What would be the effect of making SS effective terminal entry point, e.g., 150mi East of FL or BC [1], and land from the East? Likely someone around here can do the analysis? (I have no idea.)
Quote from: joek on 07/06/2019 06:38 pmStarlink is the priority "operational cargo system". Orbits required by Starlink are going to be more difficult to reach from BC than FL. That suggests FL will be priority for SS/SH operational flights. Anyone have an analysis of the penalties Starlink launches from BC would incur (calling @OneSpeed and @speedevil)?I've done some work on that. Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel. I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s. That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small. The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.
Starlink is the priority "operational cargo system". Orbits required by Starlink are going to be more difficult to reach from BC than FL. That suggests FL will be priority for SS/SH operational flights. Anyone have an analysis of the penalties Starlink launches from BC would incur (calling @OneSpeed and @speedevil)?
I've done some work on that. Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel. I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s. That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small. The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.
I've attached an image of the 39A flame trench I took a short time before the handover to SpaceX if anyone is interested.
Quote from: TheRadicalModerate on 07/06/2019 07:50 pmI've done some work on that. Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel. I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.A plane change from 550x550x33 to 550x550x53 costs about 2600 m/s. That's well beyond what Starship can do without on-orbit refueling, even if the payload is pretty small. The low-inclination VLEO orbits cost between 1200 and 2000 m/s, which are somewhat better, but aren't going to get you as much as you'd get from a stretched-fairing FH3R launch from the Cape.In this thread I made some rough calculations, and came to the conclusion that a launch ballistically due east at ~45 degrees elevation to 2km/s at which point you go ballistic till you near the atmosphere, taking you some 400km east of BC.At this point, you light up again, and proceed with the rest of the burn.This has ~2km/s penalty, not ~2.7.However, it has the major issue that SH is downrange a thousand kilometers and needs to barge land.I disagree that even a 2.6km/s plane change kills the idea.It depends on launch costs. If your primary goal is to prove out SS, and you are just fine with tiny launches, yes indeed it takes nearly all of the "100t+" payload to get to the right orbit.However, 'just' ten or twenty or fifty tons (depending on how you read the + in "100t+" and work out empty weight) may be just fine.Even five tons may be cheaper than a F9 launch, if in fact refurbishment hits cost targets, and you can launch a lot.This is without more aggressive use of the ion engines. If you use them to do 1300m/s (this has not been demonstrated as reasonably capable on the Starlink sats yet), things change rather a lot.There are many reasons SpaceX would be very happy to operate launching only tiny amounts of cargo at a time, from it makes the payload adaptors trivial, to a deployment mechanism as simple as a 9m double extension door slide out a tiny hatch.And of course the obvious of flying it a lot to qualify it for nervous users or people.
Quote from: speedevil on 07/07/2019 12:43 pmIn this thread I made some rough calculations, and came to the conclusion that a launch ballistically due east at ~45 degrees elevation to 2km/s at which point you go ballistic till you near the atmosphere, taking you some 400km east of BC.At this point, you light up again, and proceed with the rest of the burn.This has ~2km/s penalty, not ~2.7.That's an interesting trajectory. I'd never thought about a "vertical dogleg" before. Some questions:1) Did you ever de-rate this from Adelaide to DearMoon specs?2) How much SH delta-v do you lose to gravity drag in the loft?
In this thread I made some rough calculations, and came to the conclusion that a launch ballistically due east at ~45 degrees elevation to 2km/s at which point you go ballistic till you near the atmosphere, taking you some 400km east of BC.At this point, you light up again, and proceed with the rest of the burn.This has ~2km/s penalty, not ~2.7.
Quote from: DigitalMan on 07/07/2019 07:36 amI've attached an image of the 39A flame trench I took a short time before the handover to SpaceX if anyone is interested.Would you happen to have a shot from the south side?
The south side of the flame trench was filled and decked for the TEL transporter and supports to ride on. Plus the hydraulic cylinders that raise the TEL are located there too. Look at the bottom of the launch photo, you can see almost all of the exhaust exits the trench to the north.
Quote from: Zpoxy on 07/07/2019 10:59 pmThe south side of the flame trench was filled and decked for the TEL transporter and supports to ride on. Plus the hydraulic cylinders that raise the TEL are located there too. Look at the bottom of the launch photo, you can see almost all of the exhaust exits the trench to the north.Those hydraulic cylinder location is not new and not the south flame trench. The south flame trench is the side facing the HIF. The hydraulic cylinders were there during the Shuttle days too.
Quagmire, those are not hydraulic cylinders you're talking about. That area is called the catacombs and those are compressed gas storage cylinders, yes they were present for Shuttle and Apollo. The hydraulic cylinders / rams I'm talking about are indeed in the south side of the flame trench, they raise and lower the transporter erector. Those are new, installed by SpaceX.
Quote from: Zpoxy on 07/10/2019 07:48 pmQuagmire, those are not hydraulic cylinders you're talking about. That area is called the catacombs and those are compressed gas storage cylinders, yes they were present for Shuttle and Apollo. The hydraulic cylinders / rams I'm talking about are indeed in the south side of the flame trench, they raise and lower the transporter erector. Those are new, installed by SpaceX.Ah ok.... I am betting the red circle was already added to that top photo and not added by you then? That made me think you were referencing those things as being the south flame trench.
I've done some work on that. Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel. I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.
That is indeed a fair-sized indoor pachyderm. But EDL over CO, NM, and West Texas is pretty good from a sparse population standpoint. Also, I wouldn't completely rule out that SpaceX might eventually put a landing pad somewhere really desolate (how 'bout White Sands?). From there, getting a Starship back to either BC or MacGregor is pretty easy. Wide loads, even 9m-wide loads, could probably be accommodated.EDL into Florida is a horse of a different quantum number.
Quote from: TheRadicalModerate on 07/06/2019 07:50 pm That is indeed a fair-sized indoor pachyderm. But EDL over CO, NM, and West Texas is pretty good from a sparse population standpoint. Also, I wouldn't completely rule out that SpaceX might eventually put a landing pad somewhere really desolate (how 'bout White Sands?). From there, getting a Starship back to either BC or MacGregor is pretty easy. Wide loads, even 9m-wide loads, could probably be accommodated.EDL into Florida is a horse of a different quantum number.If you launch east from BC won't EDL be mostly in Mexican airspace?Is there any launch from BC that avoids Mexico for during both launch and landing?
Correct me if I'm wrong, but beyond the initial minute of flight where other airspace occupants need to be considered, the 'flightpath' (ground projection of vehicle track) is of not much concern but rather the projection of the instantaneous impact point - plus projected impact area governed by debris spread model plus time delta between off-axis thrust detection and flight termination - that needs to be steered around populated areas.
Quote from: TheRadicalModerate on 07/06/2019 07:50 pmI've done some work on that. Assuming that launching over the Southeast US or Yucatan isn't allowed, the highest inclination you can get to is about 33 degrees, launching from BC through the Yucatan Channel. I suspect that a dog-leg doesn't help very much, because by the time you clear Cancun, you're going fast enough that it's close to a full-up orbital plane change.What are the constraints here?It has been suggested that it is okay to launch south from Cape Canaveral, over flying Cuba. Cuba is about 400 miles from the Cape. The Yucatan, and New Orleans, are over 500 miles from BC. Is it just that we don't like the Cubans?The US-Mexico border runs essentially due east from BC in the Gulf of Mexico. If you launch a bit south of east you will cut across Mexican territorial waters. How high or how far east do you need to be that you don't need Mexican permission?Quote from: TheRadicalModerate on 07/06/2019 07:50 pm That is indeed a fair-sized indoor pachyderm. But EDL over CO, NM, and West Texas is pretty good from a sparse population standpoint. Also, I wouldn't completely rule out that SpaceX might eventually put a landing pad somewhere really desolate (how 'bout White Sands?). From there, getting a Starship back to either BC or MacGregor is pretty easy. Wide loads, even 9m-wide loads, could probably be accommodated.EDL into Florida is a horse of a different quantum number.If you launch east from BC won't EDL be mostly in Mexican airspace?Is there any launch from BC that avoids Mexico for during both launch and landing?