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#2240
by
Herb Schaltegger
on 13 Jan, 2016 15:51
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Not sure I understand the question....the stages are on handling fixtures prior to S1/2 mate, then the vehicle goes onto the TE. I'm saying that the SLC-40 TE is being used for the F9-21 S1. I don't know where F9-22 is in its processing flow, but I'm guessing the SLC-40 TE was empty prior to the delivery of F9-21 S1.
Okay that's the part I was missing. I read the post about the stage being raised via crane and didn't realize the T/E was out at the pad at all.
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#2241
by
Kim Keller
on 13 Jan, 2016 15:55
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Not sure I understand the question....the stages are on handling fixtures prior to S1/2 mate, then the vehicle goes onto the TE. I'm saying that the SLC-40 TE is being used for the F9-21 S1. I don't know where F9-22 is in its processing flow, but I'm guessing the SLC-40 TE was empty prior to the delivery of F9-21 S1.
Okay that's the part I was missing. I read the post about the stage being raised via crane and didn't realize the T/E was out at the pad at all.
There's no TE support for the S1 at its upper end, and so there's no way to raise the stage using the TE. Therefore, they'd need a crane to set the stage down on the holddown structure.
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#2242
by
abaddon
on 13 Jan, 2016 15:55
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I've got it - they will use the SES-9 S2 for the static fire attempt of the Orbcomm2 returned booster. S2 doesn't really do much other than get fueled up and sit there so this would be a minor risk.
Yeah, probably not, but it's more plausible than SES-9 launching on the Orbcomm2 booster 
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If they were going to use F9-22's S2 it would already be mated. Using this S1 for SES-9 is not going to happen - there's too much risk at this point in SX's reusability project.
Right, I am in agreement that SES-9 using this core was not going to happen, was making a joke/acknowledgement that my suggestion was only slightly more plausible. Didn't think it through that the S2 would already be on (and it would probably use the TEL fully instead of the crane and lowered TEL as it seems to be doing) so yeah...
Man, always fun when SpaceX throws us a curveball, although as usual the wilder speculations will end up being just that.
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#2243
by
Herb Schaltegger
on 13 Jan, 2016 16:05
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Not sure I understand the question....the stages are on handling fixtures prior to S1/2 mate, then the vehicle goes onto the TE. I'm saying that the SLC-40 TE is being used for the F9-21 S1. I don't know where F9-22 is in its processing flow, but I'm guessing the SLC-40 TE was empty prior to the delivery of F9-21 S1.
Okay that's the part I was missing. I read the post about the stage being raised via crane and didn't realize the T/E was out at the pad at all.
There's no TE support for the S1 at its upper end, and so there's no way to raise the stage using the TE. Therefore, they'd need a crane to set the stage down on the holddown structure.
Ah, of course. Thanks for explaining that in more detail. Thanks, Kim.
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#2244
by
Lars-J
on 13 Jan, 2016 16:15
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S1 from F9-21 is now vertical on SLC-40. It was placed there by a large crane, which is still attached as I write this. Rumor is there will be a static fire attempt Thursday.
Was S1 from F9-21 back inside the HIF or was it taken directly to the pad.
The use of a crane would seem to indicate the SLC-40 transporter erector is gainfully employed with the SES-9 booster.
The holddowns are part of the TE.
I thought they could be separated? They've certainly done that at VFB (see image below), and I seem to recall an image of that at SLC-40 too - although I think that was pre-v1.1.
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#2245
by
BrianNH
on 13 Jan, 2016 16:26
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Another possible speculation is that they might take one of the engines off of the returned stage and put it on the SES-9 rocket. That would allow them to get more test data on the reusability of the engines without endangering the SES-9 launch due to Falcon 9's ability to lose an engine and still complete it's mission.
Seems a bit unlikely, but not as unlikely as reusing the whole stage.
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#2246
by
abaddon
on 13 Jan, 2016 16:32
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Another possible speculation is that they might take one of the engines off of the returned stage and put it on the SES-9 rocket. That would allow them to get more test data on the reusability of the engines without endangering the SES-9 launch due to Falcon 9's ability to lose an engine and still complete it's mission.
Seems a bit unlikely, but not as unlikely as reusing the whole stage.
SES-9 would be a poor choice of mission, as it is a GTO flight and quite heavy. An engine lost early in the mission could result in the payload being delivered to a significantly lower orbit than planned, with the satellite forced to burn station-keeping fuel to make up the shortfall.
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#2247
by
BrianNH
on 13 Jan, 2016 16:35
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It would also be difficult to see them put a used engine on CRS-8, given what happened on unlucky CRS-7.
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#2248
by
sdsds
on 13 Jan, 2016 16:40
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Another possible speculation is that they might take one of the engines off of the returned stage and put it on the SES-9 rocket.
SES-9 would be a poor choice of mission
I'm hoping each of the FH side boosters gets one engine off the returned stage.
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#2249
by
robert_d
on 13 Jan, 2016 16:44
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Quote:
given what happened on unlucky CRS-7.
close quote.
Since the CRS-7 issue was not engine related, and the orbcomm engines are demonstrably "lucky" I don't think your comment necessarily follows.
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#2250
by
Flying Beaver
on 13 Jan, 2016 16:54
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Another possible speculation is that they might take one of the engines off of the returned stage and put it on the SES-9 rocket. That would allow them to get more test data on the reusability of the engines without endangering the SES-9 launch due to Falcon 9's ability to lose an engine and still complete it's mission.
Seems a bit unlikely, but not as unlikely as reusing the whole stage.
SES-9 would be a poor choice of mission, as it is a GTO flight and quite heavy. An engine lost early in the mission could result in the payload being delivered to a significantly lower orbit than planned, with the satellite forced to burn station-keeping fuel to make up the shortfall.
But whose saying that a engine from OG2 would fail anyways?
SX has proven that a Merlin can fire 20, 30 times over without any problems at McGregor.
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#2251
by
guckyfan
on 13 Jan, 2016 16:57
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SES-9 would be a poor choice of mission, as it is a GTO flight and quite heavy. An engine lost early in the mission could result in the payload being delivered to a significantly lower orbit than planned, with the satellite forced to burn station-keeping fuel to make up the shortfall.
There is a huge amount of extra fuel available. That's the fuel reserved for landing.
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#2252
by
JBF
on 13 Jan, 2016 17:45
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S1 from F9-21 is now vertical on SLC-40. It was placed there by a large crane, which is still attached as I write this. Rumor is there will be a static fire attempt Thursday.
Was S1 from F9-21 back inside the HIF or was it taken directly to the pad.
The use of a crane would seem to indicate the SLC-40 transporter erector is gainfully employed with the SES-9 booster.
The holddowns are part of the TE.
I thought they could be separated? They've certainly done that at VFB (see image below), and I seem to recall an image of that at SLC-40 too - although I think that was pre-v1.1.
The TEL at SLC-40 is of the older design were they don't separate.
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#2253
by
abaddon
on 13 Jan, 2016 17:46
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SES-9 would be a poor choice of mission, as it is a GTO flight and quite heavy. An engine lost early in the mission could result in the payload being delivered to a significantly lower orbit than planned, with the satellite forced to burn station-keeping fuel to make up the shortfall.
There is a huge amount of extra fuel available. That's the fuel reserved for landing.
Why not do engine reuse on a lighter mission where you could still land after losing an engine?
Also, it's very unclear to me the trades involved here. If you lost the engine early, would the (already presumed to be very thin) ASDS landing margin be enough to cover the originally contracted orbit?
I think any characterization of a "huge" landing margin on a >5300kg GTO flight is also a bit of hyperbole.
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#2254
by
MechE31
on 13 Jan, 2016 18:06
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S1 from F9-21 is now vertical on SLC-40. It was placed there by a large crane, which is still attached as I write this. Rumor is there will be a static fire attempt Thursday.
Was S1 from F9-21 back inside the HIF or was it taken directly to the pad.
The use of a crane would seem to indicate the SLC-40 transporter erector is gainfully employed with the SES-9 booster.
The holddowns are part of the TE.
I thought they could be separated? They've certainly done that at VFB (see image below), and I seem to recall an image of that at SLC-40 too - although I think that was pre-v1.1.
The TEL at SLC-40 is of the older design were they don't separate.
The SLC-40 TEL is newer than the VAFB one. It was redone completely for V1.1 and was completed after the launch from VAFB. I don't think either are designed to be routinely separated, even if they could be for maintenance.
Note that just because they don't separate, doesn't mean you couldn't leave the strongback horizontal while the launch mount holds a rocket vertically.
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#2255
by
rcoppola
on 13 Jan, 2016 18:34
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I, like many, thought perhaps LC-39A wasn't ready, or they found something wrong with the stage and needed the SLC-40 HIF, among other theories...but...
IIRC...there were some last minute tweaks to the Ignition Timing Sequences or the tank pressure relief valve closures or something like that because of the new densification process during the ORB-2 launch at SLC-40.
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#2256
by
mme
on 13 Jan, 2016 21:06
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I, like many, thought perhaps LC-39A wasn't ready, or they found something wrong with the stage and needed the SLC-40 HIF, among other theories...but...
IIRC...there were some last minute tweaks to the Ignition Timing Sequences or the tank pressure relief valve closures or something like that because of the new densification process during the ORB-2 launch at SLC-40.
On the flip side, this gives them a booster to run through multiple wet rehearsals at SLC-40. Maybe they decided to fine tune tanking and "launch" procedures at SLC-40 to improve the odds of meeting an aggressive launch cadence.
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#2257
by
mr. mark
on 13 Jan, 2016 21:21
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#2258
by
rcoppola
on 13 Jan, 2016 21:34
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I, like many, thought perhaps LC-39A wasn't ready, or they found something wrong with the stage and needed the SLC-40 HIF, among other theories...but...
IIRC...there were some last minute tweaks to the Ignition Timing Sequences or the tank pressure relief valve closures or something like that because of the new densification process during the ORB-2 launch at SLC-40.
On the flip side, this gives them a booster to run through multiple wet rehearsals at SLC-40. Maybe they decided to fine tune tanking and "launch" procedures at SLC-40 to improve the odds of meeting an aggressive launch cadence.
Exactly.
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#2259
by
MrHollifield
on 13 Jan, 2016 21:45
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In addition to giving a chance to prove out changes to countdown procedures at LC40, it also proves the vehicle works so when they get it back to LC39A they'll know they have a good vehicle and won't be chasing vehicle problems while trying to make sure the pad is ready.
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