Author Topic: SpaceX Falcon 9 : CRS-12 : Aug 14, 2017 : DISCUSSION  (Read 74884 times)

Online LouScheffer

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Whatever they changed did not include the final landing sequence.  It started at 4 km up, 300 m/s, and lasted 30 seconds, just like the last time, to within the precision of the webcast.

Online ChrisGebhardt

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That thing took off quick.... more thust?

Yep. New uprated engines, Block 4 booster. +11% thrust or thereabouts.

Is this speculation or was it confirmed that this was the first Block 4?

This was supposed to be the first block 4, but the grid fins were wrong and Hans said yesterday that nothing was really new with this booster.  So I'll check and see what I can find.

Offline Jarnis

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That thing took off quick.... more thust?

Yep. New uprated engines, Block 4 booster. +11% thrust or thereabouts.

Is this speculation or was it confirmed that this was the first Block 4?

Was quoted as "fact" from unnamed sources on Reddit prior to launch (implied it was from someone who knew someone who worked at SpaceX), but now that you question it, I haven't heard an official confirmation. I'm sure someone is already counting frames and figuring out if the rocket took off the pad any faster than previous ones...

Offline old_sellsword

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That thing took off quick.... more thust?

Yep. New uprated engines, Block 4 booster. +11% thrust or thereabouts.

Is this speculation or was it confirmed that this was the first Block 4?

Was quoted as "fact" from unnamed sources on Reddit prior to launch (implied it was from someone who knew someone who worked at SpaceX), but now that you question it, I haven't heard an official confirmation. I'm sure someone is already counting frames and figuring out if the rocket took off the pad any faster than previous ones...

The claims of the first Block 4 are well sourced. The claims of uprated thrust are complete speculation.
« Last Edit: 08/14/2017 06:29 PM by old_sellsword »

Offline Skylab

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There won't be any space left for this in the HIF, I guess, with the Heavy parts there and one F9 already stored outdoors. Is this going to be refurbished at LZ-1 or elsewhere?
« Last Edit: 08/14/2017 06:29 PM by Skylab »

Offline karanfildavut

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Since this is the final CRS mission awarded in the initial contract, can we do a final accounting on how much total cargo was lifted to the ISS under CRS1? Specifically I'm curious if the original terms (minimum 20 metric tons upmass to the station, including the CRS-7) were met or, if exceeded, by how much. The first couple flights under v1.0 and v1.1 were lighter due to booster restrictions, so they would have had to make up some mass in the later flights to meet the original contractual terms.

Edit:

I've used the wikipedia pages for the respective missions for the following total:

CRS-1: 905
CRS-2: 898
CRS-3: 2089
CRS-4: 2216
CRS-5: 2317
CRS-6: 2015
CRS-7: 2454 (failure)
CRS-8: 3136
CRS-9: 2257
CRS-10: 2490
CRS-11: 2708
CRS-12: 3310 2910
Total: ~26,400kg (~24,000 without CRS-7), although there is some contradictory data on wikipedia regarding pressurized and unpressurized payload so grain of salt on the total. Please let me know if you get a different number and I can update accordingly.

Edit 2: Fixed CRS-12
Edit 3: Spaceflight101 cites 23,800 kg under CRS1 to date. Link: http://spaceflight101.com/dragon-spx-12-arrives-at-space-station/
« Last Edit: 08/16/2017 06:02 PM by karanfildavut »

Offline russianhalo117

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Since this is the final CRS mission awarded in the initial contract, can we do a final accounting on how much total cargo was lifted to the ISS under CRS1? Specifically I'm curious if the original terms (minimum 20 metric tons upmass to the station, including the CRS-7) were met or, if exceeded, by how much. The first couple flights under v1.0 and v1.1 were lighter due to booster restrictions, so they would have had to make up some mass in the later flights to meet the original contractual terms.
yes under the original CRS-1 contract terms but not the exercised option to extend the number of flights under the contract.

Offline Nomadd

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Since this is the final CRS mission awarded in the initial contract, can we do a final accounting on how much total cargo was lifted to the ISS under CRS1? Specifically I'm curious if the original terms (minimum 20 metric tons upmass to the station, including the CRS-7) were met or, if exceeded, by how much. The first couple flights under v1.0 and v1.1 were lighter due to booster restrictions, so they would have had to make up some mass in the later flights to meet the original contractual terms.

Edit:

I've used the wikipedia pages for the respective missions for the following total:

CRS-1: 905
CRS-2: 898
CRS-3: 2089
CRS-4: 2216
CRS-5: 2317
CRS-6: 2015
CRS-7: 2454
CRS-8: 3136
CRS-9: 2257
CRS-10: 2490
CRS-11: 2708
CRS-12: 3310

Total: ~26,800kg, although there is some contradictory data on wikipedia regarding pressurized and unpressurized payload so grain of salt on the total. Please let me know if you get a different number and I can update accordingly.
Even without CRS-7, still 20% over the required. Not too bad. CRS-12 almost doubles the average that would have been needed if they'd all been equal.
« Last Edit: 08/14/2017 07:16 PM by Nomadd »

Online gongora

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Even without CRS-7, still 20% over the required. Not too bad. CRS-12 almost doubles the average that would have been needed if they'd all been equal.

There are various numbers floating around, it's hard to tell what was really expected.  In the June 2016 OIG report on the CRS-7 failure they give much higher numbers for the expected masses, but it's hard to tell if that's just what they ended up paying for and the 20k mT is still the contractual minimum.  The OIG report listed 35k for the targeted upmass.

Offline Norm38

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This was supposed to be the first block 4, but the grid fins were wrong...

Not necessarily "wrong".  Reuse hardware can be swapped around.  Legs can be swapped between cores, so can grid fins.  Elon said Titanium performance wasn't really needed for LEO missions.  So if they'd only built the one set of Ti fins and had AL lying around, sounds like a "use to depletion" type cutover to me.

Offline docmordrid

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The angle of attack coming in looks....impressive,
DM

Online Tulse

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I'm surprised that they'd put such lateral forces on one side of the stage.  Is there any play between the outer skin and the internal tanks?  Would this risk flexing the tanks?

Online envy887

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I'm surprised that they'd put such lateral forces on one side of the stage.  Is there any play between the outer skin and the internal tanks?  Would this risk flexing the tanks?

There are no internal tanks. Skin and tank are the same thing.

Online Kansan52

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Broadside slows it quicker.

Online vandersons

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There is no outer skin on Falcon 9. The tank walls make up most of what you see of the rocket. With the exception of the interstage and some covers for the octaweb.

Would any modern rocket actually have an outer skin covering the tank walls?

Online Lars-J

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There is no outer skin on Falcon 9. The tank walls make up most of what you see of the rocket. With the exception of the interstage and some covers for the octaweb.

Would any modern rocket actually have an outer skin covering the tank walls?

Usually there is no external *structural* layer, but many rockets do have layers of insulation outside the tank. (for example Delta IV)

Online Lars-J

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I'm surprised that they'd put such lateral forces on one side of the stage.  Is there any play between the outer skin and the internal tanks?  Would this risk flexing the tanks?

Yes, if done excessively, but they do it within acceptable parameters. Gliding sideways (very slightly) is what allows the stage to pinpoint the landing. Think of the grid fins as tail fins, and the main cylinder body as the wing. The grid fins themselves provide very little 'lift', they are just methods to aim the body to generate lift in specific directions.

But that angle is a bit deceptive, the extreme telephoto lens makes it look like a larger angle than it is.
« Last Edit: 08/14/2017 09:16 PM by Lars-J »

Online FutureSpaceTourist

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Cropped version of SoaceX landing photo. I know the side on angle isn't great, but to me it looks mainly like dirt (sand?) on the pad, the pad paint job seems to have held up pretty well?
« Last Edit: 08/15/2017 04:00 AM by FutureSpaceTourist »

Offline JAFO

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yeah thought it was going to tumble but no. Interesting that they are trying to get some lift from the stage on the way in.

The view of the first stage changing angle of attack as it came in was hair raising!

Matthew

The ultimate in post-stall maneuvering?




(The Great Firewall was breeched for a few minutes, I'm frantically downloading all the videos I can.)
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Offline Stan-1967

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But that angle is a bit deceptive, the extreme telephoto lens makes it look like a larger angle than it is.

To me, it was more the separation of the vapor/exhaust contrail from the S1 cylinder body than the photo angle that made the angle of attack look extreme.   I've watched over & over how the entry burn is straight into the velocity vector of the stage, & today's video coverage shows a pretty significant attitude change within a few seconds of the entry burn shutdown.

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