Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 3  (Read 126246 times)

Offline envy887

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #20 on: 08/09/2018 08:27 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?

It's not an issue.

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #21 on: 08/09/2018 08:47 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/
OK,  so NASA signed off on load-n-go. And ASAP is OK with it as well. Another "shuttle didn't do it this way "-argument down the drain. Good.
« Last Edit: 08/09/2018 08:48 PM by woods170 »

Online DigitalMan

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #22 on: 08/09/2018 09:11 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/
OK,  so NASA signed off on load-n-go. And ASAP is OK with it as well. Another "shuttle didn't do it this way "-argument down the drain. Good.

Interesting that there was a comment about safety for ground crew being taken into consideration.  There was a lot of discussion on that and I don't mean to imply that the consideration held any value.
« Last Edit: 08/09/2018 09:12 PM by DigitalMan »

Offline Patchouli

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #23 on: 08/10/2018 12:56 AM »
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. 

There probably would be much less of a loss of performance running stainless steel helium tanks on the crewed variant of F9 Block 5 and they would not have to certify running Merlin 1D on the warmer propellants.
« Last Edit: 08/10/2018 12:57 AM by Patchouli »

Offline Lar

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #24 on: 08/10/2018 03:49 AM »
(mod) A lot of back and forth and sniping about this race topic which is not all this thread about.. let's try to be more collegial shall we?
"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
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Offline Roy_H

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #25 on: 08/10/2018 09:05 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. 

There probably would be much less of a loss of performance running stainless steel helium tanks on the crewed variant of F9 Block 5 and they would not have to certify running Merlin 1D on the warmer propellants.

There is no plan to use warmed propellants.

"If we don't achieve re-usability, I will consider SpaceX to be a failure." - Elon Musk

Offline pospa

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #26 on: 08/11/2018 05:56 PM »
Released three more pics from CD training mockup interior, taken on Aug 2 in JSC.
Two central seats evidently tilted down on leg side, missing seat belts, handles or hand rails, camera holders, etc. Some temporary black squere bars supporting side seats... I of couse love this spacious and clean interior very much, but a bit of fine tuning / outfitting is still pending, I suppose.

Also I wonder whether "pilot(s)" will have some emergency buttons/joystick directly on the arm rest of their seats or will hold something in their hand as in Soyuz comander has now days. Some unexpected g-loads & vibrations might cause difficulty to rise their hand(s) up to the dash board and press or pull anything there.
« Last Edit: 08/11/2018 07:06 PM by pospa »

Offline John Alan

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #27 on: 08/11/2018 07:28 PM »
Also I wonder whether "pilot(s)" will have some emergency buttons/joystick directly on the arm rest of their seats or will hold something in their hand as in Soyuz comander has now days. Some unexpected g-loads & vibrations might cause difficulty to rise their hand(s) up to the dash board and press or pull anything there.

Why?
This notion that the humans aboard will know better then the network of sensors and computers really in control of the flight, is silly in a 2018 new build design...

The Abort button is only there to make the humans feel like they have control...

Reality is, IF the need to abort comes up... the system will just do so LONG before the neurons in the helmets will have fired enough times to figure it out...

The Humans are cargo... period...
And the system is designed to protect that cargo and deliver it unharmed without any of their 'help'.
My 2 cents...  ;)
« Last Edit: 08/11/2018 07:44 PM by John Alan »

Offline tyrred

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #28 on: 08/11/2018 07:39 PM »
Also I wonder whether "pilot(s)" will have some emergency buttons/joystick directly on the arm rest of their seats or will hold something in their hand as in Soyuz comander has now days. Some unexpected g-loads & vibrations might cause difficulty to rise their hand(s) up to the dash board and press or pull anything there.

Why?
This notion that the humans aboard will know better then the network of sensors and computers really in control of the flight, is silly in 2018...

The Abort button is only there to make the humans feel like they have control...

Reality is, IF the need to abort comes up... the system will just do so LONG before the neurons in the helmets will have fired enough times to figure it out...

The Humans are cargo... period...
My 2 cents...  ;)

The reality is, there is a control console that will be functional.  The controls need to be reachable by human hands or extensible tools, even under g-loads.  Redundancy is necessary. 

Yes, the missions will be programmed to fly autonomously, but it would be naive and foolhardy to relinquish all vestiges of control to automatic systems.

Offline Tomness

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #29 on: 08/11/2018 07:40 PM »
Looks like the Trainer & mock up getting closer to fidelity.

Offline pospa

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #30 on: 08/11/2018 07:49 PM »
Also I wonder whether "pilot(s)" will have some emergency buttons/joystick directly on the arm rest of their seats or will hold something in their hand as in Soyuz comander has now days. Some unexpected g-loads & vibrations might cause difficulty to rise their hand(s) up to the dash board and press or pull anything there.

Why?
This notion that the humans aboard will know better then the network of sensors and computers really in control of the flight, is silly in 2018...

The Abort button is only there to make the humans feel like they have control...

Reality is, IF the need to abort comes up... the system will just do so LONG before the neurons in the helmets will have fired enough times to figure it out...

The Humans are cargo... period...
My 2 cents...  ;)

The reality is, there is a control console that will be functional.  The controls need to be reachable by human hands or extensible tools, even under g-loads.  Redundancy is necessary. 

Yes, the missions will be programmed to fly autonomously, but it would be naive and foolhardy to relinquish all vestiges of control to automatic systems.
Exactly!  Those override buttons are not just pointless praise to the gods.

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #31 on: 08/11/2018 08:02 PM »
Released three more pics from CD training mockup interior, taken on Aug 2 in JSC.
Two central seats evidently tilted down on leg side, missing seat belts, handles or hand rails, camera holders, etc. Some temporary black squere bars supporting side seats... I of couse love this spacious and clean interior very much, but a bit of fine tuning / outfitting is still pending, I suppose.
What handles and hand-rails? They aren't needed. People in 1G can get in-and-out just fine with what you see in the photos. And you don't need handles in zero-G. The cabin is so small that a wall, ceiling, floor or seat is always within arms-reach of an astronaut.

I suggest you review on-board ISS footage. Notice the hand-rails in the modules? Now notice how often they are used by crew.

They mostly aren't.

The crew moves around by ever so slightly pushing off from (with feet and hands) whatever surface they have under reach.
Same will be case on-board Crew Dragon.

Camera holders?
Those aren't needed either. When an astro needs a camera he gets it from the designated locker. When there is a need to temporarily stowe it the astro will just simply velcro it to a wall. Because that is just about the only things missing from the images: there will be a bunch of velcro pads all over the walls. No netting, no elastic cords. None of the clutter and chaos you find aboard the USOS modules of the ISS.
Because it isn't needed. You don't need to stick countless objects on the walls of a vehicle when the crew spends less than 3 days in that vehicle (two days from launch to ISS docking and less than one day from undocking to splash-down).

If I may make a suggestion: stop assuming that the Crew Dragon interior should look like the interior of Apollo / Shuttle / ISS.

Also I wonder whether "pilot(s)" will have some emergency buttons/joystick directly on the arm rest of their seats or will hold something in their hand as in Soyuz comander has now days. Some unexpected g-loads & vibrations might cause difficulty to rise their hand(s) up to the dash board and press or pull anything there.

Again: stop thinking Apollo / Shuttle / Soyuz.
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.
If a comsat can get to orbit fully autonomously on a regular F9 than why should Crew Dragon be different? By the time the crew finally realizes something is wrong with the rocket the computer has already executed the proper abort mode. Computers far out-perform humans in this regard. Why do you think ranges are switching over to AFTS for example?

The only manual intervention modes available are on-orbit, when you are not hampered by high G-loads. Like manually intervening in the approach to ISS or manually intervening in the final phases of docking. That why there are controls for the RCS engines. There is also an option to do a manual de-orbit. But the descent phase itself, including entry and the parachute stages is again fully autonomous.
« Last Edit: 08/11/2018 08:06 PM by woods170 »

Offline John Alan

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #32 on: 08/11/2018 08:10 PM »
No... those buttons were added to appease the people paying the bills and their employees...
Humans don't like feeling out of control of their destiny...
Cars with no steering wheels frighten many of the population... But they are coming...
https://www.npr.org/sections/thetwo-way/2018/01/12/577688125/gm-says-car-with-no-steering-wheel-or-pedals-ready-for-streets-in-2019

My guess is these buttons shown above will NEVER be used...
* IMG_2521.JPG
Just my 2 cents on subtopic...  ;)
« Last Edit: 08/11/2018 08:13 PM by John Alan »

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #33 on: 08/11/2018 08:11 PM »
Looks like the Trainer & mock up getting closer to fidelity.
Correct. And please note the seat belts in the mockup (bottom image) coming though the slots in the back and sides of the seats.
The seat belts can be added and removed from the crew training mockup. They just happen to be not installed for the recent photo-op.

Below is an image from last May this year showing Suni in the same Crew Trainer. At that time the seat belts were in fact installed.
« Last Edit: 08/13/2018 12:27 PM by woods170 »

Offline pospa

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #34 on: 08/11/2018 08:24 PM »
Woods, it seems to me you have some kind of allergic reaction to my posts.  :)
Calm down, please.
I will belive your words only at the time when SpX release photos of fully finished DM-2 spacecraft interior (Q1-2019).
Until then I will freely express my own assumptions, guesses and speculations as is very usual on this forum. Sorry.
« Last Edit: 08/11/2018 09:11 PM by pospa »

Offline su27k

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #35 on: 08/12/2018 04:09 AM »
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.

Are you sure? I believe CCT-REQ-1130 requires crew to have the ability to manually trigger ascent abort, or manually turn off auto abort.

Offline Roy_H

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #36 on: 08/12/2018 04:39 AM »
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.

Are you sure? I believe CCT-REQ-1130 requires crew to have the ability to manually trigger ascent abort, or manually turn off auto abort.

I would call that fully automated with over-ride capability.
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Offline jbenton

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #37 on: 08/12/2018 04:47 AM »
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.

Are you sure? I believe CCT-REQ-1130 requires crew to have the ability to manually trigger ascent abort, or manually turn off auto abort.

I would call that fully automated with over-ride capability.

Sounds like there's no disagreement then, just two different ways to say the same thing.

Offline woods170

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #38 on: 08/12/2018 07:53 PM »
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.

Are you sure? I believe CCT-REQ-1130 requires crew to have the ability to manually trigger ascent abort, or manually turn off auto abort.
I said switches, joysticks and handles. None of that stuff is on Crew Dragon. A touchpad is however. And yes, the manual over-ride option for ascent abort is there, but the odds of it being used is extremely low because the computer is way quicker and monitoring a helluvalot more system- and performance parameters than are being presented to the crew on the main display. The option is there because of a NASA requirement with a likelihood of being used  equal to zero.

Manually turning off auto abort is only applicable BEFORE an abort is triggered. It cannot be used to terminate an abort option that is in the process of being executed. The option was added because NASA considered that there could be a very unlikely repeat of an Apollo 14 scenario.
« Last Edit: 08/13/2018 12:28 PM by woods170 »

Offline jbenton

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Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #39 on: 08/12/2018 07:55 PM »
Crew Dragon is highly automated. During the ascent phase the crew really isn't crew. They are passengers. The entire ascent to orbit is fully automated, including all the abort modes. No silly abort-mode switches or joysticks (a la Shuttle) or manual abort handles (a al Apollo). None of that stuff.

Are you sure? I believe CCT-REQ-1130 requires crew to have the ability to manually trigger ascent abort, or manually turn off auto abort.
I said switches, joysticks and handles. None of that stuff is on Crew Dragon. A touchpad is however. And yes, the manual over ride option for ascent abort is there, but the odds of it being used is extremely low because the computer is way quicker and monitoring a helluvalot more system- and performance parameters than are being presented to the crew on the main display. The option is there because of a NASA requirement with a likelihood of being used  equal to zero.

Manually turning off auto abort is only applicable BEFORE an abort is triggered. It cannot be used to terminate an abort option that is in the process of being executed. The option was added because NASA considered that there could be a very unlikely repeat of an Apollo 14 scenario.

Could you remind me what happened with Apollo 14?

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