Author Topic: SpaceX Eastern Range Landing Facilities  (Read 185420 times)

Offline bstrong

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Re: SpaceX Eastern Range Landing Facilities
« Reply #240 on: 12/27/2015 01:40 PM »
From the look of the picture above (and I know, it's not high enough resolution to be certain), it really looks like the blast pattern indicates the stage landed near the edge of the inner ring.  I know, that's not exactly what the helicopter landing video seems to show, but there is a discoloration at about the 1:30 position on the transected circle image bstrong posted.  The edge between the inner concrete pad and the outer gravel ring (I'm assuming) has been scuffed out, and the end of the "X" has been darkened into a streak that looks like it extends into the outer ring.

I wish we could have an overhead image of the pad the morning after, before the crane was attached and the Falcon could have been moved.  Just to see exactly where it landed...
My interpretation of the dark area at 1:30 was that the paint was smudged in that direction by the flow of water from fire suppression system.

Online the_other_Doug

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Re: SpaceX Eastern Range Landing Facilities
« Reply #241 on: 12/27/2015 01:58 PM »
From the look of the picture above (and I know, it's not high enough resolution to be certain), it really looks like the blast pattern indicates the stage landed near the edge of the inner ring.  I know, that's not exactly what the helicopter landing video seems to show, but there is a discoloration at about the 1:30 position on the transected circle image bstrong posted.  The edge between the inner concrete pad and the outer gravel ring (I'm assuming) has been scuffed out, and the end of the "X" has been darkened into a streak that looks like it extends into the outer ring.

I wish we could have an overhead image of the pad the morning after, before the crane was attached and the Falcon could have been moved.  Just to see exactly where it landed...
My interpretation of the dark area at 1:30 was that the paint was smudged in that direction by the flow of water from fire suppression system.

I would buy that, except for the fact that I have seen no signs at all that the fire suppression system was ever activated.  When the teams were out surveying the landed stage later that night, the concrete pad looked dry as a bone, and there was obviously no water deluge across the pad immediately following the landing.  I'm not sure there is one planned after a successful landing, either -- depending on how and where the fire hoses spray out and where the stage lands, you could produce an unstable situation, even tip the rocket over.  It's only sitting on those legs, it's not bolted down to the landing pad, after all.

So, I'm not buying that the fire suppression system ever went off...  Of course, there was some lateral motion as the stage came in, perhaps that discolored streak simply shows the horizontal approach pattern of the descending rocket plume?  In other words, it came in from the 1:30 direction and discolored the pad as it descended, but by the point of footpad contact it had arrived at or near the center of the pad...?
-Doug  (With my shield, not yet upon it)

Offline Dante80

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Re: SpaceX Eastern Range Landing Facilities
« Reply #242 on: 12/27/2015 02:13 PM »
The live video from LZ-1 Musk tweeted does show some water on the concrete. No idea whether its from the FSS.

Offline meekGee

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Re: SpaceX Eastern Range Landing Facilities
« Reply #243 on: 12/27/2015 09:31 PM »
So to compare:

The easiest feature to match is the semi circular narrow road that cuts through the gravel area of the pad.

The logistics area where the crane is, is the smaller rectangular area in the picture, the one that is almost lost in clutter.  It matches the only rectangular area in the rocket landing video.
« Last Edit: 12/27/2015 09:35 PM by meekGee »
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Offline cscott

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Re: SpaceX Eastern Range Landing Facilities
« Reply #244 on: 12/27/2015 09:45 PM »
I'd think the easiest feature to align would be the shoreline.  It looks like you've got one of the images upside down, but maybe I'm misunderstanding what you're trying to do.
« Last Edit: 12/27/2015 09:47 PM by cscott »

Offline meekGee

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Re: SpaceX Eastern Range Landing Facilities
« Reply #245 on: 12/27/2015 09:50 PM »
I'd think the easiest feature to align would be the shoreline.  It looks like you've got one of the images upside down, but maybe I'm misunderstanding what you're trying to do.
I have them in their original form.

I need to paste the CGI one onto a flat plane in a CAD program and replicate the perspective to do a good comparison...

Or perhaps just a four point distort in Photoshop will do...

Anyway, I don't think the shoreline is visible in the CGI image, just the perimeter road.
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Offline meekGee

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Re: SpaceX Eastern Range Landing Facilities
« Reply #246 on: 12/28/2015 12:24 AM »
Based on this screen capture, I laid them out approximately, here's hoping to see at least one more taking shape next month...

EDIT: The bottom right pad should be slightly lower, in line with the "across" access road.

We also know now that the crane is going to be driving around with stages hung from it, and so the CGI image is missing one important access trail, from the main pad to the logistics area...  Probably not shown because it already exists and they don't have to pave it.  heh, I was staring at it too much, misses the two curved roads that are clearly shown...

I also added the Google Maps image, for posterity, before they capture the recent mods.
« Last Edit: 12/28/2015 01:58 AM by meekGee »
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Offline JBF

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Re: SpaceX Eastern Range Landing Facilities
« Reply #247 on: 12/28/2015 02:50 PM »
Hmmm from what land they have cleared it looks like they won't be building the bottom right pad. (Looking at your modified image)
« Last Edit: 12/28/2015 02:51 PM by JBF »
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Offline cscott

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Re: SpaceX Eastern Range Landing Facilities
« Reply #248 on: 12/28/2015 03:00 PM »
"Won't be building" is a little strong.  "Haven't yet cleared," certainly.

Folks have been wondering why *five* pads were necessary for a while.  My presumption is that the inaugural FH flights will have ASDS landing for the central core, so only two pads seem worth clearing and paving in the medium term future.
« Last Edit: 12/28/2015 03:01 PM by cscott »

Online Herb Schaltegger

Re: SpaceX Eastern Range Landing Facilities
« Reply #249 on: 12/28/2015 03:27 PM »
My personal guess on the pad arrangements remains unchanged: the one large central pad will be "primary" for single-core missions simply because it's biggest, to allow for literal last-seconds contingencies, and because there won't be RTLS missions often enough to need the secondary pads.  As the technology continues to be proven operationally over a wider variety of payloads and launch trajectories (and assuming that landing accuracy and precision remain problem-free in practice for the first few RTLS flights), SpaceX will try to transition to first targeting and then regularly using these not-yet-built secondary pads. If their plans hold up over the next couple years and they build up to their hoped-for full flight cadence, having five pads gives them operational flexibility for handling a full mix of FH and F9 flights, and allows for one or more pads to be out of commission in case of a failed/hard landing or what have you. 
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Offline intrepidpursuit

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Re: SpaceX Eastern Range Landing Facilities
« Reply #250 on: 12/28/2015 04:19 PM »
I've always believed that the "contingency" pads as described in the original license had to do with one flight crashing, or even just having two flights close enough together that there is no time to clear a pad before another launch (two launch pads you know). The idea of diverting a rocket midflight from one to the other because of wind or something is rather absurd considering how quickly everything happens. Contingency is about one flight not impacting the next.

Even with heavy and all 3 boosters returning to launch site, that doesn't really account for all 5 unless you consider one pad for a dragon propulsive landing. Perhaps that is why they have not cleared space for the 5th pad. A F9 and FH launch in quick succession will be possible next year though with 39A coming online, so there are your 4.

Online John Alan

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Re: SpaceX Eastern Range Landing Facilities
« Reply #251 on: 12/28/2015 10:34 PM »
I have always thought the big pad was so a Dragon could do a hybrid landing...
Chutes with propulsive finish...
It allows the chutes some room to lay down post landing out of the brush...  ;)

Offline georgegassaway

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Re: SpaceX Eastern Range Landing Facilities
« Reply #252 on: 12/29/2015 03:56 AM »
The idea of diverting a rocket midflight from one to the other because of wind or something is rather absurd considering how quickly everything happens.

Not absurd at all. R/C Multicopters can be programed to fly autonomously, in Ardupilot, to do just that.  See "Rally Points".

http://copter.ardupilot.com/wiki/common-rally-points/

For a multcopter, if the voltage is getting too low to fly back to home, it can be programmed to automatically land at the closest "rally point".

For Falcon boosters, replace home with big center pad, and rally points as the four smaller "contingency" pads. Replace low voltage with horizontal error too far beyond some pre-determined value to likely land safely at the center pad, therefore to divert to a contingency pad if that is significantly closer, with a more  likely safer outcome.

Now, by no means am I saying Falcon is using Ardupilot software.  But I am saying that hobbyists have been doing this for some time now, for an automated flying machine to vertically land itself at an alternative landing spot if it can't safely make it to the primary landing spot. Surely SpaceX's programmers can do the same, and even more (add in criteria for where it is headed and if it can land safer at a contingency pad than to try to divert laterally to the center pad, then land at the contingency pad). 

Absurdity factor = 0. 

Not to have that capability, for a flight coming in say 150 meters south of the center pad, to sacrifice not trying to land safely on a closer contingency pad for the sake of a higher-risk lateral maneuver to land at the "X" on the center pad, THAT would be the absurd part.

If SpaceX ever has another CRS-6 type "Kamikaze" crash landing for the sake of trying to hit the "X", that will also be absurd. I hope they learned far more from that crash than just to add more hydraulic fluid.  As that also showed the landing software was too dumb to know what to do when a safe landing is hopeless (not enough throttle capability and not enough fuel left to do a near-hover horizontal maneuver like Blue Origin did when it was about to miss it's landing pad entirely in the last 50-100 feet or so above the ground). And it's better to ditch in the ocean than crash into the barge (1 destroyed rocket better than 1 destroyed rocket and 1 damaged barge). Of course, that was a learning experience, so I'm not faulting that it happened once. If that sort of thing happened again for a similar hopeless "too far out of safe parameters" landing attempt, no landing software change, that would be stunningly dumb-surd (tm!)

Now, the above portions about primary and contingency pads at LZ-1, are mostly about a single Falcon booster coming back.  For a Falcon Heavy, with two (or three) boosters coming back, the criteria would be changed, less flexible options.

- George Gassaway
« Last Edit: 12/29/2015 04:11 AM by georgegassaway »

Offline cscott

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Re: SpaceX Eastern Range Landing Facilities
« Reply #253 on: 12/29/2015 12:32 PM »
I find the idea that a booster can navigate from 100km up and then find itself in need of a "rally point" only 150m away from its proper target rather cute.

Offline Jim

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Re: SpaceX Eastern Range Landing Facilities
« Reply #254 on: 12/29/2015 12:42 PM »

Absurdity factor = 0. 


Not true at all.  RC copters have nothing in common with this

Online the_other_Doug

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Re: SpaceX Eastern Range Landing Facilities
« Reply #255 on: 12/29/2015 04:45 PM »
From the look of the picture above (and I know, it's not high enough resolution to be certain), it really looks like the blast pattern indicates the stage landed near the edge of the inner ring.  I know, that's not exactly what the helicopter landing video seems to show, but there is a discoloration at about the 1:30 position on the transected circle image bstrong posted.  The edge between the inner concrete pad and the outer gravel ring (I'm assuming) has been scuffed out, and the end of the "X" has been darkened into a streak that looks like it extends into the outer ring.

I wish we could have an overhead image of the pad the morning after, before the crane was attached and the Falcon could have been moved.  Just to see exactly where it landed...
My interpretation of the dark area at 1:30 was that the paint was smudged in that direction by the flow of water from fire suppression system.

I would buy that, except for the fact that I have seen no signs at all that the fire suppression system was ever activated.  When the teams were out surveying the landed stage later that night, the concrete pad looked dry as a bone, and there was obviously no water deluge across the pad immediately following the landing.  I'm not sure there is one planned after a successful landing, either -- depending on how and where the fire hoses spray out and where the stage lands, you could produce an unstable situation, even tip the rocket over.  It's only sitting on those legs, it's not bolted down to the landing pad, after all.

So, I'm not buying that the fire suppression system ever went off...  Of course, there was some lateral motion as the stage came in, perhaps that discolored streak simply shows the horizontal approach pattern of the descending rocket plume?  In other words, it came in from the 1:30 direction and discolored the pad as it descended, but by the point of footpad contact it had arrived at or near the center of the pad...?

OK, so I've studied the various landing videos, especially the more recently released ones that were taken from ground level, and I think I know why there is a blast pattern that flows to the 1:30 position in the image in question.

The stage wasn't translating from the 1:30 position towards the center of the pad.  It was killing horizontal velocity in the direction of the 1:30 position -- in other words, while it came down relatively straight, the engine plume was angled somewhat towards the 1:30 position.  This seems to have been to try and kill the final horizontal component of the stage's descent.  The stage landed off-vertical by about five degrees or so, because the engine was still being gimbaled to manage horizontal velocity, even right up to touchdown.

So, it is just a rocket blast scar on the concrete pad, but it happened not because the stage landed near the 1:30 edge of the pad, and not because the stage was walking from the 1:30 position towards the center of the pad.  It happened just because the engine was pointed in that direction during final descent, just enough to leave a non-symmetrical blast pattern.
-Doug  (With my shield, not yet upon it)

Offline meekGee

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Re: SpaceX Eastern Range Landing Facilities
« Reply #256 on: 12/29/2015 05:57 PM »
From the look of the picture above (and I know, it's not high enough resolution to be certain), it really looks like the blast pattern indicates the stage landed near the edge of the inner ring.  I know, that's not exactly what the helicopter landing video seems to show, but there is a discoloration at about the 1:30 position on the transected circle image bstrong posted.  The edge between the inner concrete pad and the outer gravel ring (I'm assuming) has been scuffed out, and the end of the "X" has been darkened into a streak that looks like it extends into the outer ring.

I wish we could have an overhead image of the pad the morning after, before the crane was attached and the Falcon could have been moved.  Just to see exactly where it landed...
My interpretation of the dark area at 1:30 was that the paint was smudged in that direction by the flow of water from fire suppression system.

I would buy that, except for the fact that I have seen no signs at all that the fire suppression system was ever activated.  When the teams were out surveying the landed stage later that night, the concrete pad looked dry as a bone, and there was obviously no water deluge across the pad immediately following the landing.  I'm not sure there is one planned after a successful landing, either -- depending on how and where the fire hoses spray out and where the stage lands, you could produce an unstable situation, even tip the rocket over.  It's only sitting on those legs, it's not bolted down to the landing pad, after all.

So, I'm not buying that the fire suppression system ever went off...  Of course, there was some lateral motion as the stage came in, perhaps that discolored streak simply shows the horizontal approach pattern of the descending rocket plume?  In other words, it came in from the 1:30 direction and discolored the pad as it descended, but by the point of footpad contact it had arrived at or near the center of the pad...?

OK, so I've studied the various landing videos, especially the more recently released ones that were taken from ground level, and I think I know why there is a blast pattern that flows to the 1:30 position in the image in question.

The stage wasn't translating from the 1:30 position towards the center of the pad.  It was killing horizontal velocity in the direction of the 1:30 position -- in other words, while it came down relatively straight, the engine plume was angled somewhat towards the 1:30 position.  This seems to have been to try and kill the final horizontal component of the stage's descent.  The stage landed off-vertical by about five degrees or so, because the engine was still being gimbaled to manage horizontal velocity, even right up to touchdown.

So, it is just a rocket blast scar on the concrete pad, but it happened not because the stage landed near the 1:30 edge of the pad, and not because the stage was walking from the 1:30 position towards the center of the pad.  It happened just because the engine was pointed in that direction during final descent, just enough to leave a non-symmetrical blast pattern.

Huh.  I looked at the HD helicopter video and came out with the impression that there was a streak there even before the rocket got close.
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Offline georgegassaway

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Re: SpaceX Eastern Range Landing Facilities
« Reply #257 on: 12/29/2015 06:36 PM »
I find the idea that a booster can navigate from 100km up and then find itself in need of a "rally point" only 150m away from its proper target rather cute.


Absurdity factor = 0. 


Not true at all.  RC copters have nothing in common with this

I'll add this then.

The contingency pads would only be utilized in order to enable the safe landing of a single vehicle should last-second navigation and landing diversion be required.

- George Gassaway

Offline cscott

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Re: SpaceX Eastern Range Landing Facilities
« Reply #258 on: 12/29/2015 07:31 PM »
And you think this need will be frequent?

Offline Jim

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Re: SpaceX Eastern Range Landing Facilities
« Reply #259 on: 12/29/2015 07:57 PM »


The contingency pads would only be utilized in order to enable the safe landing of a single vehicle should last-second navigation and landing diversion be required.

- George Gassaway

why?  The vehicles are autonomous.

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