Author Topic: SpaceX Falcon Heavy : STP-2 mission : LC-39A : NET Apr 30, 2018  (Read 133985 times)

I'm not going to believe any dates on this one yet, let's see how the first couple flights go.

Isn't this the second FH flight.

I thought Arabsat 6A was the second flight no?

Offline vaporcobra

I'm not going to believe any dates on this one yet, let's see how the first couple flights go.

Isn't this the second FH flight.

Based on the link in my response above, the AF has reason to believe STP-2 could be the third FH launch. But it's understandably in flux and highly dependent upon the first launch. As gongora said, our best bet is to just wait for the first launch.

Offline titusou

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I'd talk with NSPO (Taiwan) team today. It's NET Apr,2018 right now.
Titus

Offline vaporcobra

I'd talk with NSPO (Taiwan) team today. It's NET Apr,2018 right now.
Titus

Thanks! Tentatively indicates that the inaugural launch is still relatively stable for now. Can't really read far into future schedules until FH's first success, but SpaceX is clearly relatively confident in the vehicle, at least internally.

Offline Kenp51d

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I'd talk with NSPO (Taiwan) team today. It's NET Apr,2018 right now.
Titus

Thanks! Tentatively indicates that the inaugural launch is still relatively stable for now. Can't really read far into future schedules until FH's first success, but SpaceX is clearly relatively confident in the vehicle, at least internally.
Mr. Musk puplicly lowered expectations, but I'd bet internally they are very confident of at least safely clearing the pad at minimum. So is NASA, they sure as heck are not willing to loose the pad for manned flights.
If they can make it past Max Q, and can throttle down for that, then my bet is successful booster sep, stage sep, and they then make orbit.
This is gonna be way cool!
Just unimagenabl to me they'd risk the pad.

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Offline AncientU

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They wouldn't be launching if they thought the chance of failure was high.
Think about it...
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline Space Ghost 1962

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It's logistics/operations that one should fear before T0. So much has to go right before you make it to ignition. Could sit on the pad for a month. Complex beast, more like 5x the trouble for three boosters.

Next, it's the hold down time and validating vehicle before launch and after ignition. Static fire?

Then its that all the clamps go. Otherwise engine shutdown.

After off the pad, very likely to clear the tower, and find out how well the acoustics worked. Very loud as things don't scale linearly (overtones).

At some point leading up to MaxQ, the torques between the three boosters will attempt to tear apart the stack. But likely the oscillations will be damped and fall by flight software (to be later analyzed to improve vehicle performance). This starts where the most critical phase begins, ending with engine shutdown and side booster separation.

If they get through that, FH is a success as far as having a potential alternative to DIVH, which we haven't yet had ever. (Ironically, it increases DIVH's value because you have multiple alternatives so more payloads can be considered, although doubtful that has any meaning.)

Having three returning boosters land after that would be a showy tour de force.

Online gongora

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Ya'll realize this isn't the Demo Mission thread, right?

Offline Space Ghost 1962

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Applies to both. Actually, to the third flight as well, but lesser.

Offline IainMcClatchie

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....After off the pad, very likely to clear the tower, and find out how well the acoustics worked. Very loud as things don't scale linearly (overtones).

Can you elaborate how overtones don't scale linearly?  That is, how three cores would produce more than three times as much accoustic pressure in some direction.

My best guess is that you might get a bit of a phased array effect normal to the axis of attachment.

I'm also expecting something interesting to happen to the core plume as all three get underexpanded in the upper atmosphere.  A single core plume gets to expand in two dimensions.  A center core of three really only  expands along one dimension.  My guess is they'll get more of the plume crawling it's way up the sides of the rocket.  Combined with a longer burn time from running throttled down part of the way, and that center core is going to see a significantly toastier ride on the way up.  But maybe that's dominated by re-entry and landing.

Offline tyrred

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It would be interesting if the combined exhaust plumes have the appearance of the three-engine landing burns, three hydras expanding perpendicular to the core arrangement. Great big eye of Sauron?

Offline Mike_1179

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It would be interesting if the combined exhaust plumes have the appearance of the three-engine landing burns, three hydras expanding perpendicular to the core arrangement. Great big eye of Sauron?


Would have to fire up the CFD to do more than arm-waving, but remember that the 3-engine re-entry burn is done when the stage is traveling supersonic and engine first, so you get some pretty interesting shockwaves and boundary conditions. A stage accelerating up with three cores burning would look, well, different.

There's no shockwaves forcing the exhaust and firey bits into a small cone shape when the stage is going up. Instead the exhaust expands outward radially like you see from the 9 engines of a F9 as it gets closer to MECO. However, the boosters are gone well before the stage gets up as high as the F9 MECO, so we won't see the super-wide plumes we're used to seeing from all three boosters firing simultaneously. Might just be a more orange and more sooty version of a Delta IV Heavy.

Offline Jim

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It would be interesting if the combined exhaust plumes have the appearance of the three-engine landing burns, three hydras expanding perpendicular to the core arrangement. Great big eye of Sauron?


It shouldn't be much different than the two RD-180 nozzles.  Just a large scale..

Offline OneSpeed

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My best guess is that you might get a bit of a phased array effect normal to the axis of attachment.

That would be very likely for the shock wave interaction between the plumes. However, acoustic phased array effects are strongest when each source is outputting the same waveform, like in a PA system. In the case of rocket engines, the flow is turbulent, so although the spectrum is reasonably consistent over time, the waveforms are independent. The rms response can be obtained by combining those waveforms, but the result, especially at higher frequencies, can be quite chaotic, leading to effects like the crackling sound we hear from Falcon 9 and others.

It would be interesting if the combined exhaust plumes have the appearance of the three-engine landing burns, three hydras expanding perpendicular to the core arrangement. Great big eye of Sauron?
... Instead the exhaust expands outward radially like you see from the 9 engines of a F9 as it gets closer to MECO. However, the boosters are gone well before the stage gets up as high as the F9 MECO, so we won't see the super-wide plumes we're used to seeing from all three boosters firing simultaneously ...

Although the FH boosters will stage earlier, due to FH's phenomenal T/W, they will do so at a similar altitude and higher velocity than the F9 core. Forgive the crude rendering, but the plume could be quite spectacular.

Online FutureSpaceTourist

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Quote
Peter B. de Selding‏ @pbdes 35s seconds ago

Taiwan NSPO: Six US/Taiwan Formosat-7/COSMIC-2 sats to launch Q2 2018 on @SpaceX Falcon Heavy; will be 1st launch after Nov FH demo flight.

https://twitter.com/pbdes/status/908619097189027840

If I'm reading the above correctly, that puts 2nd FH flight in Q2 2018 so STP-2 presumably pushes back?

Offline Galactic Penguin SST

Quote
Peter B. de Selding‏ @pbdes 35s seconds ago

Taiwan NSPO: Six US/Taiwan Formosat-7/COSMIC-2 sats to launch Q2 2018 on @SpaceX Falcon Heavy; will be 1st launch after Nov FH demo flight.

https://twitter.com/pbdes/status/908619097189027840

If I'm reading the above correctly, that puts 2nd FH flight in Q2 2018 so STP-2 presumably pushes back?

They are actually one of the main payloads on the STP-2 flight.  ;)

That means the Arabsat flight once reported to be 2nd in queue must have slipped behind.
« Last Edit: 09/15/2017 09:28 AM by Galactic Penguin SST »
Chinese spaceflight is a cosmic riddle wrapped in a galactic mystery inside an orbital enigma... - (not) Winston Churchill

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