ESA installs six-degree-of-freedom microvibration machine

Published: 23-Mar-2016

So sensitive that it is capable of identifying the multi-axis forces induced by a dropped feather

The latest addition to the European Space Agency's (ESA’s) satellite testing facilities is a six-degree-of-freedom microvibration unit, which is sufficiently sensitive to identify the multi-axis forces induced by a single dropped feather.

Most satellites have some limits on microvibration to ensure high-quality results, especially for science, Earth observation and human spaceflight.

Minimising jitter helps to deliver ultra-high-resolution images, precision attitude control and pointing stability for optimal science measurements. Many essential satellite elements are potential sources of jitter, such as spinning reaction wheels, scanning or pointing mechanisms, solar array drives or rotating cryocoolers.

Developed for the ESA by the UK’s National Physical Laboratory, a national centre of excellence for measurement standards, this new machine is capable of characterising extremely small disturbances from satellite subsystems or to assess the performance of precision mechanisms.

In addition, it is able to generate a controlled microvibration environment by itself, allowing the assessment of an item’s performance under various conditions.

'In recent years we’ve built a portfolio of world-class microvibration test facilities with demonstrated, unprecedented performance,' said Mark Wagner, ESA’s Head of Test Facilities and Test Methods. 'This new facility is complementing these capabilities, enabling us to offer an independent characterisation of potential microvibration sources while also allowing performance testing of sensitive equipment when subjected to an injected microvibration environment.'

Standing around a metre high, the unit – being installed at the ESTEC Test Centre in Noordwijk, the Netherlands – performs two tasks at once.

Its bottom section isolates the rest of the measurement part of the machine from vibrations transferred through the ground such as nearby footsteps, seismic noise or even the waves of the nearby North Sea. Suitably detached in this way, the top section measures micronewton-scale forces and torques from the item under test.

The unit operates under a plastic tent to minimise perturbations from airflow caused by the building’s cleanroom-class air conditioning. It can also work in vacuum.

Once qualified, the machine will enter service in June.

Designed for full-scale satellite testing, the ESTEC Test Centre is a collection of facilities to simulate every aspect of the space environment. Everything is located under a single roof, within a controlled cleanroom environment tailored for delicate flight hardware. Based in a dedicated building in ESTEC, it is the largest centre of its kind in Europe, and one of the largest in the world.

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