SpaceX conducts 65th and 66th launches of 2023

by Trevor Sesnic

SpaceX launched two back-to-back Starlink missions this week. The first mission, Starlink Group 7-2, launched 21 satellites to low-Earth orbit from Space Launch Complex (SLC) 4 East at the Vandenberg Space Force Base in California. Liftoff occurred Monday, Sept. 11, at 11:57 PM PDT (06:57 UTC on Sept. 12).

SpaceX then launched the Starlink Group 6-16 mission late on Friday from SLC-40 at the Cape Canaveral Space Force Station, in Florida.

Starlink Group 7-2

Starlink Group 7-2 marked SpaceX’s 51st launch from SLC-4E and the second-quickest turnaround time of the pad to date, at nine days, 16 hours, and 31 minutes. The quickest turnaround of the pad was set in June between the Transporter-8 and Starlink Group 5-7 missions and was just marginally quicker at nine days, nine hours, and 43 minutes.

Aligning with SpaceX’s goal of launching 10 times per month by the end of 2023 and 12 times per month in 2024, teams have drastically been increasing the launch cadence out of the pad; in the middle of 2022, the pad turnaround time averaged nearly 40 days. By the start of 2023, this was brought down to roughly three weeks between flights. The pad now averages 11-13 days between missions.

For SpaceX to achieve its 144 launch goal, it will have to drastically reduce this turnaround to around six days (for a total of 60 launches next year), which would match the cadence that Of Course I Still Love You is able to support. Teams are able to turn around drone ships roughly two days quicker on the West Coast missions than on the East Coast missions due to closer proximity to the port.

With respect to this goal, the remaining launches would largely come from SLC-40, with Launch Complex 39A (LC-39A) launching the occasional Falcon Heavy or Dragon mission. With two drone ships on the East Coast (A Shortfall of Gravitas and Just Read the Instructions), this launch cadence is likely not possible; SpaceX would either have to increase its number of return-to-launch site missions or build another drone ship.

SLC-40 has also been drastically increasing its launch cadence; in the middle of 2022, the pad was launching a mission every 11-13 days. This has been more than cut in half, with the current average time between launches at between five and six days between launches. LC-39A’s launch rate has largely plateaued with a launch every ~30 days due to the pad conversions needed before Falcon Heavy and Dragon missions.

The booster supporting the Starlink Group 7-2 mission was B1071-11. As the name implies, the booster has supported 10 previous missions: NROL-87, NROL-85, SARah 1, Starlink Group 3-2, Starlink Group 4-29, SWOT, Starlink Group 2-6, Starlink Group 2-8, Transporter-8, and Starlink Group 6-15. Following liftoff, the booster will attempt to land on SpaceX’s autonomous spaceport drone ship Of Course I Still Love You. The drone ship was tugged 642 kilometers downrange, supported by GO Beyond.

Inside Falcon 9’s 5.2-meter diameter payload fairing were 21 Starlink v2 Mini internet communication satellites. Following the launch, both fairing halves (which are likely flight-proven) will be recovered by SpaceX’s multi-purpose recovery vessel GO Beyond.

The satellites were deployed just over one hour after launch into a 286 by 297-kilometer low-Earth orbit inclined 53.05 degrees. They will spend the coming weeks using their onboard argon thrusters to raise its orbit to a 525-kilometer circular orbit, inclined 53.00 degrees.

Before these two Starlink missions, SpaceX had launched 5,070 Starlink satellites. Currently, 4,724 of these remain in orbit, with 4,692 of these working. 4,044 satellites are in their operational orbits, most of which are in the Starlink first-generation constellation. However, SpaceX is now only filling its second-generation constellation.

This mission marked SpaceX’s 255th Falcon 9 launch and 65th of the year. Impressively, this marks the 187th Falcon 9 launch with a flight-proven booster and the 195th total reuse of a Falcon core. The landing is SpaceX’s 225th successful landing of a Falcon core and 151st in a row.

HR/MIN/SEC Post-launch Event
00:01:12 Max Q (Moment of peak mechanical stress on the rocket)
00:02:26 1st stage main engine cutoff (MECO)
00:02:29 1st and 2nd stages separate
00:02:35 2nd stage engine starts (SES-1)
00:03:03 Fairing deployment
00:06:19 1st stage entry burn begins
00:06:42 1st stage entry burn ends
00:08:09 1st stage landing burn begins
00:08:30 1st stage landing
00:08:38 2nd stage engine cutoff (SECO-1)
00:53:24 2nd stage engine starts (SES-2)
00:53:26 2nd stage engine cutoff (SECO-2)
01:02:19 Starlink satellites deploy

Starlink Group 6-16

SpaceX’s 62nd Falcon 9 mission of 2023 lofted 22 Starlink v2 Mini satellites into a 284 by 294-kilometer low-Earth orbit, inclined 43.00 degrees.

The booster supporting this mission, B1078-5, is one of the newer boosters in SpaceX’s ~20-core Falcon fleet. It has previously launched Crew-6, O3b mPower 3 and 4, Starlink Group 6-4, and Starlink Group 6-8. B1078 has the second-quickest average turnaround of any booster, flying on an average of 49.23 days.

Following the launch, the booster landed atop Just Read the Instructions, which was tugged over 600 kilometers downrange by Crosby Skipper.  Both payload fairings will be recovered by SpaceX’s recovery vessel Doug, which has been working double shifts as work has been done on Bob. However, Bob is now back at Port Canaveral and is expected to be used on missions again soon.

(Lead image: Falcon 9 launches Starlink 6-16 from SLC-40. Credit: Julia Bergeron for NSF.)

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