On 20 May 2018, The Chinese space agency (CNSA), launched its relay satellite Chang’e 4 to an orbit behind the Moon. On board the satellite was a Dutch radio antenna, the Netherlands Chinese Low-Frequency Explorer (NCLE). The radio antenna is the first Dutch-made scientific instrument to be sent on a Chinese space mission, and it will open up a new chapter in radio astronomy.
The radio antenna was made by engineers from the Radboud Radio Lab of Radboud University; ASTRON, the Netherlands Institute for Radio Astronomy in Dwingeloo; and the Delft-based company ISIS, astronomers want to measure radio waves originating from the period directly after the Big Bang, when the first stars and galaxies were formed.
Why is it so important for the measuring instruments to be placed behind the moon?
According to Professor of Astrophysics from Radboud University and ASTRON, Heino Falcke, radio astronomers study the universe using radio waves, light coming from stars and planets, for example, which are not visible to the naked eye. One can receive almost all celestial radio wave frequencies here on Earth, except for those below 20 MHz, as these are blocked by the atmosphere. It is these frequencies in particular that contain information about the early universe, which is why they wanted to measure them.
This radio antenna will receive radio waves with a large frequency range. In the past this was not possible and therefore a receiver with a narrow frequency band was used, in order to avoid electromagnetic interference of the satellite itself. The team has now succeeded in avoiding the electromagnetic interference and making a broadband receiver. This technology can now be used by subsequent missions and can also be used for future nano-satellites.
In 2016 the Netherlands Space Office and its Chinese counterpart CNSA signed an agreement to cooperate in this project, which was an elaboration of the Memorandum of Understanding the two space agencies signed the year before during a trade mission in presence of the Chinese President Xi Jinping and the Dutch King Willem Alexander. On April 30, the antenna successfully passed the final pre-flight test following which was launched in to orbit on 20 May, 2018.
