Spaceflight Insider

SpaceX sets record with launch of 64 satellites on SSO-A

A SpaceX Falcon 9 rocket lifts off with 64 satellites bound for orbit on the SSO-A mission that launched on Monday, Dec. 3, 2018. Photo Credit: Alex Ustick / SpaceFlight Insider

A SpaceX Falcon 9 rocket lifts off with 64 satellites bound for orbit on the SSO-A mission that launched on Monday, Dec. 3, 2018. Photo Credit: Alex Ustick / SpaceFlight Insider

LOMPOC, Calif. — Overcoming numerous delays, SpaceX completed one of its most complex missions yet – the delivery of 64 satellites to a Sun-synchronous orbit (SSO) as part of the SSO-A mission that launched today.

In sending the SSO-A payloads on their way, SpaceX set a few records in the process. Lifting off at 10:34 a.m. PST (18:34 UTC) on Monday, Dec. 3, 2018, from Space Launch Complex 4E (SLC-4E) at Vandenberg Air Force Base (VAFB) in California, the company’s Falcon 9 rocket delivered the largest number of satellites to be orbited by a U.S. launch provider on a single flight. SpaceX did so from a rocket whose first stage was making its third flight.

The flight had been originally scheduled for launch at 10:31 a.m. PST but SpaceX announced 19 minutes prior to the start of the launch window that there would be a delay of about three minutes.

The Falcon 9 Block 5’s nine Merlin 1D engines ignited three seconds before liftoff, and after the passing a quick health check, the vehicle and its payload began climbing on a pillar produced by 1.71 million pounds (7,065 kilonewtons) of sea-level thrust.

Lifting off into the partly-cloudy sky, the vehicle continued to build speed as it arced out over the Pacific Ocean, reaching the moment of maximum dynamic pressure—the time when the forces exerted on the rocket by the thrust of the engines, combined with the pressures of the thinning, but still substantial atmosphere, are greatest—approximately one minute after liftoff.

The 9 Merlin 1D engines in the rocket’s first stage continued to fire for nearly another minute and a half, lofting the vehicle to an altitude of approximately 40 miles (65 kilometers) before shutting down. After booster engine cut-off, stage separation followed approximately three seconds later.

SSO-A mission logo. Image Credit: SpaceX

SSO-A mission logo. Image Credit: SpaceX

The first stage, now separate from the rest of the vehicle, began orienting itself for the boostback burn. The second stage, meanwhile, started its lone Merlin 1D Vacuum engine to continue in its mission to deliver the 64 passengers to orbit. This engine, capable of producing 205,000 pounds (914 kilonewtons) in its vacuum configuration, began to glow from the heat of combustion as the vehicle and payload continued to accelerate. With the second stage now well-clear of the first stage, the booster restarted a subset of its nine engines to put itself on a trajectory to land on the drone ship “Just Read the Instructions” in the Pacific below.

Once clear of the thick atmosphere, and no longer needing the thermal and acoustic protection provided by the payload fairing, the aerodynamic shell was discarded 2 minutes, 43 seconds after liftoff. As the second stage and its cadre of satellites continued building speed, the first stage initiated its entry burn, nearly six minutes after liftoff.

Designed to shed speed, and the accompanying stresses the booster would encounter as it dove through the ever-thickening atmosphere, the engine firing slowed the booster on its descent to the waiting droneship.

After engine shutdown, the booster used its grid fins and cold gas thrusters to maintain a proper descent attitude, before once again lighting a group of its engines to land on the “Just Read the Instructions” Autonomous Spaceport Drone Ship It was the nineteenth successful droneship landing for SpaceX and third droneship landing for this particular booster.

While the first stage was completing its flight, the second continued on its mission to deliver its payload to orbit. Approximately ten minutes after leaving the launch pad, the second stage’s engine was cut-off as the vehicle and its satellites reached the targeted orbit. After coasting for nearly four minutes, the 64 nano and micro satellites were deployed over the next 30 minutes.

The satellites represented the work of colleges, universities, high schools, commercial operators, and even governments, coming from 34 organizations who hail from 17 nations.

Beyond being the first Falcon 9 booster to launch three times, it is also the first to have launched from all three of the company’s active launch sites — Bangabandhu-1 from LC-39A at Kennedy Space Center (KSC), Merah Putih from SLC-40 at the Cape Canaveral Air Force Station (CCAFS), and now Spaceflight SSO-A from SLC-4E at VAFB. The mission marked the company’s nineteenth of 2018, with the next being the launch of CRS-16 from LC-39A in Florida.





Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

Reader Comments

Wow. That was a well written and entertaining read.

⚠ Commenting Rules

Post Comment

Your email address will not be published. Required fields are marked *