Aligning Laser Antenna Optical Components for the LISA Space Mission

Photonics & Imaging Technology INSIDER

A 6-axis positioning and alignment system mounted upside down at the end of an articulated robot arm. This assembly is used to align and mount the numerous optical components required for the interferometer to be featured on the European Space Agency’s (ESA) Laser Interferometer Space Antenna (LISA) mission spacecraft. After assembly, the completed optics board is launched into space as part of the mission. (Image credit: UKATC)

In January, the European Space Agency's (ESA) Science Program Committee approved the Laser Interferometer Space Antenna (LISA) mission , the first scientific endeavour to detect and study gravitational waves from space. Physik Instrumente (PI), the precision motion control provider that claims to have the world's fastest photonics alignment engines, recently provided a blog update on how the optical components for the LISA spacecraft are being aligned and assembled with its H-8284 hexapod alignment system.

LISA depends on a trio of spacecraft set to follow Earth's cosmic path around the Sun. This trio will craft a remarkably precise equilateral triangle across the cosmos, each edge spanning 2.5 million kilometers — a length that exceeds sixfold the stretch between the Earth and the Moon. Across this vast expanse, the spacecraft will communicate by trading laser beams. The scheduled departure of this threesome aboard an Ariane 6 rocket is earmarked for the year 2035.

LISA is set to observe the cosmic undulations in spacetime that emanate from the colossal collisions of massive black holes residing at the heart of galaxies, reaching through the breadth of the universe. This endeavor will empower astronomers to unravel the genesis of these gargantuan entities, map their growth as they swell to millions of times the Sun's mass, and discern their influence on the cosmic ballet of galaxy evolution.

Several groups involved in the LISA project have been using PI hexapods and piezo actuators for precision alignment of optical components for the interferometers. PI hexapods were also used in optical alignment tasks for the LISA Pathfinder mission, launched in December 2015.

During the assembly of the ultra-precision optical components at the heart of the LISA project expected to launch in 2035, UKATC engineers employ precise control in 6 degrees of freedom with PI’s compact H-824 hexapod. Hexapods, with their programmable center of rotation (pivot point), are the gold standard when it comes to precise multi-axis alignment tasks, from nanometer sized structures in silicon photonics / fiber optics to big mirrors and reflectors in astronomy.

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