tater Posted February 12 Share Posted February 12 Destacked. Crews looking at the top of the booster, maybe working on the interstage claamps per NSF. Not stictly SpaceX, but this site is pretty cool for upcoming launches: https://rocketlaunch.org/ Quote Link to comment Share on other sites More sharing options...
Spaceception Posted February 12 Share Posted February 12 It'll be an awesome moment, the first time we can expect a launch every day. So, S28 static fire, restack, WDR, launch? Not counting regulatory notices and licenses. Quote Link to comment Share on other sites More sharing options...
AckSed Posted February 12 Share Posted February 12 I did notice they just lowered it on, with the arms making small adjustments to set it down near-exactly. Checking to see what the damage was? Quote Link to comment Share on other sites More sharing options...
tater Posted February 12 Share Posted February 12 My "guess" for IFT-3 is now March 3-4. For reasons. Quote Link to comment Share on other sites More sharing options...
tater Posted February 12 Share Posted February 12 I beat Elon by a couple hours. Nice. Quote Link to comment Share on other sites More sharing options...
tater Posted February 12 Share Posted February 12 Quote Link to comment Share on other sites More sharing options...
tater Posted February 12 Share Posted February 12 A couple of Starlink launches as well. Think it's 3 launches coming in 2 days. Quote Link to comment Share on other sites More sharing options...
GuessingEveryDay Posted February 13 Share Posted February 13 9 hours ago, tater said: Not stictly SpaceX, but this site is pretty cool for upcoming launches: https://rocketlaunch.org/ That's a pretty neat site, showing a map of where it's launching, but nextspaceflight.com is still the standard for me. It's run by one of the people in charge of NASA SpaceFlight. Also it's been interesting to see the quickly shrinking stretches' of time between the full test flights. First one was last year on April 20, second one was a little under 7 months on November 18, and now it'll be ~5 months if all goes well for IFT-3 to launch mid-March. IFT-4 through 6(?) are going to be epic. Quote Link to comment Share on other sites More sharing options...
tater Posted February 13 Share Posted February 13 Quote Link to comment Share on other sites More sharing options...
tater Posted February 13 Share Posted February 13 Quote Link to comment Share on other sites More sharing options...
tater Posted February 13 Share Posted February 13 Then 2 more F9s 34 minutes apart tomorrow afternoon (1 from CA, then 1 from FL) Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted February 13 Share Posted February 13 4 hours ago, tater said: So... from this, we can gather they liked the hot-staging. But I doubt they've had time to address fluid hammer - if that was the thing. Speculation: they're gonna try to get SS to the Pacific as the primary goal of the flight and just see what happens with a slower flip. Quote Link to comment Share on other sites More sharing options...
zolotiyeruki Posted February 13 Share Posted February 13 12 minutes ago, JoeSchmuckatelli said: So... from this, we can gather they liked the hot-staging. But I doubt they've had time to address fluid hammer - if that was the thing. Speculation: they're gonna try to get SS to the Pacific as the primary goal of the flight and just see what happens with a slower flip. It'll be interesting to see how they've addressed the issue of the boostback burn on SH Quote Link to comment Share on other sites More sharing options...
Spaceception Posted February 13 Share Posted February 13 Launch rehearsal coming up. Quote Link to comment Share on other sites More sharing options...
Elthy Posted February 13 Share Posted February 13 43 minutes ago, JoeSchmuckatelli said: But I doubt they've had time to address fluid hammer - if that was the thing. I think there are lots of possible solutions without altering the hardware, e.g. different timings on valves or a stagered restart of the engines. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted February 13 Share Posted February 13 59 minutes ago, Elthy said: stagered restart of the engines. delayed start / staggered start makes sense; if they can get the ship to decelerate fairly gently for a bit, most of the fluid should settle where they want it. Then they can kick back to earth. Might not be as efficient fuel-wise as they'd hoped, but could avoid a RUD. Quote Link to comment Share on other sites More sharing options...
Terwin Posted February 13 Share Posted February 13 Seems like just increasing the separation thrust of SH to keep it from reversing should be sufficient. Some slosh/waves from the turn should be less of an issue so long as the fuel is always against the rear and intakes. Quote Link to comment Share on other sites More sharing options...
JoeSchmuckatelli Posted February 14 Share Posted February 14 (edited) 4 hours ago, Terwin said: Seems like just increasing the separation thrust of SH to keep it from reversing should be sufficient. Some slosh/waves from the turn should be less of an issue so long as the fuel is always against the rear and intakes. Not a bad idea - except as I try to imagine this in 3D, it dawns on me that one of the tanks is above the COM and one below. As they rotate it the centrifugal force will push liquids to the separate ends of the craft, and then when they light, all the fluid on the far side of the craft is going to go engineward. So unless you're going to turn the whole thing while under thrust... The one thing I don't know is how violent SS's ignition is on Booster... presumably as soon as they light SS, that will cause some deceleration of Booster and inertia will start lifting the liquid propellants away from the bottom of the tanks. I'll go back to my prediction: a slow rotation, followed by deceleration to settle the fluids and finally a boostback burn. Edited February 14 by JoeSchmuckatelli Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted February 14 Share Posted February 14 Time to get the hot -gas-gas thrusters working for the flip and ullage re-settling. Stage, full shutdown, flip, ullage, re-light. Possibly use asymmetric venting on the hot-stage ring to start the flip? Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 14 Share Posted February 14 40 minutes ago, StrandedonEarth said: Time to get the hot -gas-gas thrusters working for the flip and ullage re-settling. Stage, full shutdown, flip, ullage, re-light. Possibly use asymmetric venting on the hot-stage ring to start the flip? Asymmetric venting for starting the flip is what occurred to me after IFT-2. I think I posted in different wording at the time. When you see how much force stage 2 applies it seems a no brainer to put it to work. Though I suppose merely decelerating the booster is quite useful, flipping is what seems to be the top task at that point Quote Link to comment Share on other sites More sharing options...
tater Posted February 14 Share Posted February 14 Quote Link to comment Share on other sites More sharing options...
tater Posted February 14 Share Posted February 14 Quote Link to comment Share on other sites More sharing options...
zolotiyeruki Posted February 14 Share Posted February 14 My impression is that the exhaust gases from SS don't cause SH to *decelerate*, since the core engines stayed lit during separation. Rather, they reduce SH's acceleration. I also think they've got the flip maneuver itself figured out. But that's a really big tank doing a pretty radical maneuver with little acceleration to settle the fuel except for what the still-burning engines provide, so I imagine there's a lot of slosh going on. Maybe they just need to wait a few moments longer after the flip before relighting the engines for boostback? Quote Link to comment Share on other sites More sharing options...
darthgently Posted February 14 Share Posted February 14 (edited) 1 hour ago, zolotiyeruki said: My impression is that the exhaust gases from SS don't cause SH to *decelerate*, since the core engines stayed lit during separation. Rather, they reduce SH's acceleration Ok, how about relative deceleration? But I wasn't assuming continued firing of the booster. I figure after IFT-2 they are reconsidering many things And flipping the booster seems the better goal over any flavor of booster deceleration In fact, if they want continued booster acceleration for ullage reasons, channeling as much as possible of the stage 2 plume into flipping the booster makes sense Edited February 14 by darthgently Quote Link to comment Share on other sites More sharing options...
Terwin Posted February 14 Share Posted February 14 I was under the impression that stage 2 pushed hard enough on stage 1 that it experienced rearward acceleration, likely causing the contents of both tanks to slosh forward. Also, I thought that the still burning stage 1 engines were supposed to prevent that, but stage 2 effects on stage 1 were higher than anticipated. Presumably they have a plan for taming rotational slosh as well, but I do not know if that was sufficient either.(still working out the tolerances and all with that being the first launch to get to that part of the flight) Quote Link to comment Share on other sites More sharing options...
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