Author Topic: SpaceX CCtCAP Milestones  (Read 71754 times)

Offline Roy_H

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Re: SpaceX CCtCAP Milestones
« Reply #160 on: 01/20/2018 03:35 pm »
It's not a dualism.  They have found that LiAl tankage work great... indefinite number of flights possible per EM. 
No, I think it's confirmation bias.  When SpaceX makes changes to their system that drops flight heritage it's great vs NASA potentially forcing them to do the same for their missions is insane.  And I would make the same point to those who argue that SpaceX is reckless for making such changes but refuse to recognize NASA is potentially forcing it here.  Specifically to the issue of swapping COPVs, we don't know what sort of testing results SpaceX/NASA have been seeing.  Are failures predictable and ongoing performance well characterized with their current tanks/procedures?  Sure, they have been successful so far but is that success reliable?  Without knowing what they have been finding, it's hard to criticize NASA (who does know) for pushing for a change if they feel it is warranted.  To my mind, any gain from the switch would have to be pretty significant before I felt giving up the flight heritage was worth it.  Of course, SpaceX clearly feels differently and they certainly have seen the same results. 

Quote
Why doesn't NASA change from use of solid boosters because they once killed a crew of seven?

They did.  The design of the SRB joints was altered to eliminate the cause of the Challenger disaster.
I think you just confirmed the argument here. How is that different from SpaceX changing charging procedure or re-designing the COPV vs replacing with all metal? In one case you fix the problem, in the other you change the system. The analogy in the Shuttle case would be to change to liquid boosters.
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Offline AncientU

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Re: SpaceX CCtCAP Milestones
« Reply #161 on: 01/20/2018 05:36 pm »
Confirmation bias works both ways. 

Those who are status quo adherents cannot see anyone but NASA having knowledge about rocketry and human space flight.  I believe the opposite is true.  NASA has proven that they cannot build a rocket and that their management structure, 'processes', and pseudo-risk aversion are fundamentally flawed.  This is demonstrated by their incredibly bad management decisions that resulted in loss of crews and their inability to get their act together enough to fly anything.  They are dictating the rules because they have the checkbook.
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Offline Roy_H

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Re: SpaceX CCtCAP Milestones
« Reply #162 on: 01/20/2018 06:11 pm »
AncientU, overly harsh, but I do agree strongly with your statement " This is demonstrated by their incredibly bad management decisions that resulted in loss of crews". Aversion to repeat that mistake has resulted in ASAP's 1:270 LOM. I think this is an attempt to take political decision making out of the loop, and is a good thing.
"If we don't achieve re-usability, I will consider SpaceX to be a failure." - Elon Musk

Online envy887

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Re: SpaceX CCtCAP Milestones
« Reply #163 on: 01/22/2018 05:36 pm »
It's not a dualism.  They have found that LiAl tankage work great... indefinite number of flights possible per EM. 
No, I think it's confirmation bias.  When SpaceX makes changes to their system that drops flight heritage it's great vs NASA potentially forcing them to do the same for their missions is insane...

AIUI the alternative tank design is only needed if the COPVs can't be proven safe. If Block 5 flies 7 time before crewed flights, that would be around 150 stage and COPV fillings, which should prove it safe. The Amos-6 incident was a new fueling procedure that (AIUI) had never been flown and so was not proven safe.

Changing a known safe, performant design to something less proven, less performant, and possibly more expensive, would be crazy.

Offline Lar

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Re: SpaceX CCtCAP Milestones
« Reply #164 on: 01/22/2018 06:54 pm »
Changing a known safe, performant design to something less proven, less performant, and possibly more expensive, would be crazy.
Not if NASA does it or forces it. That makes it OK.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline AncientU

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Re: SpaceX CCtCAP Milestones
« Reply #165 on: 01/22/2018 09:00 pm »
AncientU, overly harsh, but I do agree strongly with your statement " This is demonstrated by their incredibly bad management decisions that resulted in loss of crews". Aversion to repeat that mistake has resulted in ASAP's 1:270 LOM. I think this is an attempt to take political decision making out of the loop, and is a good thing.

Shuttle had a LOM risk of about 1:90, yet it flew out its last years with ops procedural changes.
What was the LOM criterion for Ares 1?
What was the LOM risk for placing crew on EM-1 which was rejected because of insufficient funding (instead of out of hand because of safety)?
What is the LOM criterion for EM-2 flying cis-Lunar?
If they are all greater than or equal to 270:1, then that is likely a reasonable number.  (But they are not.)

The problem is that political decision making is not taken out of the loop. 
NASA gets a bye because of their 'expertise' -- which is a political conjuring.
"If we shared everything [we are working on] people would think we are insane!"
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Offline Jim

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Re: SpaceX CCtCAP Milestones
« Reply #166 on: 01/22/2018 11:15 pm »
Confirmation bias works both ways. 

Those who are status quo adherents cannot see anyone but NASA having knowledge about rocketry and human space flight.  I believe the opposite is true.  NASA has proven that they cannot build a rocket and that their management structure, 'processes', and pseudo-risk aversion are fundamentally flawed.  This is demonstrated by their incredibly bad management decisions that resulted in loss of crews and their inability to get their act together enough to fly anything.  They are dictating the rules because they have the checkbook.

Proof of the bias.  Much like a flat earther, it isn't based on reality. 

The problem is that you are biased and it permeates through out your posts.  Every post is has a predetermined slant.  You can not make any objective judgement about anything non Spacex related.
 



« Last Edit: 01/22/2018 11:31 pm by Lar »

Online QuantumG

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Re: SpaceX CCtCAP Milestones
« Reply #167 on: 01/22/2018 11:17 pm »
Actually, all opinions are welcome.

 8)
Human spaceflight is basically just LARPing now.

Offline speedevil

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Re: SpaceX CCtCAP Milestones
« Reply #168 on: 01/23/2018 02:02 am »
Actually, all opinions are welcome.

No they're not.

edit: To be clear, this was both a python reference, and that I like paradoxes.
« Last Edit: 01/23/2018 02:14 am by speedevil »

Offline Lar

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Re: SpaceX CCtCAP Milestones
« Reply #169 on: 01/23/2018 02:07 am »
all well reasoned opinions are, here. As long as presented collegially. Be excellent to each other.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline mlindner

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Re: SpaceX CCtCAP Milestones
« Reply #170 on: 01/23/2018 02:09 am »
Changing a known safe, performant design to something less proven, less performant, and possibly more expensive, would be crazy.
Not if NASA does it or forces it. That makes it OK.

Am I correct in assuming this is sarcasm?
Internal combustion engine in space. It's just a Bad Idea.TM - Robotbeat

Offline Roy_H

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Re: SpaceX CCtCAP Milestones
« Reply #171 on: 04/02/2018 03:08 pm »
"If we don't achieve re-usability, I will consider SpaceX to be a failure." - Elon Musk

Offline woods170

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Re: SpaceX CCtCAP Milestones
« Reply #172 on: 04/03/2018 08:22 am »
Changing a known safe, performant design to something less proven, less performant, and possibly more expensive, would be crazy.
Not if NASA does it or forces it. That makes it OK.

Am I correct in assuming this is sarcasm?

No, it is reality.

Offline Nomadd

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Re: SpaceX CCtCAP Milestones
« Reply #173 on: 04/03/2018 08:32 am »
Actually, all opinions are welcome.

No they're not.

T. J. Would be proud.
 There's a difference between welcome and allowed.
« Last Edit: 04/03/2018 08:51 am by Nomadd »
Those who danced were thought to be quite insane by those who couldn't hear the music.

Offline the_other_Doug

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Re: SpaceX CCtCAP Milestones
« Reply #174 on: 04/04/2018 04:38 pm »
March 26, 2018 update:
https://www.nasa.gov/sites/default/files/atoms/files/ccp_presentation_for_nac_public_session.pdf

I am confused by the following SpaceX milestone, listed for April of 2018:

Flt Test w/o
Crew CR Part 2


Is this just a critical review of the status of the DM-1 spacecraft and launch vehicle?

There aren't any actual flight tests of Dragon 2 equipment coming up, are there?  Or does this milestone refer to the first flight of the man-rated Block 5 version of the Falcon 9?  This chart, at least, makes no other reference to Block 5 development.
-Doug  (With my shield, not yet upon it)

Online deruch

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Re: SpaceX CCtCAP Milestones
« Reply #175 on: 04/05/2018 11:47 am »
March 26, 2018 update:
https://www.nasa.gov/sites/default/files/atoms/files/ccp_presentation_for_nac_public_session.pdf

I am confused by the following SpaceX milestone, listed for April of 2018:

Flt Test w/o
Crew CR Part 2


Is this just a critical review of the status of the DM-1 spacecraft and launch vehicle?

There aren't any actual flight tests of Dragon 2 equipment coming up, are there?  Or does this milestone refer to the first flight of the man-rated Block 5 version of the Falcon 9?  This chart, at least, makes no other reference to Block 5 development.

The important part of that milestone is the CR, which stands for Critical Review.  It's the big pre-launch review by all the teams (including NASA) on whether they are prepared and going to meet all the requirements for the DM-1 mission.  If you look to the right, the next milestone in that row is the actual launch, "Flt to ISS w/o Crew (Demo-1)".  And if you look to the left, the previous milestone in that same row is, "Flt Test w/o Crew CR Part 1" which was completed in December 2016.

What happened was that prior to the AMOS-6 mishap, they had planned a single Critical Review for DM-1 which would take place in Feb. 2017 (~3 months ahead of the launch which was planned for May 2017).  After the mishap they decided to split the milestone into 2 parts.  The first would contain the review of all the parts that were ready and wouldn't change in the aftermath of the mishap.  This review part was actually moved forward a few months and occurred before the original planned review date (December 2016 vs February 2017).  Everything else, all the Falcon 9 stuff and whatever wasn't finalized yet with Dragon, would get pushed to a review part at a later date.  You can see this happening by looking at the schedule slides from the CCP presentations to the NAC-HEO committee from the meeting prior to and after the mishap (NB: the meeting from November of 2016 [less than a month post mishap] didn't include such a slide, so I've attached the one from Feb. 2017).
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

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