b: Can we assume the range is available any time in late December once FH is ready and SpaceX requests it? or are there also specific windows they need to squeeze into?
The site is famous as we are sourced in this PM article about the launch.http://www.popularmechanics.com/space/rockets/news/a28872/spacex-first-launch-falcon-heavy/
Nice article. The info about the staggered startup was interesting, but I would have liked to see some mention or discussion of any testing that SpaceX has done to support that kind of startup. Before AMOS-6, I could have imagined them trying it for the first time on 39A during the static test - it’s hard to believe that they’d try that now.
What does that mean? They start 9 at a time now right?
Quote from: rsnellenberger on 11/02/2017 04:36 amNice article. The info about the staggered startup was interesting, but I would have liked to see some mention or discussion of any testing that SpaceX has done to support that kind of startup. Before AMOS-6, I could have imagined them trying it for the first time on 39A during the static test - it’s hard to believe that they’d try that now.I'm sure they've tested it on the stand at McGregor. If I understand the plumbing on F9 it can currently only start the engines in groups two groups, 3 used for boost back and the remaining 6, so they wouldn't be able to do the staggered startup on a standard static fire. They are probably building the granularity into Block 5 for uniformity, but I'd guess this is one of the modifications they made in Hawthorne to the flight proven boosters.
Quote from: Norm38 on 11/02/2017 02:35 amWhat does that mean? They start 9 at a time now right?F9 can start all 9 at once but for FH to allow SLC-39A and SLC-4E to avoid a domino effect of pad damage they are to be started differently to preserve the pad's flame trench (the results of the acoustic, vibration, and thrust impingement damage estimate models and concluded reasoning were discussed in detail in multiple previous threads). It is also my understanding as I remember reading about in a thread ages ago that liftoff will be at slighlty reduced thrust until clear of the pad and FSS before switching to full thrust mode.
The side booster staging event is going to be the money event of this launch. We haven't seen a staging event like that since shuttle.
Quote from: wannamoonbase on 11/02/2017 04:01 pmThe side booster staging event is going to be the money event of this launch. We haven't seen a staging event like that since shuttle.Just how different is it from what happens on Delta 4 Heavy launches?
Quote from: rpapo on 11/02/2017 04:06 pmQuote from: wannamoonbase on 11/02/2017 04:01 pmThe side booster staging event is going to be the money event of this launch. We haven't seen a staging event like that since shuttle.Just how different is it from what happens on Delta 4 Heavy launches?It's different than the Space Shuttle and Delta IV Heavy because the Falcon Heavy side cores are NOT equipped with separation rockets, or in KSP terms "sepratrons."Cold-gas thrusters are too weak to help with the separation process.
The only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.
Quote from: ZachS09 on 11/02/2017 04:52 pmThe only crucial events that SpaceX is worried about are the initial liftoff followed by tower clearance, Max-Q, and side core separation.After that, it's treated like a normal Falcon 9 mission with the addition of two simultaneous landings of the side cores.Sounded like control authority during booster return was also a question mark since the nose cone doesn't have a good flow separation point.Do we know if all the Heavy boosters will have Ti grid fins?
Quote from: mn on 11/02/2017 01:34 pmb: Can we assume the range is available any time in late December once FH is ready and SpaceX requests it? or are there also specific windows they need to squeeze into?Don't know about holiday schedule for the range, but nobody else has any scheduled launches in December from Canaveral/Kennedy. So they should be relatively free to fit it in as they can.The next scheduled flight from Florida for a non-SpaceX launcher is an Atlas V from SLC-41 in the middle of January.
Quote from: russianhalo117 on 11/02/2017 03:49 pmQuote from: Norm38 on 11/02/2017 02:35 amWhat does that mean? They start 9 at a time now right?F9 can start all 9 at once but for FH to allow SLC-39A and SLC-4E to avoid a domino effect of pad damage they are to be started differently to preserve the pad's flame trench (the results of the acoustic, vibration, and thrust impingement damage estimate models and concluded reasoning were discussed in detail in multiple previous threads). It is also my understanding as I remember reading about in a thread ages ago that liftoff will be at slighlty reduced thrust until clear of the pad and FSS before switching to full thrust mode.The article says that it is because of a thrust torque problem damaging the ocotwebs, not because of impingement damage to the flame trench. This makes sense due to the different load paths on the Falcon Heavy. There will always be a small difference in engine start time whether intentional or not. If one side booster started all engines slightly before the other one, this would create a massive torque. Starting 2 engines at a time with a pause in between reduces the maximum unbalanced torque.