'The Netherlands is number one in radio astronomy; we must take the lead'

With the Partnerships for Space Instruments & Applications Preparatory Programme, the Netherlands is supporting technological breakthroughs and scientific cooperation in space research. The 'Partnership for Space Instruments for Interferometry in Space' is building telescopes that should earn the Netherlands a new Nobel Prize.

Mark Bentum and Chris Verhoeven dream big. Bentum is professor of radio science at Eindhoven University of Technology and head of the Astronomy & Operations department at ASTRON. Verhoeven is associate professor of microelectronics at TU Delft. Together they lead the Breakthrough Technologies for Interferometry in Space program, which they believe could potentially lead to the next Nobel Prize for the Netherlands: “we don’t see any red signs.”

An 'instant consortium' – this is how the two describe the partnership in which, besides their universities, also the University of Groningen, Radboud University, SRON, ASTRON, JIVE, TNO and about twenty Dutch SMEs participate. Together they are working on the technology for interfero
Aerial image of LOFAR | Source: Drents Landschap metry in space: small satellites with large radio antennas that together unravel the secrets of the universe.

Interferometry is a technique in which different small telescopes work together as if they were one big telescope. On Earth, this technology is already widely used, for example for the Dutch telescope LOFAR, but in space it is relatively new – and quite complex. Besides the correct satellites and antennas, you also need communication between the satellites and from the satellites to the ground. In addition, the satellites should at least stay together as a swarm, sometimes far away from Earth. Such a swarm could 'repair' itself in case one of the satellites fails due to technical problems.

 

It will be a world-class scientific reward if we manage to get it all working. 'Our' technology could shed light on the formation of galaxies in the early, dark years of the universe. With it we may study black holes. And we could study magnetic fields from exoplanets – a precondition for the presence of life. These magnetic fields have never been observed before.

There are two main reasons for conducting radio astronomy from space, says Bentum: “The radio frequencies we investigate are also widely used on Earth. So, there is a lot of interference in the observations from Earth. In addition, the Earth has an atmosphere that blocks many interesting radio signals. The most logical place for our instruments, therefore, is in space, such as at the back of the moon or in an orbit around it.”

The partnership could be a catalyst for developments that the Netherlands otherwise would not easily attempt, Verhoeven believes. The Netherlands is the world's number one in the field of radio astronomy. Nevertheless, until now we have almost always been contributors in large space projects. Now we say: let's take the lead. Together we can develop the technology. We have the scientists, the engineers, and the industry. We owe it to our ourselves to take the lead.”

Artist impression of OLFAR | Source: ASTRON The cooperation has already led to several proof-of-concept studies and even a readymade receiver for the future radio interferometer Orbiting Low Frequency Array (OLFAR). A receiver that will go into space on a pocket-cube satellite to be tested there. A second achievement is the development of a giant, inflatable antenna of ten cubic meters that, as soon as the covid measures allow it, will be tested on an Indian stratosphere balloon at an altitude of fifty kilometers.

With the ultimate radio telescope in space, Bentum believes, we may conduct ground-breaking science. But there are spin-offs too: “Interferometry could also be applied on Earth, for example to localize objects. And the algorithms needed to keep multiple satellites in the right position in space lead to a lot of experience with distributed computing.” While a swarm of telescopes around the moon searches for the origin of galaxies, a swarm of satellites around the earth equipped with the same technology can try to predict earthquakes, detect natural disasters, after which a swarm of drones can help the victims or track down suspects of a crime.

Bentum and Verhoeven want to further expand their partnership in the coming years: “In the whole world there are three to four groups working in a similar position on interferometry in space and the spin-offs that make this technology possible. The Netherlands can compete with those groups if we work together. The goals we pursue are large enough for all parties involved to benefit from them. So, when a new party presents itself, we say: “come aboard!”