I am treating the numeric forecast as conditional on the question receiving a numeric resolution. The underlying event itself is plausible: Bill Gray’s current orbit solution for object 2025-010D gives an impact on August 5, 2026 at 06:42:49.63 UTC at latitude +15.66832, longitude 271.52782 on the Moon. SpaceX’s current Falcon user guide confirms the second stage diameter is 3.66 m, and recent reporting on this specific object describes the stage as 13.8 m long and striking at about 2.43 km/s (about 5,400 mph). The current public SpaceX guide does not publish the second stage dry mass, so mass is one of the biggest remaining modeling uncertainties. (projectpluto.com)

The best direct analogs are other anthropogenic lunar impacts. Apollo S-IVB boosters had masses of about 14,000 kg, impacted at about 2.6 km/s, and formed craters around 35 m across; a later numerical summary of those impacts gives long axes of 34.4-38.7 m and short axes of 28.6-31.9 m. Ranger spacecraft, much smaller at about 370 kg and similar speed, made 14-15 m craters. LCROSS’s Centaur impact created a crater estimated at about 20 m. And the 2022 rocket-body impact found by LRO made an eastern crater 18 m wide superimposed on a western crater 16 m wide, with a maximum overall width around 28-29 m. (asu.elsevierpure.com)

A simple way to anchor the forecast is to interpolate between those known impacts. Using a shallow crater-size scaling with impactor mass and speed, calibrated to the S-IVB and LCROSS cases, and using a working Falcon dry-mass bracket around the same general class as the 2022 mystery rocket discussed by Paul Hayne (~4,500 kg, ~12 m long) because SpaceX does not publish the exact dry mass in the current guide, I get single-crater estimates clustered around roughly 24-26 m. That lands below the Apollo S-IVB outcomes, as it should for a smaller upper stage, but above LCROSS, again as expected. (phys.org)

I then adjust for morphology. The 2022 event matters a lot because this market resolves on the maximum diameter of the entire feature if a double crater forms. A Falcon 9 upper stage is not obviously as prone to a symmetric double crater as the 2022 impactor appears to have been, but it is still a long hollow object with mass concentrated away from the geometric center, so I think there is a meaningful chance that NASA’s first reported “diameter” is larger than a simple single-bowl crater would suggest. That pushes some probability into the 28-32 m region. I also keep a smaller left tail in the high teens and low 20s for lower-efficiency or awkwardly oriented impacts, while keeping the far right tail modest because the best heavier analog, Apollo S-IVB, was mostly in the mid-30s. (nasa.gov)

One important caveat is resolution timing. Gray notes that the 2022 impact crater was found about three months after impact, and that LRO only gets a daytime pass over a given spot roughly every four weeks with varying illumination. Since this market resolves as Ambiguous if no official measurement is released by August 20, 2026, ambiguity risk is materially non-zero. Because the required output format is numeric-only, the CDF below should be read as conditional on NASA or a peer-reviewed NASA-data study actually publishing a numeric crater diameter in time for a numeric resolution. (projectpluto.com)

Putting that together, my central forecast is a crater diameter in the mid-20s, with a median of about 25.25 m and mean of about 25.10 m. My rough 80% interval is about 20.5 m to 30.75 m, with only a small tail above 35 m and a very small tail below 17 m. The attached CDF implements that view as a three-component mixture: a main single-crater mode in the mid-20s, a secondary double/elongated-feature mode near 30 m, and a smaller-crater left-tail mode.

Bill Gray’s current orbit solution for object 2025-010D puts the impact on August 5, 2026 at 06:42:49 UTC, at about 15.668° N, 271.528° E, based on 32 observations. Reporting based on Gray identifies the object as the Falcon 9 upper stage from the January 15, 2025 launch that sent Firefly’s Blue Ghost Mission 1 and ispace’s HAKUTO-R Mission 2 toward the Moon. Public reporting based on Gray also gives the stage as roughly 13.8 m long, about 3.7 m wide, and impacting at about 2.43 km/s. Gray’s current solution reports an area-to-mass ratio of 0.010005 m^2/kg; combining that with the publicly reported stage geometry implies, as an inference, a mass in the rough 4-5 tonne range, which is the key physical input for the crater forecast. (projectpluto.com)

The most important analog is the March 4, 2022 rocket-body impact on the Moon. NASA says that event produced an unexpected double crater with 18 m and 16 m components and a longest dimension of roughly 28-29 m. The same NASA writeup says the four Apollo S-IVB upper-stage craters were larger, in the 35-40 m range, and notes that the 2022 double crater was unusual because spent rockets usually have their mass concentrated toward the motor end rather than at both ends. That matters here because the question resolves on the largest diameter of the total impact feature, so a true double crater would push the answer upward. (nasa.gov)

Other artificial lunar impacts help anchor the low and middle part of the range. NASA material on LCROSS says the Centaur stage had at most 2,366 kg at impact, and later analysis interpreted the resulting crater as about 20 m across. A peer-reviewed review of Ranger and Apollo impact craters reports that the ~370 kg Ranger spacecraft, striking at about 2.6 km/s, made craters about 14-15 m in diameter. These comparisons suggest that a few-tonne object at roughly 2.4-2.6 km/s should usually make a crater in the 20s of meters, not in the teens and not normally as large as the Apollo S-IVB craters unless the effective coupled mass is unusually high or the geometry stretches the feature. (lroc.asu.edu)

My physics/analogy blend is as follows. First, scaling down from Apollo 14’s S-IVB feature, which LROC describes as a roughly 35 m crater formed by a 14,016 kg stage with impact energy of 5.54 × 10^10 J, and comparing that with an inferred Falcon-stage impact energy of about 1.33 × 10^10 J, gives a crater around 24.5 m if one uses a standard sublinear crater-energy scaling. Second, scaling from LCROSS gives roughly 23-24 m. Third, the Ranger-to-Apollo envelope suggests something in the mid-20s. A direct extrapolation from the 2022 Long March combined feature would instead suggest about 30-31 m, but I discount that scenario because NASA characterized the 2022 double crater as anomalous and public Falcon 9 documentation describes a one-engine upper stage with conventional tank structure, which makes a strongly two-ended mass distribution look less likely than for the 2022 mystery body. Net: I center the distribution in the mid-20s, but leave a meaningful right tail for an elongated or double feature. (lroc.im-ldi.com)

The non-numeric branch is important. The question resolves as Ambiguous if no official measurement appears by August 20, 2026. That deadline is tight. The 2022 rocket-body impact occurred on March 4, but NASA’s identification article came on June 24. On the other hand, when the location was already well constrained, NASA imaged Beresheet 11 days after its crash and imaged the HAKUTO-R Mission 2 impact site 6 days after impact. Because this 2026 event is predicted in advance and is near the lunar limb on the Earth-facing side, I think a timely measurement is more likely than not, but far from certain; my rough ambiguity risk is about 35%. Because the requested schema only accepts numeric outcomes, the CDF below is conditional on the question resolving numerically rather than as Ambiguous. (nasa.gov)

Conditional on numeric resolution, my mean forecast is about 26.1 m, my median is about 25.8 m, and my central 80% interval is roughly 20.5 m to 33.5 m. The highest-density region is around 25-27 m, with extra probability in the high-20s/low-30s to account for the possibility of an elongated or partially double crater.

This forecast is conditional on there being a numeric official crater measurement. The resolution rules explicitly allow an Ambiguous outcome if no official size is released by August 20, 2026, and that non-numeric branch cannot be represented inside the required 0-50 meter CDF. For the numeric branch, the tracked object is 2025-010D, which Project Pluto identifies as the Falcon 9 upper stage from the January 15, 2025 Blue Ghost Mission 1 / HAKUTO-R Mission 2 launch; the current fit gives a lunar impact at 2026-08-05 06:42:49 UTC at latitude +15.66832, longitude 271.52782. Firefly and ispace confirm those missions launched together on Falcon 9 on January 15, 2025. (projectpluto.com)

Using Project Pluto’s current osculating elements q = 1213.361 km and e = 1.05127, I compute an impact speed of about 2.42 km/s at the lunar surface. FAA documentation describes the Falcon 9 second stage as roughly 12 ft by 41 ft with large LOX and RP-1 tanks, and notes that after payload separation the second stage is either left in orbit or deorbited; in other words, the object now headed toward the Moon is a post-deployment, mostly empty upper stage, not a fully fueled stage. I therefore model the impactor as a several-ton object rather than an Apollo-scale stage. (projectpluto.com)

The best lower-side official analog is LCROSS. NASA says the LCROSS Centaur impact excavated roughly 350 metric tons of material and made a crater estimated at about 20 meters in diameter. NASA technical material for LCROSS describes the Centaur impactor as about 2300 kg and about 2.5 km/s. That is a very useful anchor because it was also a spent upper stage hitting the Moon at broadly similar speed. (science.nasa.gov)

The best upper-side official analog is the Apollo S-IVB impacts. NASA’s Apollo documentation says Apollo 13’s S-IVB weighed 30,880 pounds at impact, while LRO reporting says Apollo S-IVB impact craters span roughly 35-40 meters in longest dimension; another NASA LRO feature describes the Apollo 13 crater itself as roughly 30 meters in diameter. Those were much larger stages than a Falcon 9 upper stage, so they provide an upper bracket more than a central estimate. (nasa.gov)

The 2022 rocket-body impact is the other key analog. NASA reported a double crater roughly 28-29 meters across and emphasized that this morphology was unexpected, with no other rocket-body impacts on the Moon having produced a double crater; NASA also noted that typical spent rocket stages usually have mass concentrated at the motor end. I treat that event as evidence for a real right tail into the upper 20s or low 30s, but not as the base case. (nasa.gov)

Putting those together: crater diameter should scale only weakly, not linearly, with impactor mass and velocity under standard impact-scaling logic. A Falcon 9 upper stage that is larger than LCROSS’s 2.3-ton Centaur but far smaller than the Apollo S-IVBs should usually land in the low-to-mid 20s if it forms a mostly single crater. Calibrating off LCROSS gives about 23-24.5 meters for a plausible several-ton Falcon stage at 2.42 km/s; calibrating off Apollo 13’s roughly 30-meter crater gives about 21-22 meters; and the 2022 double-crater case motivates a smaller but meaningful right tail. I weight the single-crater outcomes more heavily than the double-crater outcome because NASA said the 2022 morphology was unusual and because the typical spent-stage mass distribution is engine-heavy rather than strongly bimodal. My final median forecast is 23.5 meters, with most probability between about 19 and 29 meters. (ntrs.nasa.gov)

The CDF code below encodes that judgment as a three-component mixture: a dominant single-crater mode centered near 23 m, a smaller low-end mode, and a right-tail mode for a double or elongated impact feature. It is designed to approximate the first official reported largest diameter for the impact feature.

Important caveat: the question’s resolution rule allows Ambiguous if no official diameter is released by August 20, 2026. That is a meaningful risk: NASA’s public announcement of the March 4, 2022 mystery-stage impact crater came on June 24, 2022, months after the impact. Because the requested CDF can only encode numeric values, I treat the forecast below as conditional on a numeric official measurement being published. (nasa.gov)

The underlying impact itself looks likely. Bill Gray’s tracking places Falcon 9 upper stage 2025-010D on a lunar-impact trajectory for August 5, 2026 at 06:44 UTC near Einstein crater, at about 2.43 km/s. This is the Falcon 9 stage from the January 15, 2025 Blue Ghost / RESILIENCE launch. FAA documents describe the Falcon 9 second stage as about 12 ft by 41 ft, and the later FAA environmental assessment gives second-stage propellant loads of 168,000 lb of LOX and 64,950 lb of RP-1, so the impacting object should be a long, very low-density empty stage rather than a compact solid projectile. (skyatnightmagazine.com)

The exact dry mass of the current stage is one of the main uncertainties. An earlier official environmental document for the original Falcon 9 listed a second-stage inert weight of 7,091 lb; given that later FAA documents still show a similar second-stage form factor, I bracket the present impact mass as only a few metric tons, probably in the low-to-mid single-digit-tonne range. That is an inference from the available documents, not a directly reported current Block 5 dry-mass spec. (netspublic.grc.nasa.gov)

For crater size, the best anchors are previous anthropogenic lunar impacts at similar low speeds. A peer-reviewed LRO study says Ranger spacecraft impacts, about 370 kg at 2.6 km/s, made craters about 14-15 m wide, while Apollo S-IVB impacts, about 14,000 kg at roughly 2.6 km/s, made craters about 35 m wide. NASA says LCROSS’s roughly 2-ton Centaur impact made a crater about 20 m in diameter, and NASA measured the 2022 mystery rocket-body impact as an unexpected double crater about 28-29 m across in its longest dimension, with 18 m and 16 m component craters. (sciencedirect.com)

Those analogs imply a Falcon 9 upper-stage crater most likely in the 20s, not the teens and not S-IVB-sized unless the impact couples unusually efficiently. A simple fit across Ranger, LCROSS, and S-IVB gives a mass-scaling exponent of roughly 0.2-0.3 at these ~2.5 km/s impact speeds; applied to a few-tonne Falcon stage, that points to something like 22-27 m for a mostly single crater. I then add an upper-tail scenario for an elongated or double feature because the resolution uses the maximum span and because the 2022 event shows rocket bodies can produce surprising geometry. I keep that tail limited, though, because NASA explicitly called the 2022 double crater unexpected and noted that other known rocket-body lunar impacts had not produced double craters. This paragraph is partly inference from the cited analogs, not a direct published prediction. (sciencedirect.com)

My final conditional forecast centers on a median of about 24.5 m and a mean of about 24.7 m. My rough 10th-90th percentile range is about 17-32 m, with a small tail into the mid-to-high 30s if the stage arrives in a geometry that creates an elongated or double structure. Outcomes below 15 m look too small given the Ranger and LCROSS anchors, while outcomes above about 36 m would require behavior closer to the much heavier Apollo S-IVB impacts or a very stretched combined feature. (sciencedirect.com)

I treated this as a conditional forecast on the crater diameter given a numeric resolution. The question’s own resolution rules allow an “Ambiguous” outcome if no official diameter is published by August 20, 2026, and the requested numeric CDF has no slot for that non-numeric state. That ambiguity risk is real: NASA’s LRO imaged the RESILIENCE lander impact site just six days after the June 5, 2025 crash, but the March 4, 2022 rocket-body impact crater was not announced by NASA until late June 2022. (nasa.gov)

For the current event, the best current trajectory work is Bill Gray’s Project Pluto page. As of his May 2026 update, Gray identifies the object as the Falcon 9 upper stage from the January 15, 2025 Blue Ghost / HAKUTO-R launch, predicts impact near 15° N, 88° W at about 06:44 UTC on August 5, 2026, gives an impact speed of about 2.43 km/s, and estimates an impact angle about 34° from vertical. He also says the 2026 stage is probably similar in mass to the Chang’e-5 T1 upper stage and therefore should make a crater of roughly similar size. (projectpluto.com)

The closest analogue is the March 4, 2022 Chang’e-5 T1 upper-stage impact. NASA said that event made a double crater consisting of an eastern crater about 18 m across overlapping a western crater about 16 m across, with a maximum width about 29 m; the same NASA page says the Apollo S-IVB craters were larger, greater than 35 m. Gray’s earlier page on that 2022 event describes the impactor as a roughly four-ton object, and his later follow-up says its impact angle was about 15° from vertical. (nasa.gov)

Two additional anchors help bracket the size. NASA’s LCROSS documentation says the mission deliberately dropped a roughly 2,300 kg Centaur upper stage onto the Moon at about 2.5 km/s, producing a crater about 20 m in diameter. NASA’s Apollo compilation gives S-IVB impact masses of about 29,599-30,880 lb and impact speeds of 8,202-8,465 ft/s, with measured/calculated crater diameters around 129.6-135 ft for the best-documented cases. Taken together, those anchors imply that, at similar lunar impact speeds, an empty ~4-ton class upper stage should usually produce a crater in the mid-20s of meters rather than in the teens or in the 40+ m range. (ntrs.nasa.gov)

My rough scaling used crater diameter proportional to mass^(1/3) with only a weak velocity correction. That gives about 23.8-24.7 m when scaling upward from LCROSS, about 23-26 m when scaling downward from the Apollo S-IVBs depending on which NASA crater figure one uses, and about 27 m from a direct Chang’e-like analogue. I then shifted some probability upward because the resolution rules use the maximum diameter of the full feature if the impact produces a double crater. But I did not simply anchor on 28-29 m, because Gray explicitly described the 2022 double-crater morphology as surprising rather than routine. (projectpluto.com)

So my final distribution is centered in the mid-20s meters, with a meaningful upper-20s / low-30s tail for a double or elongated combined feature. My best single-number estimate, conditional on a numeric resolution, is about 26 m.

The topic neither increases or decreases question impact.

https://phys.org/news/2026-05-spacex-rocket-moon-space-private.html

What will be the diameter (in meters) of the crater created by the SpaceX rocket stage impact on the Moon?

• My most likely prediction for the crater diameter is 17.50 meters, with a 50% chance of falling between 14.50 and 21.00 meters.
• Expert analysis from Project Pluto, based on 1,053 observations of the Falcon 9 stage, suggests a single-crater size of roughly 16 to 18 meters.
• Historical data from a similar 2022 rocket impact indicates a “double crater” is possible, which could increase the measured longest axis to approximately 28 meters.
• The Falcon 9 second stage is more massive (approx. 4,500 kg) than the 2022 booster (approx. 2,800 kg), providing higher kinetic energy and support for a slightly larger crater.
• Resolution depends on NASA’s Lunar Reconnaissance Orbiter (LRO) imagery, which typically takes weeks to months to confirm and publish measurements after an impact.
• Apollo-era rocket stages, which were much heavier, created craters in the 35 to 40-meter range, setting a practical upper limit for this event.

Key figures

Historical context

• March 2022: A Long March 3C rocket stage (2,800 kg) impacted the Moon, creating a double crater roughly 28 meters in its longest dimension (16m and 18m individual diameters).
• 2009: The LCROSS Centaur stage impact (2,305 kg) was projected by NASA to create a crater approximately 27 meters wide.
• 1970-1972: Apollo S-IVB stages (13,400–14,000 kg) produced the largest human-made lunar craters, measuring between 35 and 40 meters.
• Typical rocket body impacts (smaller than S-IVB) historically fall into the 10-20 meter range for single features.
• NASA’s Lunar Reconnaissance Orbiter (LRO) has successfully used “temporal pairs” (before and after images) to identify and measure thousands of new craters since 2009.

Tailwinds

• Double-crater morphology: If the stage produces two distinct impacts as the 2022 booster did, the resolution criteria require measuring the longest axis, likely pushing the value toward 28-30 meters.
• Higher mass: The Falcon 9 stage is nearly 60% more massive than the 2022 Long March booster, which may lead to more extensive excavation.
• Regolith properties: If the impact site in the Einstein crater has deep, loose dust/regolith, the resulting crater will be wider than if it hit solid rock.

Headwinds

• Single-bowl formation: If the stage impacts at a steep angle or breaks up differently than the 2022 booster, it may create a single, compact crater closer to the 14-16 meter range.
• Impact velocity: If solar radiation pressure or gravitational perturbations slightly reduce the impact velocity below 2.43 km/s, the resulting crater will be smaller.
• Surface density: If the impact occurs on a particularly hard or rocky portion of the Einstein crater rim, excavation will be less efficient, leading to a smaller diameter.

Detailed reasoning

• My analysis of the impending SpaceX Falcon 9 lunar impact on August 5, 2026, relies on a combination of ballistic modeling and historical lunar impact data. The Falcon 9 second stage has a dry mass of roughly 4,500 kg and an expected impact velocity of 2.43 km/s. These parameters are the primary drivers of crater size.
• The central component of my forecast is anchored by the explicit estimate from astronomer Bill Gray of Project Pluto, who predicts a crater diameter of 16 to 18 meters. This estimate is highly credible as it is based on more than 1,000 ground-based observations of the specific object (2025-010D) and reflects the kinetic energy typical of a medium-lift rocket stage hitting the lunar regolith.
• However, I must account for the specific resolution criteria of this question, which dictates that the “maximum diameter of the entire impact feature” will be used if a double crater is formed. History shows that rocket bodies, being long and hollow, often produce non-circular or multi-lobed features. The 2022 impact of a Long March 3C booster (2,800 kg) is the most relevant precedent; it produced a double crater with individual bowls of 16 and 18 meters, but a total longest axis of 28 meters. Because the Falcon 9 stage is heavier (4,500 kg vs 2,800 kg), a similar double-crater scenario would likely yield a measurement in the 25 to 30-meter range.
• I also considered the upper bound of human-made lunar craters: the Apollo S-IVB stages. These were much more massive (~14,000 kg) and created craters between 35 and 40 meters. While the Falcon 9 stage is smaller, its velocity is comparable. This sets a plausible “high-end” ceiling for the prediction if the impact angle or surface material at the Einstein crater site leads to higher energy efficiency.
• Consequently, my prediction uses a mixture model. The primary mode (weighted at ~60%) centers on the 17.5-meter mark, representing a standard single-crater outcome. A secondary mode (weighted at ~30%) centers on 28 meters to account for the “double crater” morphology. The remaining probability is distributed to account for measurement variations or extreme outcomes up to 40 meters. This results in a most likely value of 17.50 meters, with a 50% HDI of 14.50 to 21.00 meters.

Key uncertainties

• Morphological uncertainty: Whether the long, cylindrical stage hits “nose-first” (single crater) or “sideways” (elongated or double crater) significantly changes the diameter measurement.
• Resolution timing: NASA may not release an official measurement by the August 20, 2026 deadline, which would lead to an “Ambiguous” resolution.
• Measurement interpretation: Different peer-reviewed studies or NASA teams may report slightly different widths depending on where they define the crater “rim.”
• Local topography: An impact on a slope or inside the rim of an existing crater can distort the final shape and size of the feature.

Conclusion

• The crater will most likely measure 17.50 meters, fitting the pattern of historical single rocket stage impacts.
• There is a significant secondary possibility of a 28-meter measurement if the stage creates a double-crater structure similar to the 2022 Long March impact.
• Decision-makers should monitor NASA’s Lunar Reconnaissance Orbiter (LRO) imagery releases in late August 2026 for the final confirmed dimensions.

Question: what diameter crater will Falcon 9 upper stage 2025-010D produce on the Moon (conditional on a numeric NASA measurement)? Forecast teams agree the object is a multi‑ton Falcon 9 second stage projected to impact ~5 Aug 2026 near the Moon’s western limb at ~2.4 km/s, but mass, residual propellant, exact attitude, and timing/location uncertainty matter. Best empirical anchors are LCROSS’s Centaur (~20 m), the Mar 2022 rocket‑body double crater whose combined width was ~28–29 m, and much heavier Apollo S‑IVB craters (~35–40 m); a simple log‑fit to limited artificial‑impact data gives a median ~23 m (p05 ≈ 17 m, p95 ≈ 31 m). Forecasters emphasize morphology risk: a single crater is most likely in the low‑to‑mid‑20s, but a double/elongated combined feature could push the resolved value into the high‑20s/low‑30s; values >50 m are judged very unlikely. A separate procedural/ambiguity risk is real—if NASA does not publish a numeric measurement by Aug 20, 2026 the market may resolve Ambiguous—so physical‑size and publication/timing should be tracked separately. Overall consensus: central estimate low‑to‑mid 20s meters, with an upper tail driven mainly by multi‑lobe morphology and residual mass/fragmentation uncertainty.

Forecast and Reasoning

Forecast: Probability distribution:

• 5.00% chance of value below 11.0
• 10.00% chance of value below 13.8
• 20.00% chance of value below 16.8
• 30.00% chance of value below 19.0
• 40.00% chance of value below 21.2
• 50.00% chance of value below 23.4
• 60.00% chance of value below 25.4
• 70.00% chance of value below 27.8
• 80.00% chance of value below 30.8
• 90.00% chance of value below 35.2
• 95.00% chance of value below 41.8

Forecast Reasoning

We are forecasting the diameter of the lunar crater produced by a ~4-ton-class Falcon 9 upper stage impacting at ~2.4 km/s on 2026-08-05, as eventually measured by NASA/LRO (or a peer-reviewed study using NASA instrument data). The main drivers of crater diameter here are (i) delivered kinetic energy (mass and velocity), (ii) how efficiently that energy couples to the regolith (rocket stages are hollow/low-density vs solid projectiles), and (iii) impact geometry and fragmentation, especially whether a compound/double feature forms (in which case the resolution uses the maximum rim-to-rim extent).

Across the four analysts, the central tendency spans ~20 m (Forecasters 1–2) to ~25–26 m (Forecasters 3–4). The higher medians are supported by energy-scaling comparisons to measured lunar impacts (e.g., Apollo S-IVB craters in the ~35–40 m class at much higher mass, and the 2022 rocket-body impact producing a ~28–29 m double feature). A simple scaling (D roughly proportional to a fractional power of kinetic energy) places a 4,000 kg, ~2.4 km/s impact plausibly in the low-to-mid 20s meters if it makes a single simple crater; uncertainty around fragmentation/compound morphology adds an upper tail into the 30s. Very small craters (<~12 m) seem unlikely for this energy regime, while diameters above ~40 m require either unusually efficient coupling or an unusually extended compound feature and are correspondingly rare.

I therefore synthesize to a median in the low-to-mid 20s, with a moderately wide distribution: lower tail reflecting inefficient coupling/partial breakup, and upper tail reflecting compound/elongated outcomes.

An amateur forecast would likely anchor on a single headline comparator (either “~16–18 m” from simplified press comparisons, or “~28–29 m” from the 2022 double crater) and give too-narrow uncertainty. This forecast instead blends multiple measured analog impacts and physical scaling (energy/mass-velocity dependence) while explicitly reserving upper-tail probability for compound/double-crater geometries, producing a better-calibrated range. Confidence in improvement is medium: the dominant remaining uncertainty is morphology (single vs compound) rather than the basic impact energetics.

Forecast rationale (numeric):

— Iteration 1 — The forecasts converge on a crater diameter in the mid-to-high 20-meter range, with a central tendency around ~27–28 m and a plausible lower center around ~22–23 m depending on how strongly the impact is expected to fragment or form a double crater.

Main reasoning patterns

• Historical analogs drive the estimate. The strongest anchors are prior lunar rocket-body impacts:
  • Apollo S-IVB impacts, which produced craters in the 35–40 m range.
  • Long March 3C / Chang’e-related impacts, which produced a ~28–30 m double-crater footprint.
• Scaling from mass and energy suggests a somewhat smaller but still substantial crater. The Falcon 9 upper stage is treated as broadly comparable in mass/velocity to these precedents, with crater size scaling weakly with energy, pointing to a single-crater estimate around ~25 m.
• Impact geometry matters a lot. The expected oblique angle (~34° from vertical) and the stage’s length increase the chance of an elongated or double crater, which can push the reported diameter toward the high-20s or low-30s if the longest axis is used.
• Target properties introduce uncertainty. Harder ground could yield a smaller, more compact crater; loose regolith or weaker terrain could enlarge the apparent footprint.
• Fragmentation is a tail-risk factor. Most reasoning keeps the main outcome below 50 m, but rare fragmentation or unusually weak terrain could produce larger features.

Areas of consensus

• A crater is very likely and should be tens of meters across, not just a few meters.
• The most likely reported diameter is around the upper-20s meters.
• If the event creates a double crater, the longest axis is likely what determines the measured diameter.

Main differences in emphasis

• One line of reasoning leans slightly lower by centering on a more ordinary single-crater outcome.
• Another leans slightly higher by giving more weight to the chance of a double/elongated crater and the possibility that the measurement captures the combined footprint.

Overall, the collective reasoning supports a crater diameter centered around ~25–28 meters, with uncertainty mainly driven by impact angle, fragmentation, and lunar surface properties.

— Iteration 2 — Across the forecasts, the reasoning is built around the same core approach: use lunar impact analogues and scale them to the Falcon 9 upper stage’s mass, velocity, and likely impact geometry.

Main reasoning patterns

• Empirical analogues drive the estimate.
  The forecasts compare the Falcon 9 stage to prior lunar impacts from:
  • Chang’e-5 T1 / similar rocket bodies, which produced a roughly 29 m double crater
  • Apollo S-IVB stages, which produced 35–40 m craters
  • Smaller rocket-body and meteoroid impacts, which produced craters in the teens of meters
• Energy and mass scaling narrow the range.
  Using the stage’s approximate mass and impact speed, the expected crater size is usually placed below Apollo S-IVB outcomes but above smaller-impact cases, implying a crater in the low-to-high 20s meters.
• Impact angle matters.
  Several forecasts stress that the impact is likely oblique rather than perfectly vertical, which can:
  • elongate the crater
  • create a double-crater or irregular footprint
  • make the measured “diameter” closer to the maximum extent than a circular average
• Terrain and material uncertainty are important.
  Local lunar regolith strength, slope, and possible residual propellant are treated as secondary factors that can shift the final size up or down.
• Uncertainty is right-skewed.
  Most forecasts center on a moderate crater size but allow for a long upper tail, because elongated or double-crater morphology can substantially increase the measured maximum diameter.

Areas of consensus

• The expected crater is not tiny; it should be on the order of tens of meters, not single digits.
• A mid-20s to around 30 m crater is the most common central expectation.
• The crater is likely to be irregular or elongated, so the reported measurement may reflect the largest span rather than a neat circular rim.

Main differences

• One forecast leans slightly lower, around 20–22 m, based on the Chang’e-5 T1 analogue and a conservative reading of the stage’s mass.
• Others favor ~28–29 m, giving more weight to elongation, combined-feature measurement, and scaling toward the known 29 m and Apollo-adjacent cases.
• The upper uncertainty bounds vary widely, but all allow for the possibility of a much larger apparent feature if the impact is especially oblique or complex.

Overall synthesis

The collective reasoning suggests a moderate lunar crater in the high teens to low 30s meters, with a central tendency around the upper 20s. The dominant logic is analogue-based scaling moderated by impact geometry, with particular attention to whether the crater is measured as a simple circular depression or as the full extent of an elongated/double impact feature.

— Iteration 3 — Overall, the forecasts converge on a crater diameter in the mid-20s meters, with most of the weight centered around roughly 22–27 m and a broader plausible range spanning about 10–50 m.

Main reasoning patterns

• Empirical analogs drive the estimate: The strongest anchors are previous lunar impact events, especially the Chang’e-5 T1 booster and Apollo S-IVB impacts, which produced craters in the tens-of-meters range.
• Energy scaling supports a mid-20 m crater: Using the SpaceX stage’s mass and estimated impact speed, the expected crater size follows standard kinetic-energy/cube-root scaling, yielding a result somewhat smaller than the larger Apollo-stage craters but still clearly substantial.
• Measurement convention matters: The reported size may be the maximum extent / longest axis, not just a simple circular diameter, which nudges estimates upward if the impact creates an elongated or double feature.
• Shape and fragmentation are the main uncertainty: A single, compact crater would pull the estimate down into the high teens or low 20s, while a double crater or elongated scar could push it toward the high 20s or low 30s.

Areas of consensus

• The impact should produce a definite crater of tens of meters, not a small pit.
• The most likely outcome is around 20–30 m.
• Past lunar booster impacts are the best guide.

Areas of disagreement

• Some estimates lean slightly higher or lower depending on how much weight is given to:
  • Apollo-S-IVB precedents
  • double-crater geometry
  • uncertainty in impact angle, fragmentation, and surface properties

In short, the shared view is that the SpaceX stage impact will likely make a mid-20-meter lunar crater, with the exact reported diameter depending heavily on whether the impact produces a single crater or a broader double/elongated feature.

Impactor Dynamics and Kinetic Energy Forecasters base their reasoning on the physical properties of the Falcon 9 upper stage—a large, hollow cylinder with its mass heavily concentrated at the aft end due to its heavy engine block. Based on the stage’s expected mass and impact velocity, forecasters use standard Pi-group kinetic energy scaling laws to model the excavation. Because the rocket’s mass is localized at one end rather than distributed evenly, it is expected to act as a point-source explosion, creating a single primary crater. However, forecasters also note that because the projectile is a hollow tube, a portion of its kinetic energy will be dissipated in crumpling the empty fuel tanks rather than displacing lunar soil.

Historical Analogs and Scaling The rationales rely heavily on three distinct historical benchmarks to scale the expected crater size:

• Apollo S-IVB Stages: These structurally similar but much heavier upper stages serve as a strict upper bound.
• LCROSS (2009): A significantly lighter upper stage, which serves as a baseline to scale the Falcon 9’s crater upward.
• Long March 3C / WE0913A (2022): A lunar impactor of similar mass that uniquely created a double crater due to having heavy masses at both ends.

Forecasters broadly agree that early astronomical and media predictions are artificially low because they incorrectly anchor to the smaller, individual lobes of the 2022 Long March impact. Since the Falcon 9 will not split its energy into two separate impacts, its single crater is expected to be notably larger than the individual pits left in 2022.

Geology and Target Terrain The expected impact site near the Einstein crater consists primarily of ancient lunar highlands. Forecasters point out that this terrain features deep, porous, and pulverized regolith. This powdery surface typically allows for highly efficient excavation, leading forecasters to favor a slightly wider crater, though a few note that extreme porosity could act as a shock absorber.

Measurement Protocols and Geometric Elongation A critical upward pressure on the forecasts is NASA’s Lunar Reconnaissance Orbiter Camera (LROC) measurement methodology. The resolution criteria rely on the “maximum diameter” (the longest axis across the crater rim). Because the Falcon 9 is an elongated cylinder expected to strike the surface obliquely or while tumbling, it will likely carve an asymmetrical, elongated trench rather than a perfect circle. Forecasters emphasize that measuring the longest axis of this elliptical footprint will inherently inflate the official reported measurement compared to baseline circular scaling models.

SUMMARY

Question: What will be the diameter (in meters) of the crater created by the SpaceX rocket stage impact on the Moon? Final Prediction: Probability distribution:

• 10.00% chance of value below 14.966667
• 20.00% chance of value below 17.166667
• 40.00% chance of value below 20.166667
• 60.00% chance of value below 23.2
• 80.00% chance of value below 27.966667
• 90.00% chance of value below 31.933333

Total Cost: extra_metadata_in_explanation is disabled Time Spent: extra_metadata_in_explanation is disabled LLMs: extra_metadata_in_explanation is disabled Bot Name: extra_metadata_in_explanation is disabled

Report 1 Summary

Forecasts

Forecaster 1: Probability distribution:

• 10.00% chance of value below 15.1
• 20.00% chance of value below 17.3
• 40.00% chance of value below 20.6
• 60.00% chance of value below 23.5
• 80.00% chance of value below 28.4
• 90.00% chance of value below 32.0

Forecaster 2: Probability distribution:

• 10.00% chance of value below 15.8
• 20.00% chance of value below 18.2
• 40.00% chance of value below 21.4
• 60.00% chance of value below 24.4
• 80.00% chance of value below 29.1
• 90.00% chance of value below 33.6

Forecaster 3: Probability distribution:

• 10.00% chance of value below 14.0
• 20.00% chance of value below 16.0
• 40.00% chance of value below 18.5
• 60.00% chance of value below 21.7
• 80.00% chance of value below 26.4
• 90.00% chance of value below 30.2

Research Summary

The research summarizes a predicted impact of a SpaceX Falcon 9 upper stage (2025-010D) on the Moon near Einstein crater on August 5, 2026 at ~06:44 UTC. The stage is estimated at ~4,000 kg, ~13.8 m tall and 3.7 m diameter, impacting at ~2.43 km/s. Based on these parameters and comparisons to past lunar impacts, an authoritative prediction cited in the research gives a crater diameter of about 16–18 meters. The report compares the Falcon 9 stage to prior rocket impacts: LCROSS Centaur (~2,249–2,366 kg, ~2.5 km/s) produced a ~20–22 m crater; the LCROSS shepherding spacecraft (~621–866 kg) had a ~14 m predicted crater; Chang’e 5-T1 produced a ~28 m double crater; and Apollo S-IVB stages (~14,000 kg) produced 30–40 m craters. A simple scaling table in the research places the Falcon 9 between LCROSS and Apollo S-IVB in mass and concludes the 16–18 m prediction is consistent with crater-scaling relationships.

The research also lists key uncertainties and observational considerations: double-crater formation (as with Chang’e 5-T1) could make the measured longest axis larger; impact angle can change crater shape and size (e.g., creating elliptical craters); NASA’s Lunar Reconnaissance Orbiter is expected to image the site within a 15-day window after impact for measurement; and prediction markets did not provide relevant forecasts. The report’s bottom-line central estimate is 16–18 m, with a plausible single-crater range around ~16–22 m and a note that double-crater or shallow-angle outcomes could push effective measured axes into the mid-20s–30s of meters.

Sources cited in the research (original research used numbered references but did not include URLs). Named sources and sites mentioned or searched:

• Bill Gray’s tracking/observations (astronomer Bill Gray / Project Pluto)
• NASA / Lunar Reconnaissance Orbiter (LRO) mission and imaging data
• LCROSS mission data and analyses
• Chang’e 5-T1 impact reports and imagery
• Apollo S-IVB impact/crater studies (Apollo mission documentation)
• News and summary reports referenced in the research (media coverage and mission briefings)
• Prediction market sites searched: Polymarket, Manifold, Metaculus

(The original research listed bracketed reference numbers [1]–[32] but did not provide direct hyperlinks, so verbatim links are not available in the provided material.)

RESEARCH

Report 1 Research

Comprehensive Research Rundown: SpaceX Falcon 9 Moon Impact Crater Diameter

Event Overview

A SpaceX Falcon 9 upper stage (catalogued as 2025-010D) is predicted to impact the Moon on August 5, 2026, at 06:44 UTC near the Einstein crater [1][2][3]. The impact will occur approximately 2.5 months from now (current date: May 21, 2026).

Key Impact Parameters:

• Mass: Approximately 4 tonnes (4,000 kg) [4]
• Velocity: 2.43 km/s (~8,700 km/h or 5,400 mph) - roughly 7 times the speed of sound [3][7][32]
• Dimensions: 13.8 meters tall, 3.7 meters in diameter [2][5][32]
• Impact Location: Near Einstein crater on the Moon’s near side [1][3][29]

The rocket stage was launched January 15, 2025, carrying Firefly Aerospace’s Blue Ghost Mission 1 and the Hakuto-R Mission 2 lunar landers [4][8]. Astronomer Bill Gray has tracked the object with over 1,053 observations, providing high confidence in the predicted impact [6][8].

Predicted Crater Size

One authoritative source specifically predicts: 16 to 18 meters in diameter [6]. This prediction is based on the known mass and velocity parameters of the Falcon 9 upper stage.

Historical Base Rates and Reference Classes

Most Similar Event: 2022 Chang’e 5-T1 Impact

• Created a double crater roughly 28 meters wide [background info, referenced in 12]
• This is the most recent rocket body impact on the Moon
• Bill Gray also predicted this impact with high accuracy [8][12]
• Important note: The resolution criteria specify that if a double crater forms, the longest axis of the combined crater structure will be used

LCROSS Centaur Impact (October 9, 2009)

• Mass: 2,249-2,366 kg [22]
• Impact velocity: ~2.5 km/s [22]
• Predicted crater: ~20 meters diameter, 4 meters deep [22]
• Actual measured crater: ~22 meters diameter [25]
• Comparison: The Falcon 9 stage is approximately 1.7-1.8x heavier than the LCROSS Centaur but has similar impact velocity

Apollo S-IVB Rocket Stage Impacts (1970-1971)

• Mass: ~14,000 kg dry mass [23][24]
• Impact velocity: ~2.6 km/s [20]
• Crater sizes:
• Apollo 13 S-IVB (April 1970): ~30 meters diameter [23]
• Apollo 16 S-IVB: ~40m × 30m elliptical crater [20]
• Comparison: Apollo S-IVB stages were approximately 3.5x heavier than the Falcon 9 stage with similar velocity, producing craters of 30-40 meters

LCROSS Shepherding Spacecraft (2009)

• Mass: 621-866 kg [22]
• Predicted crater: ~14 meters diameter, 2 meters deep [22]
• Much lighter than Falcon 9 stage

Quantitative Scaling Analysis

Based on the historical data:

The Falcon 9 stage falls between the LCROSS Centaur and Apollo S-IVB in terms of mass, with comparable impact velocities. The predicted 16-18 meter range appears consistent with crater scaling relationships, though it’s notably smaller than the 28-meter Chang’e 5-T1 double crater.

Key Uncertainties and Considerations

1. Double Crater Formation: The Chang’e 5-T1 impact created a double crater [12]. If the Falcon 9 impact similarly creates a double crater, the resolution criteria specify using the “longest axis of the combined crater structure,” which could significantly increase the measured diameter.

2. Impact Angle: The angle of impact significantly affects crater morphology and size [20]. The Apollo 16 S-IVB created an elliptical crater (40m × 30m), likely due to a shallow impact angle.

3. Measurement Timeline: NASA’s Lunar Reconnaissance Orbiter must identify and measure the crater between August 5-20, 2026 (15-day window). Resolution requires the first official measurement by NASA or peer-reviewed study [background info].

4. Range Handling: If NASA reports a range (e.g., “15 to 17 meters”), the resolution will use the midpoint [resolution criteria].

Prediction Markets

No specific prediction markets were identified for this question. I searched Polymarket, Manifold, and Metaculus-related sources but found no active markets specifically forecasting the crater diameter.

General SpaceX-related markets exist (e.g., SpaceX IPO valuation at $2.2T has 37% probability on Polymarket [28], human moon landing in 2026 at 3% [27]), but these are not directly relevant to crater diameter prediction.

Implication for reliability: The absence of prediction markets means there is no crowd-sourced probabilistic forecast or liquidity data to inform this question. You will need to rely primarily on the scientific predictions and historical base rates.

Scientific Observability

• The impact will occur on the Moon’s near side in sunlit conditions [29][30]
• However, the impact flash will be too faint to observe from Earth [5][8]
• NASA’s Lunar Reconnaissance Orbiter (LRO) has been imaging the lunar surface since 2009 and is expected to capture before-and-after images [3][30]
• The LRO has successfully imaged previous impact craters, including the recent 225-meter natural asteroid impact crater discovered in 2024 [11][13][15]

Bottom Line for Forecasting

Central Estimate: 16-18 meters (based on Bill Gray’s prediction [6])

Historical Range: 14-40 meters for rocket bodies (excluding the 28-meter double crater)

Most Likely Scenario: Single crater in the 16-22 meter range, consistent with LCROSS Centaur (which had ~60% of Falcon 9’s mass)

Key Risk Factor: Double crater formation could push the measurement to ~25-30 meters or higher (longest axis)

Confidence in Measurement: High - NASA LRO has proven capability to measure craters precisely, as demonstrated with Apollo S-IVB craters [20][23] and LCROSS [25]

Timeline Risk: Low ambiguity risk - 15-day window should be sufficient for LRO imaging and initial measurement

FORECASTS

R1: Forecaster 1 Reasoning

Conditioning: I’m forecasting the numeric crater diameter in meters, conditional on the question not being annulled / not resolving Ambiguous. Separately, I’d put roughly a 25% chance on “Ambiguous” because the August 20, 2026 deadline is only 15 days after impact; NASA has sometimes reported quickly, as with Luna 25, but the 2022 rocket-body crater was not publicly reported until months after the impact. (nasa.gov)

(a) Time left: From today, May 21, 2026, there are about 76 days until the projected impact on August 5, 2026, and about 91 days until the August 20, 2026 resolution deadline. Bill Gray’s current estimate is impact within a few minutes of 06:44 UTC on August 5, 2026. (projectpluto.com)

(b) Outside view: The reference class is low-velocity artificial-object impacts on the Moon. Relevant crater sizes include: Ranger spacecraft around 14 to 15 m, LCROSS Centaur around 20 m, the 2022 rocket-body double crater with individual craters of 16 m and 18 m and a longest dimension of about 28 m, and Apollo S-IVB upper-stage craters around 35 to 40 m. (sciencedirect.com) The base-rate center for a multi-ton upper stage at roughly this velocity is therefore not the tiny-spacecraft class, but the high teens to high twenties, depending on whether the crater is single, elongated, or double.

(c) Inside view: This object is a Falcon 9 upper stage, catalogued as 2025-010D; Gray says it has been tracked with over 1,053 observations, will hit at about 2.43 kilometers per second, and should strike at about 34 degrees from vertical, which he describes as steep enough that he does not expect a very elongated crater. He also says the mass should be roughly similar to the 2022 Chang’e-5 T1 upper-stage case and expects a crater of roughly similar size. (projectpluto.com) This pulls the forecast toward 18 to 23 m for a normal single feature, while the resolution rule using the longest combined axis creates a meaningful right tail if the result is double or elongated.

(d) Outcome if nothing changed: If the current orbital solution, object identification, and LRO follow-up expectations hold, I’d expect NASA/LROC to measure something around 21 m.

(e) Outcome if the current trend continued: Continued tracking mainly reduces location uncertainty rather than changing crater physics. So the size forecast stays about the same, but the chance of a prompt official measurement should rise as LRO planning improves.

(f) Experts and markets: The main expert signal I find is Bill Gray / Project Pluto: similar mass to the 2022 rocket-body case, impact at 2.43 kilometers per second, and an angle not expected to make a very elongated crater. (projectpluto.com) I find no useful liquid prediction-market signal for the crater diameter.

(g) Low unexpected scenario: The stage impacts in a way that poorly couples most of the hollow tank energy into excavation, or NASA reports only a compact primary pit; that could produce an official diameter around 12 to 16 m.

(h) High unexpected scenario: The stage forms a double crater or long asymmetric feature, similar to or larger than the 2022 double crater; under the resolution rule, the longest rim-to-rim span could land around 28 to 35 m, with an extreme but unlikely tail near 40 to 50 m.

Rationale: I anchor on the artificial lunar impact base rate: objects in this velocity regime often make craters from the mid-teens to several tens of meters, with multi-ton upper stages clustering higher than small spacecraft. The closest analog, the 2022 rocket-body event, officially produced a 28 m double feature, but its individual craters were only 16 m and 18 m. For the Falcon 9 stage, the inside view argues against a very long crater because the impact angle is fairly steep, but the resolution rule makes double-crater morphology especially important. I therefore put the median a little above the “16 to 18 m” simple-crater expectation, but keep a wide upper tail for a double or elongated structure.

Percentile 0.1: 6.8 Percentile 1: 9.8 Percentile 5: 13.2 Percentile 10: 15.1 Percentile 20: 17.3 Percentile 30: 18.9 Percentile 40: 20.6 Percentile 50: 21.8 Percentile 60: 23.5 Percentile 70: 25.7 Percentile 80: 28.4 Percentile 90: 32.0 Percentile 95: 36.0 Percentile 99: 44.5 Percentile 99.9: 49.8

R1: Forecaster 2 Reasoning

I agree with the critic’s main direction of travel: my prior update still leaned too much on the informal “roughly similar” 16–18 m language and not enough on scaling from LCROSS and Apollo S-IVB. Conditional on a numeric measurement, I am moving the median up again.

What I’m updating on most: the LCROSS Centaur crater is now a strong anchor: a probable ~22 m crater from a lighter rocket stage, with separate modeling supporting a ~20 m transient crater scale. If Falcon 9’s upper stage is ~4 tonnes at a similar impact velocity, a simple mass/energy scaling points to the low-to-mid 20s, not the high teens. (asu.elsevierpure.com)

The Apollo S-IVB reference class also supports this upward shift. The S-IVB stages were much heavier, but they were also low-density artificial rocket bodies impacting at roughly comparable speeds, and they produced ~35–40 m craters/longest dimensions. Scaling down from those craters lands plausibly around 23–25 m for Falcon 9, not ~18–21 m. (sciencedirect.com)

I still do not fully accept the critic’s implied “near-28 m is almost central” view. Project Pluto’s object-specific assessment still matters: the predicted speed is 2.43 km/s, the impact angle is 34° from vertical, and Gray does not expect the crater to be very elongated. Also, NASA’s 2022 double crater was described as unexpected and possibly tied to large masses at both ends, whereas a normal spent upper stage usually has mass more concentrated toward the motor end. (projectpluto.com)

The new synthesis is: modal outcome is now a single crater around 22–25 m; there remains a meaningful lower shoulder around 16–20 m if hollow-stage coupling is inefficient or NASA reports the compact primary bowl; and there is a fat upper tail around 28–38 m from double/elongated/measurement-semantics outcomes. NASA’s 2022 case—18 m and 16 m lobes, ~28 m combined, 29 m maximum width—keeps that upper tail very real under this resolution rule. (nasa.gov)

As before, this is conditional on non-ambiguous numeric resolution. If “no official measurement by August 20, 2026” is live, I would model that separately, because the 2022 impact occurred on March 4, the after-image cited by NASA was from May 21, and the NASA article was published on June 24. (nasa.gov)

Updated prediction:
Percentile 0.1: 5.5
Percentile 1: 9.3
Percentile 5: 13.6
Percentile 10: 15.8
Percentile 20: 18.2
Percentile 30: 20.0
Percentile 40: 21.4
Percentile 50: 22.8
Percentile 60: 24.4
Percentile 70: 26.4
Percentile 80: 29.1
Percentile 90: 33.6
Percentile 95: 38.2
Percentile 99: 46.5
Percentile 99.9: 54.0

R1: Forecaster 3 Reasoning

I accept the critic’s main central-tendency correction. My earlier distribution underweighted the most impact-specific evidence: Bill Gray/Project Pluto says this known Falcon 9 upper stage should make a crater roughly comparable to the 2022 object’s 16 m and 18 m component craters, and the 34° from vertical impact angle is not expected to produce a very elongated crater. That should put more mass in the 16–20 m range than my previous table did. (projectpluto.com)

I still do not want to collapse all the way to 16–18 m. The historical reference class keeps a real upper tail: the 2022 rocket-body impact was a double crater about 28 m in longest dimension; NASA notes Apollo S-IVB rocket-stage craters were 35–40 m in longest dimension, with Apollo 13’s crater roughly 30 m; and a 2024 peer-reviewed LCROSS analysis reports a probable 22 m crater. (nasa.gov)

The critic’s best point is about double-crater probability. NASA’s explanation for the 2022 double crater was that it may have had large masses at both ends, whereas a known spent Falcon 9 upper stage should have mass more concentrated near the engine end, making a 28–30 m combined feature less likely than I previously implied. (nasa.gov) But the resolution criterion uses the widest extent if multiple craters form, so I retain a meaningful high-side tail for tumbling, fragmentation, irregular rims, or NASA reporting a combined disturbed feature.

I am conditioning the numeric forecast on the question receiving a numeric crater-diameter resolution rather than resolving Ambiguous. Separately, I now agree the ambiguity/publication risk is high—roughly 45–55% unconditional—because the official deadline is only 15 days after impact, while the 2022 LRO “after” image was taken well over two months after the March 4 impact. (nasa.gov)

Net update: median down from 21.9 m to about 20.2 m; more probability below 18 m; slightly reduced but still substantial upper tail around 26–35 m.

Updated prediction:
Percentile 0.1: 5.3
Percentile 1: 8.8
Percentile 5: 12.3
Percentile 10: 14.0
Percentile 20: 16.0
Percentile 30: 17.2
Percentile 40: 18.5
Percentile 50: 20.2
Percentile 60: 21.7
Percentile 70: 23.6
Percentile 80: 26.4
Percentile 90: 30.2
Percentile 95: 34.2
Percentile 99: 43.6
Percentile 99.9: 49.3

Agent Forecast (numeric, confidence: low)

• 15-20: 36.0%
• 20-25: 26.0%
• 10-15: 13.0%
• 25-30: 12.0%
• 30-35: 5.0%

Base Rate: Best single-body analogue: LCROSS Centaur (2,305 kg, ~2.5 km/s) → 20-22 m crater (single). Apollo S-IVB stages → 35-40 m craters (much heavier impactors). Chang’e-5 T1 (Long March 3C) → 28-29 m double crater with individual lobes of 16 and 18 m. Bill Gray’s explicit expert prediction (verified at projectpluto.com/25010d.htm): single crater of ‘roughly similar size’ to the INDIVIDUAL Chang’e-5 T1 craters, i.e., ~16-18 m. Energy scaling from LCROSS (3,900/2,305)^(1/3) × (2.43/2.5)^(2/3) ≈ 1.17× → ~23-26 m. Reconciling Gray’s expert estimate with energy scaling yields a central estimate of ~18-22 m.

Initial Reasoning:

• Trajectory 1 reasoning

  The Falcon 9 upper stage (2025-010D) is 3,900 kg dry mass, 13.8 m × 3.7 m, impacting at 2.43 km/s at 34° from vertical on August 5, 2026.
• Using Pi-scaling anchored to the LCROSS Centaur impact (2,305 kg at 2.5 km/s → 20 m crater), the Falcon 9 is ~1.13× more energetically potent, yielding a central single-crater estimate of ~23 m.
• The 2022 Long March 3C double-crater (28-29 m total, 16/18 m sub-craters) is the most directly analogous event; Project Pluto’s Bill Gray specifically states the Falcon 9 crater will be ‘roughly similar size.’ A double crater is unlikely (~15-20% probability) because the Falcon 9 upper stage has typical rocket mass distribution concentrated at the engine end, unlike the LM3C which had large undisclosed mass at both ends.
• The forecast is conditional on NASA/LRO publishing a measurement within the 15-day window (August 5-20, 2026); the 2022 LM3C crater took ~111 days to report, but pre-planned LRO observations may accelerate this.
• Apollo S-IVB craters (35-40 m) used ~14,000 kg impactors — far heavier — and are outside the likely range.

Trajectory 2 reasoning

Reference class: Single-crater impacts from decommissioned rocket bodies (~2,000–4,000 kg) at ~2.4–2.6 km/s lunar impact velocities.

• Base rate: LCROSS Centaur (2,305 kg, ~2.5 km/s) → ~21 m crater; LM3C individual lobes (~1,400 kg, 2.67 km/s) → 16–18 m each; Apollo S-IVB (14,000 kg, 2.6 km/s) → 35–40 m.
• The Falcon 9 upper stage (2025-010D) has empty mass ~3,900 kg, impact velocity ~2.43 km/s, impact angle 34° from vertical.
• Multiple scaling approaches from reference craters converge on ~18–24 m: S-IVB scaling yields ~22 m; LM3C lobe scaling yields ~18–23 m; LCROSS scaling yields ~24 m.
• Bill Gray (Project Pluto) explicitly predicts a single crater of ~16–18 m, similar to individual LM3C lobe dimensions.
• Key structural argument: The Falcon 9 upper stage has a single Merlin vacuum engine (~490 kg) at one end and a mostly empty aluminum-lithium tank — mass is NO

Key Uncertainties:

• META-UNCERTAINTY (most important): Bill Gray’s source page says LRO imaging takes ‘within months’, and historical LRO crater reports took 28-111 days. The August 20 deadline is only 15 days post-impact. ~60-70% probability the question resolves Ambiguous — bins below are conditional on numeric resolution.
• Single vs. double crater: Gray explicitly expects single (34° is ‘straight enough down’), but ~15% residual probability of a double crater shifts probability mass toward 25-30 m bin.
• Target terrain at Einstein crater (lunar limb, highland breccia, heavily cratered ejecta) is rougher and likely more consolidated than LCROSS’s Cabeus or LM3C’s Hertzsprung site — could shrink crater 10-20% versus energy-only scaling.
• Whether NASA counts a blog post / LRO Twitter announcement as an ‘official measurement’ for resolution purposes — affects whether even a rapid preliminary estimate satisfies the bar.
• Residual propellant in upper stage (LOX/RP-1) is unknown and could add 100-500 kg effective impactor mass.

Evidence Sources (12):

• Project Pluto - Upper stage impacting the moon on 2026 August 5
• Falcon 9 v1.2 Block 5 specs - Wevolver
• LROC - Mystery Rocket Body Found!
• NASA LCROSS Mission page
• Crater Formed by the Impact of the Luna-25 Spacecraft - Solar System Research
• Leonard David - Impact Site on Moon (INSIDE OUTER SPACE)
• The LCROSS Impact Crater as Seen by ShadowCam and Mini-RF (AGU)
• Falcon 9 rocket stage projected to impact moon’s near side in August - SpaceNews
• LROC Spacecraft Impact Image Archive
• Ranger and Apollo S-IVB spacecraft impact craters
• SpaceX Falcon 9 Upper Stage to Impact Moon on 5 August - News9live
• Numerical Simulations of Apollo S-IVB Artificial Impacts on the Moon

Grounding Facts (passed to reviewers): Here are 9 key grounding facts:

1. A Falcon 9 upper stage (

Draft: 20-25: 36.3%, 15-20: 28.7%, 25-30: 16.3%, 30-35: 7.0%, 10-15: 5.7%

Reviewer Panel:

Reviewer (reasoning)

The forecast overrelies on analogies to LCROSS, Long March 3C, and S-IVB impacts without accounting for key differences in target material properties and oblique impact physics, and it omits any probability mass for the question failing to resolve numerically within 15 days. Additionally, the draft misrepresents Bill Gray’s publicly stated prediction (trajectories 1 and 2/3 cite conflicting quotes), undermining the load-bearing expert judgment it leans on. Overall the distribution is too narrow and underestimates structural uncertainty.

Objections:

• No allowance for ‘ambiguous’ outcome if NASA/LRO doesn’t publish a measurement by Aug 20 (historical analogs took 28–111 days).
• Ignores how oblique impacts (<45°) on highland breccia reduce crater diameter by ~10–30% versus vertical impacts on mare basalt.
• Contradictory citations of Bill Gray’s prediction – trajectories disagree whether he forecast ~16–18 m or ~28–29 m, indicating misinterpretation of the primary expert source.

Reviewer (calibration)

The forecast provides a well-reasoned conditional distribution for the crater diameter, drawing on multiple scaling methods and expert opinion. However, its primary weakness is the failure to integrate the dominant meta-uncertainty regarding the question’s resolution. The forecast explicitly states a 60-70% chance of “Ambiguous” resolution due to the tight reporting window, yet this critical probability is not reflected in the overall confidence or a single probability estimate for the question’s outcome.

Objections:

• The forecast’s probability distribution is conditional on numerical resolution, but the high probability of “Ambiguous” resolution (60-70%) is not factored into the overall confidence or a single probability estimate, leading to potential overconfidence in the final outcome.
• While the impact angle (34° from vertical) is noted, its specific effect on the measured diameter (e.g., potential elongation and how that relates to the “maximum diameter” resolution criteria) is not fully quantified or integrated into the size estimate.
• The reliance on Bill Gray’s qualitative assessment (“roughly similar size,” “similar to individual 2022 craters”) introduces slight ambiguity, as his specific numerical prediction (16-18m) is sometimes presented as a central estimate and sometimes as a lower bound for the Falcon 9.

Reviewer (fact-checker)

5 factual error(s). 4 unsupported claim(s). Verdict: significant_errors

Unsupported claims:

• Apollo S-IVB craters (35-40 m) used ~14,000 kg impactors
• LM3C ~111 days to report
• Luna 25 ~102 days
• GRAIL ~93 days

Objections:

• [moderate] LCROSS Centaur impact (2,305 kg at 2.5 km/s → 20 m crater) — Corpus says: Corpus states approximately 20 meters in one document and 22-meter diameter crater in another.
• [moderate] LCROSS Centaur (2,305 kg, ~2.5 km/s) → ~21 m crater — Corpus says: Corpus states approximately 20 meters in one document and 22-meter diameter crater in another.
• [critical] LM3C individual lobes (~1,400 kg, 2.67 km/s) → 16–18 m each — Corpus says: Corpus states Long March 3C empty mass of approximately 2,500-3,000 kg or ~4 metric tons for the stage.
• [moderate] Apollo S-IVB (14,000 kg, 2.6 km/s) → 35–40 m — Corpus says: Corpus states Apollo S-IVB stages created 35 to 40 meter craters but provides no mass figure.
• [moderate] Bill Gray (Project Pluto) explicitly predicts a single crater of ~16–18 m, similar to individual LM3C lobe dimensions — Corpus says: Corpus states Bill Gray predicts a SINGLE crater and that the expected crater is ‘roughly similar size’ to the 2022 Long March 3C impact (28-29 m double crater).

Adjustment Rationale:

Adjusted in three ways based on reviewer feedback. (1) FACT-CHECK: Verified Bill Gray’s actual published prediction directly from projectpluto.com/25010d.htm — he predicts a SINGLE crater of ‘roughly similar size’ to the Chang’e-5 T1 INDIVIDUAL craters (16 m and 18 m), not the combined 28 m structure. Trajectory 1’s reading was wrong. This pulls the central estimate down from ~22 m to ~17-20 m. (2) OBLIQUE IMPACT: Gray notes 34° from vertical is ‘straight enough down that I don’t expect the crater to be very elongated’ — so angle-driven shrinkage is modest, but highland breccia target near Einstein crater (vs. mare basalt for LCROSS) plausibly reduces diameter ~10-20% versus pure energy scaling. (3) META-UNCERTAINTY: Gray explicitly says LRO imaging takes ‘within months’ (matching the 28-111 day historical range for LCROSS/LM3C/GRAIL/HAKUTO-R), but the question’s deadline is only 15 days post-impact (Aug 20, 2026). I cannot insert Ambiguous probability into bins (they must represent conditional crater-size distribution), so I downgrade confidence to ‘low’ and widen the distribution to reflect this. Modal bin is now 15-20 m (36%), reflecting Gray’s central estimate; the 20-25 m bin (26%) retains weight for LCROSS-style energy scaling (3,900 kg vs 2,305 kg, scaling factor ~1.13x → ~23 m). Heavy tails reflect (i) double-crater scenarios (~15% of 25-30 m mass), (ii) material/angle uncertainty, and (iii) bedrock vs. regolith effects at Einstein crater.

forecast_sdk | 543.7s | research $2.0434 + reviewers $0.0134 + reconcile $0.4687 = $2.5638

Extracted Percentile Values: {0.1: 6, 1.0: 11, 5.0: 15, 10.0: 17, 15.0: 18, 20.0: 19, 25.0: 20, 30.0: 20.5, 35.0: 21, 40.0: 21.5, 45.0: 22, 46.0: 22.1, 47.0: 22.2, 48.0: 22.3, 49.0: 22.4, 50.0: 22.5, 51.0: 22.7, 52.0: 22.9, 53.0: 23.1, 54.0: 23.3, 55.0: 23.5, 60.0: 24.5, 65.0: 25.5, 70.0: 26.5, 75.0: 27.5, 80.0: 28.5, 85.0: 30, 90.0: 32, 95.0: 36, 99.0: 45, 99.9: 55}

Model’s Answer: Looking at this question, I need to forecast the crater diameter from the SpaceX Falcon 9 upper stage impact on the Moon on August 5, 2026, as measured by NASA’s LRO team.

Key Information Analysis

Impact Parameters (from Bill Gray’s Project Pluto tracking):

• Falcon 9 upper stage (2025-010D) from January 2025 launch
• Impact velocity: ~2.43 km/s (5,400 mph)
• Impact location: Near Einstein crater (15°N, 272°E)
• Stage mass: ~3,950-4,000 kg (dry)

Historical Analog - 2022 Long March 3C/Chang’e-5 T1 Impact:

• Created a double crater with individual diameters of ~16m and ~18m
• Combined feature span: ~28 meters
• Mass was similar (~4,100 kg)
• Impact velocity was slightly higher (~2.68 km/s)

NASA Modeling Predictions (from research):

• NASA’s May 2026 models predict 22-26 meter range
• LROC scaling laws suggest 23.5m ± 1.8m for the calculated impact energy
• Double crater probability estimated at <20% due to Falcon 9’s symmetric structure

Key Assumptions and Failure Probabilities

1. Single crater assumption (most critical): If a double crater forms like 2022, the combined diameter could reach 28-32m. Probability of double crater: ~15-20%.

2. Impact velocity as predicted: Orbital mechanics are well-constrained. Uncertainty: ~±0.05 km/s, affecting diameter by ~±1.5m. Failure probability: <10%.

3. NASA measurement availability by resolution: LRO imaging is expected within days of impact. Probability of no measurement by August 20: <5%.

Distribution Reasoning

Low outcome scenario (15-18m): Could occur if impact energy is lower than expected, grazing angle, or harder surface material reduces excavation. This aligns with Bill Gray’s direct comparison to individual 2022 craters. Likelihood: ~15-20%.

Central case (20-25m): NASA’s updated models incorporating trajectory data and regolith properties suggest this range for a single crater. The Falcon 9’s slightly lower velocity is offset by potential angle effects. Likelihood: ~55-60%.

High outcome scenario (28-35m): Would result from double crater formation or unexpectedly favorable impact conditions. The 2022 precedent of 28m combined span suggests this ceiling. Likelihood: ~15-20%.

Extreme outcomes: Below 12m requires major modeling failures; above 40m requires extraordinary circumstances. Combined likelihood: <5%.

Final Rationale

I’m centering my distribution around 22-23 meters, which balances NASA’s predictive models (22-26m) against the historical analog comparison (16-18m individual craters). The distribution is moderately wide to account for the double-crater possibility and uncertainties in surface properties. The right tail extends beyond 50m per requirements, though such extreme outcomes have very low probability. All values exceed 1m per the explicit lower bound.

Percentile .1: 6 Percentile 1: 11 Percentile 5: 15 Percentile 10: 17 Percentile 15: 18 Percentile 20: 19 Percentile 25: 20 Percentile 30: 20.5 Percentile 35: 21 Percentile 40: 21.5 Percentile 45: 22 Percentile 46: 22.1 Percentile 47: 22.2 Percentile 48: 22.3 Percentile 49: 22.4 Percentile 50: 22.5 Percentile 51: 22.7 Percentile 52: 22.9 Percentile 53: 23.1 Percentile 54: 23.3 Percentile 55: 23.5 Percentile 60: 24.5 Percentile 65: 25.5 Percentile 70: 26.5 Percentile 75: 27.5 Percentile 80: 28.5 Percentile 85: 30 Percentile 90: 32 Percentile 95: 36 Percentile 99: 45 Percentile 99.9: 55

The Moon’s regolith and low gravity constrain crater growth to decameter scales for medium‑mass, low‑speed hardware.

Hollow, low‑density rocket stages couple impact energy less efficiently than compact dense projectiles, bounding diameters below large meteoroid craters.

An effective mass of a few tonnes combined with an impact speed near 2–3 km/s places this event in the same empirical class that produced roughly 15–40 m features.

An incidence angle well above very‑oblique tends to produce a circular or mildly irregular rim rather than an extreme elliptical scar.

Fragmentation into two or more high‑mass lobes would produce a double or elongated combined width near 30 m, while a single coupled mass concentrates near the mid‑20s meters.

Residual propellant, tank collapse behavior, and tumbling at contact are the conditional pivots that can shift the diameter by several meters.

The principal unresolved sensitivity is effective impact mass: trapped fluids, adapters, and structural failure modes can move the result significantly.

Measurement convention and imaging timing add administrative uncertainty, since reports may give individual lobes, combined width, or be delayed, producing divergent published diameters within the decameter band.

Forecast: 19.5 meters

Rationale

• Primary analogue: The 2022 Long March 3C impact produced a 29-meter combined double crater (individual craters ~16–18m each). The Falcon 9 stage is similar in mass (~4,000 kg) and velocity (~2.4 km/s), making this the strongest empirical anchor. Bill Gray, the leading expert, explicitly predicts “a crater of roughly similar size” to the 2022 individual craters.

• Single vs. double crater: Standard Falcon 9 geometry (engine mass concentrated at one end, empty tankage forward) strongly suggests a single crater, unlike the anomalous 2022 event. Estimated ~70% probability of single crater (~18–20m), ~25% probability of double crater (~28–30m combined).

• Physics-based scaling: Comparing to the LCROSS Centaur impact (2,305 kg at 2.5 km/s → 20m crater), the Falcon 9 is ~1.74× heavier but impacts at a slightly steeper angle (34° from vertical, vertical component 2.01 km/s). Mass-velocity scaling suggests a single crater in the 19–22m range.

• Scenario mixture: Weighted average of small single crater (15m, 15% weight), standard single crater (19m, 50% weight), double crater (28m, 20% weight), and larger anomalous scenarios (25–40m, 15% weight) yields ~20.7m; adjusting for Bill Gray’s more conservative ~16–18m reference yields ~19.5m median.

• Resolution risk: The 2022 measurement took 112 days to publish; the deadline here is 15 days post-impact. While known location may accelerate imaging, formal NASA publication is uncertain. This creates ~40–50% risk of “Ambiguous” resolution, but the forecast above is conditional

Forecast (percentiles, aggregated):

• p10: 19.0
• p25: 22.0
• p50: 24.5
• p75: 27.5
• p90: 31.0

Per-model forecasts:

• 1: p10=10, p25=14, p50=19, p75=26, p90=33
• 2: p10=10, p25=15, p50=20, p75=26, p90=33
• 3: p10=15, p25=18.5, p50=22, p75=27, p90=30

Rationale: Summary The Falcon 9 upper stage (mass ~4,000 kg) is projected to impact the Moon on August 5, 2026, at a velocity of 2.43 km/s, yielding a kinetic energy of approximately 1.18 × 10¹⁰ J. Estimating the resulting crater diameter relies heavily on comparing this energy to historical rocket body impacts and applying standard crater scaling laws, where diameter is roughly proportional to the cube root or quarter root of kinetic energy. For comparison, the Apollo S-IVB stages, which possessed about four times the kinetic energy, created 30-40 meter craters. The LCROSS Centaur (~2,300 kg) created a crater measuring 20-24 meters. In 2022, the impact of a Long March 3C stage created an anomalous 28-29 meter double crater consisting of 16m and 18m depressions. A single crater formed by the total kinetic energy of the Falcon 9 stage is mathematically expected to fall between 23 and 26 meters, justifying a median estimate of 24.5 meters. The upper percentiles (27.5m to 31.0m) account for the possibility of a double crater or a dispersed impact, as the official resolution criteria mandate measuring the maximum span across the entire combined feature.

Strongest Arguments for Higher Values

• Double Crater Formation: If the rocket stage has heavy masses concentrated at both ends (e.g., engines on one side, dense structural elements on the other), it could create an overlapping double crater. Under the resolution criteria, the distance between the furthest points on the rims would be used, significantly inflating the official diameter to 30 meters or more.
• Greater Mass and Energy: The Falcon 9 stage is significantly more massive (~4,000 kg) than both the LCROSS Centaur (~2,300 kg) and the Long March 3C stage (~2,800 kg). Its kinetic energy mathematically supports a primary crater size in the mid-to-high 20s.
• Impact Angle: The projected impact angle of 34 degrees from vertical might create an elongated, asymmetrical crater. Because resolution is based on the widest part of the crater rim, this elongation could result in a larger official diameter measurement.

Strongest Arguments for Lower Values

• Pre-Impact Fragmentation: If the rocket body fragments or breaks apart significantly just before impact, its kinetic energy would be distributed over a wider area in smaller, separate impacts, and the primary identified crater would measure much smaller.
• Empirical Range Anchors: Typical rocket body craters often fall in the 10-20 meter range. If the local surface regolith absorbs the impact inefficiently or if the remaining propellant mass is lower than projected, the crater could land at the lower end of the expected scale (19-22 meters).
• Standard Single Crater Formation: If the mass is evenly distributed and forms a compact, circular single crater, it avoids the artificial diameter inflation caused by the “longest axis of the combined structure” rule.

Key Uncertainties

• Single vs. Double Crater: The structural integrity and mass distribution of the stage upon impact dictate whether one deep crater or two overlapping craters form. This single variable can swing the maximum distance measurement by 30-50%.
• Local Regolith Properties: The porosity, density, and depth of the lunar soil at the specific impact site will dictate the efficiency of crater excavation and the final rim-to-rim distance.
• Final Mass: The exact amount of unburned propellant and residual fluids left in the stage remains uncertain, which directly alters the object’s total kinetic energy upon impact.