Author Topic: SpaceX F9 / Crew Dragon : Crew-2 : 22 April 2021 - DISCUSSION  (Read 194738 times)

Offline Albert Lapatin

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Hello. Let me ask a question that I cannot find an answer to. Is the Drago Crew able to perform a manual descent in the event of a loss of communication with the MCC or other emergency?
Yes.  See the buttons circled in Yellow.  Image attached is a recreation of the control panel. 

Here's a link to an actual photo: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46136.0;attach=1537705;image

you want to say that it is enough to push one button and the Dragon will return home?
Probably not while docked to ISS but if free flying I've no doubt it's default landing location is programmed in so that pushing the button executes the appropriate phasing and deorbits.



If the computer system fails, then this scenario will be impossible.
Yes. Obviously there are some (extremely unlikely) scenarios where the crew won’t survive.

What are you angling for exactly here? You got an answer to your first Q, and now you are moving the goalposts?

It's simple. When you start to understand the problem, new questions arise.

Offline Vettedrmr

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Hello. Let me ask a question that I cannot find an answer to. Is the Drago Crew able to perform a manual descent in the event of a loss of communication with the MCC or other emergency?
Yes.  See the buttons circled in Yellow.  Image attached is a recreation of the control panel. 

Here's a link to an actual photo: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46136.0;attach=1537705;image

you want to say that it is enough to push one button and the Dragon will return home?
Probably not while docked to ISS but if free flying I've no doubt it's default landing location is programmed in so that pushing the button executes the appropriate phasing and deorbits.



If the computer system fails, then this scenario will be impossible.

No, if all of the redundant channels of the computer system fail, then it's impossible.  In the fighter jet work I did, a triplex-redundant computer system has a failure rate requirement that exceeds 1:1,000,000. 
Aviation/space enthusiast, retired control system SW engineer, doesn't know anything!

Offline cscott

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can i see this "preflight mission sim for the inspiration 4 crew" somewhere?
Scroll back through the inspiration 4 thread to find the discussion.  Some footage was also on Netflix, apparently.

Offline Rondaz

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Seven issued NOTMAR Hazard Areas for #Crew-2 Dragon2 reentry and splashdown on dates between 05 and 08 November. Traditional recovery locations in Cape Canaveral, Daytona, Jacksonville, Panama City, Pensacola, Tallahassee and Tampa areas.

https://twitter.com/Raul74Cz/status/1453311835910905856

Offline briantipton

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Hello. Let me ask a question that I cannot find an answer to. Is the Drago Crew able to perform a manual descent in the event of a loss of communication with the MCC or other emergency?
Yes.  See the buttons circled in Yellow.  Image attached is a recreation of the control panel. 

Here's a link to an actual photo: https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=46136.0;attach=1537705;image

I love the simplicity of these buttons. Brilliant! Even without training, any intelligent person would know what to do in an emergency. They all seem self-explanatory except for "Breakout." Can anyone enlighten me as to what that one is does and when it would be used?

Offline kdhilliard

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... They all seem self-explanatory except for "Breakout." Can anyone enlighten me as to what that one is does and when it would be used?

NASA gives go-ahead for SpaceX commercial crew test flight
Jeff Foust · Space News · February 22, 2019
Quote
Gerstenmaier said there was still one “action” to emerge from the review, regarding the performance of the flight software on the spacecraft as it approaches the ISS. He said one of the station’s international partners, later revealed to be Russia, had a dissenting opinion on the issue.

He said the concern was about what would happened if there was a failure of the main computers of the spacecraft on approach, and how it would perform a “breakout” maneuver to avoid the station. He said the computers on Crew Dragon are fault tolerant, but that the mission team will “look a little more rigorously” at fault detection procedures. “I don’t think it will be a problem once we go through the details of why it’s safe,” he said.

Online Comga

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... They all seem self-explanatory except for "Breakout." Can anyone enlighten me as to what that one is does and when it would be used?

NASA gives go-ahead for SpaceX commercial crew test flight
Jeff Foust · Space News · February 22, 2019
Quote
Gerstenmaier said there was still one “action” to emerge from the review, regarding the performance of the flight software on the spacecraft as it approaches the ISS. He said one of the station’s international partners, later revealed to be Russia, had a dissenting opinion on the issue.

He said the concern was about what would happened if there was a failure of the main computers of the spacecraft on approach, and how it would perform a “breakout” maneuver to avoid the station. He said the computers on Crew Dragon are fault tolerant, but that the mission team will “look a little more rigorously” at fault detection procedures. “I don’t think it will be a problem once we go through the details of why it’s safe,” he said.

And yet, earlier this week, "Rogozin says Crew Dragon safe for Russian cosmonauts".
(Acknowledged: This is no longer specific to the Crew 2 mission.)
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Online Targeteer

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Rob Navias stated during an interview with the US crew that a 2 hour fly around by the departing Dragon of ISS will occur if undocking/splashdown timing allows it.  The interview was on the ISSlive streaming feed but will not be released till next week.
Best quote heard during an inspection, "I was unaware that I was the only one who was aware."

Offline theonlyspace

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Nice fly around graph after undocking

Online Comga

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Nice fly around graph after undocking

How long will the fly around take with the four burns?
It could be done with a single burn, but that would take a full orbit, ~90 minutes.
Now, THAT could be a the perfectly circular trajectory illustrated.
This may be what happens when there is extremely high margins on propellants and thruster lifetime. 
They do what they want without economizing.
« Last Edit: 11/08/2021 05:25 pm by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Joffan


How long will the fly around take with the four burns?
It could be done with a single burn, but that would take a full orbit, ~90 minutes.
Now, THAT could be the perfectly circular trajectory illustrated.
This may be what happens when there is extremely high margins on propellants and thruster lifetime. 
They do what they want without economizing.

As I understand it. the fly-around is lasting a full ISS orbit, which makes sense for orbital mechanics, and I'd guess the extra burns (2-4) are for shaping the path around the ISS. We'll see if they're actually used..
Getting through max-Q for humanity becoming fully spacefaring

Offline hektor

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Is the queue behind control centre for SpaceX catering ?

Online zubenelgenubi

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Is the queue behind control centre for SpaceX catering?
Yes, that's the SpaceX lunchroom ("lunch" being generalized to 24/7 services, I believe).
« Last Edit: 11/08/2021 07:53 pm by zubenelgenubi »
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Offline Jorge

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Nice fly around graph after undocking

How long will the fly around take with the four burns?
It could be done with a single burn, but that would take a full orbit, ~90 minutes.
Now, THAT could be a the perfectly circular trajectory illustrated.

Nope. A single-burn, one-orbit, in-plane flyaround will have elliptical relative motion, with 2:1 horizontal:vertical proportion.

To fly circular relative motion requires either multiple burns, or a flyaround tilted out-of-plane 60 degrees (such that the in-plane *projection* of the relative motion retains the 2:1 proportion).

Offline Halidon

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Beautiful WB-57 thermal shot at the end of the blackout period.

Offline punder

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Well that was exciting.

Offline CameronD

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Crew-2: Astronauts Safely Return to Earth at 10:33 p.m. EST

It occurs to me that perhaps the only people not that happy about this might be the Starliner Crew astronauts.. I guess they picked the wrong horse??
« Last Edit: 11/09/2021 05:22 am by CameronD »
With sufficient thrust, pigs fly just fine - however, this is not necessarily a good idea. It is hard to be sure where they are
going to land, and it could be dangerous sitting under them as they fly overhead.

Offline Lars-J

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Crew-2: Astronauts Safely Return to Earth at 10:33 p.m. EST

It occurs to me that perhaps the only people not that happy about this might be the Starliner Crew astronauts.. I guess they picked the wrong horse??
Huh? You really think they would have preferred if they did not return safely? Care to elaborate?
« Last Edit: 11/09/2021 05:26 am by Lars-J »

Offline charlielowndes

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Thinking out loud here.

What was going on with that 4th chute? Will NASA want/need a review before launching again? What would that mean for ops on station?

I know that no-one has answered for these questions, so I guess what I'm asking is, Did that 4th chute look off nominal to anyone else for a significant period? I just didn't seem to want to inflate...

Offline Lars-J

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Thinking out loud here.

What was going on with that 4th chute? Will NASA want/need a review before launching again? What would that mean for ops on station?

I know that no-one has answered for these questions, so I guess what I'm asking is, Did that 4th chute look off nominal to anyone else for a significant period? I just didn't seem to want to inflate...
Yes they will review. And yes it inflated slowly, but it did inflate.

https://twitter.com/sciguyspace/status/1457933750151622658
« Last Edit: 11/09/2021 07:45 am by Lars-J »

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