On October 13th, 2024, humanity took a giant leap toward the future of space exploration. On that Sunday, I joined countless others in watching the fifth integrated test flight of Starship—IFT-5. During the flight (and immediately after), my part of Twitter/X exploded with awe-inspiring images and reactions. But the next day at work, few of my colleagues seemed to grasp the magnitude of what had happened. Some space enthusiasts shared my excitement, but most were only dimly aware that anything significant had taken place.

If you are one of those, you can be forgiven. Most people aren’t aware of the significance of the event, but, believe me, it was historic. Humanity crossed a very important line on October 13th, 2024. It was the moment we transitioned from asking if full reusability was possible to knowing it is.

To explain:

SpaceX has a launch tower called Mechazilla, with huge chopstick arms that lifts giant rockets, called the Super Heavy booster, onto the launch mount, and then lift the giant second stage, called Starship, onto the Super Heavy. Super Heavy is the most powerful rocket ever made, and the combined stack is not only the largest rocket ever built, it’s the largest flying object ever to exist.

On Sunday, SpaceX launched this monster for the fifth time. Super Heavy lifted the whole stack off the launch mount (SpaceX doesn’t use a pad for Starship). The crowds watching cheered with delight to see the incredible column of purple-white fire from the combined might of 33 Raptor 2 rocket engines. Mach diamonds the size of tour buses. Shock waves visibly rippling outward—unreal. Of course to onlookers it’s totally silent until suddenly it’s not, with the rocket already climbing into the sky before the deep crackle of thousands of tons of supersonic superheated gases smacking into still air reaches them. Within a minute of liftoff, the rocket was already traveling faster than the speed of sound. In a tradition we love because of the incredible views, SpaceX has a number of cameras all over both Ship and Booster, which stream HD video live over Starlink, and, with a dawn launch, we were treated to seeing the exhaust plume turn blue-green as the atmosphere thinned out.

At about that moment, having lifted Starship well above the stratosphere, the Super Heavy shut down all but three engines as Ship ignited all six of its engines to pull away from the booster. Super Heavy immediately flipped around, reigniting 13 of its engines to slow its forward momentum. After less than a minute, it had reversed direction and put itself in a high arc to return to Starbase, while Starship continued the rest of its climb to space and accelerating downrange to reach a speed within a hair’s breadth of orbital velocity. (This is intentional, so that it will for sure re-enter at the planned location, and is not dependent on a de-orbit burn.)

For a moment, all is peaceful. Both vehicles are so high there is no atmosphere to give a sense of the tremendous velocities at play. But Super Heavy is not in orbit, and is falling like the gigantic stainless steel cylinder that it is. Unlike Falcon 9 boosters, it skips a second burn to ease re-entry, coming in hot instead. Literally so. The tracking cameras pick it up dropping back down from space at three times the speed of sound, heading back to the launch tower. The bottom glowing red hot as it sheds speed punching through the thickening atmosphere. A kilometer in the air, still moving over 1000 km/h, it again relit 13 of its engines to slow to merely 200 km/h. The incoming shock wave is enormous and visible in the clouds and as it slams into the cryo-mist at Starbase. Multiple sonic booms are felt as much as they are heard.

Then, using only 3 engines, this 25 story beast slowed still further and brought itself gently into Mechazilla’s loving embrace. Mechazilla in turn closed its chopstick arms and caught the rocket in midair.

It was at this point that the world’s space-loving fandom lost its collective mind.

We knew what we had just seen. The pre-dawn glimmer of a second dawn of the space age.

There’s still a long way to go, but this was the last thing we needed to demonstrate in order to know that full re-usability is doable. To see it succeed, on the first attempt, was an indication that the rest of the remaining hurdles are just n iterations away from a solution, and that SpaceX is phenomenally good at iterating. Everything they build, they build more of it than anyone else – more rockets, more rocket engines, more satellites, more antennas than any other company, and in less time.

And the mission wasn’t over. Starship blazed through re-entry with minor damage and aced its landing, right on target, in full view of the camera buoys SpaceX had placed ahead of time. But, though we lost it again at the glorious views of the flip maneuver, we kind of knew that would happen. That was old news. The third one made it to re-entry, the fourth one made it to a lovely soft landing on a flap and a prayer and 6 km off target, so we knew the fifth one was going to do better. Note: SpaceX intends to push some limits on Starship for flight 6, so we’ll see, but on the other hand, the flight profile will have it come down when it is daylight on the Indian Ocean

Hours later (none of us were calm yet—we were all still freaking out at each other), in a move I didn’t see coming at all, Mechazilla lowered Booster down onto the launch mount and reconnected it to the fueling lines. The calm precision of this operation was almost surreal, considering the booster had just done the nearly impossible and was still bruised and battered from its extreme experience. What’s more, people didn’t even know you could remount a booster without the launch pins to line things up. Clearly, they are serious about working on rapid re-use.

This was SpaceX’s Apollo 4 moment, when the Saturn V first proved it could leave Earth under the power of the most powerful rocket ever built. This flight crossed a threshold where the greatest unknown—whether full reusability could truly be achieved—became a known. From here, it’s hard work and iteration, but starting Sunday, we all saw humanity take a huge step toward becoming a spacefaring civilization.