For the first time in more than half a century, an American-made spacecraft has made a soft landing. Moon.

There was a lot of drama and a lot of intrigue Thursday evening as the Intuitive Machines attempted to land their Odysseus spacecraft in a small crater far from the moon’s south pole. About 20 minutes after touchdown, NASA announced success, but some questions remain about the health of the lander and its direction. Why? Because when Odysseus was calling home, his signal was weak.

But after the spacecraft and its developer, Houston-based Intuitive Machines, passed through early Thursday, it was a miracle that Odysseus made it at all.

Losing your way

The landing attempt was delayed by nearly two hours when mission controllers had to put together a hasty, last-minute software patch to the lander while it was in orbit around the moon. Patching your spacecraft’s software shortly before it makes its most critical move is just about the last thing a vehicle operator wants to do. But intuitive machines were restless.

Earlier on Thursday, the company realized that its navigation lasers and cameras were not working. These rangefinders are essential for two functions during landing: terrain navigation and hazard navigation. These two modes help the flight computer on Odysseus determine where it is during the descent—by snapping lots of images and comparing them to the known topography of the Moon—and identify hazards below. Helps, like stones, to find a safe landing site.

Without these rangefinders, Odysseus was going to plant on the moon. Fortunately, the mission had a bunch of science payloads. As part of its commercial lunar program, NASA is paying about $118 million to deliver six scientific payloads to the lunar surface.

One of these payloads was the Navigation Doppler Lidar Experiment, a 15 kg package containing three small cameras. With this NDL payload, NASA sought to test technologies that could be used to improve navigation systems in future lunar landing efforts.

The only chance Odysseus had was to somehow tap into two of the NDL experiment’s three cameras and use one for terrain navigation and the other for hazard navigation. So the software was hastily written and sent to the lander. This was some real MacGyver stuff. But will it work?

A new home

The Odysseus lander began its descent from a circular orbit 57 miles (92 km) above the lunar surface, one hour and 13 minutes before its scheduled landing time. 11 minutes before touchdown on this timeline, the lander began a powerful descent using its main engine fueled by liquid oxygen and methane. During these final, critical minutes, Odysseus’ prepared terrain navigation camera scanned the surface for hazards such as rocks to ensure a safe landing site.

After touchdown, mission controllers knew it could take a minute or two for a good signal to come back from the lander, relaying the signals to large satellite dishes on Earth. First one, then two, and then five minutes passed in increasingly uncomfortable silence in the mission control room of the intuitive machines. Nothing.

Finally, after 10 minutes, Mission Director Tim Crane called out that the lander was sending a faint signal back to Earth.

“We’re not dead yet,” said Crane, the company’s cofounder.