Surge Launching

[edkyle99]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

 - Ed Kyle

[Jim]

The only real part of the "surge" is the Starlink launch.  The NRO and Italian launch were scheduled independently. 

SpaceX has workers available and they work 3 shifts, so they have to keep them busy.

[vaporcobra]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

 - Ed Kyle

I think Jim's right, it's not necessarily planned. It just happened to be when two crucial, schedule-sensitive customer missions and a Starlink payload were ready to launch. Had there been no delays, CSG-2 might have launched last November and NROL-87 was also originally supposed to launch by late 2021. It seems more like a case of coincidence mixed with SpaceX's willingness to take full advantage of its operational capabilities rather than arbitrarily extend the gap between launches.

I don't think it's much different than the Soviet Union's peak cadence years. There were numerous instances of 'salvos' of seemingly unrelated launches but it was no less common for a random set of several launches to end up evenly spaced across a few weeks.

[tbellman]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

Payloads were ready, rockets were ready, pads were ready, personnel was available, and weather was permitting; why would you not launch as much as you can then?  If they had decided to, on purpose, spread out the launches to one per week would mean they got paid for the NROL mission a week later, and got their Starlink satellites ready to earn money two weeks later.

There is also no guarantee that weather will be good next week, and the week after that to allow launches then.  If you, like SpaceX are, aim at launch once a week on average in twelve months, then you better be able to have a peak launch cadence higher than that, since there is almost certainly going to be several weeks in the year where there are various things blocking you from launching.  Getting things you can get done, done early on, gives you more margins for dealing with problems later.

[unitx]

Getting things you can get done, done early on, gives you more margins for dealing with problems later.

Can you teach my son that?

[Greg Hullender]

If SpaceX launched randomly with an average of one launch a week, then about 8% of the time, three or more launches would just happen to fall in the same week, or about four times per year. (Poisson distribution.)

The fact that we don't see so many "surges" tells us the launch dates are not random. (Not that that's a big surprise.)

[Lars-J]

If your ambition is to eventually launch daily (or more frequently) with your next generation launch system, it makes sense to  learn operational launch experience with "surge" launches. You have to push yourselves slightly to find limiting factors that might have been unexpected. You learn more by doing, not just creating an elaborate plan on paper.

It also shows flexibility for your customer - i.e. your launch is slipping closer and closer to some NASA or NRO payload with a firm launch date, but it is on a different pad so we can still launch it without a week stand-down.

[DanClemmensen]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

 - Ed Kyle

What resource becomes more highly stressed when launching from separate pads? (Other than congesting the NSF forum).  Each pad and its support structure is basically independent, Yes? Maybe there is a central mission control, or maybe each launch is traditionally followed by a party and you don't want the executives to be hung over on three consecutive days?

[Jim]

Maybe there is a central mission control,

Separate launch control centers

[edkyle99]

What resource becomes more highly stressed when launching from separate pads? (Other than congesting the NSF forum).  Each pad and its support structure is basically independent, Yes? Maybe there is a central mission control, or maybe each launch is traditionally followed by a party and you don't want the executives to be hung over on three consecutive days?

Surely there must be some common support elements at least in Florida.  Some people had to work both launches there I suspect.  It probably helped that one of the missions used RTLS.  But SpaceX is clearly staffed up for this work now.  Last year, however, after an early year surge the company seemed to go on "vacation" during hurricane season.  It will be interesting to see how the gaps work out this year.

 - Ed Kyle

[Jim]

What resource becomes more highly stressed when launching from separate pads? (Other than congesting the NSF forum).  Each pad and its support structure is basically independent, Yes? Maybe there is a central mission control, or maybe each launch is traditionally followed by a party and you don't want the executives to be hung over on three consecutive days?

Surely there must be some common support elements at least in Florida.  Some people had to work both launches there I suspect.  It probably helped that one of the missions used RTLS.  But SpaceX is clearly staffed up for this work now.  Last year, however, after an early year surge the company seemed to go on "vacation" during hurricane season.  It will be interesting to see how the gaps work out this year.

 - Ed Kyle

They moved first stage refurb; and second stage receiving, checkout and mating to HangarX on Roberts road.  The hangars at the pad are just used for vehicle to TE integration and encapsulated assembly mating.  That means they can have a static crew at HangarX, a roving crew for pad/hangar integration, roving recovery crew for landing zone and ASDS, and smaller crews based at both pad hangars.  Then there is PPF and fairing workers.

There might be shared resources among the crews.

[wannamoonbase]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

 - Ed Kyle

What resource becomes more highly stressed when launching from separate pads? (Other than congesting the NSF forum).  Each pad and its support structure is basically independent, Yes? Maybe there is a central mission control, or maybe each launch is traditionally followed by a party and you don't want the executives to be hung over on three consecutive days?

Other than the humans needed to do the work, the pacing element, I think, becomes the cycle times on the ASDS.  Seems that is 8-10 days at best.

Weather, especially in the energetic summer months will throw a wrench in the launch cadence.  Hence Starships RTLS, no navy required.

[darkenfast]

Maybe there is a central mission control,

Separate launch control centers

Jim, from somewhere I got the impression that both 39A and SLC-40 used the same KSC launch control center. Is there still a separate LCC for 40?

[Jim]

Maybe there is a central mission control,

Separate launch control centers

Jim, from somewhere I got the impression that both 39A and SLC-40 used the same KSC launch control center. Is there still a separate LCC for 40?

Still down at the entrance to the Cape.

[abaddon]

Last year, however, after an early year surge the company seemed to go on "vacation" during hurricane season.  It will be interesting to see how the gaps work out this year.

 - Ed Kyle

When nothing is ready to launch, you don’t launch.

[Conexion Espacial]

I think this high cadence we saw in so few days is also due to SpaceX plans to launch 52 missions on 2022 or what Elon Musk said a few days ago of one mission every week and a half. Also if we look at the Starlink launch manifest so far in 2022 we see that everything has been launched from 39A, probably because SpaceX wants to get as many missions out as possible before the Dragon surge, as we will soon have Ax-1, Crew-4 and CRS-25, plus Falcon Heavy.


On the other hand, Starlink does not have a launch manifest, it is only subject to the availability of the boosters and the stock of satellites, so this year's missions have been made by the availability of satellites, booster and get as much as possible of 39A before its for the other missions that do have a date.

[Twark_Main]

Three launches in four days from three pads on two coasts.  Why is SpaceX doing launches in surges?  Is this like when trucks fall into long strings on the highways, slowed by one slower truck?  An inevitable result of launching often?  Or is this planned by SpaceX?  I can't see any benefit to aligning launch campaign timing like this.  Falcon 9 really only flies once every 12 days or so on average.

 - Ed Kyle

First, we should probably figure out whether there's really any "signal" here at all.

Is the SpaceX interval between launches statistically distinguishable from the expected Poisson distribution?

If not, it's just the human pattern-recognition system playing tricks on us. We're just seeing faces in the clouds.

[alugobi]

it's just the human pattern-recognition system playing tricks on us.

No, my dude, it's SpaceX. 

Something shifty is going on.

[Twark_Main]

it's just the human pattern-recognition system playing tricks on us.

No, my dude, it's SpaceX. 

Something shifty is going on.

So (looking back at my words in their original context), you're saying that the interval between launches is statistically distinguishable from a Poisson distribution? 

There's lying with statistics, and then there's lying to yourself by ignoring statistics.

[alugobi]

Whoooosh.

That was the sarcasm flying over your head. 
_____________________

There's a cottage industry of media, national governments, and personalities, some posting here, of seeing the suspicious, nefarious, and underhanded in the activities and accomplishments of SpaceX. 

Edit:  missed a word