We've been building space apps since 2019. And we still kept missing stuff we could have seen.
Back then we shipped Space Tracker, a simple app that calculated satellite passes and showed them to you in AR. Point your phone at the sky, there's the ISS. It did one thing and it did it well. But the more we used it, the more we realized how much was missing from the whole space app ecosystem. Not just from our app. From all of them.
A Falcon 9 would launch from the Cape and someone on Twitter would post a photo of the exhaust plume visible from their backyard 200 miles away. And we'd think: wait, we could have seen that? We build space software for a living and nothing on our phones told us to go outside and look up.
That's the problem. There are more rockets going up than ever before. There are thousands of satellites bright enough to see with your eyes. And the apps that are supposed to help you follow all of this don't actually help you see any of it.
The state of space apps is rough
Launch tracker apps give you a countdown, a YouTube embed, and a push notification that says "launching now." That's the whole experience. There's no context about what the rocket is doing after it leaves the pad. No telemetry. No sense of the flight. You watch a livestream in a little picture-in-picture window the same way you'd watch it on YouTube without the app. It adds nothing.
Satellite trackers are a different kind of broken. Most of them will happily tell you that the ISS is passing over your house at 9:47 PM. What they won't tell you is whether you can actually see it. Is the sun angle right? Is it bright enough given your sky conditions? How does light pollution in your neighborhood affect things? Almost none of them do real magnitude calculations. They just plot orbits and call it a day.
Heavens Above has been doing legitimate visibility math for years and deserves credit for that. But it's a web tool from a different era. It's not something you pull out of your pocket when someone says "what's that light moving across the sky?"
And then there's the design problem. We're not going to be polite about this. Most space apps look like they were built during a hackathon in 2014 and haven't been touched since. The information is technically there, buried in interfaces that fight you at every step. None of them feel like something you'd want to open.
Space Tracker taught us a lot, but it also showed us the ceiling. A pass calculator with AR was a good start. It wasn't enough. We wanted to build the space app we actually wanted to use. Nobody else was going to do it. So we started over from scratch.
Know when you'll see a launch
This is the thing that got us started on Flyby. We compute exact T+ time windows for when a launch will be visible from your specific location. Not "a rocket is launching tonight from Florida." You'll know the precise window after liftoff when the vehicle enters your line of sight, what direction to face, and how high to look.
If you live anywhere within a few hundred miles of a launch site, you've probably seen a rocket in the sky without knowing it was coming. Or worse, you found out five minutes after it happened. That doesn't happen with Flyby. You get a notification that says the launch is in 15 minutes and you'll be able to see it looking northeast starting at T+45 seconds. That's it. Go outside.
Know where to look
Once you're outside, open the AR tool. Flyby puts a marker on the launch vehicle or satellite right in your camera view. You point your phone at the sky and there it is. No fumbling with star charts. No guessing which dot is moving.
We built AR satellite spotting back in Space Tracker and it was the feature people loved most. In Flyby it's better in every way. Smoother tracking, more objects, and it works for launches too. If we told you to go look at something, we're going to make sure you can actually find it.
Only passes worth going outside for
This is where we spent a stupid amount of time. And honestly, where our day jobs gave us a pretty unfair advantage.
We're software engineers with backgrounds in aerospace. One of us worked on Artemis. When you've spent your career on systems where getting the math wrong isn't an option, you look at how satellite apps handle visibility predictions and it's just frustrating. Most of them don't even try. They track positions and that's it.
Flyby runs full visibility calculations. Orbital geometry, solar illumination angle, atmospheric conditions, the brightness of the satellite itself, your local light pollution, even how visible stars typically are from your specific location. All of that goes into determining whether a pass is worth your time.
The result is simple. You only get notified for passes that are actually worth going outside for. No more walking into your backyard to stare at a dark sky because an app told you something was "overhead" that you never had a chance of spotting.
Feel every stage of the flight
We wanted the launch experience in the app to feel like something. Not a countdown that hits zero and then you watch YouTube.
Flyby runs a real-time ascent simulation. You get a haptic rumble at liftoff. You see stage separations as they happen. There's a persistent T- indicator so you always know where you are in the flight. Live telemetry streams onto a 3D globe so you can watch the trajectory unfold. And the livestream audio plays right alongside all of it.
If you've ever stood at a viewing site and felt the rumble in your chest, we wanted to get as close to that as a phone can get. It's not the same. But it's a hell of a lot better than a countdown timer.
The globe
We put everything on one interactive 3D globe. Launches, satellites, visible passes, live telemetry during missions. Tap any trajectory to inspect it. See who's aboard a space station right now. Browse what's in orbit and what's about to leave the ground.
The most relevant stuff for your location surfaces first. No digging through menus.
Your missions, your alerts
Notifications are completely customizable. Follow your favorite agencies and companies. Only care about SpaceX and Rocket Lab? Done. Want to know every time something leaves the planet? Also done.
Launch countdowns and pass tracking arcs show up on your lock screen and Dynamic Island through Live Activities. For both launches and passes. The information finds you. You don't have to go looking for it.
Why we built this
Space Tracker was our first attempt at making space more accessible. It worked for what it was. But the world changed. Launch cadence exploded. Tens of thousands of new objects went into orbit. And the tools people had to follow all of it stayed exactly the same.
We spent six years learning what people actually want from a space app. Turns out it's pretty simple. Tell me when something cool is happening that I can see from where I am. Show me where to look. Make the experience feel real.
Flyby is that app. We're launching in 2026. If you want to know when it's ready, join the waitlist. One email. That's it.