totm nov 2023 SpaceX Discussion Thread

[StrandedonEarth]

23 minutes ago, PB666 said:

I think the core only weighs 22.5 tons, as for a  tractor trailer this is not particularly heavy. A tractor trailer's legal weight is 40 tons. (before needing an oversized tag)

So with trailer, tractor, rear wheels probably close. Maximum weight on trailer is 34,000 lbs (15,454 kg) for normal sized load.

I meant the strength of the fuselage itself, to be able to support itself sideways. without supports in the middle. Although I suppose it is the same when on the strongback.

[CatastrophicFailure]

16 hours ago, GoSlash27 said:

You know you play too much KSP when you can "read between the lines" and recognize the failures that each of these examples obliquely references

Best,
-Slashy

And explain them TO others, in detail, while they just sit there with their eyes slowly glazing over...

Edited March 17, 2018 by CatastrophicFailure
eye kaint spil

[PB666]

11 hours ago, StrandedonEarth said:

I meant the strength of the fuselage itself, to be able to support itself sideways. without supports in the middle. Although I suppose it is the same when on the strongback.

But your asking the question is it able to support itself sideways at 22.5 tons when its full dressed weight on the LP 31 tons and when fueled is 550,000 tons (24x) that weight. Of course it can support itself,

Remember when that callout says 'pushing downrange' the force of the engines on the rocket is around 1.3g  the same sideways is experienced with a turn 1.7 degrees off vertical. Even without turning, there is significant horizontal component to bumps that are not vertical. If their are nine engines, eight of the engines are not under the axial line, those engines when they 'bump' the rocket create horizontal stress. Unfortunately one can derive from telemetry the only vertical stress on stage 2. But you can imagine it as such for a rocket at just prior to pre-Mach throttle down, most of the force that imparted by the rocket (1.3 TWR, 13 meter/sec²) is absorbed by the S1.

4/5ths of the rocket is the 1st stage, therefore 4/5ths is absorbed by S1 as it is accelerated. To know what these stress are you would need accelerometers at two orthogonal positions on the skin of the rocket.

[YNM]

11 hours ago, StrandedonEarth said:

I meant the strength of the fuselage itself, to be able to support itself sideways. without supports in the middle.

Lots of stuff meant standing erect are transported sideways as well anyway. It's not the balloon tanks of Atlas and Centaur...

If anything, holding bending moment is slightly "easier" than the stress brought by aerodynamic forces and G-loading.

Edited March 17, 2018 by YNM

[sevenperforce]

11 hours ago, CatastrophicFailure said:

And explain them others, in detail, while they just sit there with their eyes slowly glazing over...

"And so that's why the Proton has a reputation for...."

13 hours ago, Starman4308 said:

14 hours ago, Spaceception said:

14 hours ago, magnemoe said:

Its very standard rules for this, you are basically damaging cargo, same as rear ending an boat on trailer. 
And yes its an story you tell your grandchildren, I once rear ended an orbital rocket. 

I wonder what kind of fine someone would have to pay if they damaged a rocket... are there any past examples?

I suspect that unless you are either silly rich or forgiven by SpaceX, you'd wind up filing for bankruptcy and having your pay garnished until the day you die.

Though really, there's probably a whole convoy to prevent collisions. 

Oh, oh, I know this one!

The booster is insured against accidental damage every second it is on the road. However, if you run into it, you're liable. Fortunately, your auto insurance will cover it. Unfortunately, you probably don't have enough coverage to pay for a million-dollar rocket, and you'd be on the hook. Fortunately, the insurance coverage on the booster has an "underinsured motorist" provision to cover whatever your insurance won't cover. Unfortunately, that insurance company can still come after you to be paid back. Fortunately, they can only come after you if they do so within a very brief period of time, and usually they won't.

Unfortunately, no insurance company will ever sell you car insurance again if you ruin a multimillion-dollar rocket.

[PB666]

48 minutes ago, sevenperforce said:

"And so that's why the Proton has a reputation for...."

Oh, oh, I know this one!

The booster is insured against accidental damage every second it is on the road. However, if you run into it, you're liable. Fortunately, your auto insurance will cover it. Unfortunately, you probably don't have enough coverage to pay for a million-dollar rocket, and you'd be on the hook. Fortunately, the insurance coverage on the booster has an "underinsured motorist" provision to cover whatever your insurance won't cover. Unfortunately, that insurance company can still come after you to be paid back. Fortunately, they can only come after you if they do so within a very brief period of time, and usually they won't.

Unfortunately, no insurance company will ever sell you car insurance again if you ruin a multimillion-dollar rocket.

I don't want to be too presumptive here but how much damage could your average crumple front car do to a Merline 1-D engine, each engine can produce upwards of 900,000 N of thrust before being damaged. If you hit that rocket at full speed I doubt the driver would immediately know that he had been hit. I've seen a few Tractor trailor-car accidents . . . .its often difficult in the end to recognize the make and model of the car afterward.

[Confused Scientist]

2 hours ago, sevenperforce said:

[snip]

Unfortunately, no insurance company will ever sell you car insurance again if you ruin a multimillion-dollar rocket.

"Here at Liberty Mutual, we believe in driver forgiveness for your first... oh."

Looking at the picture @tater provided I'm willing to believe that a collision on the back of the rocket would most likely cause damage to the shroud they have around the engines, especially given that in most scenarios (ignoring the yellow cars they have on either end of the convoy to protect the oversized load) a motorist would not have enough clearance behind the rocket to accelerate to dangerous velocities relative to the trailer. In fact, they way they have that rocket mounted makes it seem like the engines are about as high up as the hood of your average car, which probably makes it a lot harder to bump up against them by accident. I think a much worse scenario would be a "swidesipe" occurrence where a car slowly scrapes along the side of the entire rocket, which might require replacement of the entire core or extreme refurbishment instead of swapping out one engine. But, again, it looks like the rocket is covered with a material that would conceivably withstand something like that. So, my worst-case scenario is a T-bone collision right in the middle of the rocket from a car that ran a red light at sixty miles per hour.

[tater]

Wide loads in the US usually (always?) involve escort vehicles in front, and behind. So to rear-end it, you'd have to push the following truck into the back of the rocket. I doubt they stop overnight at a motel with a rocket, I'd think they'd have a few drivers, and do it that way. It's about an 18 hour drive from the TX facility to the Cape. As a result, there would be very few intersection crossings, a few (likely planned due to the size) stops for gas/food.

[StrandedonEarth]

They’d probably just arrange to meet catering trucks and a tanker for refueling. Much like the fuel trucks and catering trucks that service construction equipment and workers at work sites. Otherwise they’d probably  clog up the rest stops. 

Edited March 17, 2018 by StrandedonEarth

[sevenperforce]

3 hours ago, PB666 said:

I don't want to be too presumptive here but how much damage could your average crumple front car do to a Merline 1-D engine, each engine can produce upwards of 900,000 N of thrust before being damaged.

The engine nozzle is under tension when it is producing hundreds of kN of thrust. It is not terribly strong against compression. Consider this:

If you hit the back end of the trailer with a vehicle big enough to actually hit one of the Merlins, that particular engine is toast.

3 hours ago, PB666 said:

If you hit that rocket at full speed I doubt the driver would immediately know that he had been hit. I've seen a few Tractor trailor-car accidents . . . .its often difficult in the end to recognize the make and model of the car afterward.

This is probably true.

2 hours ago, Confused Scientist said:

"Here at Liberty Mutual, we believe in driver forgiveness for your first... oh."

I think a much worse scenario would be a "swidesipe" occurrence where a car slowly scrapes along the side of the entire rocket, which might require replacement of the entire core or extreme refurbishment instead of swapping out one engine. But, again, it looks like the rocket is covered with a material that would conceivably withstand something like that. So, my worst-case scenario is a T-bone collision right in the middle of the rocket from a car that ran a red light at sixty miles per hour.

You'd have to really hit it hard to actually break the sidebody. But it would be unflyable for sure.

[CatastrophicFailure]

2 hours ago, Confused Scientist said:

a collision on the back of the rocket would most likely cause damage to the shroud they have around the engines, especially given that in most scenarios (ignoring the yellow cars they have on either end of the convoy to protect the oversized load) a motorist would not have enough clearance behind the rocket to accelerate to dangerous velocities relative to the trailer

Is that some kind of structural shroud, though? It looks like just shrinkwrap to me. You can clearly see the outline of the Center engine, as well as the wire tunnel down the side of the tank. Shrinkwrap is some pretty tough stuff, but it’s not impact protection. 

I could see this going badly for someone (because it’s happened to me) like this: guy in a pickup off on the left side is being an S, going too fast, swerving through traffic. Trades paint with a Porsche and both vehicles go careening across the freeway at an angle, right in front of the rear chase car and into the engine cluster. 

So I’m really curious just how strong a sea-level Merlin engine bell is. The Porsche would probably go right under them, and who knows what that might damage. 

[Confused Scientist]

4 minutes ago, sevenperforce said:

You'd have to really hit it hard to actually break the sidebody. But it would be unflyable for sure.

Yeah, I think the end result of that scenario is: Rocket, one;  Car, nothing. But you wouldn't be able to use either one afterwords.

2 minutes ago, CatastrophicFailure said:

Is that some kind of structural shroud, though? It looks like just shrinkwrap to me. You can clearly see the outline of the Center engine, as well as the wire tunnel down the side of the tank. Shrinkwrap is some pretty tough stuff, but it’s not impact protection. 

I see the shroud as being more "scraping protection" than "accelerator wedged to the floor protection" in a collision scenario. You could definitely  damage the bells if you were going fast enough, but cracking them for example is probably much harder if they aren't exposed. The thing I want to compare the shroud to is a laptop case: it can handle a lot of minor abuse, but it's no good for one giant collision.

Edited March 17, 2018 by Confused Scientist

[PB666]

5 hours ago, tater said:

Wide loads in the US usually (always?) involve escort vehicles in front, and behind. So to rear-end it, you'd have to push the following truck into the back of the rocket. I doubt they stop overnight at a motel with a rocket, I'd think they'd have a few drivers, and do it that way. It's about an 18 hour drive from the TX facility to the Cape. As a result, there would be very few intersection crossings, a few (likely planned due to the size) stops for gas/food.

"Its difficult to make something foolproof because fools are damn clever" said the escort driver as someone in  red Lamborghini passes in front of him and slams into the lowest Merlin- 1-D engine decapitating himself in the process.

Seriously, guys I want to know how they are going to get a 30 ft fuselag from, is it hawthorne, to Boca Chica, or 39A or whatever.

[tater]

I thought they were looking at a facility at the port in LA.

 

[PB666]

I thought they were going to build one on the Port of Brownsville, nothing there to shake a stick at but there is development going on at the port, for sure.

[CatastrophicFailure]

1 hour ago, PB666 said:

Seriously, guys I want to know how they are going to get a 30 ft fuselag from, is it hawthorne, to Boca Chica, or 39A or whatever.

Where do you think they got the whole "point to point" idea from in the first place? 

Yeah, nah, they're gonna barge 'em through the Canal. At least at first. Tho their facility at Hawthorne is right on an airport...

...yet some quick Google mapping confirms, yeah they ain't gonna move something 30' tall by road anywhere near there. But I thought the whole point of reducing the BFR size to 9m was so they could build it at their existing facility? If they plan to be launching in two or three years, they'd better get to work on that new factory like yesterday.

[sevenperforce]

5 hours ago, CatastrophicFailure said:

Where do you think they got the whole "point to point" idea from in the first place? 

Yeah, nah, they're gonna barge 'em through the Canal. At least at first. Tho their facility at Hawthorne is right on an airport...

...yet some quick Google mapping confirms, yeah they ain't gonna move something 30' tall by road anywhere near there. But I thought the whole point of reducing the BFR size to 9m was so they could build it at their existing facility? If they plan to be launching in two or three years, they'd better get to work on that new factory like yesterday.

Launching in less than a year, actually.

[monophonic]

On 18.3.2018 at 12:27 AM, CatastrophicFailure said:

But I thought the whole point of reducing the BFR size to 9m was so they could build it at their existing facility? If they plan to be launching in two or three years, they'd better get to work on that new factory like yesterday.

I thought that size had to do with what they can fit inside the current factory. Not anything with what can be carried around on the roads.

[NSEP]

On 18/03/2018 at 4:47 AM, sevenperforce said:

Launching in less than a year, actually.

They plan on Grasshopper-like testing in less than a year and full-scale orbital tests in 2-3 years.

[CastleKSide]

 

[sh1pman]

SpaceX indicates it will manufacture the BFR rocket in Los Angeles.

Quote

The company seeks to use an 18-acre site at Berth 240 in the port "for the construction and operation of a facility to manufacture large commercial transportation vessels." Operations at the site would include "research and development of transportation vessels and would likely include general manufacturing procedures such as welding, composite curing, cleaning, painting, and assembly operations." Completed vessels would need to be transported by water due to their size, the document states, as a means to explain why the company needs a facility immediately adjacent to the water.

https://arstechnica.com/science/2018/03/spacex-indicates-it-will-manufacture-the-bfr-rocket-in-los-angeles/

[CatastrophicFailure]

2 hours ago, sh1pman said:

SpaceX indicates it will manufacture the BFR rocket in Los Angeles.

Funny you should mention that...

Right about here.

And now this is stuck in my head. 

 

 

Edited March 20, 2018 by CatastrophicFailure

[CatastrophicFailure]

 

seriously jonesing for some SpaceX activity, here... 

[Ultimate Steve]

3 hours ago, CatastrophicFailure said:

seriously jonesing for some SpaceX activity, here... 

Aww, yeah! Birthday launch!

Although there was a SpaceX launch last year that was supposed to be on my birthday but was delayed a day...

 

Also Reddit's screaming that the in flight abort test is currently scheduled for sometime in May. That's, like, two months from now! EDIT: This is incorrect, sadly. It also looks like Boeing is going to fly crew before SpaceX.

Edited March 21, 2018 by Ultimate Steve

[CatastrophicFailure]

36 minutes ago, Ultimate Steve said:

Also Reddit's screaming that the in flight abort test is currently scheduled for sometime in May. That's, like, two months from now!

Hm, that would be something new. Last I heard the flight abort test wouldn’t be until after the unmanned orbital flight.