On the 24th of May, SpaceX launched a Falcon 9 rocket filled with 60 satellites into space. This marked the beginning of their ambitious new project called “Starlink” which aims to provide high-quality broadband internet to the most isolated parts of the planet, while also providing low latency connectivity to already well-connected cities.
SpaceX aims to make their broadband as accessible as possible, claiming that anyone will be able to connect to their network if they buy the pizza box-sized antenna which SpaceX is developing themselves. This launch of 60 satellites, was just the first of many.
SpaceX has 12,000 satellites  planned for launch over the next decade, dramatically increasing the total amount of spacecraft around Earth’s orbit.
This will cost SpaceX billions of dollars, so they must have a good reason for doing so. Let’s see how this network will work, and how it will compete with existing internet providers. Back in 2015, Elon announced that SpaceX had begun working on a communication satellite network, stating that there is a significant unmet demand for low-cost global broadband capabilities.
Around that time, SpaceX opened a new facility in Redmond, Washington to develop and manufacture these new communication satellites. The initial plan was to launch two prototype satellites into orbit by 2016 and have the initial satellite constellation up and running by 2020.
But the company struggled to develop a receiver that could be easily installed by the user for a low cost, this delayed the program and the initial prototype satellites weren’t launched until 2018.
After a successful launch of the two prototypes, Tintin-A and B, which allowed SpaceX to test and refine their satellite design, SpaceX kept pretty quiet about what was next for the Starlink project, until November 2018 when SpaceX received the approval from the FCC to deploy 7,500 satellites into orbit, on top of the 4,400 that were already approved. On May 24th, the first batch of production satellites was launched into orbit and people around the world quickly started to spot the train of satellites moving across the night sky.
This launch is a sign of things to come, while these initial groups of satellites are not fully functional, they will be used to test things like the earth communications systems and the krypton thrusters which will be used to autonomously avoid debris and de-orbit the spacecraft once it has reached the end of its lifecycle.
Let’s look at these functionalities first. Ion thrusters essentially use electric potential to fire ions out of the spacecraft to provide propulsion. Xenon is ideally used because it has a high atomic mass allowing it to provide more kick per atom while being inert and having a high storage density lending itself to long term storage on a spacecraft. However, SpaceX opted for krypton, as xenon’s rarity makes it a far more expensive propellant. This ion thruster will initially be used to raise the Starlink satellites from their release orbits at 440 km to their final orbital height of 550 km.
They will also be used in conjunction with onboard control momentum gyroscopes located here, and the US Governments’ space debris collision prediction system to allow the satellites to adjust their orbits to dodge collisions. When the satellites have reached the end of their service life they can then use the same attitude controls and thrusters to de-orbit the satellite. Space X has included all the necessary hardware to minimize space debris risk.
In their Federal Communications Commission approval application, they claim that 95% of the satellite will burn up on re-entry. However, with only the ion thruster internal structure, and silicon carbide components, it does stand a chance of survival.
Those silicon carbide components are likely to survive, as they are essential materials for the operation of lasers and thus have an extremely high melting point of 2,750°C. Which brings us to our communications abilities, the primary function of the satellite, which will be discussed in the part II of Why SpaceX wants to create Starlink.
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17 November, 2019