SpaceX Falcon 9 : SAOCOM 1A : Oct. 7/8, 2018 : Vandenberg - DISCUSSION

[whitelancer64]

If SpaceX confirmed a good static fire for the October 6/7 date, why would they slip until later?

Unless they say, we'll never know exactly. There are thousands of possible issues that could have done it. Static fire might have popped something up. Maybe the payload's not quite ready. Could be a range equipment problem. Slip happens.

[Alexphysics]

If SpaceX confirmed a good static fire for the October 6/7 date, why would they slip until later?

Right after static fire they do the quick look review and tweet it if the result was ok but they formaly run a Launch Readiness Review (LRR) that ends sometime between 48 and 24 hours before launch and they look deeply into all the data from the static fire. If they find something that they don't like, they reschedule the launch and look more into it. It has happened before on multiple missions, so no surprise at all. They can still find more small issues on the way leading to the launch even if the LRR goes ok.

[Lar]

The hassle of transporting the recovered boosters is an appreciable one at the Cape.  Whereas for the VAFB recoveries, everything will be taking place not just within the base but, if they're doing the refurb work in the HIF of SLC-4, within the perimeter of a single launch complex.  This means it's much less of a disruption for the other users of the base and requires much less scheduling and coordination with security/police for escort/traffic control/etc.  These are not totally trivial considerations and could help in speeding up average turn around times.

Not trivial, but close to meaningless in the big picture. I imagine it takes at most a day to move the booster from the landing to the prep area. Probably much less then a day. So until your refurbishment time is down into 'a week' time range, you aren't putting a meaningful dent into the processing time.

I said it before but it got lost.

If you are doing "24 hour cycle time" cycles, spending 2 or 3 hours (instead of 1/2 hour or less) to get the booster from the landing site to the barn? Matters...  Are we there yet? no. But that's the goal. So yes, it matters, and the article ref was legit.

[crandles57]

If you are doing "24 hour cycle time" cycles, ...

Big if. Isn't that 24 hour cycle time a theoretical minimum that they will never get close to unless some very weird circumstances arise?

[Jdeshetler]

I didn't expected 19 degree westward, is that norm for this type of satellite?

[ZachS09]

It's normal for SSO missions from Vandenberg to follow down a launch azimuth of 199 degrees.

[georgegassaway]

I didn't expected 19 degree westward, is that norm for this type of satellite?

While I'm not sure if this mission is truly polar, to make a polar orbit the Earth's rotation eastward needs to be negated. So, that's a basic reason to launch with  a partial westward vector rather than truly due south. Also of course in the case of VAFB, they need to have  it launch over the ocean, not over land, so they can't launch 180 degrees due south for that reason.  Once farther downrange to assure not overflying land, a launch vehicle can always do  bit of a "dogleg" course change for the intended orbital inclination, as propellant margins allow.

[gongora]

I didn't expected 19 degree westward, is that norm for this type of satellite?

While I'm not sure if this mission is truly polar, to make a polar orbit the Earth's rotation eastward needs to be negated. So, that's a basic reason to launch with  a partial westward vector rather than truly due south. Also of course in the case of VAFB, they need to have  it launch over the ocean, not over land, so they can't launch 180 degrees due south for that reason.

What land would they fly over if they went due south?  It looks like they'd even miss the Channel Islands.  (If the online calculator I found is correct then the azimuth for going directly to the target inclination would be 189.6 degrees.)

[gongora]

SpaceX will need a new or amended FAA launch license for 3 of the next 4 missions, so if you run across the next one please post a copy (the links don't always stay available if all of the launches on the license are completed.)

[DaveJes1979]

Any word on the weather conditions at VAFB for Sunday night?

[hootowls]

Any word on the weather conditions at VAFB for Sunday night?

Clear.  Forecasted weather looks great.

[Lar]

If you are doing "24 hour cycle time" cycles, ...

Big if. Isn't that 24 hour cycle time a theoretical minimum that they will never get close to unless some very weird circumstances arise?

off topic for this thread but not necessarily.

[groknull]

On topic, or more precisely, On Subject comment...

I appreciate that this is launching South and not North, but leaving off the N in DISCUSSION was bugging me.

Subject fixed in this comment.  Carry on.

[Kabloona]

Also of course in the case of VAFB, they need to have  it launch over the ocean, not over land, so they can't launch 180 degrees due south for that reason.  Once farther downrange to assure not overflying land, a launch vehicle can always do  bit of a "dogleg" course change for the intended orbital inclination, as propellant margins allow.

Actually, Jason-3 launched at an azimuth of even less than 180 degrees; IIRC it was around 155 degrees. See the azimuth discussion from the Jason-3 thread about allowable azimuths from VAFB:

https://forum.nasaspaceflight.com/index.php?topic=29457.msg1393254#msg1393254

155 degrees or thereabouts seems to be the lower limit these days according to Newton_V.

[Alexphysics]

Iridium missions also launch to an azimuth lower than 180°. Otherwise they would end up in orbits with inclinations higher than 90° and we know that's not the case for Iridium sats (I think it is something like 86° or something like that, I can't remember it well).

[ZachS09]

Iridium missions also launch to an azimuth lower than 180°. Otherwise they would end up in orbits with inclinations higher than 90° and we know that's not the case for Iridium sats (I think it is something like 86° or something like that, I can't remember it well).

When running the Iridium launches in Orbiter Simulator, I saw the vehicle's launch azimuth was around 179 degrees.

[dgates]

Basic question and probably covered *somewhere* but:
What’s the launch window for tomorrow’s launch? Instantaneous? A few minutes? So much info, so little time...

Thanks!

[Brovane]

Basic question and probably covered *somewhere* but:
What’s the launch window for tomorrow’s launch? Instantaneous? A few minutes? So much info, so little time...

Thanks!

https://www.vandenberg.af.mil/

I think it is instantaneous. 

[Steven Pietrobon]

Some circular markings on the landing pad. There are also four sets of marks above and below the lower right arm of the X. The large square in the middle could be the remnants of the old launch pad, or perhaps a different type of concrete so as to reflect radar waves better. The structure at bottom left could perhaps be used to hold the vehicle before transferring to horizontal.

[Lars-J]

None of the old concrete remains, visible. SpaceX aren't that strapped for cash.    It was probably just the first section that was poured, your image editing exaggerates the difference.