Recent observations of the BlueWalker 3 prototype satellite show that it is one of the brightest objects in the night sky, rivalling the brightest stars. Astronomers have now raised concerns that large communication satellites like the Bluewalker 3 could compromise the ability to observe stars from Earth and perform radio astronomy.
A study, details of which were published recently in a paper in the Nature journal, led by an international team of scientists including those from the Imperial College of London (ICL), examined how the BlueWalker 3 prototype satellite, which was launched in September 2022 by ATS SpaceMobile, could impact astronomy.
This satellite is a prototype for a planned constellation of over a hundred similar satellites for use in mobile communications, a press statement by ICL explains. Within weeks of its launch, observations from the satellite confirmed that it was among the brightest objects in the sky.
Currently, several companies are planning ‘constellations’ of satellites, which can deliver mobile or broadband services anywhere in the world. However, they have to be in low-Earth orbit and can be significantly large and bright. Hence, they could disrupt people’s view of the night sky.
The researchers documented BlueWalker 3’s brightness over a period of 130 days. The new data show “a sudden increase coinciding with the complete unfolding of the antenna array, which at 64 square meters is the largest commercial antenna system ever deployed into low-Earth orbit,” the statement from ICL explains.
For scientists, the night sky is a one-of-a-kind laboratory where they can conduct a variety of experiments. “Astronomical observations have provided insights into fundamental physics and other research at the boundaries of our knowledge and changed humanity’s view of our place in the cosmos,” Dave Clements, from the Department of Physics at ICL, says in the statement. Now, the group of satellites could hinder these experiments and observations.
Along with disrupting observations, BlueWalker 3 could also interfere with radio astronomy, as it uses wavelengths close to those that radio telescopes observe in and existing observatory protections from radio interference may not be sufficient, the researchers say in the statement.
While the researchers understand the importance of the satellites, their interference with astronomical observations could significantly affect progress in understanding of the cosmos. Therefore, they advise that the satellite’s deployment should be conducted after considering their possible side effects.