With Starlink's launch, a constellation that would one day offer wireless internet service to the entire globe, SpaceX has attracted lots of attention and criticism. The organization deployed over 800 satellites and is developing them at a rate of 120 a month. Before the decade is over, there are also proposals to have a network of 42,000 satellites in space.
There have, though, been several concerns in the route as well. Experts found three malfunctioning satellites, aside from the everyday worries regarding light emission and Radio Frequency Interference (RFI). About 3% of Starlink's satellites have proved to be unresponsive and no longer maneuver in orbit, which can prove risky to other orbital satellites and spacecraft.
SpaceX equips its spacecraft with krypton Hall-effect thrusters (ion engines) to lift their altitude, maneuver in space, and deorbit at the end of their lives to avoid collisions in space. However, according to two new SpaceX notices released during the summer (mid-May and late-June) to the Federal Communications Commission (FCC), some of their satellites have lost maneuvering functionality since they were launched.
Unfortunately, not enough detail was given by the organization to show which of their satellites were impacted. For this cause, the Harvard-Smithsonian Centre for Astrophysics (CfA) and Chandra X-ray Centre astrophysicist Jonathan McDowell proposed his study of the orbital activity of the satellites to indicate which satellites have crashed.
The study was reported on McDowell's website (Jonathon's Space Report), where he mixed SpaceX's data with sources from the US government. He estimated that about 3% of the constellation's satellites have crashed because they are no longer responding to commands. Naturally, a degree of turnover is unavoidable, and, as failure rates go, 3 percent is reasonably low.
But any satellite that is unable to navigate (due to issues with its communications or propulsion system) poses a possibility for other satellites and spacecraft to collide.
While the failure rate is not egregious, McDowell said it's no worse than anybody else's failure rates. "The concern is that even a normal failure rate in such a huge constellation is going to end up with a lot of bad space junk," he told Business Insider.
SpaceX started deploying the Starlink constellation on May 23, 2019, with the first batch of 60 satellites. Their new launch, which nearly brought their constellation to 835, took place on October 24. Therefore, a 3% failure rate suggests that approximately 25 satellites would malfunction and become part of the increasing "space garbage" epidemic.
Kessler Syndrome, named after NASA scientist Donald J. Kessler, who first suggested it in 1978, relates to the danger of accidents in space. This adds to disastrous breakups that cause more debris that would lead to more crashes and breakups. This syndrome inevitably rears its ugly head as one takes into consideration failure rates and SpaceX's long-term ambitions for a "mega constellation."
Not long ago, SpaceX granted the Federal Communications Commission (FCC) approval to launch approximately 12,000 Starlink satellites in orbits varying from 200 to 360 mi (328 km to 580 km). More recent filings with the International Telecommunications Union (ITU) indicate that the corporation aims to build as many as 42,000 satellites as a mega constellation.
A 3% loss rate in this situation results in 360 and 1,260 (respectively) 250 kg (550 lbs) satellites being defunct over time. As of February 2020, there are 5,500 satellites in Earth's orbit, according to the ESA Space Debris Office (SDO), of which about 2,300 are already active. That implies that the amount of non-functioning satellites in orbit may increase by 11 percent to 40 percent by a complete Starlink mega constellation.
Design of the Starlink constellation to surpass the NASA guidelines for debris reduction and an "aggressive tracking scheme" to locate potential problems and deorbit damaged satellites.
There's also the possible case that if their propulsion systems malfunction and cannot lift their orbit or apply corrective thrust, Starlink satellites would inevitably deorbit. But even with their lower orbits, this phase would also take 1 to 5 years relative to other telecommunications satellites. There are no promises at the end of the day, only vigilance and preparedness.
Deployment of 60 Starlink satellites confirmed pic.twitter.com/x83OvjB4Pa — SpaceX (@SpaceX) October 6, 2020
In the meantime, Musk announced earlier this month that Starlink is preparing to conduct a trial test of its internet service with the current batch of its satellites launched into space.
"Once these satellites reach their target position, we will be able to roll out a fairly wide public beta in the northern US & hopefully southern Canada. Other countries to follow as soon as we receive regulatory approval," he tweeted.
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