SpaceX Dragon 2 Updates and Discussion - Thread 3

[SWGlassPit]

Side note to the side note: there are flight regimes in which parachutes would not have sufficient time to take over from a failing propulsion system.  I'm not sure how that one gets resolved.

By realizing Elon's stated eventual goal: that spacecraft become as safe and reliable as today's aircraft.
Admittedly that will take time, but it is the ultimate answer to the question.

That's a "what", not a "how".  A goal, not a plan.

[clongton]

Side note to the side note: there are flight regimes in which parachutes would not have sufficient time to take over from a failing propulsion system.  I'm not sure how that one gets resolved.

By realizing Elon's stated eventual goal: that spacecraft become as safe and reliable as today's aircraft.
Admittedly that will take time, but it is the ultimate answer to the question.

That's a "what", not a "how".  A goal, not a plan.

No. That *is* the plan.

[SWGlassPit]

Meeting the goal is the plan.  Got it. 

[Lee Jay]

Side note to the side note: there are flight regimes in which parachutes would not have sufficient time to take over from a failing propulsion system.  I'm not sure how that one gets resolved.

By realizing Elon's stated eventual goal: that spacecraft become as safe and reliable as today's aircraft.
Admittedly that will take time, but it is the ultimate answer to the question.

That's a "what", not a "how".  A goal, not a plan.

No. That *is* the plan.

Then that's an awful plan.

Aircraft aren't safe because they're reliable.  They're safe because they have tons of safe abort modes in the event of failures.  There are engine outs, loss of control authority, bird strikes, and tons of other failures almost every day in commercial aviation.  You don't hear about it because they almost always result in a safe landing.

[whitelancer64]

Side note to the side note: there are flight regimes in which parachutes would not have sufficient time to take over from a failing propulsion system.  I'm not sure how that one gets resolved.

By realizing Elon's stated eventual goal: that spacecraft become as safe and reliable as today's aircraft.
Admittedly that will take time, but it is the ultimate answer to the question.

That's a "what", not a "how".  A goal, not a plan.

No. That *is* the plan.

Then that's an awful plan.

Aircraft aren't safe because they're reliable.  They're safe because they have tons of safe abort modes in the event of failures.  There are engine outs, loss of control authority, bird strikes, and tons of other failures almost every day in commercial aviation.  You don't hear about it because they almost always result in a safe landing.

There are also literally several tens of thousands of flights per day with no failures.

So it can be (and is, for aircraft) reliability.

Fault tolerance / recovery is important, too, and for aircraft even in a dire situation you may be able glide to a landing. You do want options in the event of a failure.

[JAFO]

I think we need to accept that spaceflight will never be 100% safe. Fixed wing commercial aviation is on a run of safety for a lot of reasons, but rotary wing aviation will always have a larger black zone of unsurvivablility because of the nature of the vehicle. Likewise, I think that there is no way to design a failproof spacecraft without making it too heavy to fly. The only way to operate a 100% safe spacecraft would be to never fly it.

[Barley]

Building codes are written in blood.  So are aviation safety rules.

Space flight has many orders of magnitude less experience, failures. and spilled blood than aviation.

[Ken the Bin]

https://twitter.com/SpaceX/status/1202378920752041984

This week SpaceX completed the 7th successful system test of Crew Dragon’s upgraded Mark 3 parachutes, which will provide a safe landing back on Earth for astronauts returning from the @space_station

[FutureSpaceTourist]

In response to SpaceX tweet:

https://twitter.com/astrobehnken/status/1202438925224071170

Recently visited this @SpaceX team & they're having the time of their lives ensuring this critical hardware is fully understood before use on @Space_Station missions. The most successful teams in the world find this intersection of having a challenge in front of them & loving it!

[TheRadicalModerate]

Did I just hear the guy narrating the CRS-19 launch say that the in-flight abort test is now NET February?

[envy887]

Did I just hear the guy narrating the CRS-19 launch say that the in-flight abort test is now NET February?

Apparently mixed up with DM-2.

https://twitter.com/lorengrush/status/1202643820690771969

[ncb1397]

Did I just hear the guy narrating the CRS-19 launch say that the in-flight abort test is now NET February?

Apparently mixed up with DM-2.

https://twitter.com/lorengrush/status/1202643820690771969

They gave dates for DM-2 of first quarter 2020 and IFA of February 2020. So, they meant DM-2 is February 2020 and IFA is first quarter 2020? That doesn't make much sense as you have to do the IFA before DM-2.

[Draggendrop]

Host may have got ahead of himself...misspoke...?

https://twitter.com/StephenClark1/status/1202651561157111813

"I’m told Crew Dragon in-flight abort might still occur before the end of this month. The host of SpaceX’s webcast apparently misspoke when he said February 2020."

-----------------

https://twitter.com/gleesonjm/status/1202653411256274944

"Targeting no earlier than December for Crew Dragon’s launch escape test in Florida"

-------------------

possible slip of DM-2 for February?

edit..spelling

[clongton]

"Targeting no earlier than December for Crew Dragon’s launch escape test in Florida"

December 2019 is earlier than February 2020.

[Draggendrop]

"Targeting no earlier than December for Crew Dragon’s launch escape test in Florida"

December 2019 is earlier than February 2020.

Generally true for most calenders ....this tweet was in reference to the prior listing for the IFA...note the tweet was also made in December...hedging that one...

All the content from my prior post was to point to NET's prior to the misspoken comment of IFA in February 2020.

also...

https://forum.nasaspaceflight.com/index.php?topic=45279.420



https://twitter.com/thesheetztweetz/status/1202657201048948738

https://twitter.com/thesheetztweetz/status/1202660222382333953

side note...the person who mispoke is also a Dragon engineering manager....that date may have meant something to him...

Time will tell...no panic if the IFA actually does slip...but it sure got a few riled up....

edit...spelling again...

[Draggendrop]

https://twitter.com/StephenClark1/status/1203128237364105217

Xpost from mission thread

"Hello from Hawthorne. Got to see the Dragon for the Demo-2 crewed mission. SpaceX aims to ship it out of factory by the end of year for thermal vacuum testing. Gwynne Shotwell says the target date for the in-flight abort test is Jan. 4. She says Demo-2 as soon as February."

[FutureSpaceTourist]

NASA Kennedy
KSC-20191204-PH-SPX01_0002
SpaceX completed the 7th successful system test of the Crew Dragon spacecraft’s upgraded Mark 3 parachutes in the western U.S. in December 2019. The parachutes will provide a safe landing on Earth for astronauts returning from the International Space Station in partnership with NASA’s Commercial Crew Program.
Photo credit: SpaceX

https://www.flickr.com/photos/nasakennedy/49193792442/

[ngilmore]

Although I've seen various discussions about the supposed reasons and requirements for the change from seven seats to four seats in Crew Dragon, this seems to be new definitive information:

December 7, 2019 Stephen Clark writing at Spaceflightnow reports:

A requirement change from NASA also contributed to delays, Shotwell said.

After SpaceX had already designed the interior layout of the Crew Dragon spacecraft, NASA decided to change the specification for the angle of the ship’s seats due to concerns about the g-forces crew members might experience during splashdown.

The change meant SpaceX had to do away with the company’s original seven-seat design for the Crew Dragon.

“With this change and the angle of the seats, we could not get seven anymore,” Shotwell said. “So now we only have four seats. That was kind of a big change for us.”

https://spaceflightnow.com/2019/12/07/after-redesigns-the-finish-line-is-in-sight-for-spacexs-crew-dragon/

[woods170]

Although I've seen various discussions about the supposed reasons and requirements for the change from seven seats to four seats in Crew Dragon, this seems to be new definitive information:

December 7, 2019 Stephen Clark writing at Spaceflightnow reports:

A requirement change from NASA also contributed to delays, Shotwell said.

After SpaceX had already designed the interior layout of the Crew Dragon spacecraft, NASA decided to change the specification for the angle of the ship’s seats due to concerns about the g-forces crew members might experience during splashdown.

The change meant SpaceX had to do away with the company’s original seven-seat design for the Crew Dragon.

“With this change and the angle of the seats, we could not get seven anymore,” Shotwell said. “So now we only have four seats. That was kind of a big change for us.”

https://spaceflightnow.com/2019/12/07/after-redesigns-the-finish-line-is-in-sight-for-spacexs-crew-dragon/

This is a prime example of how SpaceX has been having trouble to satisfy NASA's changing wishes. When SpaceX was awarded the CCtCAP contract NASA retained the right to change requirements, pretty much at will.

NASA got a REALLY good deal with CCtCAP: Firmed Fixed Price yet able to change requirements late into the game.

And some of those requirement changes have come to bite SpaceX pretty hard. One famous example is the switch to water landings which indirectly has resulted into the current extended (and costly) parachute testing campaign.

Another one is presented here: change the angle of the seats. And thus making it impossible to fly seven folks. Which in turn makes the vehicle unattractive for purely tourist flights.

The thermal "issues" that DM-1 had was also the result from a NASA requirement change. You see, on DM-1 there weren't any actual thermal issues. DM-1 had the originally designed thermal control set-up which actually met the original NASA thermal requirements.
But you guessed it: NASA changed the thermal requirements. And NASA did so pretty late into the planning cycle for DM-1. Those new requirements could not be met by the DM-1 setup. Which in turn required a waiver to fly DM-1 with the original thermal set-up but also requiring substantial rework to the DM-2 vehicle to meet NASA's new, more stringent thermal requirements.

And there have been several more major requirement changes. The result is that SpaceX spent much more money on CCtCAP development effort than originally planned. Elon mentioned hunderds of millions and that's a number that was confirmed to me by several other SpaceX sources. The requirement changes are also mentioned to me as being "substantial contributors to delays in meeting targeted flight dates".

In other words: NASA proclaiming that the CCP contractors are delayed "due to working thru technical issues" is only HALF THE STORY.
Good thing that Gwynne called this out, albeit it slightly veiled, in recent interviews.

SpaceX is not alone in this however. Boeing has had its fair share of requirement changes, and resulting delays, as well.

[Johnnyhinbos]

Although I've seen various discussions about the supposed reasons and requirements for the change from seven seats to four seats in Crew Dragon, this seems to be new definitive information:

December 7, 2019 Stephen Clark writing at Spaceflightnow reports:

A requirement change from NASA also contributed to delays, Shotwell said.

After SpaceX had already designed the interior layout of the Crew Dragon spacecraft, NASA decided to change the specification for the angle of the ship’s seats due to concerns about the g-forces crew members might experience during splashdown.

The change meant SpaceX had to do away with the company’s original seven-seat design for the Crew Dragon.

“With this change and the angle of the seats, we could not get seven anymore,” Shotwell said. “So now we only have four seats. That was kind of a big change for us.”

https://spaceflightnow.com/2019/12/07/after-redesigns-the-finish-line-is-in-sight-for-spacexs-crew-dragon/

This is a prime example of how SpaceX has been having trouble to satisfy NASA's changing wishes. When SpaceX was awarded the CCtCAP contract NASA retained the right to change requirements, pretty much at will.

NASA got a REALLY good deal with CCtCAP: Firmed Fixed Price yet able to change requirements late into the game.

And some of those requirement changes have come to bite SpaceX pretty hard. One famous example is the switch to water landings which indirectly has resulted into the current extended (and costly) parachute testing campaign.

Another one is presented here: change the angle of the seats. And thus making it impossible to fly seven folks. Which in turn makes the vehicle unattractive for purely tourist flights.

The thermal "issues" that DM-1 had was also the result from a NASA requirement change. You see, on DM-1 there weren't any actual thermal issues. DM-1 had the originally designed thermal control set-up which actually met the original NASA thermal requirements.
But you guessed it: NASA changed the thermal requirements. And NASA did so pretty late into the planning cycle for DM-1. Those new requirements could not be met by the DM-1 setup. Which in turn required a waiver to fly DM-1 with the original thermal set-up but also requiring substantial rework to the DM-2 vehicle to meet NASA's new, more stringent thermal requirements.

And there have been several more major requirement changes. The result is that SpaceX spent much more money on CCtCAP development effort than originally planned. Elon mentioned hunderds of millions and that's a number that was confirmed to me by several other SpaceX sources. The requirement changes are also mentioned to me as being "substantial contributors to delays in meeting targeted flight dates".

In other words: NASA proclaiming that the CCP contractors are delayed "due to working thru technical issues" is only HALF THE STORY.
Good thing that Gwynne called this out, albeit it slightly veiled, in recent interviews.

SpaceX is not alone in this however. Boeing has had its fair share of requirement changes, and resulting delays, as well.

Interesting info Woods170. Enlightening.

I wonder if a small silver lining in these tightening and changing of requirements is that SpaceX has been able to refine human LSS to a higher degree and that in turn can directly be applied to Starship LSS design.