A Dutch radio antenna on the farside of the Moon has successfully provided its first data.

The Netherlands-China Low-Frequency Explorer (NCLE) is onboard China’s Queqiao relay satellite in a halo orbit about the Earth-Moon L2 Lagrange point.

From that position, Queqiao is enabling communications between the China’s Chang’e-4 farside lander and Yutu-2 rover and the Earth.

NCLE is an instrument designed to measure radio waves from the Universe and was developed by a team from the Radboud Radio Lab of the Radboud University, the Netherlands Institute for Radio Astronomy (ASTRON) and the company Innovative Solutions in Space (ISIS).

The Netherlands-China Low-Frequency Explorer (NCLE) is onboard China’s Queqiao relay satellite.
Credit: Radboud Radio Lab of the Radboud University, the Netherlands Institute for Radio Astronomy (ASTRON) and the company Innovative Solutions in Space (ISIS)

Data looks good

The NCLE data show that the radio antenna is doing well under the extreme conditions in space and operates as planned.

“Now, the most dangerous phase of the mission is behind us,” says Christiaan Brinkerink from Radboud Radio Lab in a statement. “We are very happy to see that NCLE is in perfect health. The data look good, and we can now proceed with the next phases of our research.”

Radio antennas of the Netherlands Chinese Low-Frequency Explorer (NCLE), developed by ASTRON, Radboud Radio Lab, ISIS and the National Astronomical Observatories of China (NAOC).
Credit: Radboud Radio Lab/ASTRON/Albert-Jan Boonstra


Next phase

The next phase lasts for one month, and is meant to investigate how the performance of NCLE varies under the changing conditions during one orbit around the Earth.

After the first full month of commissioning is done with stowed antennas, the following run of measurements will be performed with partially deployed antennas.

“This process will allow us to perform a complete characterization of the instrument response at different positions in space and for different antenna lengths. It will provide data that we need to calibrate science measurements in the future”, says Albert-Jan Boonstra from ASTRON.

Image from Queqiao relay satellite shows NCLE stowed antenna, the Earth, and farside of the Moon. Queqiao is in a halo orbit at L2 Lagrange point.
Courtesy: Radboud Radio Lab

Full length deployment

The collection of actual scientific data by NCLE is planned to start in six months. At that point, the antennas will be deployed to their full length of a little over 16 feet (5 meters).

“This is what we are really looking forward to,” adds Eric Bertels from ISIS. “The calibration of the instrument is a crucial step in the project, but in the end we are looking for science data.”

According to Marc Klein Wolt from the Radboud Radio Lab: “We are taking it step-by-step working towards doing real science, but getting the first data of the instrument is a major step in the right direction.”

Pathfinder experiment

NCLE focuses on measurements at low radio frequencies, spanning the spectrum from 1 to 80 megahertz. The science cases of NCLE are diverse, and include the study of solar storms, the interaction of planetary magnetospheres with the solar wind, the mapping of low-frequency Galactic emission and ultimately to study the signature of neutral hydrogen in the early Universe.

The Dutch radio instrument the Netherlands-China Low-Frequency Explorer (NCLE) on the Chinese Queqiao satellite behind the moon, has successfully collected data.
The DVD with the data is handed over to Taake Manning, counsel for science and technology of the Dutch Embassy in Beijing.
Courtesy: Radboud Radio Lab/Radboud University


NLCE is described as a pathfinder experiment. Experience with its operation and data will be useful to aid in the development of future radio astronomy instruments.

The Chinese Queqiao relay satellite and Dutch antenna were launched from China in May 2018, prior to the Chang’e-4 farside. Queqiao means “Bridge of Magpies” referring to a Chinese folktale about magpies forming a bridge with their wings to allow Zhi Nu, the seventh daughter of the Goddess of Heaven, to reach her husband.

Go to this video showing one of the NCLE antenna elements deploying during a pre-launch test.


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