Zero-G Flight Test of Caging System

The Caging System for Drag Free Satellites was tested on each of four parabolic flights during a NASA Flight Opportunities Campaign in April 2013 at Ellingont Field, Houston, TX.

Ground Test Systems

In order to build a realistic drag-free proof mass system for the MGRS, a ground test system is needed. Therefore, a magnetic levitation system was built that can levitate and hold a hollow sphere in vacuum, simulating zero-g operation. An electronics board has been built that is required for a stable feedback control system to drive the coil and hold the ball in a stable levitated position. The board has a switch to reverse the current direction through the coil in case the sphere becomes magnetized and sticks to the coil in vacuum.

Grating Angular Sensor

Grating Angular Sensor (GAS) does a highly precise angular measurements by using a custom made optical grating surface. GAS is a crucial instrument for the development of the Modular Gravitational Reference Sensor (MGRS). Recently we proposed and demonstrated the use of grating angular sensor can be far more sensitive than a simple reflection scheme for two reasons. First, the diffracted angles can vary more than the incident angle when the grating rotates. The grating thus magnifies the variation of the input angle.

Differential Optical Shadow Sensor

The Differential Optical Shadow Sensor (DOSS) is a sensor for measuring the position of a spherical test mass relative to a given reference system (housing). The major difference between the Shadow Sensor and an interferometric measurement is that the measurement for the Shadow Sensor is at the intensity level. That means, that there is no necessity for a coherent light source. The dynamic range of the shadow sensor is large as compared to an interferometric sensor.


Precise control over the potential of an electrically isolated proof mass is critical for many devices, such as the MGRS. During flight, direct charging and secondary electron emission can lead to a charge imbalance between the proof mass and housing, leading to electrostatic forcing. The UV LED project aims to develop a full non-contact charge control system using AlGaN UV LEDs operating at 255 nm.

Small Satellite Series

In cooperation with NASA Ames and KACST a series of small satellites is developed to demonstrate and test core technologies for science missions like LAGRANGE or LISA.

LAGRANGE: LAser GRavitational-wave ANtenna at GEo-lunar Lagrange points

LAGRANGE: LAser GRavitational-wave ANtenna at GEo-lunar Lagrange points

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