Author Topic: SpaceX Dragon 2 Updates and Discussion - Thread 3  (Read 659688 times)

Offline Stimbergi

  • Member
  • Posts: 97
  • Liked: 266
  • Likes Given: 83
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1680 on: 05/24/2022 08:27 am »
https://twitter.com/lavie154/status/1528773848635539463

Quote
Hang on. This is a thing Iíve been aware of for quite a while. Know some people that are very well in the know and this is not the story Iíve heard.
...
I canít go into many details, but the part about hypergolics is, as far as Iím aware, flat out untrue. Crew-4ís heat shield is not compromised. And the NESC signed off on all of this.
...
How does hypergol intrusion into the heat shield even make any sense? How does it get there? The entire propulsion systems are walled off.

Either way, youíre telling me the prop system has been quietly leaking hypergolics inside the capsule? That should be a much bigger issue

Offline eeergo

Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1681 on: 05/24/2022 11:24 am »
In a discussion like this, I like to know what is the source, who is speaking. This Space Explored web site and Derek Wise are completely new to me.

Are they recent ? what is their background, their business model, their target audience ? can it be a case of a new web site seeking to establish notability ?

As long as the sources are who they claim to be in the article and the information accurate, I wouldn't care one iota at what their target audicience or business models are. The website shows article from as far back as 2 years ago from a quick glance.
-DaviD-

Offline hektor

  • Senior Member
  • *****
  • Posts: 2309
  • Liked: 887
  • Likes Given: 34
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1682 on: 05/24/2022 11:44 am »
There is a wide range of business models, and it can go from The Washington Post to the Weekly World News.

Offline eeergo

Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1683 on: 05/24/2022 11:59 am »
There is a wide range of business models, and it can go from The Washington Post to the Weekly World News.

I agree and I understand your argument - still, my point regards the information nuggets alone, devoid of subjective commentary on top: it could be the Onion or InfoWars as far as I'm concerned, as long as its sources are reliable and the information veridic.
-DaviD-

Offline Robotbeat

  • Senior Member
  • *****
  • Posts: 34750
  • Minnesota
  • Liked: 18552
  • Likes Given: 9852
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1684 on: 05/24/2022 01:04 pm »
It does seem to be sensationalized, and they also seem to not really understand the technicals very well, so itís questionable the issue is actually factually how they present it.

NESC would study the issue even if it was just an accelerated ablation rate. Or just a hypergol leak alone. Stuff like this happens, and itís carefully investigated as it should be. Itís unfortunately common to have near misses that are investigated, as spaceflight is still early.

So itís not possible to tell the severity of the issue by the sensationalization of this one outlet.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline whitelancer64

Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1685 on: 05/24/2022 03:45 pm »
https://spaceexplored.com/2022/05/23/spacex-heat-shield-issues/

I've just seen this posted on Facebook. Some relevant quotes from that article:

SpaceX Dragon hypergolic leak risked crew, NASA investigation underway

*snip*

If this article is accurate (a big "if"), would not ASAP have had something to say about it?

I wouldn't doubt that they're looking at the issue, but NASA ASAP issues periodic statements and reports, they wouldn't immediately blast their first hot take out on Twitter the second it crossed their desks.
"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk
"There are lies, damned lies, and launch schedules." - Larry J

Offline eeergo

-DaviD-

Offline gemmy0I

  • Full Member
  • **
  • Posts: 249
  • Liked: 451
  • Likes Given: 1623
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1687 on: 05/24/2022 06:34 pm »
See: https://forum.nasaspaceflight.com/index.php?topic=50309.msg2371562#msg2371562

i.e. most likely fully debunked.
Cross-post of the official NASA statement from the Axiom-1 thread:

Here's the full official statement from NASA that Davenport is quoting from, as recently retweeted on the main @NASASpaceflight (Chris B) account:

https://twitter.com/lorengrush/status/1529144891472748544

Some interesting information in here, including the fact that SpaceX has in fact reused some PICA-X tiles on previous *cargo* Dragon flights (which may have been stated publicly before, but was new to me at least).


Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 35502
  • Cape Canaveral Spaceport
  • Liked: 17425
  • Likes Given: 394
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1688 on: 05/24/2022 08:16 pm »
Its interesting seeing Boeing using a plug style door. I'm assuming they have a clever way of preventing the 100lb hatch from smacking someone in the face if they needed to use the top hatch. This is verses the Dragons hinge mechanism which restrains the hatch (presumably for earthbound ease of access to the top hatch).

This got me thinking about the logistics for Dragon rescue. Are the pyros strong enough to push the nose cone off so that they can utilize the top hatch? Is the nose cone actuator strong enough to actuate in earth gravity?

Apollo used the same method as Boeing and it was an alternate escape route.

Offline king1999

  • Full Member
  • ****
  • Posts: 414
  • F-Niner Fan
  • Atlanta, GA
  • Liked: 281
  • Likes Given: 1258
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1689 on: 05/25/2022 02:15 am »
Dragon has a obstructed forward hatch. How does it ditch the nose cone / provide access to the front hatch? Starliner is also in a similar boat with their NDS hatch cover.
Why do they need to ditch the nose cover? It has a hinge and may act like a car trunk cover which you can open from inside or outside.

Offline cohberg

  • Full Member
  • *
  • Posts: 136
  • Liked: 417
  • Likes Given: 36
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1690 on: 05/28/2022 12:44 am »
Side hatch close out panel has changed to a "quick release" design between crew-2 and crew-3

We now have detailed instructions for the toilet, clearly demonstrating a separate urinal funnel and waste bags for solids

Quote from: D2 Zero Gravity Toilet Setup Instructions - iss067e034516 - https://www.nasa.gov/image-feature/nasa-astronauts-bob-hines-and-kjell-lindgren-5
All
1. Install camera caps
2. Retrieve Daily Bag from Location 18, stage near toilet
3. Ensure Location 21 is closed
4. Retrieve privacy curtain from Location 8, install
Solid Waste
5. Unpin, deploy toilet
6. Remove toilet lid, temp stow in privacy curtain
7. Install fecal bag in toilet
8. Turn on waste fan, confirm airflow
Urine
9. Turn on waste fan
10. Destow funnel, confirm airflow
« Last Edit: 05/28/2022 12:45 am by cohberg »

Offline cohberg

  • Full Member
  • *
  • Posts: 136
  • Liked: 417
  • Likes Given: 36
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1691 on: 06/03/2022 08:29 pm »
Dragon Abort QRH from Crew 4 ascent photos.

Of note:

All aborts from Stage 1 (1A + 1B) are with the trunk for aerodynamic reasons.

Most aborts from Stage 2 (2A - 2D) are performed without the trunk. This makes sense as you are already high enough in the atmosphere and you want the additional performance

Additionally, powered aborts (2A - 2D) fire in various orientations (ranging from heavily prograde to partially retrograde) depending on phase of flight.

I annotated the downrange abort exclusion zone figure Jorge linked, to illustrate Dragon orienting to make the St Johns or Shannon landing areas.



« Last Edit: 06/10/2022 02:31 am by cohberg »

Offline Jorge

  • Senior Member
  • *****
  • Posts: 6368
  • Liked: 446
  • Likes Given: 50
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1692 on: 06/03/2022 10:51 pm »
Dragon Abort QRH

Most 2 'X' (2nd stage aborts) are performed without the trunk (vs stage 1 modes 1A + 1B with trunk for aerodynamic reasons). This makes sense as you are already high enough in the atmosphere and you want the additional performance

Additionally, it appears that not all the abort thrust directions are entirely prograde? Some 2X aborts appear to be firing partially retrograde. Is this for g loading /  to make a recovery zones?

The latter. See:
https://ntrs.nasa.gov/api/citations/20170001943/downloads/20170001943.pdf

Page 47, "3.3.1.7 Aborts outside DAEZ". There's a figure on page 183. Basically if the instantaneous impact point (IIP) of the spacecraft is already past St. John's, the abort would be retrograde to get back to it.
JRF

Offline jketch

  • Full Member
  • *
  • Posts: 119
  • California
  • Liked: 150
  • Likes Given: 10
Re: SpaceX Dragon 2 Updates and Discussion - Thread 3
« Reply #1693 on: 06/03/2022 11:18 pm »
NASA has reportedly purchased an additional 5 Crew Dragon flights, bringing the total to 14.

https://arstechnica.com/science/2022/06/nasa-just-bought-all-the-seats-needed-for-space-station-crews-into-2030/

Offline hektor

  • Senior Member
  • *****
  • Posts: 2309
  • Liked: 887
  • Likes Given: 34

Tags: Stage 2 burn 
 

Advertisement NovaTech
Advertisement SkyTale Software GmbH
Advertisement Northrop Grumman
Advertisement
Advertisement Brady Kenniston
Advertisement NextSpaceflight
Advertisement Nathan Barker Photography
1