Author Topic: SpaceX Falcon 9 : SES 11/Echostar 105 : Oct 11, 2017 : Discussion  (Read 70025 times)

Offline wardy89

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I noticed that the time from MECO to second engine start is 5 seconds. Iridium-3 was 13 seconds and SES-10 was 11 seconds.
The benefits of reduced coast time between stages is obvious, but I'm surprised they have managed to reduce the coast by more than 50% compared to the last SES mission.

Note that all numbers are taken from the mission press kits's.

I might be totally wrong on this but i thought that the "long" coasts we have been seeing between MECO and 2nd stage ignition recently is purposely done so that the 1st stage has a chance to begin its flip, so that when the 2nd stage ignites the exhaust plume does less dames to the interstage and all the electronics housed within.

Offline EspenU

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I noticed that the time from MECO to second engine start is 5 seconds. Iridium-3 was 13 seconds and SES-10 was 11 seconds.
The benefits of reduced coast time between stages is obvious, but I'm surprised they have managed to reduce the coast by more than 50% compared to the last SES mission.

Note that all numbers are taken from the mission press kits's.

I might be totally wrong on this but i thought that the "long" coasts we have been seeing between MECO and 2nd stage ignition recently is purposely done so that the 1st stage has a chance to begin its flip, so that when the 2nd stage ignites the exhaust plume does less dames to the interstage and all the electronics housed within.

I understand the reasoning. However, this flight has an ASDS landing, so it involves a flip.
In addition, the last expendable launch (Intelsat 35e) also had an 11 sec coast (again, the time is from the press kit, not from web cast measurements).

Offline deruch

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I at one time tracked the amount of time allowed for stage separation from a bunch of press kits and I found that there was a large amount of variability in the listed times from one mission to the next.  None of which seemed to agree with those observed in the actual webcasts.  I don't think you can take the press kit timings as being accurate for that particular interval.
« Last Edit: 10/11/2017 01:41 PM by deruch »
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Offline wardy89

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I noticed that the time from MECO to second engine start is 5 seconds. Iridium-3 was 13 seconds and SES-10 was 11 seconds.
The benefits of reduced coast time between stages is obvious, but I'm surprised they have managed to reduce the coast by more than 50% compared to the last SES mission.

Note that all numbers are taken from the mission press kits's.

I might be totally wrong on this but i thought that the "long" coasts we have been seeing between MECO and 2nd stage ignition recently is purposely done so that the 1st stage has a chance to begin its flip, so that when the 2nd stage ignites the exhaust plume does less dames to the interstage and all the electronics housed within.

I understand the reasoning. However, this flight has an ASDS landing, so it involves a flip.
In addition, the last expendable launch (Intelsat 35e) also had an 11 sec coast (again, the time is from the press kit, not from web cast measurements).

The press kit does say that they are approximate timings you would have to check the webcasts to see what the actual timing are. This flight will require a flip yes but because there is no boost back burn for this mission they aren't is so much of a rush to get it done perhaps?

As for Intelsat 35e perhaps flying expendable with that mission they ended up with more margin.

The other possibility is that it is a typo in the press Kit.

Offline Crispy

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Just realised the launch window opens at 3 minutes to sunset.
https://www.timeanddate.com/sun/usa/cape-canaveral
Should make for some beautiful launch footage and photos :)

Offline envy887

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Looks pretty clean for a used rocket.

Offline jpo234

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LD giving the abort instructions. 

If urgent, call "HOLD HOLD HOLD" over the net.

If non-urgent, brief the LD and a decision whether or not to abort will then be made.

Was this just an explanation of the abort procedure or was there an abort called?
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Offline Rebel44

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LD giving the abort instructions. 

If urgent, call "HOLD HOLD HOLD" over the net.

If non-urgent, brief the LD and a decision whether or not to abort will then be made.

Was this just an explanation of the abort procedure or was there an abort called?

Just an explanation

Offline gongora

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For all those who think SpaceX is waiting on payloads...

Quote
[SpaceflightNow] SES-11 Coverage

Halliwell said SES did not receive a significant financial discount from SpaceX in switching the SES 11/EchoStar 105 launch to a reused booster, but the agreement did result in an earlier launch date.
...
"We should have launched a year ago, Halliwell said. "We've been waiting for a launch for a long, long time."
...
Without taking the opportunity to fly on a reused rocket, Halliwell said it's likely the launch of SES 11/EchoStar 105 "would have been somewhat delayed because we would have had to wait for hardware to become available for us."

Offline Craig_VG

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Some interesting yellow beams added to the T/E

Offline mvpel

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I was wondering about those too. I wonder if it might be FH-related.
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Offline clegg78

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Back to using the aluminum grid fins?  I thought for high energy entries like this they would be using Ti for all of them.   These popped out much faster too so I am assuming block 3 mechanisms and such behind the fins?
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Offline clegg78

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Whoa that sucker was coming in HOT... never seen plasma come off the base like that!
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Offline jimbowman

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Scared me for a minute as well haha. All good.
« Last Edit: 10/11/2017 11:02 PM by jimbowman »

Online Jdeshetler

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Boy, it's time for Block 5 booster......

Offline clegg78

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That is amazing...  that sucker was burning up coming in and still nailed it!  I wonder how much of the gridfins were left?!
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Online Joffan

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Wow, I thought that SpaceX had overcooked that one. But yet another great landing.
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Offline whitelancer64

Some interesting yellow beams added to the T/E

Those held a strap for supporting the fairing for the X-37B launch. It may be used again for large or heavy payloads.
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Offline catdlr

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This mark's the first time two 1st stage Falcon's are on barges out on the ocean at the same time.
« Last Edit: 10/11/2017 11:04 PM by catdlr »
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Online clevelas

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I thought for sure they'd lost it when telemetry cut out.  Glad to see it on deck.

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