With the initial landing attempts, it was not a big deal, twas all an experiment and they only reused Block 1-4 boosters once at best. So holding a launch because of weather at the landing site downrange on the barge (LZ-1, being 10-20 miles from LC-40/LC-39A and SLC-4E/4W being 500m apart maybe not an issue) was not a real issue.

Now that Block 5 is in full service, and a core is expected to fly 10 times or more, a lost core is expensive.

An interesting historical example was the Space Shuttle program, which being manned had different rules of course, would hold a launch due to weather issues at abort sites.

Will SpaceX hold flights, because conditions at the landing site?

  • $\begingroup$ I think it is relevant to mention that STS was scrubbed a number of times due to conditions at the downrange abort sites. I think one of the factors is what the Payload provider paid for. I would imagine there might be a new rocket premium which might offset the loss of a core. If you go for the cheaper option, they might make you wait so that they get the core back to use on the next one. Kind of like a lease vs buy option. $\endgroup$
    – tl8
    Jul 26, 2018 at 6:41
  • $\begingroup$ @tl8 Is that pure speculation, informed speculation or based on sources you're willing to share? $\endgroup$
    – Mast
    Jul 26, 2018 at 9:10
  • $\begingroup$ @Mast: "imagine"! $\endgroup$ Jul 26, 2018 at 12:57
  • $\begingroup$ @Mast Probably closer to pure speculation, but properly reusable rockets are very new and payment schemes other than buy the whole rocket outright are now viable. $\endgroup$
    – tl8
    Jul 26, 2018 at 22:56

2 Answers 2


The Iridium 7 mission, Jul 25, 2018 gives a partial practical answer.

Throughout the webcast John Innsbruker reminded everyone that conditions for landing in the Pacific for the JRTI (Just Read The Instructions) ASDS were the worst they have ever tried to land in.

Yet they continued the launch when they had a back up launch window 23:55 hours later.

This was the first flight of that Block 5 core, of which only 4 are in the fleet at the moment. (1046 is being disassembled after first flight. 1047 at the time was on OCISLY coming back to port, this mission was 1048, and 1049 is being prepped for a mission in 12 days). Their remaining manifest for 2018, in the short term, is dependent on recovery and reflight of every stage.

Core 1046 is out of service indefinitely. They have 16 or so more flights to do, and the factory cannot make cores that fast.

Thus in some ways, this is the literal worst case. At a moment when there are not enough cores in the fleet to absorb a lost core without affecting the manifest (I.e. the part of the buisness that makes all the money, actual launches) and on the first flight (most expensive moment in a flight), they still launched when they had a backup window only day later.

Now it is possible that even though these were the 'worst' conditions they have ever tried to land in, it was still good enough, per their models to actually land.

But this is a pretty good data point on how much risk they are willing to take.

  • 1
    $\begingroup$ With only one potentially "bad landing weather" Block 5 launch so far, isn't it a bit premature to make generalizations? The OP asks "Will SpaceX delay launches..." and seems be asking about a policy or trend a single-case example may not be sufficient as an answer in this case. $\endgroup$
    – uhoh
    Jul 25, 2018 at 17:36
  • 2
    $\begingroup$ @uhoh It is just a good data point of one. Thus one can extrapolate a long term trend, as one does these days. (Note I said "partial practical answer"), so I think this answer was scoped appropriately. Short of a definitive answer by a SpaceX exec no way to otherwise know. $\endgroup$
    – geoffc
    Jul 25, 2018 at 17:43
  • 1
    $\begingroup$ Honestly I think they tried it in bad weather once just to see how well it would go. It's a worst-case scenario test, literally. Policy will most probably be based on the results of that test, but the test itself is hardly policy. $\endgroup$
    – Mast
    Jul 26, 2018 at 9:12

The Hispasat 30W-6 mission in March 2018 was properly fitted with titanium grid fins and landing legs, however the weather in the offshore landing area was too bad for the drone ship Of Course I Still Love You to handle.

Weather might have improved over the course of the next few days, but SpaceX launched on time anyway, and lost the core without a drone ship to recover it. A the time the titanium grid fins were the Falcon 9 production bottleneck, which made this an expensive loss for the company and may have had launch manifest repercussions.

  • $\begingroup$ It wasn't CRS-14 as CRS missions are typically a return to launch site recovery. Wikipedia shows it being the Hispasat 30W-6 mission. CRS-14 was expended for testing because it was the second launch of that booster and it probably did have the grid fins on it to facilitate that testing but it was planned from the start. en.wikipedia.org/wiki/… $\endgroup$ Jul 25, 2018 at 16:37
  • 1
    $\begingroup$ Good example. Wrong mission, but still. It was a block 4 so only one more flight was possible. Not as big an example as a first use Block 5. But good one! $\endgroup$
    – geoffc
    Jul 25, 2018 at 17:09
  • $\begingroup$ Yes, of course! Up until sometime last year I remembered each and every mission, including the months leading up to that. Now they are so frequent I'll sometimes hear about a launch having passed without even having thought about it coming up soon. $\endgroup$
    – dotancohen
    Jul 25, 2018 at 17:34

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