Hidden Worlds in Sight

10. september 2026 | FAULHABER Nordic ApS

• Motion & Drives

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With FAULHABER drive technology in the search for exoplanets

Space has always held a special fascination for humankind. Countless secrets remain concealed within the seemingly endless expanse between billions upon billions of stars, many of them still undiscovered today. While some celestial bodies are visible to the naked eye, most remain beyond our direct view: distant stars, galaxies, and planets waiting to be found. It is precisely this challenge that the Nancy Grace Roman Space Telescope is designed to address. The mission aims to detect and observe previously hidden exoplanets beyond our solar system. Its goal is not only to reveal new worlds, but also to help answer one of astronomy’s most compelling questions: Is there somewhere in the universe a planet similar to Earth, potentially capable of supporting life? Making such discoveries possible requires cutting-edge technology, including drive systems from FAULHABER. Integrated into the telescope’s highly precise coronagraphs, these drive systems play an important role in making the light of distant stars and the planets hidden in their glare visible to scientists.

To detect distant exoplanets, the Nancy Grace Roman Space Telescope is equipped with a range of highly specialized scientific instruments. A key component is the Coronagraph Instrument (CGI), for which engineers and scientists at the Max Planck Institute for Astronomy have developed essential optical components. The CGI will test an innovative camera concept in space for the first time, enabling the direct imaging of exoplanets located close to distant stars. The challenge is immense: planets reflect only a tiny fraction of the light emitted by their host stars and are almost completely overwhelmed by their brightness. The search becomes even more demanding when targeting smaller, Earth-like planets orbiting comparatively close to their stars. To make such worlds visible at all, the CGI combines two proven observational techniques for the first time in a space-based application: coronagraphy and adaptive optics.

Making the invisible visible
Using specially designed masks, a coronagraph suppresses the intense surrounding starlight, creating the conditions necessary to detect much fainter objects in its immediate vicinity. However, this alone is not sufficient when searching for potentially habitable planets. Astronomers are looking for celestial bodies that are billions of times dimmer than their host star while orbiting at a distance that could allow the existence of liquid water, one of the key prerequisites for life as we know it on Earth.

To directly image such faint planets located next to their host stars, the Coronagraph Instrument (CGI) must operate with near-perfect precision. This is only possible in space, beyond Earth’s atmosphere, which introduces turbulence and distorts incoming light. Yet even in orbit, residual vibrations and thermal disturbances affecting the space telescope must be corrected using adaptive optics. By minimizing the remaining optical aberrations, adaptive optics further enhances the contrast between star and planet. Only this extraordinary level of precision makes it possible to separate the faintest signals from the depths of space from their bright background.

Clear night sky with numerous stars and a shooting star above the silhouettes of conifer trees.
A key role within the Coronagraph Instrument is played by the so-called Precision Alignment Mechanisms (PAMs). The Max Planck Institute for Astronomy developed and manufactured a total of six flight models and six additional engineering models of these highly precise positioning systems. Their task is to align optical components such as mirrors and filters with extreme accuracy and keep them stable throughout observations. Only when these elements are positioned with absolute precision can the CGI reliably capture the extremely faint light signals emitted by distant exoplanets.

Maximum precision powered by FAULHABER
To ensure that the PAMs can perform their positioning and stabilization tasks reliably, the development team turned to the drive technology and expertise of FAULHABER. The solution combines brushless DC motors from the 1628 … B family with 15/10 series planetary gearheads. In addition, the connection cables were individually modified to ensure an optimal fit and the best possible performance.

Dr. Oliver Krause, Head of the Infrared Space Astronomy Group at the Max Planck Institute for Astronomy, explains the key criteria behind the product selection:

"Our primary requirement was the size of the drive system. We needed a compact solution that is also highly stable and capable of positioning with absolute precision, as the optical elements must not tilt. We were equally impressed by its low power consumption."

Detailed view of a module of the coronagraph positioning unit with an integrated FAULHABER drive system that performs positioning and stabilization tasks.
Before the components on board the Nancy Grace Roman Space Telescope could begin their journey into space, they had to undergo an extensive qualification program. After all, conditions in space bear little resemblance to those on Earth. The drives and mechanisms were therefore subjected to rigorous testing under conditions that closely simulated their intended operating environment.

This included temperature tests ranging from approximately −35°C to +80°C, as well as high-vacuum testing to verify component performance in the near-total absence of air. Radiation resistance was another critical factor. For example, the Hall sensors integrated into the motors were exposed to targeted radiation tests to ensure reliable operation under the expected conditions. In addition, the complete system had to pass demanding vibration and shock tests designed to simulate the extreme mechanical loads experienced during launch and operation. Only after successfully completing this comprehensive test program was the technology proven capable of meeting the exceptional demands of a multi-year space mission.

A milestone for exoplanet research
The requirements placed on the Precision Alignment Mechanisms (PAMs) developed at the Max Planck Institute for Astronomy are extraordinary. Over an observation period of more than eight hours, the optical elements of the Coronagraph Instrument, including mirrors, filters, and coronagraphs, must not tilt by more than 40 milliarcseconds. To put this into perspective, this angle is roughly equivalent to the apparent size of a person in Los Angeles viewed from Heidelberg.

This extreme level of precision highlights the technological complexity of the Coronagraph Instrument (CGI), which is regarded as one of the most sophisticated and demanding scientific instruments ever developed for use in space. Yet its significance extends far beyond the current mission. If the instrument can be successfully commissioned and validated in orbit, it will provide astronomy with a powerful tool for future research. At the same time, the CGI could pave the way for a new generation of coronagraphs. The insights and technologies gained from its operation will form the foundation for future space telescopes with even greater capabilities, enabling scientists to study Earth-like planets with a level of accuracy that has so far been out of reach.

As a result, the Coronagraph Instrument is not only a key to discovering new worlds but also an important milestone on the path toward the great observatories of the future, supported by precision technology that is already pushing the boundaries of what is technically possible today.