totm nov 2023 SpaceX Discussion Thread

[zolotiyeruki]

2 hours ago, mikegarrison said:

It's all a matter of cg location.

Unfortunately, for dynamic stability you want the cg to be toward the nose, while for stability standing on the surface you want the cg to be toward the tail.

At least on the Moon there are no wind loads.

The "cg toward the nose" is applicable if you're 1) in the atmosphere, and 2) intending to fly nose-first.  Neither are true on the moon.  The concern about CG on the moon is a valid one, though-- the SS prototypes up to this point have all been landing very tail-heavy, with nothing but empty space and a header tank in the nose.  On the moon, there won't be a need for a header tank in the nose (no bellyflop), which should help shift the CG toward the engines, but it *will* have a whole bunch of cargo in the nose, which will shift the CG way up.

[tater]

6 hours ago, mikegarrison said:

This is not always true.

First of all, certain types of undercutting pricing are fraud. For instance, if you learn through non-public sources what your competitors are bidding and use that information to adjust your own bid, that's illegal. Many companies have been caught doing that over the years, and the penalties for it are pretty draconian.

For example, McDonnell Douglas managed to acquire a large number of confidential documents (a whole roomful, if I recall correctly) from Lockheed Martin. This was before they merged with Boeing, but it was discovered after the merge. A bunch of contracts were shifted from Boeing to Lockheed Martin. There were also penalties paid. And stuff like this can result in people going to prison, too.

Another kind of undercutting is deliberately low-balling cost estimates. Sometimes this happens accidentally, but sometimes it is intentional. Once the contract is awarded and now the entire program is dependent on this single source, suddenly things get more expensive. Change orders happen, and the price goes up. It becomes a game of brinksmanship with the program being held hostage. It's hard to prove when this is deliberate or just caused by overconfidence, unless there is a convenient trail of documents that prove some kind of bad intent.

All true, but SpaceX has done lower priced bids from the start. I remember Shotwell talking about Delta IV Heavy and saying something like, "we don't know how to make a $300M rocket."

They obviously have a history with NASA for both COTS and Commercial Crew for similar contracts... oh, and now Gateway resupply.

[RCgothic]

I enjoyed this talk with Eric Berger about SpaceX:

 

 

 

[tater]

Meanwhile, one of the three companies who proposed HLS landers is going to orbit for the 117^th time (?) tomorrow:

 

[tater]

Tug pulling JRTI is having some issues, and other ships have been sent, but if they can't get JRTI to the recovery site, they will scrub tonight.

[CatastrophicFailure]

This is interesting. 

 

Also, wild Thwomp sighting. 

[NFUN]

12 hours ago, SpaceFace545 said:

I would love to watch the first Mars settlements go full Jamestown as the colonists turn their society into a canabilistic autocracy like the pilgrims. All while sipping some nice whisky (really anything would be nice, those fools on Mars only would have water to drink) that those silly colonizers couldn’t bring to save on weight.

what

[kerbiloid]

He is all for ISRU ethanol production.

[SpaceFace545]

10 minutes ago, kerbiloid said:

He is all for ISRU ethanol production.

Mmmmm, torpedo juice.

[tater]

Slip presumably because of the tug issue I mentioned up the thread, JRTI needs to get to recovery area.

[tater]

 

[RCgothic]

2nd static fire: 

 

 

 

[CastleKSide]

17 hours ago, KSK said:

And of course, doing the same with Raptor is yet another question which I’m guessing is why the Red  Dragon concept has been ditched - any data that SpaceX could get from it won’t be relevant to Starship.

They scrapped propulsive landing of dragon entirely because of problems with the landing gear coming thru the heatshield. Red dragon was canceled along with that

[SunlitZelkova]

21 hours ago, Flying dutchman said:

...

I don't like what this thread has become.

This is what happens when they launch a SN/Starship in the fog. It breaks people's regular intake of Starship-test-amine, and they go into withdrawal and have pointless arguments over Starship because they have no 4K videos of the flight to analyze and dissect.

EDIT- For clarification, this is a joke, with no ill will intended towards anyone

Edited April 28, 2021 by SunlitZelkova
Clarification

[tater]

 

[Brotoro]

...when they are sitting still.

[tater]

43 minutes ago, Brotoro said:

...when they are sitting still.

On the plus side 2 static fires, no change of engines.

[RCgothic]

4 hours ago, CastleKSide said:

They scrapped propulsive landing of dragon entirely because of problems with the landing gear coming thru the heatshield. Red dragon was canceled along with that

It had more to do with being unable to convince NASA that propulsive landing of a crew capsule was a good idea.

Edited April 28, 2021 by RCgothic

[kerbiloid]

When the legs would pierce the shield and impale the crew on engines failure, it's definitely not so good idea.

***

Landing legs of a smoker,

Spoiler

 

Landing legs of a healthy man.

Spoiler

 

Edited April 28, 2021 by kerbiloid

[YNM]

On 4/27/2021 at 10:21 AM, tater said:

I'd have thought the point of androgynous ports was exactly to allow either side to be active. Apparently there is a permanently passive variant as well...

They're intended for station operations - like, you wouldn't active dock from a station to a smaller ship. Also I presume for permanent docking of modules etc.

On 4/27/2021 at 11:59 AM, kerbiloid said:

Cargo Dragon doesn't have a docking port at all, only the passive berthing mechanism.

After the change to Dragon V2, it's basically the exact same as the crewed version.

[kerbiloid]

2 minutes ago, YNM said:

After the change to Dragon V2, it's basically the exact same as the crewed version.

Yes, I mean Cargo Dragon rather than Cargo Crew Dragon.

Sometimes it seems that SpaceX system of names is intentional.

Edited April 28, 2021 by kerbiloid

[YNM]

3 minutes ago, kerbiloid said:

Yes, I mean Cargo Dragon rather Cargo Crew Dragon.

Well they're not going to be produced and launched anymore. All the upcoming CRS flights are going to use the IDA ports.

I honestly kinda lament the loss since this means that they can only use the IDA and not the CBM, and as we can see already it makes for a very tight scheduling. No dual-docking of Dragon and Starliner, for instance...

Edited April 28, 2021 by YNM

[kerbiloid]

1 minute ago, YNM said:

are going to use the IDA ports

Both IDSS-compatible docking port existing in the whole Universe, and mounted on the same module, which is attached to the rest of the Universe with a single CBM port having 16 bolts.

Let's raise a toast in honour of 16 puny metal sticks holding the human progress.

[YNM]

Just now, kerbiloid said:

mounted on the same module

to be pedantic, two separate modules but connected to one node module XD

[Cuky]

8 minutes ago, kerbiloid said:

Yes, I mean Cargo Dragon rather than Cargo Crew Dragon.

Sometimes it seems that SpaceX system of names is intentional.

Isn't it something like this:

1. Dragon

• Cargo Dragon (discontinued)
• Crew Dragon (planned at first, but never produced)

2. Dragon V2

• Cargo Dragon
• Crew Dragon

 

I haven't seen V2 Cargo Dragon ever referred to as Cargo Crew Dragon tbh. Though I heard them refer to it in live streams as a Dragon 2 Cargo variant and Dragon 2 Crew variant.