of experiments and is not operational all the time. MAMS operates from the Glenn Research Center Telescience Support Center at appropriate times. After initial installation on the Station, MAMS requires a minimum of four days of continuous operation to characterize the sensors' performance and to calculate any sensor bias. MAMS was set up and activated on May 8, 2001, and continued operation for eight days to collect data during normal Station operations. Since then, it has been reactivated several times to record dockings and other disturbances. Multiple calibrations taken over long periods of operation can be used to further improve the accuracy of MAMS data.

MAMS supports many of the on-orbit microgravity experiments, many of which have Earth applications. MAMS measurements and data analysis done by the PI Microgravity Services (PIMS) project may be applied to terrestrial acceleration measurement and analysis, such as oil exploration, machinery vibration monitoring, seismic monitoring, etc.

Most microgravity experiments require a quiescent environment in which the effects of gravity and other accelerations are reduced below a threshold level (determined by experiment parameters and design). Knowledge of the acceleration environment in which an experiment was operated is provided by MAMS data.

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Facility Operations

  • The crew activates and deactivates MAMS as necessary.

  • When necessary the crew moves hardware to alternate application locations when the microgravity environment for other payloads needs to be measured.

  • The crew performs a filter cleaning/change out as required.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

One of the major goals of the ISS is to provide a quiescent low-gravity environment to perform fundamental scientific research. However, small disturbances aboard the ISS impact the overall environment in which experiments are being performed. Such small disturbances need to be measured in order to assess their potential impact on the experiments. MAMS is used on board the ISS to do just that.

MAMS data have been analysed to examine the quasi-steady regime on station with a frequency below 0.01 Hz. These are related to aerodynamic drag, gravity gradient and rotational effects, venting of air or water, and appendage movement, such as that of the solar arrays and antennas. Characteristics were found in the data that were unexplainable for a short period of time. Analysts determined that the movement of the Ku-band antenna was the source of the unusual characteristics in the quasi-steady data collected by MAMS. (A Ku-band antenna is used to transmit payload science data and video from ISS to Earth.) The correlation was made after comparing the data with real-time observations from ISS (DeLombard  2002, 2004).

A special study using MAMS data was performed by ISS science officer Don Pettit during Expedition 6 as a part of Saturday Science. Pettit examined the motion of air bubbles in water to see how it correlated with quasi-steady accelerations, vibrations that are at or below a frequency of 0.01 Hz for a period greater than 100 seconds (DeLombard et al. 2005).

MAMS data was analyzed during periods of Progress, Soyuz, and Space Shuttle docking and undocking as well as disturbances during Extra Vehicular Activities (EVA) and orbit corrections.  The purpose of this analysis is to quantify the MAMS data for each of these known activities in order to filter out these disturbances when other unknown disturbances are being analyzed (Belyaev 2013)

MAMS data was also correlated with SAMS-II data during ISS quiescent periods in order to identify discrete and continuous spectrum vibrations.  The continuous data was identified to be the small amplitude elastic vibrations in the ISS construction. The small discrete data was connected to operations of onboard equipment (Zavalishin 2013).

Results Publications

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Ground Based Results Publications

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ISS Patents

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Related Publications

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Related Websites

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image NASA Image: ISS003E6010 - Culbertson poses with MAMS hardware in the U.S. Laboratory during Expedition 3.
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image NASA Image: ISS007E06980 - Back-dropped by the blackness of space and Earth's horizon, an unmanned Progress supply vehicle approaches the ISS during Expedition 7. Inset image shows microgravity acceleration data provided by the MAMS hardware during a Progress docking with ISS.
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image NASA Image: ISS013E65575 - Shown is the Microgravity Acceleration Measurement System (MAMS) used to measure acceleration during specific ISS operations. MAMS is located in EXPRESS Rack 1 in the U.S. Laboratory.
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