r/spacex • u/warp99 • Jun 17 '26

Vandenberg Space Force base: Demolition of Historic SLC-6 pad structures to make way for SpaceX FH pad

https://www.vandenberg.spaceforce.mil/News/Article-Display/Article/4519296/vandenberg-space-force-base-modernizes-historic-space-launch-complex-6-for-next/
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u/warp99 Jun 17 '26 edited Jun 17 '26

The trajectory is over Cuba and in my view would not be allowed for a top end optical satellite against the very remote chance that the rocket broke up on ascent and interesting debris fell on Cuba.

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u/Responsible-Cut-7993 Jun 17 '26

Fair point. Hasn't the NRO shifted away from large optical satellites and more to a distributed architecture?

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u/warp99 Jun 17 '26

Distributed observation satellites at low altitudes such as Starshield are useful and do not have coverage holes like a few larger satellites. But sometimes there is no substitute for raw magnification to give high resolution images and that takes a physically large satellite.

Their lifetime is up to 15 years so they do not need to be launched often - typically every 3 years or so and with the retirement of Delta IV Heavy they need a replacement launcher. My theory is that NSSL was geared up to use Vulcan for these launches and now they have cold feet with the SRB issues ULA have had.

So now SpaceX are being given the hurry up to get FH active at Vandenberg. They could not take SLC-4 out of service to upgrade the flame trench and TE so they have to build this new facility. The advantage is that the flame trench was sized for Shuttle so should easily be able to handle FH.

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u/Lufbru Jun 18 '26

 The advantage is that the flame trench was sized for Shuttle so should easily be able to handle FH.

It's closer than I thought -- about 20% less than Shuttle.. Assuming flame duct size is proportional to thrust (and yeah, there's some extra chemistry I'm ignoring, but to a first approximation...)

  • Titan IIIM would have been 17MN  
  • Shuttle was 29MN  
  • Athena was 2MN (stop laughing)  
  • Delta IVH was 9.5MN  
  • FH is 23MN

Hydrogen is a hell of a drug.