SpaceX continues to launch satellites in orbit while the space community worries

In early 2020, SpaceX became the operator of the world’s largest constellation of active satellites, with 180 satellites in orbit around the planet. The milestone is a mere starting point for Starlink, SpaceX’s ambitious project to provide Internet capabilities to every inch of the world. To get that kind of connectivity, the company wants the option to launch up to 42,000 satellites in the next decade. That’s about 21 times the number of operating satellites currently in space, and the true impact of the company’s nascent mega constellation remains a mystery.

In the history of the world, downloading a lot of new things in one place generally has some consequences, and many within the space community have expressed concern about possible side effects of Starlink. Perhaps the biggest protest has come from astronomers who see Starlink as a great threat to their work. Satellites already accumulate images of the night sky, so even plus Spacecraft that zoom on the Earth could significantly hamper their ability to see distant objects in the Universe.

Meanwhile, people involved in satellite tracking are more concerned about how these spacecraft will influence an already quite crowded space environment. Space debris already creates an intricate space highway of intersecting orbiting traffic lanes, dominated by satellites moving thousands of kilometers per hour. Adding more will increase the risk of collision and could make launching into space much more difficult in the future.

SpaceX has heard the complaints of concerned scientists and satellite observers. The company has taken some steps to mitigate the astronomy problems that many fear, and has also published more data on the positioning of its satellites to help with the monitoring. But those steps are not enough for some defenders. And some of the decisions that several groups are pushing for, such as changing the design of satellites, can potentially reduce a problem for one group but cause more problems for others. SpaceX declined to comment on this story.

These are the problems that will continue to arise as SpaceX launches its Starlink satellites, 60 spacecraft at a time.

Space traffic

With SpaceX planning to send so many satellites, the chances of these objects approaching other satellites are much greater. And that is a terrifying perspective. Collisions between high-speed objects in orbit are prone to create hundreds to thousands of pieces of debris, which can then threaten other objects in space. The expert tracking of Starlink satellites, and all satellites, is key to ensuring that these vehicles are not accidentally located with each other.

At this time, the main resource for satellite tracking is the Air Force Space Surveillance Network, which is responsible for controlling everything in orbit using a series of terrestrial sensors. The problem is that the Air Force tracking data is not always accurate. Create estimated orbits by taking periodic measurements of objects as they pass over; You cannot track them directly. For expert satellite trackers, the best way to understand where there is something in space is to combine Air Force estimates with positioning data collected by the satellite itself. Together, this data can provide a clearer view of where a satellite really is in the sky.

When SpaceX started launching, there was some frustration that the company was not sharing as much satellite positioning data as it could. The company also suffered an embarrassing problem of lack of communication in September when one of its satellites uncomfortably approached a European satellite. But things have changed with the company’s latest release in January. Before the mission was carried out, SpaceX shared its estimates of the basic direction, speed and location that its satellites would take after its deployment, and the company will continue to share GPS data on board through the Air Force. This information can be accessed through a website called Space Track, for anyone who has an approved account with the website.

The movement has been praised by satellite trackers, but even with all this information, it is still difficult to know what SpaceX satellites are going to do and where they will be in the future. Each Starlink spacecraft is equipped with a novel autonomous evasion system that causes the vehicle to get out of the way of a possible collision, by itself. It requires less information from people on the ground, but it also makes it difficult to predict what satellites will do in the future, according to T.S. Kelso, a satellite tracker that operates a tracking site called CelesTrak. Most satellite operators can predict their satellite routes for up to seven days in the future, while SpaceX predicts up to 32 hours, says Kelso.

“This approach reduces resources on the ground, but it can be very difficult for the terrain to simulate what the satellite will really do,” Kelso wrote in an email to The edge. “Then, even if it spread further, his knowledge of the next maneuvers becomes increasingly uncertain.”

In addition, an investigator argues that SpaceX should share its data more widely beyond the Air Force website and that there should be no barrier to obtaining this information. “If you are really interested in space safety and that sort of thing, then you want the largest possible audience to know where your objects are located,” Moriba Jah, an associate professor at the University of Texas who specializes in tracking orbital debris . He says The edge. “It is in your best interest that everyone knows.”

There is a precedent for private companies such as SpaceX to make this positioning data public. The companion planet satellite operator, which recently won the title of the world’s largest satellite constellation, has been sharing all its data publicly since it began launching its vehicles in 2013. “Initially, there was no great mechanism to share that information, so we publish it on a public website, “says Mike Safyan, vice president of launch of Planet, The edge.

Finally, the trackers agree that SpaceX is moving in the right direction with respect to transparency. But satellites are far from transparent, and that is causing problems for a different space community.

Astronomy

Astronomers had some concerns before the first launch of SpaceX’s Starlink, but no one was prepared for the appearance of the satellites. “I knew they would be bright, but not as bright as they are,” says Patrick Seitzer, a professor of astronomy at the University of Michigan. The edge. “It was a dazzling moment last May when the first group was launched, and this chain of 60 satellites could be seen crossing the sky.” The brightness even surprised SpaceX officials, according to company representatives.

Starlink satellites can capture sunlight beyond the hours of twilight, and because they are destined to orbit quite close to Earth, about 550 kilometers high, that makes them even more visible than satellites located further away . Then there are the satellites themselves. The combination of their orientation in space and their design makes them abnormally bright. “They are now brighter than 99 percent of objects in orbit,” says Seitzer.

Starlink satellites captured as they passed over the Cerro Tololo Inter-American Observatory in Chile.
Image: NSF / CTIO / AURA / DELVE National Optical Infrared Astronomy Research Laboratory

Satellites, especially super bright ones, are a great nuisance to astronomers trying to observe stars, space rocks and other objects throughout the Universe. Astronomers say they could potentially handle the first proposed batch of 1,500 satellites. “What the current simulations show is that we could handle that in terms of observation,” says Vivienne Baldassare, Einstein’s postdoctoral fellow in astronomy at Yale, The edge. “But they are not only 1,500”. The concern is that once the mega-constellation grows, astronomers find it much harder to do their job.

In a solution attempt, SpaceX covered one of the 60 satellites in the most recent launch to make it look fainter in the sky. In the coming weeks and months, amateur trackers and astronomers will observe this dark horse satellite and calculate how bright it is compared to the rest of the pack.

“They can reduce the brightness a bit, but these things are already so bright,” says Marco Langbroek, satellite tracker and space situation awareness consultant for the Space Security Center of the Royal Dutch Air Force. The edge. The notes that, even with a coating, satellites can interfere with astronomical instruments. “Even modest and bright astronomical telescopes will still pick them up,” says Langbroek.

The company may have other options to reduce brightness beyond a cosmetic change. If the orientation of the satellites is partially to blame, then it is possible that they can raise the spacecraft’s orbits, or point the vehicles and their extra-bright solar panels in a different direction to reduce brightness. “There is probably a configuration of that solar array that would not produce that reflection,” says Hugh Lewis, an engineering professor at the University of Southampton specializing in space debris. The edge. “Although it is affecting the performance of the spacecraft because it is making it a little harder to climb, and potentially a little harder for it to get enough sunlight to generate energy for the first day.”

For now, SpaceX plans to continue launching its ultra-bright satellites to the same orbits while realizing if the lining will work. And that is not right with astronomers. “For me, the protective coating on one of every 60 satellites is not enough if you are going to continue launching those that you already know are problematic,” says Baldassare.

There could also be some compensation when it comes to coating satellites. On the one hand, changing the exterior of the satellite could alter the way in which the vehicle responds to the hostile environment of the space where temperatures oscillate wildly between suffocation and freezing. Making the satellite darken could cause it to absorb more heat, eliminating the temperature of the precious electronic components it contains. “Most of the electronic components will have been designed, built and assembled in an environment at room temperature,” says Lewis. “And that is the environment they like.” An excessive temperature change could ultimately cause a satellite to break or fail while in orbit.

Dead satellites in space instantly become garbage that can threaten nearby spacecraft. And given the potential size of the Starlink population, it is better to break as little satellites as possible. “Let’s say what it does is increase the probability of failure of some of the electronic components by 1 percent,” says Lewis. “When you throw 50,000 of those, 1 percent is actually a significant number.”

What is going to happen?

The truth about Starlink is that there is no solid truth. Depending on who you ask, the constellation will not be a big problem or will lead to a space apocalypse. For example, some are even worried that such a large influx of satellites can completely overwhelm our tracking capabilities, making it difficult to see all satellites in orbit. “Currently, the tracking network already has problems with the number of objects in orbit,” says Langbroek. “They will probably need more computer power; They will need more sensors. You don’t build that kind of network in a short time. “

Ultimately, we don’t really know how the constellation will change the low Earth orbit, and there hasn’t been much rigorous research examining what will happen with the entire Starlink constellation in operation. A handful of studies examined the risks of collision with Starlink and other proposed megaconstalations before its launch, but it was not a large amount of data, and there have not been many studies on the impact on astronomy.

Most people in the space community agree that they would like to see more research and discussions on how to move forward. Jah argues that greater dialogue between SpaceX, astronomers and satellite trackers is key, as there are many compensations when a particular design or operational choice is made. “There must be that kind of scientific exchange, in which we say ‘We will have this global project’,” says Jah, “It will be voluntary, but we will all make the data available and we will all do it so that the good of the community reach a consensus on how we should manage this finite resource. ”

What is worrying to some is that these discussions are just beginning to happen now, as SpaceX continues to launch at a rapid pace. SpaceX is licensed by the Federal Communications Commission to launch about 12,000 satellites if desired, and the company is following international guidelines on how to manage its constellation. It depends primarily on SpaceX if the company feels that it is doing enough to satisfy as many people as possible.

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