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When it comes to SpaceX, or perhaps more accurately from its somewhat eccentric founder and CEO, Elon Musk, it can be difficult to separate facts from fiction. With as much incredible success as SpaceX has experienced, there are an equal number of projects or ideas that are quite delayed or totally abandoned as soon as it becomes apparent that the technical challenges are bigger than expected. We must also deal with the particular humor of Elon; most people have assumed that the first payload of the Falcon Heavy would be his own Tesla Roadster was a joke until he tweeted the first shots of his installation inside the rocket fairing.
That's why, a few years ago, when Elon first mentioned Starlink, SpaceX's plan to provide broadband Internet access around the world via a mega-constellation of 12,000 satellites, it is not not surprising that many of them have been questionable. Starlink's profitability was intrinsically linked to SpaceX's ability to significantly reduce the cost of launching reusable launchers, an ability that the company had not yet demonstrated. It looked like a classic cart before the horse scenario.
But today, not only have SpaceX started to regularly reuse the latest version of their Falcon 9 rocket, but Starlink satellites will soon be in orbit around the Earth. These are old prototypes that are not as efficient as the final production versions, and with only 60 of them at the first launch, we are still far from the thousands of satellites that would be needed for the system to reach the operational status, but no doubt they are real.
During a press conference on May 15, Elon Musk let out more technical information about Starlink satellites than ever before, providing us with the first concrete details about the satellites themselves, about the company's goals. and even on a rough idea. the network could become operational.
Start the first generation
Elon has repeatedly said that these satellites would be the first generation of at least three generations of satellites that would ultimately constitute the Starlink network. They are closer to the final satellites than the Tintin A and Tintin B technology demonstrators launched in 2018, but still lack key features needed for optimal performance.
The biggest omission of these first satellites is the lack of laser communication links between vehicles, which means that each satellite will have to relay everything via ground stations. In other words, if a Starlink satellite wants to send data to one of its peers, it will have to send them to a ground station which will then forward the information over the terrestrial Internet to another ground station within reach of the recipient. . This not only increases latency, but also requires a large number of ground stations spread around the world.
To solve this problem, Elon said that future versions of Starlink satellites would use laser communications to form interconnected links, creating a mesh network in the space. Data should not always be sent to Earth, but can be routed via the satellite network. Of course, ground stations will still need data from and to the Internet, but much less will be needed and their geographical location will be less critical. This technology, which allows global communications with little or no terrestrial infrastructure, could also be applied to constellations of satellites orbiting the Moon or Mars. something that SpaceX certainly thinks in the long run.
In addition, Elon reiterated that these first 60 satellites did not include the "Design for Demise" optimizations implemented after the Federal Communications Commission (CFF) was concerned about SpaceX's inability to ensure that Starlink re-inserted satellites can be safely confined to the ocean. In response to the FCC, SpaceX promised that future satellite versions would be designed to burn completely during the fall, eliminating any risk of falling debris endangering life or property. of the man.
Experimental technology
There may be some key features missing from these first generation Starlink satellites, but they are not placeholders either. Although we have to wait for a moment before seeing a laser communication or a completely degradable construction, they certainly have unique capabilities that will likely attract the attention of other aerospace players if they succeed.
According to Elon, these satellites are the first vehicles to use a krypton ion propulsion system in space. NASA experienced this type of propulsion in the early 1990s, but never achieved operational status because it is less efficient than xenon-like propellers. That said, krypton is cheaper than xenon and, with low-cost satellites that should only make occasional adjustments to their orbit during their relatively short life span, the use of a propeller to lower yield was actually more economical.
With regard to orbital adjustments, these satellites will also test an autonomous obstacle avoidance system that should be of interest given the growing concern over "space debris" in low Earth orbit. The satellites will receive orbital debris data from a NORAD database and use it to decide for themselves whether or not to perform avoidance maneuvers. Traditionally, such decisions are made by the ground controllers, but with tens of thousands of satellites in the latest Starlink network, SpaceX has explained that this is a task that could benefit from automation.
Shipping and handling
It's interesting to learn about the technical aspects of the satellites themselves, but the biggest question most people have about Starlink is how SpaceX intended to place 12,000 satellites in orbit over the next two years. For reference, since the launch of Sputnik 1 in 1957, humanity has orbited fewer than 9,000 objects around the Earth. Seen in this light, one might think that Starlink's constellation of satellites would represent a new landmark in the use of space by mankind.
The possibility of reusing the Falcon 9 was a huge piece of the puzzle, but it would still not be economically feasible if SpaceX could not maximize the number of satellites that could mount at each launch. To this end, they have developed a new concept of "flat pack" for Starlink satellites. Inside the payload fairing, the satellites are arranged in a server rack-like layout and, once deployed, they deploy their solar panels and antennas in operational position. Elon admitted there was a chance that some of them would join at the exit, but added that this should not cause any serious problems considering their relative speed.
With 60 satellites weighing 227 kg each, plus the weight of auxiliary equipment such as the rack itself, this first Starlink launch will tip the balance to 18.5 tons; the largest mass that a hawk has ever put into orbit. Still, Elon said launching Starlink satellites would cost SpaceX more than building these satellites.
So how do you sign up?
Unfortunately, we have not learned much about when and how consumers can sign up for the Starlink Internet service. In the best case, Elon estimated that it would take another six launches before the network could even be activated, and twelve to provide enough coverage for it to be usable. After that, SpaceX will start looking for business partners to actually start selling Internet services and distribute their Phased Array terminals, probably to rural customers. At least for the moment, it seems that SpaceX prefers to partner with traditional Internet service providers rather than go to war, which will probably be a disappointment for those who hoped that Elon could revolutionize the telecommunications sector.
The satellite coverage is taken from the excellent Mark Handley video on Starlink.
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