Dutch solar sensors crucial for the success of ESA mission LISA
The Dutch company Lens R&D B.V. (LRD) will supply 33 sun sensors for ESA’s scientific space mission LISA. The development of the technology was stimulated by NLSA through various programs of the European Space Agency (ESA). The order is the crowning achievement so far for founder and director Johan Leijtens: ‘We are the smallest company supplying technology for this almost unimaginable mission.’
The Laser Interferometer Space Antenna (LISA) is a European scientific space mission for research into gravitational waves. Starting in 2038, three satellites will fly through space 50 million kilometers away from Earth, spaced 2.5 million kilometers apart. Using a laser link, minuscule changes in position between the satellites are measured. In this way, LISA can detect gravitational waves caused by supermassive black holes that merged in the early universe.
The LISA satellites must be perfectly oriented for the mission to succeed. This is achieved using so-called star trackers, which know what the night sky looks like. These star finders are intended solely for fine-tuning. If the satellites lose their full orientation for any reason, they search for a single star to determine their position again: our Sun. They do that with the sun sensors from LRD.
‘On top of the world’
Johan Leijtens founded Lens R&D in April 2012, initially to develop sensors for solar farms on Earth. In 2015, he decided to focus entirely on solar sensors for space. Sensors that continue to function for fifteen to twenty years in the vacuum of space, while being bombarded by cosmic radiation day in and day out. And that can withstand temperature fluctuations ranging from 105 degrees above zero to 65 degrees below zero.
It took Leijtens ten years to develop the sensors and qualify them for ESA, so that they could be used on European space missions. The Netherlands Space Agency played a crucial role in this. First, by giving Leijtens a place in the space incubator ESA BIC in Noordwijk. Later, with three grants under ESA’s ARTES-programme and one grant from ESA’s GSTP-programme. The latter brought Lens R&D’s sensors to the ESA demonstration mission Proba-3, showing everyone: they work.
When the technology demonstrably worked, there was interest from the market. But it was, and still is, difficult to secure the really big contracts, says Leijtens: ‘My company consists of only five people. In the eyes of major satellite mission contractors, that is far too small.’ In addition to the quality of his sensors, he therefore also worked on scaling up his production capacity. Together with the company PhotonFirst in Alkmaar, he is now able to produce hundreds of sensors per month.
Following the success of Proba-3, orders followed for, among others, the MMX rover to Mars and the Lunar Pathfinder communications satellite from ESA’s Moonlight program. But the contract Leijtens signed for LISA at the end of February is an absolute highlight: ‘As far as our product is concerned, I feel on top of the world. LISA is a major scientific ESA mission that will bring about a tremendous amount. If anyone ever asks questions about the quality of our solar sensors again, I only have to point to LISA. The fact that they are flying on them speaks for itself.’
Quality and volume
For ten years, Leijtens continued to believe that his solar sensors deserved a place in space, sometimes against his better judgment. Looking back now, two choices were crucial to his success. First: quality standards. ‘In my designs, I always based my work on the strictest quality standards and a long lifespan for the sensors. I never compromised on that. Only later did I investigate how I could produce the sensors more cost-efficiently.’
And second: optimization for production in larger volumes. When Leijtens started his company, he foresaw a major development in space. Instead of a few very large satellites, like the climate satellite Envisat at the time, multiple small satellites would be built in the future, which could potentially work together in constellations. ‘From the start, it has been my ambition to supply SCOTS: Space Grade Commercial Off The Shelf, or in other words: sun sensors that I can supply from stock in batches of tens or even hundreds at a time.’
With the order for LISA secured, Leijtens is investigating a potential contribution to the European communications satellite constellation IRIS2. In addition, there is sufficient interest from international space parties. ‘Space is often a long-term endeavor. That certainly applies to the development of our sun sensors as well,’ says Leijtens. ‘I am glad that I have continued to invest, develop technology, and believe in this product all these years.’
