Jump to content

SpaceX Discussion Thread


Skylon
 Share

Recommended Posts

33 minutes ago, mikegarrison said:

I would disagree that the Apollo Command Module was "designed to get as much lift as possible". Re-entry capsules are generally designed to be much more focused on managing heat and decel loading than on trying to maximize glide distance.

remembers Gemini paraglider

 

Link to comment
Share on other sites

Pictures from my trip to Starbase!!!

image1.jpeg

I'm tiny right up next to the letters....

Friends+Starships=heck of a great time!

image1_2.jpeg

image3.jpeg?width=526&height=701

Fr. Tony and I with SN15+16

image5.jpeg?width=526&height=701

I like this one for a scale

image1_1.jpeg?width=526&height=701

I tol 'ya that they named it Rocket Road!

And that's the best ones! I have a LOT more, but they're a pain to upload

 

Link to comment
Share on other sites

**EDA's Elon Musk Interview - Part 1:**

Booster:

* The things in between the grid fins on B4 are load points for lifting (may be also used for catching).
* Booster target for dry mass "should" be under 200 tons.
* Grid fins not folding in looks to be final but Elon doesn't rule out a change
* Grid fins weigh around 3t each - Elon suggests that they could cut the grid fin weight in half

Raptor:

* Raptor V2 is already in production - should be testing V2 in about a month.
* Volume production  of Raptor will move to McGregor, Hawthorne will be used for dev and RVac
* Raptor v2 to be able to reach 230t at 298 bar. Elon wants to squeeze an extra 2bar out of it to make it 300 bar

HLS:

* HLS thruster system is still under debate - Musk indicates that NASA will be able to help them with that.
* HLS could have the same thrust layout as the normal ship

Stage Sep:

* Booster and ship will go into a "spin" before engine shutdown - the aim is that the Ship and booster will seperate by themselves (much like Starlink)
* RCS thrusters on the ship will help with seperation
* Ullage gas (venting) on SH will be used as RCS. Hot gas thrusters have been ELIMINATED according to EDA.
* Elon suggests on-the-spot that ullage gas could be used on the ship as well in order to eliminate cold gas. (May be replace cold gas or may not)

Msc:

* None of the failures of the previous prototypes were on the internal "risk list"

 

Part 2 will probably be more about raptors and possibly other Starshio thrusters (cold gas, hot gas, maybe Lunar Starship prototype thrusters?)

It was also confirmed that part 3 will talk at least a bit about the Florida production site

Edited by Beccab
Link to comment
Share on other sites

9 minutes ago, CatastrophicFailure said:

Wait, what?! :o

When I heard that part, I was assuming the kick spin was for getting the booster pointed the right way for boostback. But now that I think about it, if aero loads are light enough, spinning slightly to release the upper stage with centrifugal "force" (yeah it's not a force but it's easier to say it that way) solves a lot of problems neatly. Performance impact should be minimal. It helps the booster get in the right direction for boostback quicker. It eliminates all the mass that a separation system would take up. And, it makes stacking way easier and turnaround faster because there is no separation system to reset, you just plop it right down on the booster.

Link to comment
Share on other sites

31 minutes ago, Ultimate Steve said:

solves a lot of problems neatly.

Yeah but… that’s usually exactly what you don’t want during separation… didn’t a Falcon 1 fail for exactly that reason? And what about the performance hit from re-orienting the Starship? This ain’t Kerbal after all… I mean, I’m sure they’ve considered all this and what not but still, mind kinda blown right now… :confused:

Gonna be one interesting launch, that’s for dang sure…

and of course the headlines will read, “massive SpaceX rocket nearly spins out of control!”

Link to comment
Share on other sites

17 minutes ago, CatastrophicFailure said:

Yeah but… that’s usually exactly what you don’t want during separation… didn’t a Falcon 1 fail for exactly that reason? And what about the performance hit from re-orienting the Starship? This ain’t Kerbal after all… I mean, I’m sure they’ve considered all this and what not but still, mind kinda blown right now… :confused:

Gonna be one interesting launch, that’s for dang sure…

and of course the headlines will read, “massive SpaceX rocket nearly spins out of control!”

it's delightfully counterintuitive!

Link to comment
Share on other sites

13 minutes ago, CatastrophicFailure said:

Yeah but… that’s usually exactly what you don’t want during separation… didn’t a Falcon 1 fail for exactly that reason? And what about the performance hit from re-orienting the Starship? This ain’t Kerbal after all… I mean, I’m sure they’ve considered all this and what not but still, mind kinda blown right now… :confused:

Gonna be one interesting launch, that’s for dang sure…

and of course the headlines will read, “massive SpaceX rocket nearly spins out of control!”

I think the falcon 1 fail was due to residual thrust from the first stage. Assuming raptor thrust is on a constant downward slope with no increases during shutdown, and that there is no active separation mechanism like in falcon 1, recontacting shouldn't be an issue.

Performance impact shouldn't be much more than a couple seconds of burning above prograde, which they might need to do anyway depending on the flight profile to get the apo up. Unless of course they wait for one whole rotation to do ignition (I doubt it).

Should be offset by a faster boostback and reduced mass, at least that is my intuition. I could still be completely wrong about this though.

Ullage/prop settling for stage two ignition might be a concern with that rotation.

Link to comment
Share on other sites

I was under the impression that on-the-spot suggestion was to use ullage gas as the propellant storage for the ship's hot gas thrusters, not to not burn it at all, but looking back at it I don't think it's clear either way. At any rate, this interview certainly is one heck of an info dump, so many questions I had are already answered!

Link to comment
Share on other sites

 

3 hours ago, Elthy said:

That video gives a nice sense of the size of that thing. I allways assumed the tiles were way smaller, about the size of a hand.

Look how light those things are. They just pick them up with a couple fingers like it's a dinner plate

Link to comment
Share on other sites

4 minutes ago, Lukaszenko said:

 

Look how light those things are. They just pick them up with a couple fingers like it's a dinner plate

I heard that the shuttle tiles were very light because they had a low density, probably these are as well

Also:
E78T5FPWYAUp71j?format=jpg&name=largeE78T5FRXsAI8VoG?format=jpg&name=large
This thing is going to be beautiful

Link to comment
Share on other sites

46 minutes ago, Beccab said:

I heard that the shuttle tiles were very light because they had a low density, probably these are as well

Also:
E78T5FPWYAUp71j?format=jpg&name=largeE78T5FRXsAI8VoG?format=jpg&name=large
This thing is going to be beautiful

I said it once...or twice and I will say it again...

Hi S20! Nice to meet you!:valblush:

Link to comment
Share on other sites

22 minutes ago, Brotoro said:

That staging sequence sounds dubious to me.

The ends butt together, most stages have engines shrouded in a way that requires a more precise separation.

An RCS pitch up, then release seems reasonable. The CM will be inside SS, so it will rotate about that, the release will throw the SH down/forward.

Link to comment
Share on other sites

4 minutes ago, tater said:

The ends butt together, most stages have engines shrouded in a way that requires a more precise separation.

An RCS pitch up, then release seems reasonable. The CM will be inside SS, so it will rotate about that, the release will throw the SH down/forward.

Talk about wishing there was a a camera that could resolve this and let us watch from the 3d person perspective 

21 hours ago, CatastrophicFailure said:

 

How are they going to catch off to the side and then rotate around to the launch platform?  I've yet to see anything on the tower that looks like it can do that 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...