SMPAG has organized an extensive deflection campaign involving multiple space agencies and various launch vehicles

• A total of 8 spacecraft of various designs, all using Solar Electric Propulsion (SEP) have been under development for the last 2.5 years

• Only six spacecraft were completed on time

• The six launches occurred over a 3-week period in March (2 months ago) on Delta-IVH class vehicles; one launch failed, leaving a total of 5 KI spacecraft to carry out the deflection in February 2024

• The KI spacecraft use an intercept trajectory that will boost the velocity of the asteroid, thereby moving the asteroid’s impact point eastwards into the Pacific Ocean

• The intercept trajectory is difficult to attain, requires a long flight time, and arrives at the asteroid at a relatively low velocity of 8 km/s

• Two spacecraft have been readied for launch one month from now on a mission to rendezvous with 2017 PDC in May 2023, 3 years from now

• Decision makers have discussed whether or not to install nuclear explosive devices on these spacecraft, but decided not to do so

• The spacecraft were designed to carry such devices, and currently carry a dummy mass that could be replaced by the nuclear device; there is still time to make the switch

• The spacecraft will arrive in time to observe the series of KI deflections scheduled for Feb. 2024

• The images sent back would be invaluable for assessing the results of the deflection and establishing new trajectories for both components of the binary asteroid

Impact Risk Assessment Summary

• Simulated 1000 impact cases for each swath point, sampling from uncertainty distributions of size (diameter or H-mag/albedo), density, and strength according to the given knowledge about the asteroid for each inject option.

• Local population affected by blast overpressure and/or tsunami is computed for each sampled impact case.

• For blast overpressure, different fractions of the population are counted as affected depending on the blast overpressure level: 10% of people within the 1-2 psi zone, 30% within the 2-4 psi zone, 60% within the 4-10 psi zone, and 100% within the 10+ psi zone.

• For tsunami, fractions of the inundated population are counted as casualties depending on flood depth (averaging to about 10% of the inundated population).

• The maximum affected population from blast or tsunami is taken as the affected population for each sampled impact case.

Theflybyrevealedthat2017PDCisabinary,consistingofaprimarybodyabout 270 meters in size and a moon (“secondary”) roughly 100 meters across

• Theorbitalradiusofthesecondaryisatleast1-2km,considerablylargerthan the norm for binaries in this size range; orbital period on the order of a few days

• Asaresult,thesecondaryisonlylooselyboundtotheprimary

• ApproachimagesfromthespacecrafthaveprovidedenoughdataforIAWNto estimate an approximate mass for both components; the mass is 20% higher than had been assumed

• Size,shapeandvolumearenowknownmuchbetter;combinationwiththemass estimate yields a density of 1.9 g/cm^3

https://cneos.jpl.nasa.gov/pd/cs/pdc17/Chodas-Day3-Briefing.pdf

(http://www.autoadmit.com/thread.php?thread_id=5015402&forum_id=2#43837587)

LJL it's still gonna hit

(http://www.autoadmit.com/thread.php?thread_id=5015402&forum_id=2#43839204)