SpaceX Dragon 2 Updates and Discussion - Thread 3

[FutureSpaceTourist]

SpaceX Dragon Crew Extraction Rehearsal (NHQ201908130001)
Teams from NASA and SpaceX gather at the Trident Basin in Cape Canaveral, Florida, on August 13, 2019 to rehearse extracting astronauts from SpaceX’s Crew Dragon, which will be used to carry humans to the International Space Station. Using the Go Searcher ship SpaceX uses to recover their spacecraft after splashdown and a mock-up of the Crew Dragon, the teams worked through the steps necessary to get NASA astronauts Doug Hurley and Bob Behnken out of the Dragon and back to dry land. Hurley and Behnken will fly to the space station aboard the Crew Dragon for the SpaceX Demo-2 mission. Photo Credit: (NASA/Bill Ingalls)

[FutureSpaceTourist]

SpaceX Dragon Crew Emergency Evacuation Rehearsal (NHQ201908150001)
A quick moving storm passes as teams from NASA and SpaceX practice procedures for medical emergency evacuation onboard the GO Searcher ship, Friday, August 15, 2019 in the Atlantic Ocean off the coast of Cape Canaveral, Florida. SpaceX will use the GO Searcher ship during the Demo-2 mission to recover NASA astronauts returning from the International Space Station in their Crew Dragon spacecraft. Photo Credit: (NASA/Bill Ingalls)

[FutureSpaceTourist]

https://twitter.com/cathofacker/status/1163472096753836032

Also gives update on Crew Dragon timeline: Another in-flight abort test is scheduled for October or November, with the Demo-2 crewed flight "hopefully early next year." #AiaaPropEnergy

Edit to add: different quote on Demo-2 ...

https://twitter.com/jeff_foust/status/1163472275498307586

At the AIAA Propulsion & Energy Forum this morning, SpaceX’s Hans Koenigsmann says the company is planning an in-flight abort test of Crew Dragon in October or November; “hopefully” do Demo-2 crewed test flight this year. #AIAAPropEnergy

I’ve now watched the video and Jeff Foust is correct.

[QuantumG]

You can trust Jeff. <3

[FutureSpaceTourist]

Not sure if there’s any significance to timing of these tweets?

twitter.com/spacex/status/1172215123777216512

Ahead of our in-flight abort test for @Commercial_Crew—which will demonstrate Crew Dragon's ability to safely carry astronauts away from the rocket in the unlikely event of an emergency—our team has completed over 700 tests of the spacecraft's SuperDraco engines

https://twitter.com/spacex/status/1172215126344122368

Fired together at full throttle, Crew Dragon's eight SuperDracos can move the spacecraft 0.5 miles—the length of over 7 American football fields lined up end to end—in 7.5 seconds, reaching a peak velocity of 436 mph

[FutureSpaceTourist]

NASA Kennedy  KSC-20180830PH_SPX01_0001

NASA astronauts Doug Hurley and Bob Behnken familiarize themselves with SpaceX’s Crew Dragon, the spacecraft that will transport them to the International Space Station as part of NASA’s Commercial Crew Program. Their upcoming flight test is known as Demo-2, short for Demonstration Mission 2. The Crew Dragon will launch on SpaceX’s Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. In March 2019, SpaceX completed an uncrewed flight test of Crew Dragon known as Demo-1, which was designed to validate end-to-end systems and capabilities, bringing NASA closer to certification of SpaceX systems to fly a crew. NASA image use policy.

[whitelancer64]

NASA Kennedy  KSC-20180830PH_SPX01_0001

NASA astronauts Doug Hurley and Bob Behnken familiarize themselves with SpaceX’s Crew Dragon, the spacecraft that will transport them to the International Space Station as part of NASA’s Commercial Crew Program. Their upcoming flight test is known as Demo-2, short for Demonstration Mission 2. The Crew Dragon will launch on SpaceX’s Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida. In March 2019, SpaceX completed an uncrewed flight test of Crew Dragon known as Demo-1, which was designed to validate end-to-end systems and capabilities, bringing NASA closer to certification of SpaceX systems to fly a crew. NASA image use policy.

Nice view of the life support system connection in the last picture!

[Arb]

What's 'HEX'?

[Vettedrmr]

What's 'HEX'?

My guess would be "Heat Exchange"

[PM3]

NASA Blog today

Commercial Crew Program Testing Fosters Improvements in Parachute Safety

As part of NASA’s Commercial Crew Program, SpaceX has been developing and testing the Crew Dragon parachute system, which is comprised of two drogue parachutes and four main ring-sail parachutes—the same type of parachutes that have been commonly and successfully used for human spaceflight in the past.

In the last four years, SpaceX has completed 30 drop tests and 18 system-level tests of their parachute system, including the successful Demo-1 mission flight test. Through this test campaign, the SpaceX team, in partnership with NASA, has gained insight that could change the way parachutes are developed, tested and integrated into spacecraft design. Throughout this process, NASA has shared lessons learned from its own human spaceflight heritage to assist in parachute development.

One of the most relevant benefits originating from the rigorous, multi-year parachute testing campaign is a better understanding of how to safely design and operate parachute clusters. Specifically, NASA and SpaceX now have greater insight into what is termed “Asymmetry Factor,” an integral part of how safety in design is measured and weighed. This asymmetry factor is an indicator of uneven load distribution between individual suspension lines attached to the parachute canopy. As a cluster of parachutes is deployed, the first parachute to open may crowd or bump others as they open up, causing an uneven load distribution on the main parachutes. If the lines or the joints are not designed to account for the unevenness or asymmetry, they might get damaged or even fail.
Crew Dragon parachutes successfully deploy during a development test.

In April 2019, SpaceX performed a developmental test designed to simulate the loss of one of its four main parachutes. During the test, there was an unexpected failure which has offered a unique insight into parachute loading and behavior. The test results have ultimately provided a better understanding of parachute reliability and caused a closer examination of the current industry standard used to calculate the asymmetry factor.

SpaceX is using this new data to calculate structural margins and influence parachute design. The unique results allow more accurate prediction of reliability in the flight parachute configuration. In fact, this new data further verified SpaceX’s most recent successful developmental test, which simulated a pad abort, where the vehicle is tumbling at low altitude before parachute deploy.

Through testing, SpaceX has sought to better characterize margins on their current and future parachute designs, using more robust materials, operational mitigations, and continuation of model refinement based on data from almost 50 recent tests and counting, 19 Cargo Dragon parachute landings, and the successful Demo-1 mission, to ensure that Crew Dragon has the safest parachute design possible. Additionally, these new findings are being shared within NASA to ensure that all human spaceflight applications are assessed for adequate margin and reliability.

[...]

[gaballard]

this new data further verified SpaceX’s most recent successful developmental test, which simulated a pad abort, where the vehicle is tumbling at low altitude before parachute deploy.

Wasn’t the pad abort 3-4 years ago now? The post mentions a test on April 2019, so it’s not an old post reprinted, but I’m confused as to that statement, especially with DM-1 having occurred...

EDIT: Thanks for the clarification everyone - I considered the pad abort test from a few years ago to be a simulation of a pad abort, but it might be more accurately called a simulation of a real pad abort.

[spacebleachers]

this new data further verified SpaceX’s most recent successful developmental test, which simulated a pad abort, where the vehicle is tumbling at low altitude before parachute deploy.

Wasn’t the pad abort 3-4 years ago now? The post mentions a test on April 2019, so it’s not an old post reprinted, but I’m confused as to that statement, especially with DM-1 having occurred...

I think what they are saying is that the most recent test purposely induced the tumbling so they could determine how the system reacted and if it behaved as expected.

[gongora]

this new data further verified SpaceX’s most recent successful developmental test, which simulated a pad abort, where the vehicle is tumbling at low altitude before parachute deploy.

Wasn’t the pad abort 3-4 years ago now? The post mentions a test on April 2019, so it’s not an old post reprinted, but I’m confused as to that statement, especially with DM-1 having occurred...

They're just talking about parachute tests.  They did a test with initial conditions similar to what a pad abort would cause.

[spacebleachers]

My question is what does this mean?

Does SpaceX and CrewDragon get to check the box for Parachute testing? Or is this just a no SpaceX is not ready yet, but thanks for helping us with future parachute designs? What does it mean for other craft (Orion, Starliner, etc...)?

I know when I was at the National Space Committee luncheon earlier this month, Boeing Indicated they were 100% complete with Parachute testing. They had checked the box.

However, if I read this, then it would seem all the craft using parachutes for landing, which are currently in dev, need continued testing and enhancement before they are ready to carry humans to space.

[gongora]

It says a SpaceX test this year found conditions that caused it to fail.  That would lead to some redesign and further testing of the SpaceX system.  Boeing could very well be done with their testing if lessons learned from the SpaceX tests don't necessarily point to failure of the Boeing system.

[cosmicvoid]

It says a SpaceX test this year found conditions that caused it to fail.  That would lead to some redesign and further testing of the SpaceX system...

Hmm, I thought NASA required SpaceX to use parachutes because it was a reliable and mature technology.  Did SpaceX fail to copy the "mature and reliable" part correctly?

[Robotbeat]

It says a SpaceX test this year found conditions that caused it to fail.  That would lead to some redesign and further testing of the SpaceX system...

Hmm, I thought NASA required SpaceX to use parachutes because it was a reliable and mature technology.  Did SpaceX fail to copy the "mature and reliable" part correctly?

SpaceX was baselining parachutes since long before they were even talking about vertical landing.

[woods170]

It says a SpaceX test this year found conditions that caused it to fail.  That would lead to some redesign and further testing of the SpaceX system...

Hmm, I thought NASA required SpaceX to use parachutes because it was a reliable and mature technology.  Did SpaceX fail to copy the "mature and reliable" part correctly?

SpaceX was baselining parachutes since long before they were even talking about vertical landing.

But when they offered their proposal for CCtCAP the baseline was propulsive landing, with parachutes as back-up. NASA picked SpaceX (and Boeing) but not until they made d*mn sure that the first several Crew Dragon landings would be performed by parachute. Propulsive landing would enter the mix later.
By the time SpaceX started to prove that propulsive landing could actually work NASA decided on what requirements SpaceX would have to fulfill for propulsive landing to be allowed as the primary means of landing Crew Dragon.
That set of requirements was so massive that SpaceX figured it wasn't worth the trouble and parachutes returned to be the baselined landing method.

The parachute problem referenced in the NASA blog did not occur when Crew Dragon was still baselined to have three parachutes despite the fact that the three-chute layout was involved in over a dozen drop-test.
The problem started manifesting itself when, on suggestion by NASA, SpaceX added a fourth parachute to lessen landing-loads (on a nominal mission Crew Dragon is still carrying a very substantial fuel-load upon splash-down). What became clear over subsequent drop(testing) is that a four-chute canopy shows substantially more (and different!) dynamic behaviour than a three-chute canopy. That ultimately resulted in the deployment failure referenced in the NASA blog.

Although the NASA blog only mentions it in passing, the deployment failure of the four-chute canopy - under non-nominal circumstances - took almost the entire industry by surprise.
What was thought to be a well-understood and well-modeled environment was in fact not-so-well understood and not-very-well-modeled.
Hence the fact that the mishap during the Crew Dragon parachute test affects ALL current US manned spacecraft. All of the previously used parachute models (for Orion, Starliner and Crew Dragon) are now considered to be insufficient.
Fortunately for Orion parachute qual was already complete by the time all of this happened.
Starliner was not so lucky and has to perform additional (drop)testing to demonstrate that reality closely matches the revised models.
Crew Dragon is most unlucky of all because the load of required additional (drop)testing is a helluvalot bigger, given to the unique four-chute setup.

[Arb]

...
Fortunately for Orion parachute qual was already complete by the time all of this happened.
...

If true (and woods170 is a reliable source) this is triggering my redacted detector. Given that the models are wrong then the Loss of Crew estimates must be affected, which means the Orion model needs re-validating regardless of having passed qualification or not. If there's an argument it should be about who pays not what needs to be done. Should arguably be top of the agenda at every ASAP meeting...

Crew Dragon is most unlucky of all because the load of required additional (drop)testing is a helluvalot bigger, given to the unique four-chute setup.

Do you know if they considered (for example) dumping the landing fuel after reaching orbit. That might have reduced weight sufficiently to stick with the three parachute setup. Be interesting to know how the trades went.

[DLK]

What's 'HEX'?

I thought it might be a Terry Pratchett (Discworld) reference.