Jump to content

SpaceX Discussion Thread


Skylon

Recommended Posts

On 12/5/2017 at 1:39 PM, tater said:

I'm so glad I left my coffee on the counter when I went to wake up the kids, else there'd be snot-mixed coffee on my keyboard right now.

Then my work here is done. :)

 

Link to comment
Share on other sites

16 minutes ago, Kerbal01 said:

SpaceX posted about how the booster and capsule are "flight proven" doesn't show a pic of the sooty first stage. REEEEEEEEE

 

That's because the picture was taken on the way up.

The "pinstripes" on the lower half of the reused first stage are weld inspections. You have to scrub off the soot before you can do an electromagnetic inspection of the underlying Al-Li weld. But they only scrubbed off what they needed to.

Estimates say about 2.5 kg of total soot on the first stage, which is only a ~250 gram reduction in payload to LEO, so the mass isn't an issue.

Are we sure the FH core is coming down on OCISLY? The Roadster is pretty low-mass; even for a trans-martian injection burn, the center core may have enough dV to boostback.

I wonder what the odds are that the upper stage jettisons the Roadster, does a nitrogen-thruster flip, and burns backward to come back for an entry attempt. Just enough of a burn to bring it into an aerobraking trajectory, with PICA-X panels covering the PAF and fairing-style steerable chutes tucked around the Merlin Vac.

Link to comment
Share on other sites

18 minutes ago, sevenperforce said:

I wonder what the odds are that the upper stage jettisons the Roadster, does a nitrogen-thruster flip, and burns backward to come back for an entry attempt. Just enough of a burn to bring it into an aerobraking trajectory, with PICA-X panels covering the PAF and fairing-style steerable chutes tucked around the Merlin Vac.

It’ll be an 11km/s reentry, way hotter than Dragon LEO reentry. Also, drained upper stage is probably aerodynamically unstable and will flip engine-first. I also doubt that it is strong enough to withstand the g-load from TMI aerobraking.

Edited by sh1pman
Link to comment
Share on other sites

13 minutes ago, IncongruousGoat said:

I would assume so, just to demonstrate the capability.

....but why not demonstrate the capability to RTLS?

15 minutes ago, tater said:

Is there a third landing zone at the Cape?

90% sure there is.

3 minutes ago, sh1pman said:

It’ll be an 11km/s reentry, way hotter than Dragon LEO reentry. Also, drained upper stage is probably aerodynamically unstable and will flip engine-first. I also doubt that it is strong enough to withstand the g-load from TMI aerobraking.

The US will probably have enough spare prop to brake by at least 2 or 3 km/s before entry. And the engine bell may act as a shuttlecock.

Link to comment
Share on other sites

15 minutes ago, tater said:

Is there a third landing zone at the Cape?

Only two, and the second one is just getting finished or will be “soon™.”

22 minutes ago, sevenperforce said:

Are we sure the FH core is coming down on OCISLY? The Roadster is pretty low-mass; even for a trans-martian injection burn, the center core may have enough dV to boostback.

I really doubt it’s gonna be just the roadster, this is a capability test too after all. I expect lots of instrumentation and still some common ballast. 

5 minutes ago, sh1pman said:

It’ll be an 11km/s reentry, way hotter than Dragon LEO reentry. Also, drained upper stage is probably aerodynamically unstable and will flip engine-first. I doubt that it is strong enough to withstand the g-load from TMI aerobraking.

This. Recovering the upper stage sounded iffy enough to begin with just from LEO velocity. Since we’ve heard nothing else, I expect that plan’s scrapped, unless they sourced some kind of transfer stage for the Tesla. 

5 minutes ago, sevenperforce said:

The US will probably have enough spare prop to brake by at least 2 or 3 km/s before entry. And the engine bell may act as a shuttlecock.

The engine bell would get torn apart in very short order. That thing is incredibly fragile when it’s not firing. 

 

Link to comment
Share on other sites

Just now, sevenperforce said:

And the engine bell may act as a shuttlecock.

Don’t think so. My KSP experience tells me there won’t be enough atmo pressure to keep it stable, and since the engine is heavier than the fuel tank, it will flip towards the plasma stream. 

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.

×
×
  • Create New...