Precision satellite payloads commonly require isolation from bus disturbance sources, such as reaction wheels, thrusters,
stepper motors, cryo-coolers, solar array drives, thermal popping, and other moving devices. Since nearly every satellite
essentially has a unique construction, custom isolation systems are usually designed to attenuate a wide bandwidth of
disturbance frequencies. The disadvantage of these custom solutions is that they are not easily reusable or transferable
and are generally not robust to changes in payload geometry and mass properties during the development. The MVIS-II
isolation system is designed to provide vibration disturbance attenuation over a wide bandwidth, as well as being able to
adapt to changes in payload mass properties and geometry, through active control of a smart material.
MVIS-II is a collaborative effort between the Air Force Research Laboratory (AFRL) Space Vehicle Directorate and
Honeywell Defense and Space to validate miniature hybrid (passive/active) vibration isolation of sensitive optical
payloads. The original flight experiment was intended to isolate a non-critical representative payload mass for
demonstration purposes; however, the MVIS-II has been adapted to support the primary optical payload onboard the
Tactical Satellite 2 (TacSat-2). Throughout the program MVIS-II has been able to adapt to changes in the payload
geometry and mass properties with modification limited to support structures only.
The MVIS-II system consists of a hexapod of hybrid struts, where each strut includes a patented passive 3-parameter DStrut
n series with a novel hydraulically amplified piezoelectric actuator with integral load cell. Additionally,
Honeywell's Flexible I/O controller electronics and software are used for command and control of the hardware. The
passive D-Strut element provides a 40 dB/decade passive roll-off to attenuate mid-to-high frequency disturbances, while
the active piezoelectric actuator is used for enhanced low frequency isolation. MVIS-II struts are 90% smaller in size
and have 91% less mass than previous struts including Honeywell's Vibration Isolation, Suppression, and Steering
(VISS). The MVIS-II system is currently integrated in the TacSat-2, which has successfully launched from Wallops
Flight Facility on Wallops Island, Virginia in December 2006. MVIS-II was launched under direction of the DoD Space
This paper will discuss the adaptive design of the MVIS-II isolation system including simulation, testing, and
integration. Active and passive strut test results will be presented that demonstrate the wide bandwidth attenuation of
vibration disturbances. Simulation results of expected on-orbit performance will also be discussed.
In recent years, there has been a significant interest in, and move towards using highly sensitive, precision payloads on space vehicles. In order to perform tasks such as communicating at extremely high data rates between satellites using laser cross-links, or searching for new planets in distant solar systems using sparse aperture optical elements, a satellite bus and its payload must remain relatively motionless. The ability to hold a precision payload steady is complicated by disturbances from reaction wheels, control moment gyroscopes, solar array drives, stepper motors, and other devices. Because every satellite is essentially unique in its construction, isolating or damping unwanted vibrations usually requires a robust system over a wide bandwidth. The disadvantage of these systems is that they typically are not retrofittable and not tunable to changes in payload size or inertias.
During the Phase I MVIS program, funded by AFRL and DARPA, a hybrid piezoelectric/D-strut isolator was built and tested to prove its viability for retroffitable insertion into sensitive payload attachments. A second phase of the program, which is jointly funded between AFRL and Honeywell, was started in November of 2002 to build a hexapod and the supporting interface electronics and do a flight demonstration of the technology. The MVIS-II program is a systems-level demonstration of the application of advanced smart materials and structures technology that will enable programmable and retrofittable vibration control of spacecraft precision payloads. This paper describes the simulations, overall test plan and product development status of the overall MVIS-II program as it approaches flight.