SpaceX continues to blast satellites into orbit as the space community worries

Early in 2020, SpaceX became the operator of the world’s largest active satellite constellation, with 180 satellites orbiting the planet. The milestone is a mere starting point for Starlink, SpaceX’s ambitious project to provide internet capabilities to every inch of the globe. To get that kind of connectivity, the company wants the option to launch up to 42,000 satellites over the next decade. That’s about 21 times the number of operational satellites currently in space — and the true impact of the company’s nascent mega-constellation is still very much a mystery.

In the history of the world, dumping a large amount of new stuff into a place usually comes with some consequences, and many within the space community have expressed concern about Starlink’s potential side effects. Perhaps the biggest outcry has come from astronomers who view Starlink as a huge threat to their work. Satellites already muck up images of the night sky, so having even more spacecraft zooming above Earth could significantly hinder their ability to view distant objects in the Universe.

Meanwhile, people involved in tracking satellites are more concerned with how these spacecraft will influence an already fairly crowded space environment. Space debris already creates an intricate space highway of crisscrossing lanes of traffic in orbit, dominated by satellites moving at many thousands of miles per hour. Adding more will up the risk of collision and could make launching to space much more difficult in the future.

SpaceX has heard the complaints of concerned scientists and satellite watchers. The company has taken some steps to mitigate the astronomy problems that many fear, and it has also released more data about the positioning of its satellites to help with tracking. But those steps aren’t enough for some advocates. And some of the decisions that various groups are lobbying for — like changing the design of the satellites — can potentially reduce an issue for one group but cause more problems for others. SpaceX declined to comment on this story.

Here are the issues that will continue to play out as SpaceX launches its Starlink satellites, 60 spacecraft at a time.

Space Traffic

With SpaceX planning to send up so many satellites, the chances of these objects getting close to other satellites are a lot higher. And that’s a scary prospect. 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. Expertly tracking the Starlink satellites — and all satellites, for that matter — is key to ensuring these vehicles don’t accidentally run into one another.

Right now, the premier resource for satellite tracking is the Air Force’s Space Surveillance Network, which is responsible for keeping tabs on everything in orbit using an array of ground-based sensors. The problem is that the Air Force’s tracking data isn’t always precise. It creates estimated orbits by taking periodic measurements of objects as they pass overhead; it can’t track them directly. For expert satellite trackers, the best way to understand where something is in space is to combine the Air Force’s estimates with positioning data gathered by the satellite itself. Together, this data can provide a clearer view of where a satellite truly is in the sky.

When SpaceX first started launching, there was some frustration over the fact that the company wasn’t sharing as much satellite positioning data as it could. The company also suffered an embarrassing miscommunication issue in September when one of its satellites got uncomfortably close to a European satellite. But things have changed with the company’s most recent launch in January. Before the mission took place, SpaceX shared its estimates of the basic direction, speed, and location its satellites would take after they deployed, and the company will continue to share onboard GPS data through the Air Force. That info can be accessed through a website called Space Track, for anyone who has an approved account with the website.

The move has been lauded by satellite trackers, but even with all of this information, it’s still somewhat difficult to know what SpaceX’s satellites are going to do and where they’re going to be in the future. Each Starlink spacecraft is equipped with a novel autonomous avoidance system that triggers the vehicle to move out of the way of a potential collision, all on its own. It requires less input from people on the ground, but it also makes it difficult to predict what the satellites are going to do in the future, according to T.S. Kelso, a satellite tracker who operates a tracking site called CelesTrak. Most satellite operators can predict the paths of their satellites up to seven days in the future, whereas SpaceX predicts up to 32 hours, Kelso says.

“This approach reduces resources on the ground, but it can be notoriously difficult for the ground to simulate what the satellite will actually do,” Kelso wrote in an email to The Verge. “So, even if you propagated out further, your knowledge of the upcoming maneuvers becomes more and more uncertain.”

Additionally, one researcher argues that SpaceX should share its data more widely beyond just the Air Force’s website and that there shouldn’t be any barrier to getting this information. “If you’re really interested in space safety and that sort of stuff, then you want to let the widest audience possible know where your objects are located,” Moriba Jah, an associate professor at the University of Texas who specializes in tracking orbital debris, tells The Verge. “It’s in your own best interest for everybody to know.”

There is some precedent for private companies like SpaceX making that positioning data public. Fellow satellite operator Planet, which recently held the title for the world’s largest satellite constellation, has been sharing all of its data publicly since it first started launching its vehicles in 2013. “Initially, there wasn’t a great mechanism to be able to share that data, so we just posted it on a public facing website,” Mike Safyan, the vice president of launch at Planet, tells The Verge.

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

Astronomy

Astronomers had some concerns leading up to SpaceX’s first Starlink launch, but no one was prepared for what the satellites would look like. “I knew they would be bright, but not as bright as they are,” Patrick Seitzer, a professor of astronomy at the University of Michigan, tells The Verge. “It was a stunning moment last May when the first group was launched, and you could see this chain of 60 satellites going across the sky.” The brightness even took SpaceX officials by surprise, according to company representatives.

The Starlink satellites can catch the Sun’s light well beyond twilight hours, and because they are meant to orbit fairly close to Earth — about 550 kilometers high — that makes them even more visible than satellites located farther out. Then there are the satellites themselves. The combination of their orientation in space and their design makes them abnormally bright. “They are brighter than 99 percent of the objects on orbit now,” says Seitzer.

Satellites — especially super bright ones — are a major nuisance to astronomers who are 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 current simulations show is that we would be able to manage that in terms of observing,” Vivienne Baldassare an Einstein Postdoctoral Fellow in astronomy at Yale, tells The Verge. “But it’s not just 1,500.” The worry is that once the mega-constellation grows, astronomers may find it much harder to do their jobs.

In an attempt at a solution, SpaceX coated one of the 60 satellites on the most recent launch to make it appear dimmer in the sky. Over the upcoming 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 herd.

“They might manage to bring the brightness down a bit, but these things are so bright already,” Marco Langbroek, a satellite tracker and space situational awareness consultant for the Space Security Center of the Royal Dutch Air Force, tells The Verge. He notes that, even with a coating, the satellites may still interfere with astronomical instruments. “Even bright modest astronomical telescopes will still pick them up,” Langbroek says.

The company might have other options to bring down the brightness beyond a cosmetic change. If the orientation of the satellites is partially to blame, then it’s possible that they could raise the spacecrafts’ orbits, or point the vehicles and their extra shiny solar panels in a different direction to reduce the glow. “There’s probably a configuration of that solar array that wouldn’t produce those reflection,” Hugh Lewis, a professor of engineering at the University of Southampton specializing in space debris, tells The Verge. “Though you’re affecting the performance of the spacecraft because you’re making it a bit harder for it to climb, and potentially a bit harder for it to gather enough sunlight to generate power for the first day.”

For now, SpaceX plans to continue launching its ultra-bright satellites to the same orbits as it figures out whether the coating will do the trick. And that isn’t sitting well with astronomers. “Protective coating on one out of 60 satellites is not, to me, enough if you’re going to continue launching the ones that you already know are problematic,” says Baldassare.

There could also be some trade-offs when it comes to coating the satellites. For one, changing the outside of the satellite might alter how the vehicle responds to the harsh environment of space where temperatures swing wildly between sweltering and freezing. Making the satellite darker could cause it to absorb more heat, throwing off the temperature of the precious electronics within. “Most of the electronic components will have been designed, built, and assembled in a room temperature environment,” says Lewis. “And that is the environment that they like.” Too much of a temperature change could ultimately lead a satellite to break or fail while in orbit.

Dead satellites in space instantly become junk that can threaten nearby spacecraft. And considering the potential size of the Starlink population, it’s best if as few satellites break as possible. “Let’s say what that does is it increases the chance of the failure of some of the electronic components by 1 percent,” says Lewis. “When you launch 50,000 of those, 1 percent is actually a significant number.”

What’s going to happen?

The truth about Starlink is that there is no solid truth. Depending on who you ask, the constellation either won’t be that much of a problem, or it will lead to a space apocalypse. For instance, some are even concerned that such a large influx of satellites could overwhelm our tracking capabilities altogether, making it difficult to see every satellite that’s in orbit. “Currently the tracking network already has problems with the amount 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 amount of time.”

Ultimately, we don’t really know how the constellation will change low Earth orbit, and there hasn’t been a lot of rigorous research that examines what will happen with the full Starlink constellation up and running. A handful of studies examined the risks of collision with Starlink and other proposed mega-constellations before they launched, but it wasn’t a lot of data, and there haven’t been many studies about the impact to astronomy.

Most people in the space community agree that they’d like to see more research and discussions about how to move forward. Jah argues that more dialogue between SpaceX, astronomers, and satellite trackers is key since there are so many tradeoffs when a particular design or operational choice is made. “There needs to be that sort of scientific exchange, where we say ‘We’re going to have this global project,’” says Jah, “It’s going to be voluntary, but we’re all going to make data available and we’re all going to do it for the greater good of the community to come to some consensus on how we should manage this finite resource.”

What’s worrisome to some is that these discussions are only just starting to happen now — as SpaceX continues to launch at a rapid pace. SpaceX has licensing from the Federal Communications Commission to launch nearly 12,000 satellites if it wants, and the company is following international guidelines for how to manage its constellation. It’s mostly up to SpaceX if the company feels like it’s doing enough to satisfy as many people as possible.

https://www.theverge.com/2020/1/14/21043229/spacex-starlink-satellite-mega-constellation-concerns-astronomy-space-traffic