Satellite electronics show up in radio images
A Curtin University-led study has documented unintended radio emissions from Starlink satellites across frequencies used by the Square Kilometre Array's low-frequency observatory in Western Australia. The findings add a hardware-leakage problem to the better-known challenge posed by satellites' visible brightness.
According to a report summarizing the research, the team analyzed about 76 million radio images collected over 29 days with Engineering Development Array 2, a prototype station for SKA-Low. Researchers catalogued 112,534 emissions associated with 1,806 individual Starlink satellites between 73 and 235 megahertz. Some detected signals were reported to be as much as 10,000 times stronger than the faint astronomical signals the observatory is designed to measure.
These emissions are distinct from Starlink's intended communications links. They are described as electromagnetic leakage produced by onboard electronics and coupled through the satellite structure. The study identified recurring narrow tones near 137 megahertz on some spacecraft, but the unwanted signals are not scheduled transmissions that astronomers can simply avoid during known windows.
A gap in spectrum protections
SKA-Low is being built to investigate extremely weak signals, including neutral hydrogen from the period when the universe's first stars and galaxies formed. Strong moving sources in the same frequency range can contaminate images or increase the processing needed to recover useful observations. A rapidly growing constellation increases how often satellites cross the instrument's wide field of view.
International radio rules protect designated astronomy bands from authorized transmitters, but unintended radiation from satellite electronics is less directly covered. The report characterizes that as a regulatory gap: an operator may comply with limits on its communications beams while hardware noise still enters frequencies used for science.
Software mitigation may help identify or remove some interference, but researchers cautioned that unpredictable leakage is difficult to model and that the processing burden could be substantial. Engineering changes to future spacecraft offer a more direct route, provided manufacturers can identify and shield the components responsible.
SpaceX has previously worked with scientific bodies on satellite impacts, including optical brightness and higher-frequency coordination. The report says researchers shared the latest results with the company and that dialogue about future hardware changes is possible. It does not describe a committed redesign.
The study's large sample provides evidence that the issue is not limited to a handful of anomalous satellites. The next question is whether observatories, regulators and constellation operators can establish measurable leakage standards and incorporate them into spacecraft design before low-frequency radio observations become substantially harder.
