SpaceX And/Or Rocketry In General

Gary Charpentier
Gary Charpentier
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RE: That's beautiful. It

Quote:
That's beautiful. It shows the kinetics of the whole deal nicely. I know it is ( almost ) silly to say it, but obviously you have to come back down by more or less the same path* that you went up ... :-)
* No. Actually you don't have to.


Actually you can't. You can't stop on a dime and reverse! While you are reversing your downrange speed you are in free fall, the first part still going up as that part of your boost phase is countered by gravity. As you get close to the landing site, that is when you need to manage your fall rate. You will end up doing a big loop like track in the sky. Of course near the ground both tracks will look somewhat the same as you want to land standing up.

That track is fuel efficient as you burn more weight at height not worrying about the speed you are falling. So as you get close to the ground you are lighter and need less fuel to slow down.

Mike Hewson
Mike Hewson
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Well in generality there's

Well in generality there's lots of options depending how much fuel you want to spend and how long you want to take doing it. You could flip the craft around centre of mass and come back down close to the up going path, with the hot end pointing toward orbit & then flip again closer to landing, but why would you ? :-)

{ They do burn fuel at height and thus lose mass but that also achieves a height gain as well. Those vanes do a hell of job to soak up the KE though ... it would be interesting to know their limits. I think Elon was implying they are already making fullest use of that mechanism. }

Whatever happens from the moment of separation ( from second stage ) you have to bleed K.E. to zero and gravitational potential to zero relative to LZ-1 ( restating the definition of a landing ). And not break the thing. It would be interesting to get the insider look at why the current method was chosen eg. why not loop under ? For most rocket launches it is only the upgoing leg that needs crafting .... and we don't have knowledge of their constraints to hand.

Cheers, Mike.

( edit ) I found a better resource on the fuels, but the RP-1 spec is wider than expected. Typical average RP-1 molecular weight is ~ 175 and within that hydrogen to carbon ratio is about 1.95 ( by number & so C12H24 is a tad light with C13H26 a tad heavy ), so a complete pure burn to carbon dioxide and water is about 2.4 to 1 mix LOX/kero ( by mass ) but that isn't going to happen on the day in said rocket engine. Either way a 2.56 is on the oxygen rich side and still largely preserved by the new cooling strategy. I also discovered that the Russians were doing the super cooling too some time ago .... but with different engines obviously. RP-1 has the best bulk density.

I have made this letter longer than usual because I lack the time to make it shorter ...

... and my other CPU is a Ryzen 5950X :-) Blaise Pascal

Anonymous

Did some looking for the LZ

Did some looking for the LZ at Vandenburg and came across this location.

The image date is jun of '12 so it is fairly old. Nothing else I "could see" though looked as promising. The only thing its missing is the "SpaceX" logo. But they might not id it here.

archae86
archae86
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Multiple press reports plus

Multiple press reports plus Wikipedia say that the SpaceX Vandenberg landing pad location is within the SLC-4 complex. So the same complex from which they launch, though a different specific location.

So try to find modern photos near:

34.632706°N 120.613393°W

The Google Earth shot is 2012, so predates any LZ work.

These guys are pretty brave, putting the landing pads so close to things you don't want to mess up.

There is an image linked from Reddit which is labelled as being the Vandenberg Landing Zone pad under construction. Maybe some matching of visible older buildings could confirm or deny that this is on SLC-4 somewhere.

Anonymous

RE: Multiple press reports

Quote:

Multiple press reports plus Wikipedia say that the SpaceX Vandenberg landing pad location is within the SLC-4 complex. So the same complex from which they launch, though a different specific location.

So try to find modern photos near:

34.632706°N 120.613393°W

The Google Earth shot is 2012, so predates any LZ work.

These guys are pretty brave, putting the landing pads so close to things you don't want to mess up.

There is an image linked from Reddit which is labelled as being the Vandenberg Landing Zone pad under construction. Maybe some matching of visible older buildings could confirm or deny that this is on SLC-4 somewhere.

Your probably right. The one I singled out was considerably more inland from the coast but still on the Vandenburg property. This one (your coords) is right on the coast and seems much more likely. While the imaging is still 2012 the "look" feels more in step with the image from Redit in your post.

[EDIT] Noticed the "large image sizes" so I downsized them.

archae86
archae86
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It appears that Terraserver

It appears that Terraserver has more up-to-date images of the SLC-4 complex, and I think the obvious shape is probably the SpaceX landing pad location.

This is not quite so terrifying close to active buildings as it looks, and the structure just to the west of the pad is very sturdy and no longer used launch site concrete. on the other hand, there is plenty of more active stuff not so very far to the east.

Mike Hewson: As the SLC-4 complex has a long history of Titan launch work, it is possible that the impression you got that the Cape Canaveral landing site was on Titan historic ground was a mixup with aspects of this location.

David S
David S
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Russian Federal Space Agency

Russian Federal Space Agency dissolved, becomes a State Corporation (but keeps the name Roscosmos)

David

Miserable old git
Patiently waiting for the asteroid with my name on it.

Anonymous

RE: Russian Federal Space

Disturbing. I imagine more emphasis will be placed on strategic importance i.e., military use, rather than in furthering the advancement of humankind.

mikey
mikey
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RE: RE: Russian Federal

Quote:

Disturbing. I imagine more emphasis will be placed on strategic importance i.e., military use, rather than in furthering the advancement of humankind.

+1

Chris S
Chris S
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Read a bit further chaps

Read a bit further chaps ...

Russian President Vladimir Putin is dissolving the country's Federal Space Agency, known as Roscosmos, and turning it into a state-run corporation, according to a statement by the Kremlin. That means Roscosmos will transform from a solely government-funded agency into a company that's overseen and partially backed by the government. It allows the organization to pursue the country’s overarching space goals while additionally conducting commercial affairs like other private spaceflight companies. The move is meant to fix an agency that has been plagued by corruption and major financial scandals.

Waiting for Godot & salvation :-)

Why do doctors have to practice?
You'd think they'd have got it right by now

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