SpaceX Starlink satellites 'use multiple strategies to prevent debris generation in space'

Featured Image Source: Starlink Render Created By @ErcXspace via Twitter.

SpaceX has U.S. Federal Communications Commission (FCC) approval to launch 12,000 Starlink satellites to provide high-speed broadband internet access. The constellation is designed to serve the entire planet, especially rural and remote regions where internet access us unreliable or completely unavailable. SpaceX has launched around 2,200 satellites as of today and provides internet service to over 250,000 users across 29 countries. The Starlink satellite service has demonstrated to be reliable in communities where internet is nonexistent and in regions that are facing difficult life circumstances, like the Kingdom of Tonga after the volcanic eruption destroyed the islands' undersea fiber-optic internet cable, and in Ukraine during the ongoing Russian war which has destroyed critical infrastructures. Starlink is helping country leaders and emergency response teams have reliable communication to coordinate civilian safety operations.

SpaceX’s goal is to expand coverage to all remote locations on Earth to ensure every community has equal access to the world wide web. The company has faced opposition from some astronomers who claim that the Starlink constellation of thousands of internet-beaming satellites could potentially affect their astronomical observations. SpaceX has implemented upgrades to Starlink satellites, in collaboration with leading astronomers, aimed at reducing the satellites’ brightness in orbit to reduce the probability of the satellites interfering with their research. Each satellite is equipped with a visor that moves to cover the satellites' most reflective areas from the Sun as it rises into a higher altitude.

Some satellite competitors voiced their concerns over the constellation potentially posing a threat of collision to other orbiting satellites. However, SpaceX Starlink constellation is the world’s most advanced infrastructure in orbit. The satellites are equipped with advanced technology and sensors that enable each to autonomously move to avoid colliding with other orbiting objects based on tracking data by the U.S. Department of Defense. “SpaceX has high fidelity location and prediction data for our satellites from deployment through end-of-life disposal, and we share this information continuously with the U.S. Space Force, LeoLabs and other operators for tracking and collision avoidance screening. SpaceX satellites regularly downlink accurate orbital information from onboard GPS. We use this orbital information, combined with planned maneuvers, to accurately predict future ephemerides, which are uploaded to Space-Track.org three times per day,” the company shared. 

SpaceX is also taking the necessary steps to ensure the Starlink broadband constellation does not create space debris when a satellite is no longer operational. The satellites are designed to completely burn up upon entering Earth’s atmosphere when they are no longer useful. Each is equipped with krypton-powered Hall thrusters which allow them to deorbit. The company provided details about how satellites “use multiple strategies to prevent debris generation in space,” via an update on its website. “SpaceX is deeply committed to maintaining a safe orbital environment, protecting human spaceflight, and ensuring the environment is kept sustainable for future missions to Earth orbit and beyond,” it wrote. SpaceX designed and manufactured “highly reliable, maneuverable satellites that have demonstrated reliability of greater than 99% […] following the deployment of over 2,000 satellites, where only 1% have failed after orbit raising.” The company operates the satellites “at low altitudes (below 600 km) to ensure no persistent debris, even in the unlikely event a satellite fails on orbit.”

The Falcon 9 rocket deploys a fleet of Starlink satellites in Low Earth Orbit “at an especially low altitude to verify health prior to raising into their on-station/operational orbit.” The satellites are deployed into a low altitudes under 300 kilometers above the planet. After engineers verify that the satellites are working properly, the satellites use their integrated electric propulsion thruster to rise into an operational altitude of approximately 540-kilometers. When satellites do not work, engineers can send a command to deorbit the satellites or allow atmospheric drag to move the satellites to burn in the atmosphere. “SpaceX has safely deorbited over 200 satellites utilizing this approach. By building reliable, debris minimizing satellites, planning for active deorbit and designing for full demisability, we ensure we’re keeping space sustainable and safe.” 

SpaceX demonstrated its on-orbit debris mitigation in February, after a geomagnetic storm caused 38 newly-launched Starlink satellites to fall into Earth’s atmosphere due to increased drag. “Despite such challenges, SpaceX firmly believes that a low insertion altitude is key for ensuring responsible space operations,” they said. 

“With space sustainability in mind, we have pushed the state-of-the-art in key technology areas like flying satellites at challenging low altitudes, the use of sustainable electric propulsion for maneuvering and active de-orbit, and employing inter-satellite optical communications to constantly maintain contact with satellites,” the company said. “SpaceX is striving to be the world’s most open and transparent satellite operator, and we encourage other operators to join us in sharing orbital data and keeping the public and governments updated with detailed information about operations and practices.” 

The satellites are designed to have a lifespan of only 5 to 6 years to avoid creating long-term space junk, unlike other satellites with a long lifespan that take decades to decay in orbit, as shown in the graph below. “Our satellites use multiple strategies to prevent debris generation in space: design for demise, controlled deorbit to low altitudes, low orbit insertion, low operating orbit, on-board collision avoidance system, reducing the chance small debris will damage the satellite with a low profile satellite chassis and using Whipple shields to protect the key components, reducing risk of explosion with extensive battery pack protection, and failure modes that do not create secondary debris,” the company says. You can read more elaborate details at SpaceX’s official website: spacex.com/updates

Images Source: SpaceX.com