If the weather and the Falcon 9 rocket cooperate, SpaceX's first batch of Internet satellites will be launched from Florida on Wednesday night. With a mass of 18.5 tons, this will be the company's heaviest launch to date, either for the Falcon 9 or Falcon Heavy rocket.
The Wednesday rocket will boost 60 Starlink satellites, each weighing 227 kg, at an altitude of 440 km. This is the first block of Starlink satellites for what should eventually be a much larger constellation, and will help SpaceX measure its performance and test several key systems. In the coming months, these first satellites will be joined by six additional launches with payloads of similar size. These launches will take the constellation to an initial "operational" capacity.
There is no guarantee that everything will work out, said SpaceX founder Elon Musk during a teleconference with reporters on Wednesday night. "This is very difficult," said Musk. "There is a lot of new technology, so it's possible that some of these satellites will not work, there's a small chance that all these satellites will not work."
Release and launch
The start window opens at 10:30 pm on Wednesday (02:30 UTC on Thursday) and closes 90 minutes later. A backup start window will open at the same time on Thursday. It is forecast that the weather conditions will be favorable by 80 percent for the launch
The initial part of the launch will be familiar to people who have seen a SpaceX launch before. This first stage of Falcon 9 has flown twice before, and will attempt to land on the Of course I still love you Dronism in the Atlantic Ocean. The actual action will occur approximately 1 hour 2 minutes after the launch, when the second stage begins to deploy the Starlink satellites.
– Elon Musk (@elonmusk) May 12, 2019
To save mass, each of the 60 satellites will not have its own release mechanism, like a spring. Instead, Muskk explained, the upper stage of the Falcon rocket will start a very slow rotation, and each of the satellites will be released in turn with a different amount of rotational inertia.
"It will almost seem like extending a deck of cards on a table," Musk said. There may actually be some contact between the Starlink satellites, he added, but they are designed to handle it.
After deployment, the satellites will start to light their ion units and open their solar panels. They will move at an altitude of 550 km under their own power. Musk said he is concerned about the deployment of the solar panel, and noted that there are two different deployment mechanisms in satellites for this purpose. He also said that satellites have incorporated new technology with propellers, as well as phased array antennas that have not yet been fully tested in space.
Satellites are designed to control costs. For example, each will maneuver with the Hall effect propellers, ion thrusters in which an electric field accelerates the propellant. The conventional fuel for such a propellant is xenon, which offers high performance. The Starlink satellites, however, will use a different noble gas: krypton. It has a lower density, so satellite fuel tanks must be larger and have less performance than xenon. But krypton can be purchased at only a tenth of the cost of xenon, which is important if a company wants to feed thousands of satellites.
"It costs a lot less than xenon," Musk said of the krypton. (He also joked, in response to a question from Ars about this fuel, that the satellites would be immune to the invasion of the native world of Superman).
During the call, Musk said that each Starlink satellite costs more in the orbit than it costs to manufacture. The list price for a Falcon 9 release is $ 62 million. By taking into account the reuse discount and wholesale rates, this means that Starlink satellites cost significantly less than $ 1 million each to build.
SpaceX is competing with a half-dozen other companies to develop low-latency Internet and high bandwidth from space. One competitor, OneWeb, launched six of its own satellites in February. But SpaceX seems to be way ahead of most of the rest of the field.
With six more launches and a total of about 400 satellites, Musk said the constellation reached the point of being able to offer some initial connectivity to land users. A dozen launches would provide "meaningful" connectivity, he said, and 24 releases will provide an almost global service.
After several recent rounds of fundraising, SpaceX has enough capital to launch the first 400 satellites and start selling the service to telecommunications companies and governments that want to serve populated areas of low and medium density. If there are significant problems with the deployment or performance of the first 400 satellites, he said SpaceX would probably have to go back to the capital markets.
Over time, Musk anticipates that Starlink will become a commercial success for SpaceX and will allow its goal of building a self-sufficient city on Mars. Potential revenue per launch reaches a maximum of around $ 3 billion a year for the company, he said, but capturing only 3 percent of the global Internet market could generate around $ 30 billion. "We see this as a way that SpaceX can generate revenues that can be used to develop more and more advanced rockets," he said.
Musk acknowledged the validity of concerns about orbital debris from so many satellites (SpaceX has a license to launch more than 11,000 Starlink satellites, much more than the total number currently in orbit of about 2,000). But he also said that the chosen altitude of 500 km and the design of the satellites will help ensure that the constellation cleans itself due to interaction with the Earth's atmosphere.
The launch webcast, included below, should start approximately 15 minutes before launch.