SpaceX breaks 2021 record with 32nd launch of the year

by Trevor Sesnic

SpaceX broke several records on the Starlink Group 3-2 mission. Launching from Space Launch Complex 4 East (SLC-4E) at the Vandenberg Space Force Base in California, the Falcon 9 Block 5 placed 46 Starlink internet communication satellites into the third shell of the constellation.

Liftoff was scheduled for July 21, 2022, at 10:39 AM PDT (17:39 UTC), but the countdown was aborted at T- 46 seconds due to a valve sensor reading on the first stage. Launch successfully occurred at the same time on July 22, marking SpaceX’s 32nd launch of 2022. This broke SpaceX’s 2021 record of most launches in a year when they launched 31 times.

With the eventual goal of being able to turn around SLC-4E as quickly as SLC-40 in Florida, SpaceX has been making a large number of upgrades to the Transporter/Erector (T/E) and pad infrastructure at pad 4E. The T/E is responsible for transitioning the Falcon 9 vehicle from horizontal to vertical. Once vertical, it provides the vehicle and payload with structural support, power and telemetry, and is used to fuel the vehicle through the Quick Disconnects (QDs).

Unlike the T/E at SpaceX’s other two Falcon 9 launch sites—LC-39A and SLC-40—SLC-4E utilizes an older design: the strong back falls 13º away from the rocket, starting at T-4 minutes, and is finished moving by T-3 minutes. From this position, the T/E does not move further and remains stationary during liftoff. This is drastically different from the “throwback” T/E style, which moves just under 2º away from the vehicle at roughly T-4 minutes, then falls the remaining distance from the vehicle (~45º) after liftoff.

By falling away further from the vehicle after liftoff, the T/E further avoids the Falcon 9’s exhaust, lessening the amount of refurbishment needed between launches. LC-39A has featured the throwback style T/E since SpaceX’s first launch from the pad (CRS-10), and SLC-40’s T/E was upgraded to the throwback style following AMOS-6. However, SpaceX currently has no plans to swap out SLC-4E’s T/E for a throwback style T/E.

SpaceX’s upgrades to SLC-4E have allowed for drastically reduced turnaround time between launches to just 11 days and 16 hours between Starlink Group 3-1 and Starlink Group 3-2. The previous record was 22 days, 11 hours, and 20 minutes between SARah-1 and Starlink Group 3-1. This also marks the fastest turnaround time for a non-throwback T/E.

The booster supporting this mission is B1071-4, which has flown three previous missions. This launch marks the 166th launch of the Falcon 9 and the 104th launch with a flight-proven booster. 

B1071’s missions Launch Date (UTC) Turnaround Time (Days)
NROL-87 February 2, 2022 20:27 N/A
NROL-85 April 17, 2022 13:13 73.70
SARah 1 June 18, 2022 14:19 62.05
Starlink Group 3-2 July 22, 2022 17:39 34.14

B1071-4 landed on SpaceX’s West coast Autonomous Spaceport Drone Ship (ASDS) Of Course I Still Love You (OCISLY), stationed 635 km down range. As usual for West coast launches, OCISLY was towed downrange by Scorpius, and GO Quest is serving as ASDS support. Upon the successful landing—which marked SpaceX’s 132nd overall and 58th consecutive booster landing—the booster’s designation changed to B1071-5.

SpaceX will attempt to recover both fairing halves with their recovery asset NRC Quest 635 km down range. Both fairings will be recovered from the water ~50 minutes after launch.

The inside of a recovered Falcon 9 fairing from the Starlink Group 3-1 mission. (Credit: Jack Beyer for NSF)

The Starlink Group 3-2 mission lofted another 46 satellites into the third shell of the Starlink constellation. Assuming none of the satellites fail, this will take shell 3 to 27.3% completion (in terms of working satellites) and the overall completion of the first five shells of Starlink deployments to 59.32%.

Shells Inclination (°) Orbital Altitude (km) Planes Satellites per Plane Number of Satellites Working Satellites % Complete
Shell 1 53 550 72 22 1,584 1,534 94.5
Shell 2 70 570 36 20 720 51 7.1
Shell 3 97.6 560 6 58 348 49 14.1
Shell 4 53.2 540 72 22 1,584 972 61.4
Shell 5 97.6 560 4 43 172 0 0

Assuming SpaceX holds its current launch cadence, it is expected the company will complete shells 3 and 4 by the end of the year, as shell 3 will require about eight launches to fill and shell 4 will require about 32 launches to fill. After these two shells are complete, it is unclear whether SpaceX will prioritize the 70° inclination Shell 2 or the polar orbiting Shell 5.

SpaceX is currently offering several Starlink packages, including Starlink for home, business, RV, and marine. In addition to the services already being offered, De Havilland Aircraft of Canada announced they are partnering with SpaceX to offer high-speed internet on their aircraft thanks to Starlink.

Launch sequence

Given the “go” from the technical go/no-go poll at T-38 minutes, Falcon 9 began its fueling sequence at T-35 minutes when the vehicle began to load sub-cooled RP-1 on both stages and super chilled liquid oxygen (LOX) on the first stage.

By T-20 minutes, Falcon 9’s second stage is fully fueled with RP-1, and the T/E is purged to prepare for LOX loading on the second stage. Due to the significantly cooler temperature of LOX, it is loaded after RP-1 on the second stage to minimize boiloff/expansion.

By T-16 minutes, the T/E is purged and loading of LOX onto the second stage begins.

Seven minutes before launch, the vehicle begins chilling the engines on the first stage. This is done to reduce the thermal shock on the engines as LOX flows through them at ignition. At T-4 minutes, the T/E is rotated back to launch position–13 degrees from the vehicle.

One minute before launch, the vehicle enters startup–a process where the rocket’s onboard computers take control of the launch sequence. Three seconds before launch, the rocket commands ignition of all nine first stage engines, which is done in a staggered manner to reduce transients on the vehicle.

Assuming all nine engines report a nominal start-up, at T0 the vehicle commands the hydraulic launch clamps to release it, allowing it to lift off. 

The first stage burned for two minutes and 32 seconds before separating from the second stage. While the second stage completed a just-over-six-minute burn, the fairings separated from the vehicle and the first stage completed two burns to land on OCISLY.

The second stage then coasted for ~45 minutes, before igniting again for just under a second. The stage then began rotating end-over-end to deploy the satellites at T+1:03:03 into low Earth orbit.

After payload deployment, the MVac engine will perform a third burn to deorbit itself over the Southern Pacific Ocean.

SpaceX has one more launch planned for July: Starlink Group 4-25 will launch on July 24 from LC-39A in Florida. The Korean Pathfinder Lunar Orbiter (KLPO) will then launch on a Falcon 9 from the East Coast on August 2.

(Lead photo: Falcon 9 emerges from the fog at SLC-4E. Credit: SpaceX)

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