Have you looked up into the night sky recently and seen a bizarre line of luminous dots? Have you noticed an uptick in the number of UFO reports mentioned in the news and social media? If so, you may have already been touched by what many have come to affectionately call Elon Musk’s “Space Train”: a line of tightly grouped Starlink satellites that are making their way around the globe.
Some have wondered what’s so unique about the Starlink satellites that allows them to be visible from the ground by the naked eye, but that’s actually nothing new. It’s all about being in the right place at the right time, for both the observer and the spacecraft in question. The trick is having the object in space catch the light from the Sun when it has, from the observer’s point of view, already set. It’s essentially the same reason the Moon shines at night, but on a far smaller scale.
What makes the Starlink satellites unique isn’t that we can see them from the ground, but that there’s so many of them flying in a straight line. The initial launch released 60 satellites in a far tighter formation than we’ve ever seen before; Elon even warned that collisions between the individual Starlink satellites wasn’t out of the realm of possibility. The cumulative effect of these close proximity satellite flares is a bit startling, and understandably has people concerned about what the night sky might look like when all 12,000 Starlink satellites are in orbit.
The good news is, the effect is only temporary. As the satellites spread out and begin individual maneuvers, that long line in the sky will fade away. But before Elon’s “Space Train” departs for good, let’s look at how it was created, and how you can still catch a glimpse of this unique phenomena.
When it comes to SpaceX, or perhaps more accurately its somewhat eccentric founder and CEO Elon Musk, it can be difficult to separate fact from fiction. For as many incredible successes SpaceX has had, there’s an equal number of projects or ideas which get quietly delayed or shelved entirely once it becomes clear the technical challenges are greater than anticipated. There’s also Elon’s particular brand of humor to contend with; most people assumed his claim that the first Falcon Heavy payload would be his own personal Tesla Roadster was a joke until he Tweeted the first shots of it being installed inside the rocket’s fairing.
So a few years ago when Elon first mentioned Starlink, SpaceX’s plan for providing worldwide high-speed Internet access via a mega-constellation of as many as 12,000 individual satellites, it’s no surprise that many met the claims with a healthy dose of skepticism. The profitability of Starlink was intrinsically linked to SpaceX’s ability to substantially lower the cost of getting to orbit through reusable launch vehicles, a capability the company had yet to successfully demonstrate. It seemed like a classic cart before the horse scenario.
But today, not only has SpaceX begun regularly reusing the latest version of their Falcon 9 rocket, but Starlink satellites will soon be in orbit around the Earth. They’re early prototypes that aren’t as capable as the final production versions, and with only 60 of them on the first launch it’s still a far cry from thousands of satellites which would be required for the system to reach operational status, but there’s no question they’re real.
During a media call on May 15th, Elon Musk let slip more technical information about the Starlink satellites than we’ve ever had before, giving us the first solid details on the satellites themselves, what the company’s goals are, and even a rough idea when the network might become operational.
There’s no shortage of ways a satellite in low Earth orbit can fail during the course of its mission. Even in the best case scenario, the craft needs to survive bombardment by cosmic rays and tremendous temperature variations. To have even a chance of surviving the worst, such as a hardware fault or collision with a rogue piece of space garbage, it needs to be designed with robust redundancies which can keep everything running in the face of systemic damage. Of course, before any of that can even happen it will need to survive the wild ride to space; so add high-G loads and intense vibrations to the list of things which can kill your expensive bird.
After all the meticulous engineering and expense involved in putting a satellite into orbit, you might think it would get a hero’s welcome at the end of its mission. But in fact, it’s quite the opposite. The great irony is that after all the time and effort it takes to develop a spacecraft capable of surviving the rigors of spaceflight, in the end, its operators will more than likely command the craft to destroy itself by dipping its orbit down into the Earth’s atmosphere. The final act of a properly designed satellite will likely be to commit itself to the same fiery fate it had spent years or even decades avoiding.
You might be wondering how engineers design a spacecraft that is simultaneously robust enough to survive years in the space environment while at the same time remaining just fragile enough that it completely burns up during reentry. Up until fairly recently, the simple answer is that it wasn’t really something that was taken into account. But with falling launch prices promising to make space a lot busier in the next few years, the race is on to develop new technologies which will help make sure that a satellite is only intact for as long as it needs to be.