Context: A recent study published in ‘Astronomy & Astrophysics’ reveals that Elon Musk's Starlink satellites are disrupting the work of astronomers. Experts argue that this growing issue underscores the urgent need for regulations governing satellite operators, similar to those in place for controlling radio pollution from ground-based sources like cell-phone towers.
The impact of Starlink Satellites on Radio astronomy:
- Starlink, a satellite internet constellation operated by SpaceX, currently has over 6,300 active satellites orbiting Earth at an altitude of approximately 550 km.
- While these satellites are instrumental in delivering high-speed internet to remote areas, they are also a source of unintended electromagnetic radiation (UEMR), commonly referred to as ‘radio noise.’
- This interference poses significant challenges to radio astronomers, as it disrupts their ability to observe celestial objects from Earth.
Understanding Radio astronomy and Radio noise:
- Radio astronomy is a specialized branch of astronomy that focuses on studying celestial bodies by detecting radio frequencies, which are much higher in wavelength and lower in frequency than the visible light detected by optical telescopes.
- Unlike optical telescopes, which rely on visible light, radio telescopes are designed to capture radio waves emitted by objects in space.
- However, much like how bright visible light can overwhelm a viewer’s vision-akin to the glare of oncoming car headlights-radio frequencies can similarly ‘blind’ radio astronomers.
- Cees Bassa, a researcher at the Netherlands Institute for Radio Astronomy (ASTRON), explained that the radio noise from satellites is making it increasingly difficult to study the faint signals from distant objects in the universe.
- ‘Blinding’ scientists means that the eyes are collecting too much light to see anything clearly.
The growing challenge of UEMR:
- The study found that Starlink’s second-generation satellites-though currently accounting for less than a third of the overall network-emit UEMR at levels that are 32 times brighter than their first-generation counterparts.
- This is a worrying trend, especially since the first-generation satellites had already raised concerns regarding radio leakage.
- The situation could worsen further as the satellite industry continues to expand. With advancements in technology making satellite launches cheaper, estimates suggest that up to 100,000 satellites could be orbiting Earth by 2030.
- As of June 2023, the United Nations Office for Outer Space Affairs (UNOOSA) reported the presence of around 11,330 satellites in orbit.
- The growing number of satellites will only increase the risk of UEMR and radio interference for astronomers.
Need for regulatory oversight:
- These developments underscore the urgent need for regulations governing satellite operators, much like the existing regulations that control radio pollution from ground-based electronic sources such as cell-phone towers.
- Currently, astronomers rely largely on good faith agreements with companies like Starlink to minimize interference.
- However, this informal approach may not be enough as the number of satellites and the intensity of UEMR increase.
- In the absence of stringent regulations, the increasing UEMR from satellite constellations could pose an existential threat to radio astronomy, blinding telescopes to the faint signals that scientists rely on to explore the universe.
About Starlink Project:
- It is the world's first and largest satellite constellation using a Low Earth orbit to deliver broadband internet capable of supporting streaming, online gaming, video calls, and more.
- It delivers high-speed, low-latency internet to users all over the world. This system is ideally suited for rural and geographically isolated areas where internet connectivity is unreliable or non-existent.
- The satellites are equipped with Hall thrusters, which are used to manoeuvre in orbit, maintain altitude, and guide the spacecraft back into the atmosphere after their missions. Hall thrusters generate an impulse using electricity and krypton gas.
- It operates on a satellite internet service technology that has existed for decades. Instead of using cable technology to transmit internet data, a satellite system uses radio signals through the vacuum of space.
- It offers unlimited high-speed data through an array of small satellites that deliver up to 150 Megabits per second (Mbps) of internet speed.
- It uses Low Earth Orbit (LEO) satellites and a phased array antenna to help keep its performance intact during extreme weather conditions.
- In 2019, SpaceX initiated the launch of these satellites into space.
- Unlike conventional internet providers, it operates without the need for ground infrastructure. Users only require a small satellite dish or a receiver device, similar to satellite TV, to access high-speed internet.
- It can withstand extreme cold, heat, hail, sleet, heavy rain, gale-force winds, and even rocket engines.
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