Author Topic: SpaceX Falcon 9 / Dragon 2 : SpX-DM1 : March 2, 2019 : DISCUSSION  (Read 403165 times)

Offline clongton

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I seem to recall that the Egress Hatch is at the Crew's feet but can't put my finger on any photos that show the interior arrangement. If that's true then because the parachutes are anchored directly above the hatch, wouldn't the crew be in a head-down position the entire time they are under parachute? Does anyone have an interior shot of the seats and hatch?
This photo in Elon's tweet from the hatch opening is pretty instructive

https://twitter.com/SpaceX/status/1102194489500753921

so you see the astronauts arm coming through the hatch in the "front" of the vehicle. To Ripley's feet there is two windows and between them is the sideways hatch that they ingress and egress once inside the atmosphere. So when bobbing in the see the picture is basically in normal orientation. To the right there is the main hatch that's pointing a bit upwards and you may be able to see the sea through the windows.

So definitely Feet-Up and Head Down while descending under parachute.
Spacenick's photo shows the hatch at the crew's feet so in the photo below the crews' feet would be to the left side of the capsule (where the hatch and chute attach points are) and their heads to the right.
« Last Edit: 03/08/2019 03:46 pm by clongton »
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Online NX-0

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The parachutes seemed to do a lot of bumping into each other.
Is this cause for any concern?

It really seemed like 3 would have done the job nicely, anyway.

Offline Apollo-phill

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BIG CHEESE TIME, Gromit and Ripley !😃

" We had the Right Trousers  on today, Ripley !"😁

Congratulations to ALL t SpaceX/NASA on DM1


PhillParker
UK

Then again one could just ask one of the Apollo astronauts.

Some of those guys barfed, didn't they? And I don't think they were in the water as long as Dragon crew will be.

https://twitter.com/m45sh/status/1104044000330375169

Apollo crews averaged 52.36 minutes in the water.  Longest was 88 minutes, shortest was 37 minutes.

Crew Dragon was in the water for 67 minutes and their target for this mission was 60 minutes.  I'm guessing over time that the average for Crew Dragon will be roughly similar to Apollo's average.

The parachutes seemed to do a lot of bumping into each other.
Is this cause for any concern?

It really seemed like 3 would have done the job nicely, anyway.

I checked previous drop tests... standard behaviour.  Looked nominal.

Offline clongton

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The parachutes seemed to do a lot of bumping into each other.
Is this cause for any concern?

It really seemed like 3 would have done the job nicely, anyway.

Three chutes would have been more than enough. But NASA insisted on adding a 4th chute, saying that it was needed as a safety backup for if one of the other 3 mains failed.

Here is where I have a problem with NASA wrt Dragon.
Dragon Crew has a dry mass of 9,525 kg and NASA says it needs 4 chutes for a safe descent.
Orion has a dry mass of 10,387 kg yet NASA says it only needs 3 chutes for a safe descent.
So if Dragon masses LESS than Orion, then why does it have to have more parachutes than Orion?
Maybe there is a valid reason for that but it escapes me.
Enquiring minds want to know.
« Last Edit: 03/08/2019 04:16 pm by clongton »
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Online deruch

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Do we know of ANY anomalies on this flight? It seems that it performed completely perfectly at every step. No launch delays, no errors on approach, perfect reentry and landing, etc. That is an incredible achievement for the first flight of a vehicle like this.
2 potential ones.  A thermal issue--Dragon was a few degrees warmer than expected.  And the increased alcohol concentration noted in the ISS air (plus chemical smell) after hatches were opened.  Assuming it came from Dragon, if it was spiking the ISS's air, even very modestly, then the concentrations inside the capsule prior to docking may be of higher concern.  But regardless, they'll try to find what was causing it and work on a fix.
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Offline mn

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I checked previous drop tests... standard behaviour.  Looked nominal.

Except that ASAP seems to think this 'standard behaviour' is not nominal.

And I think I'll duck and run for cover ;)

Offline EnigmaSCADA

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I seem to recall that the Egress Hatch is at the Crew's feet but can't put my finger on any photos that show the interior arrangement. If that's true then because the parachutes are anchored directly above the hatch, wouldn't the crew be in a head-down position the entire time they are under parachute? Does anyone have an interior shot of the seats and hatch?
This photo in Elon's tweet from the hatch opening is pretty instructive

https://twitter.com/SpaceX/status/1102194489500753921

so you see the astronauts arm coming through the hatch in the "front" of the vehicle. To Ripley's feet there is two windows and between them is the sideways hatch that they ingress and egress once inside the atmosphere. So when bobbing in the see the picture is basically in normal orientation. To the right there is the main hatch that's pointing a bit upwards and you may be able to see the sea through the windows.

So definitely Feet-Up and Head Down while descending under parachute.
Spacenick's photo shows the hatch at the crew's feet so in the photo below the crews' feet would be to the left side of the capsule (where the hatch and chute attach points are) and their heads to the right.
The seats appear to be adjusted depending on the circumstance (launch/orbit vs reentry).


Offline Helodriver

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So the DM-1 Dragon was built with side windows located between the SuperDraco pods but they were covered up on the outside of the spacecraft with thermal protection material that stayed in place throughout the flight, leaving only two functional.  The oval patch covering the window is visible on the departure pix. I'm curious if future flightworthy Crew Dragons will have those side windows deleted entirely or uncovered for crew viewing.  I haven't heard this addressed elsewhere although it may have been.
« Last Edit: 03/08/2019 04:29 pm by Helodriver »

Offline clongton

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Do we know of ANY anomalies on this flight? It seems that it performed completely perfectly at every step. No launch delays, no errors on approach, perfect reentry and landing, etc. That is an incredible achievement for the first flight of a vehicle like this.
2 potential ones. <snip>

2-1/2. One parachute landed over the top of the spacecraft. That's a potential problem depending on whether or not the crew needs to egress the spacecraft for some reason before the recovery boats can get there (onboard fire or leaking hatch for example). If the chute covers the hatch the crew could potentially become entangled with the shroud lines. Which raises another question: can they swim with the IVA suits on or would they need to shed them first?

I don't know that there is a solution to this (that's why the "1/2") because a cut chute dropping over the spacecraft has always been a potential occurrence on all spacecraft that return under parachute to a water landing. Dragon cuts the lines as soon as it senses that it is in the water. They could possibly cut them sooner but that would present potential additional problems of their own.
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Offline punder

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So the DM-1 Dragon was built with side windows located between the SuperDraco pods but they were covered up on the outside of the spacecraft with thermal protection material that stayed in place throughout the flight, leaving only two functional.  The oval patch covering the window is visible on the departure pix. I'm curious if future flightworthy Crew Dragons will have those side windows deleted entirely or uncovered for crew viewing.  I haven't heard this addressed elsewhere although it may have been.

They may have covered that window to make the light level constant for filming Ripley. Prevent bright sunlight pouring in at the wrong moment.

Offline Helodriver

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It appears the one on the other side was covered over as well.  Covers for lighting could have been similar to what was installed inside the spacecraft over the other two windows after docking.

Offline DasBlinkenlight

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I read somewhere (But I don't recall where,) that they wanted a few windows to test, but didn't install all of them, in order to save a little money... the blocked windows are not covered, they simply are not there.

Early mockups have the control panel lowering down to the crew... the last demo showed the seats move up to the control panel instead... and as the above pictures show, the seats do indeed re position based on launch and landing. so the crew should not be in a feet up position.

The apollo era flights had inflatable life preservers so that in the event of an emergency egress, the crew did not have to doff their flight suits first.   I assume (but have no proof) that a similar system will be in place for Dragon.

Online Joffan

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Quote
Dragon Trunk cataloged as  object 44064 in a 395 x 401 km orbit,  only a bit below ISS which is in a 406 x 411 k m orbit. Looks like the Dep-3 and Dep-4 burns were quite small.
This is good from the point of view of rapid return to Earth. If Dragon only makes small departure burns, they've just tested re-entry from a relatively high orbit. The long wait we saw on DM-1 between departure and re-entry is likely not going to happen with crew on board.

I assume that once Dragon is outside the approach zone, it is free to fire thrusters without considering effects on the ISS. So  it could in principle go from ISS undocking to splashdown in under two hours.
Max Q for humanity becoming spacefaring

Online edzieba

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I seem to recall that the Egress Hatch is at the Crew's feet but can't put my finger on any photos that show the interior arrangement. If that's true then because the parachutes are anchored directly above the hatch, wouldn't the crew be in a head-down position the entire time they are under parachute? Does anyone have an interior shot of the seats and hatch?
The 'chutes are not anchored directly above the hatch.

Dragon hangs from the cute mounts just below the nose cap. The seats are (well) below the nose cap, and tilted to descent under the 'chutes - and more importantly, impact with the water - occurs with the pasengers sitting horizontally with head roughly level with the knees, in a very similar folded pose to Soyuz.

Offline alang

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Been bobbing in the water for an hour now. I imagine any crew that would be aboard after months in microgravity  might be feeling pretty damn queasy by now.

I wonder if staying in microgravity might actually inhibit sea sickness at least to a degree. According to the following ESA video astronauts get really resistant to disorientation nausea.


This is explained with the brain basically concluding after a few days that its inner ear gyroscope is basically useless and ignoring it. So I'd think that they might actually be less affected.

Decades ago I attended a lecture on motion sickness. The claim was made that alcohol would change the density of fluid in the inner ear and suggest acceleration to the brain when none existed. In other words the claim was that alcohol in sufficient quantities would induce motion sickness.
If true then I quite seriously wonder if the traditional association between sailors and drunkenness was in part due to the ability to tolerate one of the several unpleasant side effects of booze.
Naturally I do not suggest the consumption of beer as a form of astronaut training.

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So the DM-1 Dragon was built with side windows located between the SuperDraco pods but they were covered up on the outside of the spacecraft with thermal protection material that stayed in place throughout the flight, leaving only two functional.  The oval patch covering the window is visible on the departure pix. I'm curious if future flightworthy Crew Dragons will have those side windows deleted entirely or uncovered for crew viewing.  I haven't heard this addressed elsewhere although it may have been.
@woods170 has indicated that DM-2 will have those windows present and accounted for.  As noted above what you see on the inside of DM-1 is strictly cosmetic.

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I'm surprised that trunk jettison was prior to the de-orbit burn.  Was that due to concerns over potential impacts with it during re-entry?  And is that going to remain the standard timeline for return operations going forward?  Should there be some unexpected issue with the deorbit burn, not having the solar panels and radiators would, I imagine, seriously limit the amount of time the capsule can remain healthy while a fix is worked on.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline Lars-J

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I seem to recall that the Egress Hatch is at the Crew's feet but can't put my finger on any photos that show the interior arrangement. If that's true then because the parachutes are anchored directly above the hatch, wouldn't the crew be in a head-down position the entire time they are under parachute? Does anyone have an interior shot of the seats and hatch?
This photo in Elon's tweet from the hatch opening is pretty instructive

https://twitter.com/SpaceX/status/1102194489500753921

so you see the astronauts arm coming through the hatch in the "front" of the vehicle. To Ripley's feet there is two windows and between them is the sideways hatch that they ingress and egress once inside the atmosphere. So when bobbing in the see the picture is basically in normal orientation. To the right there is the main hatch that's pointing a bit upwards and you may be able to see the sea through the windows.

So definitely Feet-Up and Head Down while descending under parachute.
Spacenick's photo shows the hatch at the crew's feet so in the photo below the crews' feet would be to the left side of the capsule (where the hatch and chute attach points are) and their heads to the right.

No, they are laying flat when hanging from the parachute.

Offline Lars-J

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I'm a bit amazed that people think that a parachute covering the capsule is a critical flaw. That's just the luck of the draw when dealing with parachutes like this. For any round parachute there is a wind direction that could push it on top of the capsule or jumper.

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