SpaceX is on the cusp of launching three Falcon 9 rockets in a handful of days. Minor issues with two of the three missions, however, have complicated the already hard process of coordinating so many launches at the same time.
For many reasons, rocket launches are an inherently difficult thing to schedule, and that difficulty only gets magnified when attempting to launch rockets as quickly as possible for customers with very different needs while using a fixed number of launch pads. SpaceX’s upcoming series of launches demonstrates the slippery nature of high-cadence rocket launch scheduling better than most.
Last month, SpaceX ran into issues (mainly bad weather) that delayed its Starlink 4-34, 4-35, and 4-36 missions by varying degrees. Before those delays, SpaceX had intended to break its LC-40 pad turnaround record with Starlink 4-35 and then repeat the feat with Starlink 4-36, but that opportunity closed when Starlink 4-34’s several weather delays pushed Starlink 4-35 from September 19th to the 24th and raised the risk of the next launch, Starlink 4-36, interfering with customer missions planned in the first half of October.
That burst of customer missions, all of which take priority over SpaceX’s own Starlink missions, meant that a few-day delay for a mission two launches prior ultimately pushed Starlink 4-36 from the end of September to no earlier than October 20th. It will launch out of Cape Canaveral Space Force Station’s (CCSFS) LC-40, the same pad that launched Starlink 4-35 on September 24th and will launch Intelsat’s Galaxy 33 and 34 satellites no earlier than (NET) October 6th and Eutelsat’s Hotbird 13F satellite NET October 13th. All four launches (including Starlink 4-36) are thus contingent upon each other, so a delay with one mission would likely delay each subsequent mission to leave enough time for pad turnaround and rocket processing.
|10/04/22||Starlink 4-29||Falcon 9||California||VSFB SLC-4E|
|10/04/22||SES-20/21||Atlas V||Florida||CCSFS LC-41|
|10/05/22||Crew-5||Falcon 9||Florida||KSC LC-39A|
|10/06/22||Galaxy 33/34||Falcon 9||Florida||CCSFS LC-40|
|10/13/22||Hotbird 13F||Falcon 9||Florida||CCSFS LC-40|
|10/20/22||Starlink 4-36||Falcon 9||Florida||CCSFS LC-40|
SpaceX isn’t the only company that launches out of Cape Canaveral, Florida. Originally scheduled in late September, the United Launch Alliance’s (ULA) Atlas V launch of the SES-20 and SES-21 geostationary communication satellites was delayed by the same weather system that indirectly hampered Starlink 4-35 and 4-36. That mission is now set to launch NET 5:36 pm EDT (21:36 UTC) on October 4th.
Up first, however, is SpaceX’s Starlink 4-29 mission out of California’s Vandenberg Space Force Base (VSFB). Delayed to October 4th hours before its October 3rd target, the new schedule will give SpaceX “more time for pre-launch checkouts,” Falcon 9 will now lift off as early as 4:48 pm PDT (23:48 UTC), a little over two hours after Atlas V. However, making the whole situation even more interlinked, SpaceX says it will stand down from its October 4th Starlink launch attempt if its next Florida mission – Crew Dragon’s fifth operational NASA astronaut launch – remains on track for its current noon EDT (16:00 UTC), October 5th launch target.
In an October 3rd briefing following a mostly clean launch readiness review (LRR), NASA and SpaceX officials revealed that three new minor issues – “not showstoppers” – had appeared after a busy period of ground testing. An otherwise successful astronaut dry dress rehearsal and a subsequent wet dress rehearsal and static fire uncovered a possible fire extinguisher leak in the Dragon spacecraft and a minor issue with one of the Falcon 9 rocket booster’s nine Merlin 1D engines. A communications issue was also discovered on the SpaceX drone ship Crew-5’s rocket booster is meant to land on in the Atlantic Ocean.
SpaceX and NASA officials weren’t especially worried about the issues and were confident they would be resolved in time for an October 5th launch. If they aren’t and Crew-5 slips to October 6th, SpaceX should be able to launch Starlink 4-29 on October 4th, but then it’s unclear if the company will also be able to launch Intelsat’s Galaxy 33 and Galaxy 34 geostationary communications satellites on the same day as Crew-5. Galaxy 33/34 is scheduled to launch NET 7:07 pm EDT on October 6th, likely ~6 hours after Crew-5’s own October 6th launch window.
If Crew-5 slips and Galaxy 33/34 can’t launch on the same day, it would likely delay both Hotbird 13F and Starlink 4-36. It’s also unclear if Starlink 4-29 can launch on the same day as Crew-5 if it flies after Dragon. Either way, SpaceX could potentially end up launching Crew-5, Galaxy 33/34, and Starlink 4-29 on October 5th and 6th – potentially less than a day and a half apart.
As SpaceX continues to push the limits of what is possible with its existing Falcon launch and landing infrastructure, chaotic scheduling situations like this, where small issues impact large strings of launches, will become the norm instead of the exception