In a surprising last-minute move, Space X has moved Falcon Heavy Flight 3's center core landing on the drone ship, Of Course I Still Love You (OCISLY) from 40km to more than 1240 km (770 miles) off of the coast of Florida.
This means that Space X is on course to break their own record for distance traveled during a booster recovery.
A new record?
The standing record for distance traveled during booster recovery is ~970 km, set by the Falcon Heavy center core B1055 on its Arabsat-6A mission in April 2019.
If it succeeds, Space X's Falcon Heavy center core B1057 will beat that record by almost 30%.
And we finally have the new FCC permit coordinates for Of Course I Still Love You. Center booster landing will now be the farthest-ever down range #Falcon booster landing, beating ArabSat-6A by more than 260 km. Landing is 1,245 km out in the Atlantic. #FalconHeavy#STP2#SpaceXhttps://t.co/BG11rwsIgE— Chris G - NSF (@ChrisG_NSF) 18 June 2019
Falcon Heavy Flight 3 is scheduled to lift off no earlier than 11:30 pm ET on June 24th. A routine static fire test at Pad 39A helped prepare it for launch on Wednesday, June 19th.
A surprising change of plans
The change in distance is a surprising revelation; not least because the difference between a center core landing 40 km or 1300 km from the launch site is a huge distance that Space X engineers have to account for.
The landing ship is already being towed to the landing location due to the large distance it has to travel, at a very slow towing speed.
As Teslarati puts it, for Falcon Heavy, the center core shuts down and separates from the rest of the rocket up to a minute after the rocket’s two side boosters. This has the potential to double the booster's relative velocity at separation.
That extra minute of acceleration means that the center core could be as much as 50-100+ km downrange at the point of separation.
So landing at 40km offshore would require a very aggressive maneuver to reach drone ship OCISLY.
Why the change? We can only speculate
So having STP-2's center core recovery moved to 1240 km is a huge change in the rocket's mission plan and launch trajectory.
However, the reason for the change has not been disclosed by Space X. Despite this, observers are speculating it could be down to a mystery payload, and that the last-minute change was made to add increased safety margins.