Author Topic: Why do SpaceX launches have fewer call outs before launch? (Read 3381 times)

EspenU · « **on:** 12/09/2017 09:16 am »

Apologies if this has been covered elsewhere, but I could not seem to find it.

Leading up to launch SpaceX seems to have much fewer call outs on the nets than other launch providers.
In my mind there are two possible reasons for this.

1. There are just as many call outs, just on other nets that we can't hear on the webcast.
2. Their launch flow is much more automated and therefore requires fewer human call outs.

Or a combination of the two.

I haven't taken notes on the amount of call outs, so it may also be a difference created in my own imagination.

Does anyone know the actual reason?

Jarnis · « **Reply #1 on:** 12/09/2017 10:57 am »

Probably a bit of both.

Before launch, SpaceX has the go/no-go poll long before webcast starts (at the start of prop load, over an hour prior if I recall right) so that means the count is already quite close to launch when stream starts.

Beyond that, two fairly recent examples would point towards public countdown net not being used for a lot of communication:

When F9 1.0 had an engine-out during ascent, it was apparently completely ignored on the countdown net. I noticed something was a bit off during the webcast when the timelines didn't match with the expected (stage separation later than estimated). I can't imagine everyone just being quiet over such an event...

When Atlas V ended up second or two away from dropping Cygnus into the drink (mixture problem leading to early staging and Centaur having to make that up, which it did ever so barely - thank god for those margins), the only effect was that the callouts from NASA about upcoming Centaur shutdown were off by a lot, which made it obvious that something was up. Only later tweets explained the reason.

I have no idea if this is due to the few second delay in the webcast (which gives them the ability to "mute out" stuff they don't want sent out to everyone or even outright cut the webcast) or because a lot of the communications is not broadcast - probably the latter. Maybe someone who actually knows can chime in and tell how wrong I am

docmordrid · « **Reply #2 on:** 12/09/2017 12:52 pm »

Could part of it also be SpaceX using their Autonomous Flight Safety System? Fewer bags of mostly water on microphones.

John Alan · « **Reply #3 on:** 12/09/2017 03:28 pm »

What IS the purpose of call outs on the net...

With a highly automated system...
With displays that tell the relevant people what they need to know, when they need to know it...
The launch COULD be done in total silence... (unless there is a problem)

BUT... there are people who have a need to know (but not looking at screens) and the public feed for those watching from elsewhere... that kinda make some sort of a running dialog a needed thing...

It's like a baseball game...
Sitting in the park and glancing at the scoreboard... you could be deaf and still know what's going on using your eyeballs...
On TV... you need a little commentary to fill in what the camera is not showing going on...
On Radio... you need a running dialog and a good imagination

2 cents on topic...

Jim · « **Reply #4 on:** 12/11/2017 06:25 pm »

Quote from: Jarnis on 12/09/2017 10:57 am

Probably a bit of both.

Before launch, SpaceX has the go/no-go poll long before webcast starts (at the start of prop load, over an hour prior if I recall right) so that means the count is already quite close to launch when stream starts.

Beyond that, two fairly recent examples would point towards public countdown net not being used for a lot of communication:

When F9 1.0 had an engine-out during ascent, it was apparently completely ignored on the countdown net. I noticed something was a bit off during the webcast when the timelines didn't match with the expected (stage separation later than estimated). I can't imagine everyone just being quiet over such an event...

When Atlas V ended up second or two away from dropping Cygnus into the drink (mixture problem leading to early staging and Centaur having to make that up, which it did ever so barely - thank god for those margins), the only effect was that the callouts from NASA about upcoming Centaur shutdown were off by a lot, which made it obvious that something was up. Only later tweets explained the reason.

I have no idea if this is due to the few second delay in the webcast (which gives them the ability to "mute out" stuff they don't want sent out to everyone or even outright cut the webcast) or because a lot of the communications is not broadcast - probably the latter. Maybe someone who actually knows can chime in and tell how wrong I am

launch teams have little role during flight. Post launch commentary is not a launch team job