Tag: spaceflight

Click for original image.

According to astronomer Bill Gray, who also tracks orbital objects, the upper stage of the Falcon 9 that launched Firefly’s Blue Ghost and Ispace’s Hakuto-R2 lunar landers in January 2025 will hit the Moon on August 5, 2026.

For some time, I’ve provided some software tools astronomers can use to identify satellites in their data. I use the US military’s publicly available satellite data for many objects, and compute orbits for high-orbiting objects the military doesn’t track.

This object falls squarely in the latter category. In September 2025, my software for computing orbits analyzed the observations and projected an impact with the moon on 2026 August 5.

While this looked like a pretty solid prediction, I couldn’t be totally sure of it at the time. The motion of space junk is mostly quite predictable; it simply moves under the influence of the gravity of the earth, moon, sun, and planets. We know those with immense precision. If those were the only factors involved, I could probably tell you where and when this object would hit the moon to within a few meters and a fraction of a second.

The problem is that space junk in general, and 2025-010D in particular [the upper stage], is also pushed around by sunlight (“solar radiation pressure”). This is an extremely gentle force, but over months, it can really build up. And it’s not entirely predictable. As an object tumbles, it may catch more or less sunlight, and may reflect some of it sideways. So sunlight is mostly pushing the object away from the sun, but there’s a slight bit of pushing in other directions as well.

With enough data, we can actually figure out where the forces are pushing an object. But they do change a little over time in ways that aren’t perfectly predictable. So I can be sure it will impact near the time and place I’ve predicted, but those varying forces mean that the actual impact will be at least a little off from that time and place. That’s the largest source of uncertainty in all this, and there’s no way to correct for it; we just have to wait and see what actually happens. (But come August, we’ll have a quite precise idea of where it will hit.

At present, Gray predicts the impact will occur at 2:44 am (Eastern) on August 5, 2026. The image above is his present estimate of where it will hit, as seen from Earth. If this prediction holds, the impact itself will likely not be visible from Earth, as it will occur in daylight and at the very western limb of the Moon. This prediction however could change somewhat in the next few months.

When it hits Gray estimates the stage will be moving at about 5,400 miles per hour, or 1.51 miles per second. Expect the science team for Lunar Reconnaissance Orbiter (LRO) to try to image this impact after the fact.