The SpaceX company of Elon Musk has put into orbit this night the first constellation of 60 Starlink satellites, a small part of the 12,000 programmed for broadband internet coverage on a planetary scale, which will allow access to the web even from rural areas and from the oceans.
The mission started at Cape Canaveral’s 40 launch complex with a Falcon 9 rocket, and it was a success from all points of view, although, as we recall, the two previous attempts were canceled. A first time on May 15th, for high winds at high altitude, and the second time on May 16th, for a software update of the satellites. Even Musk himself had stated that there was a high probability of mission failure.
Instead, at 4:30 am on May 24, Italian time, when it was 10:30 pm on May 23 in Florida, the Falcon 9 turned on the engines without any problem. All the maneuvers were performed impeccably, with the recovery of the first stage, landed gently on the OCISLY barge in the Atlantic Ocean, and the recovery of the ogives, as planned. The first stage was already on its third flight, carrying a Telstar satellite in the fall of 2018 and an Iridium satellite in January of this year, further demonstrating the reliability of the reuse of the Falcon 9 Block 5 boosters.
The second stage continued its journey towards the orbit, planned at 440 km altitude, performing two ignitions, the first 2 and a half minutes after the launch, very long, approximately 6 minutes, to bring the load to the desired altitude . The second one at 46 minutes from the launch, very short, of only 3 seconds, to circularize the orbit. Everything went smoothly, even this stadium fulfilled its duty to perfection and after 15 minutes it released the load all at once, the 60 satellites with the rack that contained them. At 5:32 am the Falcon 9 mission ended successfully.
For small satellites, work is not yet finished. Once released into orbit they slipped slowly from the rack, like cards from a deck thrown in the air, with no release or ejection mechanisms, in a messy motion. Abandoned the nest they will have to explain the solar panels, make checks and position themselves in the operating orbit at 550 km altitude, higher than the orbit where they are currently parked.
A single satellite weighs only 227 kg, much less than classic telecommunications satellites, to facilitate mass production and to send the largest number in a single launch. They are equipped with an electric propulsion engine with krypton ion, instead of the classic xenon, more efficient and normally used for these purposes. Krypton was chosen to allow mass production and to reduce costs, as it costs about 90% less than xenon.
Even the radio communication system uses an efficient method of pointing the signal, without moving parts, exploiting the multipolar phase synchronization to direct the wave front towards the desired target. This technological device makes it possible to decrease the total mass of the satellite and to eliminate rotation mechanisms that could limit its average life.
Starlink is not the only high-speed communication prototype in low orbit, there are dozens of competitors that are entering the market in these years, some have already shipped prototypes in space, others are still in the planning stage, but the Elon Musk’s company currently has the most operational satellites. To be able to provide the service to customers it will be necessary to reach at least 400 satellites for the first tests and 800 for the first phase with an acceptable level of service.
Astronomer Dr. Marco Langbroek noted on his blog that he calculated where the satellites would be orbiting, and waited with his camera. The result is a spectacular one: a string of bright dots flying across the sky