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#480
by
Jcc
on 27 Mar, 2017 23:43
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
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#481
by
Lars-J
on 28 Mar, 2017 00:43
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
I believe the base (around the octaweb and legs) and the interstage are the only areas covered by "traditional" spam. The rest is metal covered by thinner paint coatings that are easier to wash. But I could be mistaken.
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#482
by
CameronD
on 28 Mar, 2017 01:16
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
I believe the base (around the octaweb and legs) and the interstage are the only areas covered by "traditional" spam. The rest is metal covered by thinner paint coatings that are easier to wash. But I could be mistaken.
If they keep up this re-launch thing they might have to try anodising..
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#483
by
envy887
on 28 Mar, 2017 01:38
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
The RP-1 tank and interstage still look pretty sooty. The LOX tank is always clean, and obviously the 2nd stage is bright white.
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#484
by
Comga
on 28 Mar, 2017 03:37
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Has anybody considered the PR that companies like SES get for being the first to launch on a new SpaceX configuration. I know that personally I know a lot more about SES now then before their flights. I think Iridium got a boost from the PR too.
If we said "no" to your question, would you believe us?
Have you read this thread and the parallel L2 thread?
It's really hard to come up with new considerations here as we approach 500 posts in this thread alone. That's not one.
Feel free to debate whether SES would consider PR a reason to assume significantly greater risk to their satellite.
Feel free to debate whether PR is financially significant to SES.
Would you be more likely to sign a contract with them, vs their competition, because they are "first to launch on a new SpaceX configuration"?
On what do you base your conclusion the "Iridium got a boost"?
Unless that's a pun....
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#485
by
CameronD
on 28 Mar, 2017 04:11
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
The RP-1 tank and interstage still look pretty sooty. The LOX tank is always clean, and obviously the 2nd stage is bright white.
The "scars of battle" I suppose. Presumably someone in SpaceX decided that a grubby-looking stage would/should perform no differently to a freshly-painted one whilst saving a few $k in paint and labour.
Perhaps the grubby-ness is part of their testing regime? You know, to see if it gets more grubby??
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#486
by
Semmel
on 28 Mar, 2017 05:58
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How many seconds between ignition and T0?
Is this time consistent or has anyone noticed that number moving around on various launches?
Looked at the last couple press kits, it's been T-3 Merlin-1D ignition T-0 liftoff.
Pinning down the ignition to 0.1 sec. or something is probably a futile attempt. So many things happen in short succession that you can't really say that one of the events is the ignition time. 2 to 3 sec before liftoff might be as good as it gets.
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#487
by
CraigLieb
on 28 Mar, 2017 12:39
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
The RP-1 tank and interstage still look pretty sooty. The LOX tank is always clean, and obviously the 2nd stage is bright white.
The "scars of battle" I suppose. Presumably someone in SpaceX decided that a grubby-looking stage would/should perform no differently to a freshly-painted one whilst saving a few $k in paint and labour.
Perhaps the grubby-ness is part of their testing regime? You know, to see if it gets more grubby??
One reason to not re-paint is that fresh paint adds weight. Extra pounds on the first stage reduces stack overall performance to orbit. If the existing paint is still doing its proper job, leave it alone. Wash it, check it, paint over patches where it is damaged if necessary and go back to work. Washing off the soot also saves weight (and possibly reduces drag) and restores launch to nominal performance values.
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#488
by
Lar
on 28 Mar, 2017 13:19
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The core doesn't appear to be sooty at all. I suppose besides washing it, they put on a fresh coat of spam?
The RP-1 tank and interstage still look pretty sooty. The LOX tank is always clean, and obviously the 2nd stage is bright white.
The "scars of battle" I suppose. Presumably someone in SpaceX decided that a grubby-looking stage would/should perform no differently to a freshly-painted one whilst saving a few $k in paint and labour.
Perhaps the grubby-ness is part of their testing regime? You know, to see if it gets more grubby??
One reason to not re-paint is that fresh paint adds weight. Extra pounds on the first stage reduces stack overall performance to orbit. If the existing paint is still doing its proper job, leave it alone. Wash it, check it, paint over patches where it is damaged if necessary and go back to work. Washing off the soot also saves weight (and possibly reduces drag) and restores launch to nominal performance values.
"We run the tightest (space)ship in the shipping business"
UPS might not like them using that slogan but yeah. UPS washes trucks a lot, (it saves fuel), but doesn't repaint them unless they have to. (it adds weight)... same exact thinking.
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#489
by
jpo234
on 28 Mar, 2017 14:55
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Washing off the soot also saves weight (and possibly reduces drag) and restores launch to nominal performance values.
Isn't the first stage covered by ice anyway (from the cryogenic fuels)?
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#490
by
mheney
on 28 Mar, 2017 15:19
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Washing off the soot also saves weight (and possibly reduces drag) and restores launch to nominal performance values.
Isn't the first stage covered by ice anyway (from the cryogenic fuels)?
Yes - right until liftoff. Vibration and airflow tend to clean the ice off pretty effectively.
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#491
by
old_sellsword
on 28 Mar, 2017 15:33
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Our CTO Martin Halliwell talks about #SES10 and the launch on #flightproven rocket!
https://twitter.com/ses_satellites/status/846742078310690818
https://www.periscope.tv/w/a6kjoTFETEtCeURWT2FEUUp8MWpNSmdZd3JPYXlLTOkPzfjLKb6zX572-CwWcPxK89_4GMQLEeCpVDy3-Oo7
Here are some notes:
* Mass is 5281.7 kg, insertion orbit will be 35410 km x 218 km at 26.2º, so
barely subsynchronous GTO. Orbit raising will be done with chemical engines.
* SES block bought SES-10, SES-11, SES-14, SES-16. Then last August they were approached with the opportunity to use a pre-flown booster.
* Essentially no change in the insurance premium, 100th of a percent.
* First stage booster is contractually obligated to make certain altitude, velocity, downrange, etc. SpaceX works with the leftovers for landing. This will be a very hot landing, but if it comes back, SES gets "bits" for their boardroom.
* Satellite requires 13 hours of checkouts once the full stack is vertical on the pad.
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#492
by
WmThomas
on 28 Mar, 2017 15:59
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Isn't the first stage covered by ice anyway (from the cryogenic fuels)?
If you look at the returned stages, the bottom half is always very dark, and it looks almost painted that way. That's because, as you note, the cold LOX tanks create ice on the exterior, and this keeps most of the soot off of that (upper) half of the stage. But the bottom half (yes, it's not exactly half) contains warmer RP-1, and that's one reason it collects a lot more soot in the landing process.
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#493
by
Comga
on 28 Mar, 2017 16:48
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#494
by
king1999
on 28 Mar, 2017 17:04
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Isn't the first stage covered by ice anyway (from the cryogenic fuels)?
If you look at the returned stages, the bottom half is always very dark, and it looks almost painted that way. That's because, as you note, the cold LOX tanks create ice on the exterior, and this keeps most of the soot off of that (upper) half of the stage. But the bottom half (yes, it's not exactly half) contains warmer RP-1, and that's one reason it collects a lot more soot in the landing process.
Doesn't that mean that a layer of ice had been with the booster all the time until it landed? I think the soot was from the three burns, probably most from the first two burns.
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#495
by
Lars-J
on 28 Mar, 2017 17:07
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Isn't the first stage covered by ice anyway (from the cryogenic fuels)?
If you look at the returned stages, the bottom half is always very dark, and it looks almost painted that way. That's because, as you note, the cold LOX tanks create ice on the exterior, and this keeps most of the soot off of that (upper) half of the stage. But the bottom half (yes, it's not exactly half) contains warmer RP-1, and that's one reason it collects a lot more soot in the landing process.
Doesn't that mean that a layer of ice had been with the booster all the time until it landed? I think the soot was from the three burns, probably most from the first two burns.
Exactly... A very thin ice layer must stay with the tank throughout most of the flight. Either that, or the colder surface of the LOX tank makes it more difficult for the soot to adhere.
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#496
by
edkyle99
on 28 Mar, 2017 17:12
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Doesn't that mean that a layer of ice had been with the booster all the time until it landed? I think the soot was from the three burns, probably most from the first two burns.
Exactly... A very thin ice layer must stay with the tank throughout most of the flight. Either that, or the colder surface of the LOX tank makes it more difficult for the soot to adhere.
In-space photos of old Atlas sustainer stages during Mercury missions showed a layer of what I would call "frost" still visible on much of the exterior of the LOX tank after Mercury capsule separation. Most of the heavy "ice" itself was vibrated off during the engine start phase.
- Ed Kyle
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#497
by
baldusi
on 28 Mar, 2017 17:31
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Our CTO Martin Halliwell talks about #SES10 and the launch on #flightproven rocket!
https://twitter.com/ses_satellites/status/846742078310690818
https://www.periscope.tv/w/a6kjoTFETEtCeURWT2FEUUp8MWpNSmdZd3JPYXlLTOkPzfjLKb6zX572-CwWcPxK89_4GMQLEeCpVDy3-Oo7
Here are some notes:
* Mass is 5281.7 kg, insertion orbit will be 35410 km x 218 km at 26.2º, so barely subsynchronous GTO. Orbit raising will be done with chemical engines.
* SES block bought SES-10, SES-11, SES-14, SES-16. Then last August they were approached with the opportunity to use a pre-flown booster.
* Essentially no change in the insurance premium, 100th of a percent.
* First stage booster is contractually obligated to make certain altitude, velocity, downrange, etc. SpaceX works with the leftovers for landing. This will be a very hot landing, but if it comes back, SES gets "bits" for their boardroom.
* Satellite requires 13 hours of checkouts once the full stack is vertical on the pad.
I get 1,788m/s of delta-v deficit. So, while technically slightly subsynchronous, it would still be better than Cape standard 1,804m/s.
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#498
by
ChrisGebhardt
on 28 Mar, 2017 18:22
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During the presser this morning, I asked about the prolonged static fires for SES missions. Halliwell said it wasn't a company request, it's just something SpaceX seems to do for their missions.
NOTE: Posting this because it was after their periscope live feed ended.
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#499
by
francesco nicoli
on 28 Mar, 2017 18:23
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so tomorrow is the day of the beginning of the new Space Era?
cool times to live in!
