On the afternoon of November 3, Carl Hergenrother of the Catalina Sky Survey (CSS) near Tucson, Arizona, obtained and made available additional observations of object 2000 SG344 from the CSS image archives. These pre-discovery observations significantly improved the certainty of the object's position in 2030 and effectively ruled out the chance of an Earth impact in that year. As explained in the earlier release from the International Astronomical Union (IAU), this was the most likely outcome of the continuing investigations. With the new data, we can say that the closest the object can approach the Earth in 2030 is 11 lunar distances on September 23. These results are in agreement with those of Andrea Milani at the University of Pisa, Italy.

The earlier announcement of a possible Earth impact in 2030 made by the Technical Review Team of the IAU followed the recently established process for reviewing Torino Scale 1 impact predictions. In the first use of this procedure, the Team formed a consensus opinion and, following the IAU mandate, made their results public within 72 hours.

While the new orbital calculations have ruled out the 2030 event, they have also increased the likelihood of encounters in years after 2030. For example, for the date September 16, 2071, current computations indicate roughly a 1 in 1000 chance of an Earth impact. However, these calculations assume that object 2000 SG344 is asteroidal in nature. There remains the significant possibility that this object is a spacecraft booster rocket from the Apollo era and studies are continuing to assess this possibility. Additional observations of the object will be possible in the coming months and these should further refine the calculations and conclusions.

NASA Near-Earth Object Program Office, Jet Propulsion Laboratory
Don Yeomans
Paul Chodas
Steve Chesley