### Starcrossed

On April 19, 2020, stargazers in Britain watched in awe and bewilderment as a glittering chain of light moved through the sky. Bright as any other stars in the sky, the crawling constellation held about 50 points of light. Some watchers posted to Twitter, wondering what they were seeing. Airplanes? Meteors? Aliens? Hours later, the lights were identified as satellites — part of SpaceX’s Starlink.

Starlink is one of the latest ventures by SpaceX, a space technology company founded by billionaire Elon Musk. It aims to provide global internet access with a network of satellites. It operates at speeds matching or surpassing conventional internet providers, utilizing a never-before-seen scale of satellites in orbit. However, it’s not without its consequences — some of which may threaten scientific research and the way we view the sky.

A New Frontier

Internet technology has come a long way in just a few decades. In the year 2000, most American homes were using dial-up, a method of internet access via telephone line that was very slow, and struggled to process high-resolution images. A decade later, a majority of households upgraded to broadband connections, bringing modern must-haves like voice chat, Wi-Fi, and video streaming to the everyday citizen. And as more and more communities replace their old copper wiring with fiber-optic cabling, high-definition movies can download in mere minutes. However, these amenities have been out of reach for most outside of urban and suburban areas. The cost of installing cabling over long distances is prohibitive for many remote communities; a problem Starlink’s satellite network doesn’t have.

While satellite internet is nothing new, it’s only ever been a last resort. In an article about Starlink’s architecture and business model, NASA software architect Casey Handmer wrote, “Traditional satellite companies have had to serve specialty customers and charge high rates for their data. Airlines, remote outposts, ships, war zones and critical infrastructure pay around $5 per megabyte, which is 5,000 times higher than the cost for a traditional [internet] connection, despite the poor latency and relatively low bandwidth of a satellite link.” Starlink is set to blow past those limits, offering service competitive with modern service providers, thanks to two main factors: proximity and scale. SpaceX debuts its Falcon 9 launch from 39A with CRS-10 Dragon mission. Falcon 9 is a two-stage rocket designed and manufactured by SpaceX. (Shutterstock.com) Suspended in low earth orbit, the satellites are near enough to the surface that their movements across the night sky seem brisk compared to the stars behind them. That close proximity brings multiple benefits, including lower power usage (compared to high-altitude orbits) and faster response times for users. Combined with the fact that light travels through air faster than through optic tubes, Starlink’s response times surpass traditional internet providers. However, that speed has a cost. “There is a tradeoff between low altitude, which allows smaller beam sizes and higher data rates,” wrote Handmer, “and high altitude, which allows fewer satellites to cover the whole Earth.” To compensate, SpaceX has been preparing an unprecedented number of satellites. In 2020, roughly 6,000 satellites orbited Earth, with less than half actually functional, according to the UCS Satellite Database. Starlink is set to hyperinflate that number; over a thousand Starlink satellites are already in orbit, and 40,000 are queued for production in the coming years. Because of their previous aerospace experience, SpaceX has the infrastructure to produce satellites at a much cheaper price — “around$100K per satellite, more than 1,000 times cheaper than a conventional [commercial satellite] launch,” according to Handmer’s analysis.

All of this investment into high-speed infrastructure makes Starlink a premium product — which makes SpaceX’s target audience hard to see. The promise of global internet access would benefit remote and impoverished communities the most; Starlink’s own website describes it as “Ideal for rural + remote communities.” However, at a fixed $99/month price point plus an additional$499 upfront equipment cost, it seems out of reach for the people across the globe who may need it the most. (SpaceX’s president has already dismissed the idea of tiered pricing.) In analyzing Starlink’s use cases, Handmer suggests “hundreds of millions of suburban subscribers with a pizza box-sized antenna on their roof” as the default audience, but also includes other, more metropolitan groups, such as financial firms looking to get industry information as fast as possible.

SpaceX Starlink satellite 3d render by Aleksandr Morrisovich.

The Fault in our Stars

Starlink’s biggest problem isn’t price or power; it’s about the planet. When stargazers saw Starlink satellites move across the sky, they saw light from the sun reflected off the shiny exterior of several Starlink satellites. What was at first a novelty — watching a shining train drift across the sky — may become an inescapable constant.

“It’s worth reminding ourselves that what they’re talking about is affecting humankind’s view of the night sky in general,” said Dr. Michael Strauss, chair of Princeton University’s Department of Astrophysical Sciences. “A legacy that all of humankind experiences: the opportunity to look at the night sky. It’s a shared thing of beauty, of natural wonder, that will be very directly affected by these large numbers of satellites.”

Starlink’s scale, set to raise the number of active satellites in orbit by over 650 percent, could introduce so much sunlight to the night sky that it fundamentally changes what humans see when they look at the stars.

Lighting the night sky, for better or worse, is nothing new. “We humans have been affecting the way that we look at the sky for a century and a half with the invention of artificial lighting of all sorts,” said Strauss. “The view that we have of the night sky today is, at least in anything other than the most rural of areas, fundamentally different from how people 150 years ago saw the night sky. It means that many people who have grown up in cities have never had the experience of seeing the Milky Way directly.” As cities have grown and artificial lighting has become ubiquitous, many of the night sky’s most beautiful features have faded from sight.

The problem is more than simply aesthetic. “The night vision of certain wildlife is far more sensitive than ours. Think of an owl, or geese (navigating by the stars). We don’t know the effect of these constellations on wildlife,” said Dr. Gaspar Bakos, professor at the Department of Astrophysical Sciences at Princeton University and youngest awardee of Popular Science’s annual Brilliant 10 Award. Among other concerns, Bakos also raised the issue of the Kessler effect: a potential future in which the density of satellites in low orbit becomes so high that satellite collisions cause a sort of domino effect, creating debris that causes additional collisions and creating more debris until placing satellites in low-earth orbit at all becomes untenable.

Fortunately, the light that satellites give off is most dramatic during launch, and fades out of sight as it reaches its final elevation. “The satellites will be bright during and shortly after launch, after which they will fade to a level that is only visible from very dark sites and with a very good night vision,” said Bakos. “However, in a pair of binoculars, often used for sweeping through the beauties of the night sky, satellites will be quite frequent, and strikingly well visible. For casual starwatchers with small telescopes, the initial annoyance will be small, but will gradually grow over time.”

To raise awareness and call for action, Bakos started an online petition. The second line in its description stands alone and is unambiguous: “We are on the precipice of losing the night sky.”

Astronomers have been reporting massive disturbances in their space imaging: long, bright, white streaks like window shutters trailing through photos of space. “The way an astronomical camera works — for the most part, [it] doesn’t take snapshots in which what you see is a point of light associated with these satellites,” said Strauss. “We tend to take long exposure [photos], so you leave the shutter open for a fairly long time. Something that’s moving ends up giving you a streak across the sky. If there’s a bunch of things moving, you get a bunch of streaks.”

These issues first began cropping up when the number of Starlink satellites in the sky was under 1,000. By the time all 40,000 are in the sky, the interference may be unavoidable. “When we take astronomical pictures, these streaks will appear in every picture,” said Strauss. “If you’re looking to understand the stars and the galaxies …, having these streaks across the sky in every picture is just gonna drive us nuts.”

Leaving these problems unchecked could bring deep consequences. In November of 2020, astronomer James Lowenthal told the New York Times, “If there are lots and lots of bright moving objects in the sky, it tremendously complicates our job. It potentially threatens the science of astronomy itself.”

One of the most prominent examples of astronomy in jeopardy is the Vera C. Rubin Observatory, an ambitious facility in north-central Chile, built to, among other goals, map the Milky Way and probe dark matter. One of those mapping projects is the Legacy Survey of Space and Time (LSST), a 10-year survey of the southern sky. According to a Rubin Observatory paper, their simulations show that, when all 40,000 satellites are in orbit, “as many as 30 percent of all LSST images would contain at least one satellite trail” and “nearly every LSST image taken during twilight would be affected by at least one satellite trail.”

This photo from 2018 shows a safety inspection of the Vera C. Rubin Observatory’s telescope mount assembly. The Rubin Observatory has been working with SpaceX engineers to mitigate the impact of Starlink’s reflective satellites on astronomy. (Rubin Observatory)

Out of Sight, Out of Mind

SpaceX is aware of these issues, apparently due to notable outreach from the astronomy community. “There has been an active discussion between, in this case, Starlink people and people from the Rubin Observatory to figure out mitigating effects,” said Strauss. “The good news is that the SpaceX/Starlink people are actually listening to astronomers and going ‘oh my goodness, I didn’t realize this would be such a problem’ — they’re not saying ‘oh, we’re going to drop the whole process,’ but ‘what can we do to make these things darker?’”

Starlink’s website also notes this collaboration, highlighting their belief in the “importance of a natural night sky for all of us to enjoy.”

Unfortunately, reducing satellite reflectivity — otherwise known as “albedo” — is a challenge without simple solutions. “You want to take out a can of black paint and slather [it] on them before you launch it? For all kinds of interesting technical reasons, … it’s not that simple,” said Strauss. “From the engineer’s point of view, white is good because if the object is not reflecting sunlight — if it’s black — it’s absorbing sunlight. Then it’s heating up, and the engineer says it’s going to get too hot.”

However, there are other solutions.

In an article titled “Astronomy Discussion with National Academy of Sciences,” SpaceX writes, “The Vera C. Rubin Observatory was repeatedly flagged as the most difficult case to solve, so we’ve spent the last few months working very closely with a technical team there to do just that. Among other useful thoughts and discussions, the Vera Rubin team has provided a target brightness reduction that we are using to guide our engineering efforts as we iterate on brightness solutions.”

The article lists a variety of mitigation efforts, including solar visors that block the sun during sunrise and sunset, and automatic rotations to reduce the number of sun-exposed surfaces. Even so, it admits that the problem cannot be fully solved, only mitigated: “[Large telescopes] are so sensitive that it won’t be possible to build a satellite that will not produce streaks, in a typical long integration.”

A “train” of Starlink satellites viewed from Argentina. Able to broadcast internet at competitive speeds, these satellites could revolutionize revolutionize human connectivity. The price, however, can be prohibitive; for example, despite trailing through their night sky, the $99/month pricetag is out of reach for many Argentinians, whose average monthly gross salary is$862 in USD. (Photo by BugWarp)

The Invisible Hand of Tomorrow

While SpaceX’s work to mitigate visibility is not without merit, another, broader problem looms on the horizon: competition.

“The thing that worries me is that SpaceX and Elon Musk are not the only people talking about this,” said Strauss. “There are a variety of other companies that are saying ‘well, if Elon Musk can figure out a way to make money off of this, we want to be in the game as well.’ Whether they’re all going to listen to the astronomers and go out of their way to make their satellites particularly dark is the challenge here.” Other mega-corporations have already began to plan and launch their own Starlink competitors, including OneWeb and Amazon’s Project Kuiper.

Much like SpaceX, OneWeb and Amazon have both reportedly been in talks with astronomers to mitigate their projects’ impact on astronomy. Furthermore, SpaceX has alluded to sharing their findings and improvements with other low-earth orbit initiatives. “While SpaceX is the first large constellation manufacturer and operator to address satellite brightness, we won’t be the last,” reads a SpaceX post on Starlink’s website. “As launch costs continue to drop, more constellations will emerge and they too will need to ensure that the optical properties of their satellites don’t create problems for observers on the ground. This is why we are working to make this problem easier for everyone to solve in the future.”

Encouraging as the cooperation with scientists and other providers may be, there’s no guarantee that future competitors will operate with as much goodwill.

“As they started saying they’re going to put up lots of these [satellites], everyone started asking ‘Are they allowed to do that? What about the rules that say they can’t do that?’ and the answer is, no such rules exist,” said Strauss. “The bottom line is, regulations don’t exist. It’s taken the worldwide community decades to build the regulatory infrastructure for radio, and we’re not going to invent that level of regulation with international treaties and everything over the next six months, which is the timescale in which Elon Musk wants to put enormous numbers of these up.”

The promise of global, high-speed internet access is a sci-fi dream soon becoming reality, and if future models focus more on affordability, it could be a massive step forward for remote and impoverished communities.

While the unintended consequences of these endeavors are broad and, in some areas, alarming, the cooperation between Starlink and astronomers gives hope as the issue reaches a pivotal moment. Though it likely isn’t enough to keep the night sky as clear as it was a decade ago, instituting proper regulation could see the best of both worlds: a bright future with a clear sky. Whether that manifests in time is up to activism, corporate restraint, and ultimately, legislators.