Author Topic: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION  (Read 144978 times)

Offline Comga

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #20 on: 03/16/2017 09:52 PM »
I can't believe that ROSA array fits in the trunk.  Going by the people in the picture as 2m, the array is more than 4m wide, which is greater than the trunk dimensions.  Does it tri-fold or something?

I looked for a deployment video and only found this: 

Is this array used to provide extra power to the station?  If not, what is the load?  Also, the press release says the experiment only runs 7 days.  What happens to the array after that?  It can't be rolled up and put back in the trunk.  Does it remain at ISS permanently? 

A wiseguy might ask what part of "Roll-Out" is hard to understand?
A serious person would say yes, it rolls out to much wider than it's packaged dimensions.
According to the video, all eight rolls on each side start in one plane.  They fold out into two stepped lines and then spread.
Who says it can't be rolled up?  We don't see the mechanisms, but they do plan to roll it back up.
The fifth goal is listed as "Characterize retraction loads and kinematics."
It talks about determining power generation, but not delivering power to the ISS.  It probably has a dummy load.
It has it's own thread.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Norm38

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #21 on: 03/17/2017 02:56 PM »
Thanks for the link to the dedicated thread.  I'll take array specific questions there.
The video I linked isn't this exact array, so don't go by that, this is a single roll.

My question on how this fits in the trunk is still on topic.  Yes the array rolls up along the long axis, but nothing shows it folding along the short axis, and the length of the short axis seems to be longer than the trunk can hold.  Is it going in at an angle?

Offline gongora

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #22 on: 03/17/2017 03:28 PM »
Thanks for the link to the dedicated thread.  I'll take array specific questions there.
The video I linked isn't this exact array, so don't go by that, this is a single roll.

My question on how this fits in the trunk is still on topic.  Yes the array rolls up along the long axis, but nothing shows it folding along the short axis, and the length of the short axis seems to be longer than the trunk can hold.  Is it going in at an angle?

The picture I included in the second post of the thread may not actually be ROSA.  After looking at their site again, ROSA may be the one shown in the middle row of this picture being deployed.  That looks a lot smaller.  This is one of several payloads that have to go into the trunk on standard payload adapters so I doubt anything will be stuck in there at an angle.

edit:  They have several sizes on their site that seem to be labeled ROSA, they seem to be using it as a more general term for their rolled solar arrays, and not necessarily just for the one in this experiment.  I really don't know what size they're sending up, but I think we can assume it's a size that will easily fit in the trunk with the other payloads.
« Last Edit: 03/17/2017 03:36 PM by gongora »

Offline FutureSpaceTourist

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #23 on: 03/28/2017 03:29 PM »
Quote
Jeff Foust‏ @jeff_foust 26s27 seconds ago

NASAís Paul Hertz says at Natíl Academies meeting that NICER payload to ISS set to launch May 14 on SpX-11 Dragon mission.

https://twitter.com/jeff_foust/status/846745556559036420

Offline psloss

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #24 on: 03/28/2017 04:53 PM »
Quote
Jeff Foust‏ @jeff_foust 26s27 seconds ago

NASAís Paul Hertz says at Natíl Academies meeting that NICER payload to ISS set to launch May 14 on SpX-11 Dragon mission.

https://twitter.com/jeff_foust/status/846745556559036420
Corroborated in the NAC HEO ISS status presentation, some time in May.
« Last Edit: 03/28/2017 05:12 PM by psloss »

Offline Lars-J

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #25 on: 03/28/2017 05:09 PM »
https://twitter.com/jeff_foust/status/846766790919245827

Quote
Jeff Foust @jeff_foust
Gatens: SpX-11 mission to the ISS in May will be the first to re-fly a Dragon capsule.

Offline psloss

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #26 on: 03/28/2017 05:12 PM »

Offline Lars-J

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #27 on: 03/28/2017 05:16 PM »
So, this might use another "flight proven" F9? ("SpaceX is determining which launch vehicle to assign to this mission")
« Last Edit: 03/28/2017 05:17 PM by Lars-J »

Offline KaiFarrimond

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #28 on: 03/28/2017 05:18 PM »


"SpaceX is determining which launch vehicle to assign for this mission"????
Of Course I Still Love You; We Have A Falcon 9 Onboard!

Online ugordan

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #29 on: 03/28/2017 05:19 PM »
So, this might use another "flight proven" F9? ("SpaceX is determining which launch vehicle to assign to this mission")

I don't read it that way at all (hasn't NASA publicly opted for a wait-n-see approach to booster reuse?). I read it as determining which of the new boosters in the production pipeline (i.e. serial numbers) will end up being assigned for this flight.
« Last Edit: 03/28/2017 05:19 PM by ugordan »

Offline Coastal Ron

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #30 on: 03/28/2017 05:26 PM »
So, this might use another "flight proven" F9? ("SpaceX is determining which launch vehicle to assign to this mission")

I don't read it that way at all (hasn't NASA publicly opted for a wait-n-see approach to booster reuse?). I read it as determining which of the new boosters in the production pipeline (i.e. serial numbers) will end up being assigned for this flight.

Maybe.  But NASA doesn't care what the serial number of a new booster is (and they don't get a say as to which one is assigned to them), and new Falcon 9 boosters are all the same.

I would not eliminate the possibility that a previously flown stage is under consideration...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Online ugordan

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #31 on: 03/28/2017 05:30 PM »
But NASA doesn't care what the serial number of a new booster is

I really wouldn't go that far... They very likely have insight into the processing flow of hardware assigned for their mission. Doesn't mean they get to pick the hardware, nor did I ever say that. Other than the contract expecting new boosters. The CRS-10 press conference was pretty clear about using flown boosters, IIRC.
« Last Edit: 03/28/2017 05:36 PM by ugordan »

Offline mn

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #32 on: 03/28/2017 05:38 PM »
But NASA doesn't care what the serial number of a new booster is

I really wouldn't go that far... They very likely have insight into the processing flow of hardware assigned for their mission. Doesn't mean they get to pick the hardware, nor did I ever say that.

Does anyone really think that if hypothetically NASA requested a specific core that SpaceX would say NO?

It might not be in the contract, but they are a big enough customer that I suspect they get to pick and choose to their hearts content.

Offline Sesquipedalian

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #33 on: 03/28/2017 05:56 PM »
and new Falcon 9 boosters are all the same.

We can't assume this.  At last report, SpaceX hadn't yet flown a Block 4 or Block 5 booster.

Offline ChrisGebhardt

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #34 on: 03/28/2017 06:51 PM »
But NASA doesn't care what the serial number of a new booster is

... Other than the contract expecting new boosters. The CRS-10 press conference was pretty clear about using flown boosters, IIRC.

That might be changing.  ;)

(Not for CRS-11, but in general.)
« Last Edit: 03/28/2017 06:54 PM by ChrisGebhardt »

Offline Coastal Ron

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #35 on: 03/28/2017 07:28 PM »
and new Falcon 9 boosters are all the same.

We can't assume this.  At last report, SpaceX hadn't yet flown a Block 4 or Block 5 booster.

Customers buy transportation services, not launch vehicles.  So from that standpoint stages are interchangeable.

However, I would agree that some customers may require certifications for configuration changes (i.e. block upgrades) that others don't, and that would affect which stages are available to be assigned to a launch.  But regardless, unless the customer pays SpaceX to have the ability to choose which stage they want, they are going to get whatever SpaceX decides on using.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Sesquipedalian

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #36 on: 03/28/2017 09:11 PM »
and new Falcon 9 boosters are all the same.

We can't assume this.  At last report, SpaceX hadn't yet flown a Block 4 or Block 5 booster.

Customers buy transportation services, not launch vehicles.  So from that standpoint stages are interchangeable.

The quote was "SpaceX is determining which launch vehicle to assign to this mission".  SpaceX is not the customer.

Offline vanoord

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #37 on: 03/29/2017 08:19 AM »
Looking at the update sheet it looks like someone decided they needed to put information about the launch vehicle to fill the space. Should it be taken as 100% fact?

Presumably the choice of S1 booster is made some time out but *could be* subject to change if the order of flights changes.

There are potentially two new cores due to be flown before CRS-11 (NROL-76 and Inmarsat-5 F4), but if there are slips with launches and a need to get CRS-11 aloft, there would be an option for CRS-11 to be brought forward and use the booster that's currently pencilled in for Inmarsat-5?

Online Mike_1179

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #38 on: 03/29/2017 01:54 PM »
and new Falcon 9 boosters are all the same.


I remember that shuttle missions would choose  SSMEs that were "hotter" for missions that were heavier. Engine performance is characterized during qualification, while the design spec might be an ISP or thrust of some value, the actual performance of an individual engine will be near that but not exact. For really heavy shuttle flights (STS-117 comes to mind - speckled tank!) I thought they picked out engines that were able to give a little more assurance of success, especially in the event of an early engine shutdown.

I'm curious as to how SpaceX handles differences in engine performance. With 9 engines (FH will be even more complicated) do you need to balance a mix of engines around a central value of performance or do you save really high performing engines for flights that would benefit from it.
« Last Edit: 03/29/2017 01:55 PM by Mike_1179 »

Online abaddon

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Re: SpaceX Falcon 9 : CRS-11 : June 3, 2017 : DISCUSSION
« Reply #39 on: 03/29/2017 02:06 PM »
I'm curious as to how SpaceX handles differences in engine performance. With 9 engines (FH will be even more complicated) do you need to balance a mix of engines around a central value of performance or do you save really high performing engines for flights that would benefit from it.
I don't think liquid engines are the same in this regard as SRMs.  The performance characteristics don't vary as much and engine performance is constrained by the rate of flow of fuel/oxidizer to the engines.  SRMs just light off and go, so there is no ability to control the rate of burn dynamically once the motor is cast.

In any case, no Merlin-1D has yet flown with the full qualified thrust, that will come with Block 5 (or the ever-mysterious Block 4 perhaps).  I would expect that all engines at that point will be able to perform to that level and will not be run "hotter".

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