SpaceX has completed its third-ever launch of the world’s most powerful operational rocket. Monday’s launch, dubbed by CEO Elon Musk as its “most difficult ever,” was almost a complete success as it delivered the 24 satellites into space. Unfortunately, the company failed to land the center core after lift-off.
The Department of Defense’s Space Test Program-2 mission, also known as STP-2, lifted off from Launch Complex 39A at Florida’s Kennedy Space Center at 2:30 a.m. Eastern. The launch used the Falcon Heavy in its second-ever commercial mission, following the Arabsat-6A launch in April, and it was the first time SpaceX reused two side boosters in a Falcon Heavy mission.
The company started deploying the satellites 12 minutes after liftoff, a process that finished three hours and 32 minutes after liftoff. The whole process was considered SpaceX’s most complex mission yet, involving four separate upper-stage engine burns, three separate deployment orbits, and a propulsive passivation maneuver to finish.
While the satellites deployed and completed the mission, SpaceX had set itself a monumental task in aiming to land all three booster cores. The two side boosters correctly landed at Landing Zones 1 and 2:
Unfortunately, the center core, which was meant to land on the drone-ship Of Course I Still Love You, missed its target.
“Center core RUD,” Musk noted on Twitter. “It was a long shot.” RUD stands for “Rapid Unscheduled Disassembly.”
The team also failed to land the center core during the Heavy’s inaugural February 2018 mission. While it did land the core during the Arabsat-6A mission, but it was unable to secure the core as it came into the port.
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SpaceX Falcon Heavy: Why the Booster Landing Was So Ambitious
Days prior to the launch, SpaceX made an unexpected change to the landing procedures. The drone-ship was originally expected to stay relatively close to the shore, but on June 18 a new FCC permit showed the booster was now going to land 1,245 kilometers (774 miles) out in the Atlantic Ocean. That’s an even further distance than the Arabsat-6A landing by 260 kilometers (161 miles), and would have been the farthest-ever landing of its kind.
This further distance means the center core had to travel longer and faster than the previous mission. Teslarati noted ahead of the launch that this would create the most intense conditions for a booster landing ever. The previous record holder, from the Arabsat-6A mission, detached from the rest of the vehicle 62 miles above the ocean at a speed of 1.9 miles per second.
Musk was downbeat about the STP-2 center core’s chances. Ahead of the launch he noted that the odds of survival were about 50 percent, as it would come in to land four times faster than a rifle bullet.
That begs the question, why did SpaceX make the last-minute change and up the ante?
“High payload/delta-V missions will always be far downrange,” Musk explained on Twitter. “Value of boost stage is measured (essentially) by horizontal velocity imparted to upper stage. Altitude is almost unimportant.”
SpaceX Falcon Heavy: The Most Powerful Rocket Advances
Monday’s launch was notable for a number of reasons. Added together, it makes the center core miss pale in comparison to the achievements of the team.
The launch was a particularly long mission for SpaceX, as they normally last around an hour. The mission was for the Department of Defense, and involved the deployment of a wide variety of both department-focused satellites and student projects. One of the more minor projects was a “CubeSat” designed to sail using solar.
The mission demonstrates the effectiveness of the Falcon Heavy. The rocket provides more than five million pounds of liftoff thrust at launch, making it the most powerful rocket currently in existence. That bodes well for the Starship, which is set to improve on this further to take the first humans to Mars.
But the reuse of the Falcon Heavy’s side boosters is perhaps the area of most interest to future missions. Randy Kendall, vice president of launch programs for Aerospace Corp that advises and supports the Air Force in related areas, told SpaceNews ahead of the launch that STP-2 “will be the first trial to look at how SpaceX processes, refurbishes and re-flies vehicles.”
Perfecting its recovery technology means it can save money on future launches. That frees up funds to spend on more ambitious missions, paving the way for Musk’s dream of a city on Mars.