Thirteen months have passed since Epoch 2. A rapid-response flyby reconnaissance space mission was launched towards 2023 PDC just after Epoch 2, and it encountered the asteroid a few days ago, on Nov. 27, 2025, after a flight of about 400 days.
The flyby recon spacecraft imaged the asteroid extensively both before and after the flyby. These images were used to provide a substantial reduction in the orbital uncertainty of 2023 PDC, which has resulted in a much improved prediction of the impact location.
The latest orbit estimate indicates that 2023 PDC is headed for impact within the African countries of Nigeria or Benin. The diagram below shows the current predicted impact region. The impact date is unchanged, Oct. 22, 2036, 11 years from now.
The images from the recon mission have also yielded a greatly improved estimate of the size of asteroid 2023 PDC, and even its approximate shape. Some size and volume uncertainty still remains because a portion of the asteroid was unilluminated throughout the the closest part of the flyby. The most likely size now ranges from 550 to 860 meters (1800 to 2800 feet), with a median of 700 meters (2300 feet).
The newly revised size range is at the high end of the size range derived from Earth-based brightness measurements because the albedo (reflectivity) of 2023 PDC is a little lower than average, and the size could only be inferred from the statistics of typical asteroid albedos.
Analysis of the flyby-recon images has provided important information on other physical properties of the asteroid as well, such as its spectral class. The asteroid is confirmed to be C-type, which implies a carbonaceous stony composition. C-type asteroids are typically a little less dense than other asteroid types, and the assumed range of possible densities can now be constrained a little more tightly.
The improved estimates of 2023 PDC’s size, shape and density have led to a much better estimate of its total mass. Combined with the predicted impact velocity, this has produced a greatly refined estimate of most likely range of impact energies: 1.2 to 9.3 Gt. (See the Impact Risk briefing for the details.)
A second, more elaborate reconnaissance mission was launched towards 2023 PDC 6 weeks ago to further characterize the asteroid. That spacecraft will use Solar Electric Propulsion to match up with the asteroid’s orbit and rendezvous with 2023 PDC November 2026. It will spend many months surveying the asteroid and, for the first time, make direct measurements of the asteroid mass. Its images will yield measurements which can further improve the asteroid orbit and, together with all the other orbital data, help pinpoint the exact impact location.
The parameters required for a successful deflection of the 2023 PDC trajectory away from Earth impact have now become better defined. The impact region is now located closer to the eastern limb of the risk corridor than the western limb, and it has become more compact. To move the entire region off the Earth capture disc in the target b-plane, the asteroid trajectory would have to be shifted roughly 5700 km southeastwards.
More importantly, the mass of the asteroid, the key parameter affecting deflection, is now better constrained. Unfortunately, as a result of the asteroid being somewhat larger than expected, the range of most likely mass values has converged towards the upper end of the range estimated previously, based only on Earth-based data.
The requirements that a Kinetic Impactor campaign would need for a successful deflection have now come into better focus. For example, it is now clear which direction is easier. Although kinetic impactor deflection for 2023 PDC is more effective going westwards, the impact region is close enough to the southeastern end of the risk corridor that an southeastwards KI deflection can be carried out with less effort than in the other direction.
Using the same kinetic impactor nominal launch date and launch capability as described in the Epoch 2 briefing (June 11, 2028 and the maximum mass payload launched on a Falcon Heavy), the number of launches required for a successful deflection of the entire impact region was assessed as a function of the revised range of possible masses of 2023 PDC. For the current most likely value for the asteroid mass, roughly 90 Falcon Heavy missions would be required, while for the 95th percentile mass, well over 200 missions would be required. Those numbers assume a momentum enhancement factor (beta value) of 3.0, similar to the enhanced deflection observed after the DART deflection test in 2022. While use of a larger launch vehicle might reduce these numbers by a factor of several, the number of KI deflections likely required for success is still likely to be prohibitively large.
On the other hand, the launch requirements for a successful standoff nuclear deflection of 2023 PDC, moving the impact region 5700 km southeastwards off the Earth, are modest by comparison. A single mission launched on a Falcon Heavy in October 2027, carrying a payload of 5 NEDs would likely be more than sufficient to deflect the entire impact region off the Earth (see the Mission Options Briefing on the Epoch 2 tab).
Deflection requirements will become even better defined a year from now after the rendezvous reconnaissance mission has arrived at 2023 PDC and surveyed the asteroid for several months. Both the impact location and the asteroid mass will be very well known at that point.
|
| 2023 PDC Impact Footprint at Epoch 3 |
A Google Earth kml file for these impact points is available here.
A Google Earth kmz map file showing the damage swaths and example damage footprints at Epoch 3 is available here. A presentation giving an introduction to damage maps is available here.
While the orbit for the updated Epoch 3 trajectory for 2023 PDC has not been loaded into JPL’s HORIZONS system, the orbit for the nearby Epoch 2 trajectory is there, and can be accessed via the name “2023 PDCa” or “PDC23a”. HORIZONS can be accessed with this object preloaded via this web-interface here.
This Epoch 2 trajectory for 2023 PDC, is also available as an SPK, available here:
https://ssd.jpl.nasa.gov/ftp/xfr/2023-PDC/2023_PDCa-s8-merged-DE441.bsp