2022 will go down in orbital launch history as the year that SpaceX’s Falcon 9 finally broke all of its launch and reuse records. And, the most amazing thing, without any failure (so far, of course). Today, September 11, 2022 at 01:20 UTC, SpaceX launched the Starlink 4-2 mission from ramp 39A at the Kennedy Space Center. On board were 34 Starlink satellites and the Blue Walker 3. The first highlight of this mission is that the first stage B1058 was flying for the 14th time and, once once more, it was successfully recovered. This is the largest number of missions flown by a Falcon 9 first stage to date. It is followed by stages B1051 and B1060, both with 13 missions behind them, B1061, with 10 launches, and B1062, with 9 missions. Stage B1058 has completed these 14 missions in just over two years, let’s not forget that it debuted in May 2020 on Crew Dragon’s DM-2 manned mission. On the other hand, in this mission the second stage carried out five firings, another new SpaceX record, to deploy the Starlink and BlueWalker 3 satellites in different orbits (in addition to the final firing to deorbit the stage).
So far this year, SpaceX has already launched 41 Falcon 9 missions, a spectacular figure that surpasses all other space agencies and private companies (not even China, the second space power in terms of orbital missions, has launched so many rockets so far). , even taking into account the different versions of the Long March launchers). The figure is more striking if we take into account that in the last two years SpaceX launched 31 and 24 Falcon 9, respectively… and let’s not forget that there are still three and a half months left until the end of 2022. Of these 41 missions, 27 of them have been fully or partially dedicated to launching Starlink satellites into orbit. This mission was named Starlink 4-2 as it was intended for the layer —shell— or group number 4. The 34 satellites in this launch will allow for 1,260 operational satellites in this layer. Let us remember that the Starlink mega-constellation will be made up of five layers with inclinations of 53º, 70º and 97.6º. Layer number 4 will be made up of 1,584 satellites at a height of 540 kilometers in orbits with an inclination of 53.2º, divided into 72 different orbital planes.
Falcon 9’s first stage has landed on the A Shortfall of Gravitas droneship – completing SpaceX’s first 14th flight of a first stage booster pic.twitter.com/F6Stba4bU3
— SpaceX (@SpaceX) September 11, 2022
Throughout this year, Elon Musk’s company has launched a whopping 1,349 Starlink 1.5 into space. The Starlink mega-constellation already has more than three thousand satellites in orbit (!), with regarding 2,500 of them operational (the rest will be in the coming months). Although there are several mega-constellation plans in the works, Starlink’s numerical advantage over its competitors is simply staggering. In this blog we have repeatedly talked regarding the negative impact of mega-constellations on the night sky and, precisely, this launch reminds us that the danger does not come only from SpaceX. The reason is that, along with the 34 Starlink satellites, BlueWalker 3, a 1.5-tonne satellite from the AST SpaceMobile company in Texas (USA), was put into orbit. Costing around $85 million, BlueWalker 3 is a prototype of a constellation that the AST SpaceMobile company wants to deploy for direct communications with mobile phones. To do this, the satellite, which was originally going to be launched with a Soyuz rocket, has a large deployable antenna 10 meters in diameter and an area of 64 square meters. The antenna is made up of 148 individual antennas divided into sections of 4×4 blocks called Microns. Although there are communications satellites with comparable antennas, most are thousands of kilometers away, in geostationary orbit. By contrast, the BlueWalker 3 was placed in an orbit of regarding 513 kilometers high. With such a large antenna, satellites like BlueWalker 3 will be quite bright and promise to become a new nightmare for amateur and professional astronomers.
Building on the experience of BlueWalker 3, AST SpaceMobile plans to deploy an operational constellation of satellites with huge antennas. These communications satellites will be called BlueBirds and the first five copies, to be launched by SpaceX next year, will have dimensions similar to BlueWalker 3, while the rest will be even larger (precise figures unknown). The final constellation will be made up of 168 satellites in a first phase, with the option to be expanded to 243 units later. The satellites will be located between 725 and 740 kilometers high, in orbits inclined at 0º, 40º and 55º. AST SpaceMobile has already signed contracts with more than ten telephone operators around the world to offer its services. In any case, it is important to emphasize that the greater the height of a satellite, the greater the global impact on astronomical observations (and in terms of contamination of the radio spectrum). The reason is that, although their brightness will be lower when they are higher, they will spend more time flying over the same area of the sky, so the chances of interfering with some observation are greater.
The impact of a constellation of satellites with such large antennas on astronomy has not been properly evaluated, which is not surprising considering that it was not until the first launches of Starlink satellites that the community of astronomers and radio astronomers began to worry regarding the mega constellations. Well, now it’s time to worry regarding the constellations of satellites with large antennas. As in the case of Starlink, the problem is not limited to this new constellation of AST SpaceMobile, since multiple companies are planning similar constellations for direct communication with mobile devices. If mega-constellations were already a headache, what will happen to the night sky when we have hundreds or thousands of satellites equipped with huge antennas?
