Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 3  (Read 86791 times)

Offline Chris Bergin

Third thread for Dragon 2 updates.

Thread 1:
https://forum.nasaspaceflight.com/index.php?topic=35381.0

Thread 2:
https://forum.nasaspaceflight.com/index.php?topic=41016.0

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News Articles:
https://www.nasaspaceflight.com/?s=%22Dragon+2%22

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Stay on topic and always be civil. These threads are very, very active so remember you're not just talking to other posters, but many thousands who are reading the posts.

Second thread wandered twice. This thread will start and continue to be specific on Dragon 2. Posts that are not will be deleted to avoid thread being derailed.

Offline A12

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1 on: 08/07/2018 10:04 AM »
Probably already asked  multiple Times, of so, please point me to the right thread/message

I read the upcoming cargo flights will be flown with D2.

What about the different size of  berthing passage when compared to the smaller docking one ?

Will be largest cargo moved to Cygnus ?

Offline MATTBLAK

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #2 on: 08/07/2018 10:28 AM »
Will the unmanned test flight of Crew Dragon be carrying cargo? And what is happening to the Dragon 1 spacecraft/hulls: how many times can they be or have been used?
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Offline rpapo

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #3 on: 08/07/2018 10:30 AM »
Will the unmanned test flight of Crew Dragon be carrying cargo? And what is happening to the Dragon 1 spacecraft/hulls: how many times can they be or have been used?
It's already been stated around here that the D1 hulls were intended to be used up to three times.
An Apollo fanboy . . . fifty years ago.

Offline MATTBLAK

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #4 on: 08/07/2018 10:37 AM »
Thank you, it's appreciated; I never saw that. Even I can't read every thread and every post.
"Those who can't, Blog".   'Space Cadets' of the World - Let us UNITE!! (crickets chirping)

Offline Elmar Moelzer

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #5 on: 08/07/2018 01:29 PM »
Will the unmanned test flight of Crew Dragon be carrying cargo? And what is happening to the Dragon 1 spacecraft/hulls: how many times can they be or have been used?
It's already been stated around here that the D1 hulls were intended to be used up to three times.
I must have missed that too. Where does the 3 times come from? From all I remembered they wanted to reuse them a lot more often.

Offline Alexphysics

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #6 on: 08/07/2018 01:43 PM »
Jessica Jensen was been asked about that on the previous CRS missions and she has always said that Dragon 1 is rated for at least 3 reuses. Dragon 2 is supposed to be rated for more reuses but not for crew use yet, it's not on NASA's plans yet.

Offline rpapo

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #7 on: 08/07/2018 01:49 PM »
Jessica Jensen was been asked about that on the previous CRS missions and she has always said that Dragon 1 is rated for at least 3 reuses. Dragon 2 is supposed to be rated for more reuses but not for crew use yet, it's not on NASA's plans yet.
Thanks for answering that.  This site's search facility is a real pain to work with, and I couldn't find the reference I was looking for, which I could have sworn was in the past 2-3 days, and was related to the recent recovery of CRS-15.
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Offline cscott

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #8 on: 08/07/2018 02:05 PM »
To be pedantic, I think the Dragon 1 is *certified* for three flights.  That's the number NASA has agreed to at this time.  That's different from "rated" (the number of flights Dragon 1 was *designed* for) or the # SpaceX thinks might be possible, etc.

When this question has come up the SpaceX side has seemed to leave it open as to whether they might go back to NASA and try to get a higher # of flights certified in the future.  I think like with Block 4 there's a certain amount of compromise here: as long as NASA is willing to buy brand new capsules, SpaceX gets to retire some of their older hardware and standardize on newer revisions.  There might be renewed certification action once SpaceX gets to the point where they want to shut down or downsize their Dragon 1 production line.  Then again, they might prefer at that point just to shift everything to Dragon 2 and retire the remaining Dragon 1 hulls.

Long way of saying *at this point* Dragon 1 is certified for three flights.

Offline yg1968

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #9 on: 08/07/2018 03:16 PM »
Probably already asked  multiple Times, of so, please point me to the right thread/message

I read the upcoming cargo flights will be flown with D2.

What about the different size of  berthing passage when compared to the smaller docking one ?

Will be largest cargo moved to Cygnus ?

There will be Dragon1 missions until Spx-20.

I recall SpaceX or NASA saying that most cargo can be divided into smaller bags or containers, etc., so the fact that cargo D2 will dock (and not berth) isn't much of an issue.  Incidentally, I think that DC will initially berth (even though it it is also able to dock). So 2 out of 3 spacecrafts for CRS2 will initially berth.
« Last Edit: 08/07/2018 03:50 PM by yg1968 »

Offline FutureSpaceTourist

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #10 on: 08/08/2018 11:42 PM »
Another good Eric Berger article, this one describing the work left for SpaceX to do for CC:

Quote
Here’s what SpaceX must do to win the commercial crew race
Demo test, abort test, finish COPVs, test fuel loading, and so on. It's a long list.

ERIC BERGER - 8/9/2018, 7:59 AM

https://arstechnica.com/science/2018/08/heres-what-spacex-must-do-to-win-the-commercial-crew-race/

Edit to add: article includes status of Demo 1 hardware

Quote
Lueders said the Block V variant of the Falcon 9 rocket first stage, as well as its upper stage, will soon ship from SpaceX’s factory in Hawthorne, California, to the company’s facilities in McGregor, Texas, for engine testing. Afterward, the rocket is scheduled to arrive at Florida’s Cape Canaveral in September. The company has also delivered the spacecraft to Florida, but they still need to finish the Dragon’s trunk for the mission and ship that.
« Last Edit: 08/08/2018 11:46 PM by FutureSpaceTourist »

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #11 on: 08/09/2018 12:46 PM »
Another good Eric Berger article, this one describing the work left for SpaceX to do for CC:

Quote
Here’s what SpaceX must do to win the commercial crew race
Demo test, abort test, finish COPVs, test fuel loading, and so on. It's a long list.

ERIC BERGER - 8/9/2018, 7:59 AM

https://arstechnica.com/science/2018/08/heres-what-spacex-must-do-to-win-the-commercial-crew-race/

Edit to add: article includes status of Demo 1 hardware

Quote
Lueders said the Block V variant of the Falcon 9 rocket first stage, as well as its upper stage, will soon ship from SpaceX’s factory in Hawthorne, California, to the company’s facilities in McGregor, Texas, for engine testing. Afterward, the rocket is scheduled to arrive at Florida’s Cape Canaveral in September. The company has also delivered the spacecraft to Florida, but they still need to finish the Dragon’s trunk for the mission and ship that.

The quote about getting the trunk ready refers to installation of the conformal solar arrays and other (minor) work.

Offline TripleSeven

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #12 on: 08/09/2018 05:57 PM »
" … to Win the Commercial Crew Race".  Ughhh.  This is not a "race", and I hope that the contractors don't see it that way.  The first to orbit is not the "winner".  (Indeed, "racing" to orbit might produce the opposite result.)   

Kudo's will come to the first - it's only natural. And personally I'm rooting for both.

That said, a year after the second Commercial Crew provider is operational pretty much everyone will forget who flew first since we'll be focused on who is flying next.

I dont agree with that

whoever flies first will have the place in the history books, and whoever flies second will be just a note. 

it will be compared to the wright brothers in so so many ways. 

Edward Vernon Rickenbacker, Captain Eddie once said "Aviation is the proof that we have the capacity to carry out the impossible"

whoever goes first will be the first space spectacular that will "mark a date" that I believe will live in history

since Armstrong. 

It is a race.  Boeing just lost it.  they have come back from losing before obviously, but no one will remember when they do it

Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #13 on: 08/09/2018 06:20 PM »
Quote
The NASA manager overseeing development of Boeing and SpaceX’s commercial crew ferry ships says the space agency has approved SpaceX’s proposal to strap in astronauts atop Falcon 9 rockets, then fuel the launchers in the final hour of the countdown as the company does for its uncrewed missions.

https://spaceflightnow.com/2018/08/09/nasa-signs-off-on-spacexs-load-and-go-procedure-for-crew-launches/

Offline Brovane

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #14 on: 08/09/2018 07:12 PM »
From the above linked article. 

Quote
On some more demanding launches, the lost lift capacity from warmed propellant would prevent the Falcon 9 from satisfying mission requirements.

What Commercial Crew mission requirement would require this much payload to the ISS for the F9?  I would have thought that using warmed propellant would cause about a 20-30% drop in performance which would require the F9 to perform a barge landing instead of RTLS recovery for the booster. 
"Look at that! If anybody ever said, "you'll be sitting in a spacecraft naked with a 134-pound backpack on your knees charging it", I'd have said "Aw, get serious". - John Young - Apollo-16

Offline gongora

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #15 on: 08/09/2018 07:17 PM »
From the above linked article. 

Quote
On some more demanding launches, the lost lift capacity from warmed propellant would prevent the Falcon 9 from satisfying mission requirements.

What Commercial Crew mission requirement would require this much payload to the ISS for the F9?  I would have thought that using warmed propellant would cause about a 20-30% drop in performance which would require the F9 to perform a barge landing instead of RTLS recovery for the booster.

I didn't read that as necessarily referring to Commercial Crew missions, I thought he was just talking about Falcon 9 missions in general.

Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #16 on: 08/09/2018 07:24 PM »
From the above linked article. 

Quote
On some more demanding launches, the lost lift capacity from warmed propellant would prevent the Falcon 9 from satisfying mission requirements.

What Commercial Crew mission requirement would require this much payload to the ISS for the F9?  I would have thought that using warmed propellant would cause about a 20-30% drop in performance which would require the F9 to perform a barge landing instead of RTLS recovery for the booster.

I didn't read that as necessarily referring to Commercial Crew missions, I thought he was just talking about Falcon 9 missions in general.

Precisely. CC missions are within the performance range of F9 with boiling props. However using boiling props requires modifications to the GSE, the vehicle, and the pre-launch procedures, just for crew flights.

Online LouScheffer

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #17 on: 08/09/2018 07:33 PM »
From the above linked article. 

Quote
On some more demanding launches, the lost lift capacity from warmed propellant would prevent the Falcon 9 from satisfying mission requirements.

What Commercial Crew mission requirement would require this much payload to the ISS for the F9?  I would have thought that using warmed propellant would cause about a 20-30% drop in performance which would require the F9 to perform a barge landing instead of RTLS recovery for the booster. 
It does not need to be Commercial crew missions that need the performance.   You need to factor in that they want the same procedures in all launches, so they can use as many launches as possible to expand the experience base.  NASA typically wants at least N launches, done the same way, before letting people fly.  If they use a different. lower performance, procedure for crewed flight, then many of the prior missions that need full performance (such as almost all GTO missions) can't be used to satisfy this requirement.  This would at best delay certification, and at worst be less safe, since they would be using less-tested procedures.

Offline Brovane

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #18 on: 08/09/2018 07:45 PM »
From the above linked article. 

Quote
On some more demanding launches, the lost lift capacity from warmed propellant would prevent the Falcon 9 from satisfying mission requirements.

What Commercial Crew mission requirement would require this much payload to the ISS for the F9?  I would have thought that using warmed propellant would cause about a 20-30% drop in performance which would require the F9 to perform a barge landing instead of RTLS recovery for the booster.

I didn't read that as necessarily referring to Commercial Crew missions, I thought he was just talking about Falcon 9 missions in general.

I sure which the article would have called this out a little clearer. 

Some people could read it as that NASA agreed to the loading change because, without it the F9 couldn't satisfy all the Commercial Crew mission requirements. 
"Look at that! If anybody ever said, "you'll be sitting in a spacecraft naked with a 134-pound backpack on your knees charging it", I'd have said "Aw, get serious". - John Young - Apollo-16

Offline Thorny

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #19 on: 08/09/2018 07:59 PM »
Precisely. CC missions are within the performance range of F9 with boiling props. However using boiling props requires modifications to the GSE, the vehicle, and the pre-launch procedures, just for crew flights.

Is this ever going to be an issue with ISS missions? Aren't the launch windows instantaneous?

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