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I'm curious if there is a statistically demonstrable tendency not to schedule launches on certain days, such as those that contain leap seconds (see answers below this question), year changes, or superstitious connotations like Friday the thirteenth for example.

The three sources where I believe I can find or from where I can at least assemble a fairly complete list of orbital launch attempts are:

  1. Scrape the Space Launch Report site, (found in this answer).
  2. Download the complete SatCat from Celestrak and then do some sorting/filtering.
  3. Go to the JSR Launch Vehicle Database as mentioned here, and download potential orbital launches and launch attempts in lists G (Harvard 1957-62), O (COSPAR 1963-), U (Uncataloged (sic)), F (Orbital Failures), and E (Orbital pre-launch Explosions) all found in the list of lists on this page.

But even if I did all three of these, then filtered and merged, I would be missing most/all scrubbed launches; launches that were indeed scheduled, but didn't happen and were rescheduled for the next launch window.

Are there any, even partial lists that would include scrubbed launches for reasons like faulty non-critical sensor data, weather, downrange interference (e.g. fishing contests) etc? Even if not exhaustive, it may still be helpful and informative.

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uhoh
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  • If you want to avoid a day, you won't even get to a scrub, you won't schedule an attempt at all. – Hobbes Jul 10 '17 at 09:58
  • @Hobbes please think it through more carefully. If a launch didn't happen, the possibilities include both 1. schedule avoidance, and 2. scheduling followed by scrub. With only historical records, one can only tentatively rule out 1 if one can rule in 2. It's not foolproof, but it is at least helpful to know. Simply put, if there are unusually few launches on a given day, one must rule out multiple scrubs before one can suggest there might be active avoidance. – uhoh Jul 10 '17 at 10:25
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    There's another way to look at it though: there are enough launches by now (at least 3000) that you'd expect at least 10 launches on any given date in the year. So without including scrubs, your dataset is large enough that a day with 0 launches will stand out. – Hobbes Jul 10 '17 at 11:41
  • @Hobbes I believe that it is better to have as complete a data set as possible first, and then to do as thorough an analysis as possible before venturing any potential conclusions or inferences. Right now I'm on step 1 of 3. leap seconds and Friday 13's are just examples, let's see what the whole year looks like, who knows what might show up. – uhoh Jul 10 '17 at 11:59
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    'Space Shuttle Missions Summary" has detail on each mission's scrubs, delays, etc. Sorry I can't post link (on primitive device) but I site this in many of my answers and I think it's in the references list on meta. – Organic Marble Jul 10 '17 at 14:01
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    @OrganicMarble ok got it! Space Shuttle Missions Summary from 2011 that you mention in this comment. There are python pdf-reading packages that may be able to quickly reduce to text for automated search. There are 603 instances of scrub* on 249 pages, and 125 instances of scrubbed on 66 pages. Thanks! – uhoh Jul 10 '17 at 14:16
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    Maybe you should also categorize this by launch provider. chinese launches may avoid completely other days/dates then american ones, for example. I'm not very versed in chinese superstitions, but I can imagine they differ wildly from ours. – Polygnome Jul 11 '17 at 07:34
  • @Polygnome yep good thinking! I plan to just make a short python script that would mine everything from most up-to-date original sources, rather than make yet another list. This way anyone can use it anytime. – uhoh Jul 11 '17 at 08:21
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    It would actually be very interesting to see if there is any correlation between region and date(s), and to see how cultures diverge. You have definitely piqued my interest. One thing to note: For launches at the KSC, there is often naval warnings for boats, maybe you can find a way to scrape those for attempts. – Polygnome Jul 11 '17 at 08:41
  • @Polygnome I'll post a skeleton script fairly soon. I'm sure there's someone out there who will know how to look for stuff. I guess this should be a community effort, maybe a community Wiki. Check back later. – uhoh Jul 11 '17 at 08:43
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    @uhoh: when you do it, could you give an answer to a question of mine: what percentage of attempted (planned) launches is scrubbed? e.g. what's the chance on the average that given launch will be scrubbed? – SF. Aug 19 '17 at 23:22
  • @SF. thanks for the reminder! OK I'll try to get back on this. It's interesting and fun, just gotta not do something else in order to make a time slot. Please feel free to ping! me again in a week if I haven't. – uhoh Aug 20 '17 at 03:40

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