It’s a truly exciting time for space enthusiasts. Humanity is finally shaking itself out of the half-century-long doldrums of deep space exploration and planning a return to the Moon and a push to Mars. Yes, exciting things have happened since the glory days of Apollo. We’ve reached out into the outer planets, drilled holes in asteroids, and made tracks across the face of Mars in an improbably durable rover. We’ve built magnificent space telescopes, created a permanent space station to replace a couple of temporary ones, and put an intricate constellation of satellites into service.
Those are all laudable achievements, but not a single living creature has intentionally achieved approached Earth escape velocity since three astronauts and five mice did it aboard Apollo 17 at 3:46 AM on December 7, 1972. Since then, we’ve all been stuck down here at the bottom of Earth’s gravity well, with only a lucky few of us getting a tease of what space travel is really like with low Earth orbit (LEO) missions.
But if NASA has its way, and certain difficulties with launch vehicles can be ironed out, in 2020 Earthlings will once again slip the surly bonds and make a trip to deep space. Of course those Earthlings will just be cultures of yeast carried into orbit around the Sun on a cubesat, but it’s a start, and it’s a good bet that more complex organisms won’t be far behind.
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.
It’s true that I’m not known for keeping particularly regular hours, but even I had my doubts about this plan. We’d go to sleep around midnight, wake up at 3 AM, drive up the coast aimlessly, then turn around and attend a full-day event where we’d have to maintain at least some semblance of professionalism. It was a bad idea, terrible even. But there I was at 11:30 PM sitting in a Waffle House with Thomas, the Supplyframe videographer, getting dangerously close to signing off on it.
Officially we were there to cover the Cornell Cup Finals being held at Kennedy Space Center, but as it so happens, our arrival in Florida perfectly coincided with the launch of CRS-17, SpaceX’s latest International Space Station resupply mission. Technically this was not part of our assignment. But really, what choice did we have?
Even if our respective bosses didn’t see it as a wasted opportunity, we had to consider the locals. In the few hours we’d been here, it seemed the launch was all anyone wanted to talk about. Everyone from the airport shuttle driver to the waitress who brought us our hash browns reminded us a rocket would be lifting off soon. If we didn’t go, then come Friday afternoon we’d be the only people in Cape Canaveral who didn’t have a personal account of the event. By all indications, an unforgivable cultural faux pas in central Florida.
Of course, the truth of the matter is that we didn’t actually need any convincing to go on this adventure. We had the supreme good fortune of finding ourselves in the vicinity of Kennedy Space Center a few hours before they were going to send a rocket thundering off into the black, and there was no way we could just sleep through it. No, there was never any choice in the matter. We were going.
Where does the Earth’s atmosphere stop and space begin? It is tempting to take the approach Justice Potter Stewart did for pornography when judging a 1964 obscenity case and say “I know it when I see it.” That’s not good enough for scientists, though. The Kármán line is what the World Air Sports Federation (FAI) defines as space. That line is 100 km (62 miles or about 330,000 feet) above sea level. A recent student-built rocket — Traveler IV — claims to be the first entirely student-designed vehicle to pass that line.
The students from the University of Southern California launched the rocket from Spaceport America in New Mexico. The new record is over twice as high as the old record, set by the same team. The rocket reached approximately 340,000, although the margin of error on the measurement is +/- 16,800 feet, so there’s a slight chance they didn’t quite cross the line.
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 are hundreds if not thousands of artifacts from the Apollo program scattered around the globe, some twisted wrecks at the bottom of the ocean, others lovingly preserved and sitting in museums or in the hands of private collectors. All of what’s left is pretty much pure unobtainium, so if you want something Apollo-like, you’re probably going to have to make it yourself.
[Ben Krasnow] took up the challenge to make an electroluminescent Apollo-era DSKY display from scratch, with outstanding results. The DSKY, or “display and keyboard”, was the user interface for the Apollo Guidance Computer, the purpose-built digital navigation system that got a total of 24 men there and back again. [Ben] says it took a long time to recreate the display, and we can see why. He needed to master quite a few skills, including screen printing to get the glass-panel display working. The panel is a sandwich of phosphorescent paint, a dielectric, and conductive ink. The ink is silkscreened on the back to form the characters, all applied to indium tin oxide (ITO) conductive glass. A PCB with the same pattern of character segments lays behind that, driving each segment with 300 volts or so through a trio of HV507 high-voltage shift registers. It’s an impressive bit of engineering and gives off a decidedly not-homebrew vibe.
In the video below, [Ben] goes into detail about the trials he experienced on the way to this amazing endpoint, not least of which was frying chip after chip due to ineffective protection diodes in the shift registers. That’s an epic debugging story that’s worth the price of admission all by itself. It’s not the only DSKY in town, of course – [Fran Blanche] has been working on one for a while too – but there’s just something about that blue glow that we really like.
Imagine what it must have been like for the first human to witness an aurora. It took a while for our species to migrate from its equatorial birthplace to latitudes where auroras are common, so it was a fairly recent event geologically speaking. Still, that first time seeing the shimmers and ribbons playing across a sky yet to be marred by light pollution must have been terrifying and thrilling, and like other displays of nature’s power, it probably fueled stories of gods and demons. The myths and legends born from ignorance of what an aurora actually represents seem quaint to most of us, but it was as good a model as our ancestors needed to explain the world around them.
Our understanding of auroras needs to be a lot deeper, though, because we now know that they are not only a beautiful atmospheric phenomenon but also a critical component in the colossal electromagnetic system formed by our planet and our star. Understanding how it works is key to everything from long-distance communication to keeping satellites in orbit to long-term weather predictions.
But how exactly does one study an aurora? Something that’s so out of reach and so evanescent seems like it would be hard to study. While it’s not exactly easy science to do, it is possible to directly study auroras, and it involves some interesting technology that actually changes them, somehow making the nocturnal light show even more beautiful.