totm nov 2023 SpaceX Discussion Thread

[Wjolcz]

Just now, Canopus said:

Maybe they should focus on getting the Autopilot to work reliably before equipping it with compressed gas blasters?

Maybe they are doing both?

[Canopus]

1 minute ago, Wjolcz said:

Maybe they are doing both?

Just feels like he‘s jumping over some steps, Like building an economic and reliable electric car, straight to jet equipped monstrosity. And seriously, while it sounds cool, what do rockets accomplish on a car that powerful brakes and sophisticated abs couldn‘t?

[cubinator]

He's going to make a Batmobile at this rate.

Edited June 10, 2018 by cubinator

[KSK]

16 minutes ago, Canopus said:

Just feels like he‘s jumping over some steps, Like building an economic and reliable electric car, straight to jet equipped monstrosity. And seriously, while it sounds cool, what do rockets accomplish on a car that powerful brakes and sophisticated abs couldn‘t?

Looking awesome.

And possibly pointless. But still awesome.

[StrandedonEarth]

16 minutes ago, Canopus said:

Just feels like he‘s jumping over some steps, Like building an economic and reliable electric car, straight to jet equipped monstrosity. And seriously, while it sounds cool, what do rockets accomplish on a car that powerful brakes and sophisticated abs couldn‘t?

Automotive brakes are ultimately limited by how strong the tires can grip the road. Rocket brakes would have no such limitation and would augment wheel brakes. Bonus: If about to rear-end a car, cold-gas thrusters would push the stooped car a little further ahead. Not much, but still

[Canopus]

So nobody here sees any problem with this? Well i guess we‘ll see if any of this even get‘s beyond twitter post. I doubt this would fare very well in actual traffic conditions.

[Rakaydos]

"Using the setup you describe (compressed air gas thrusters) makes sence, but we're going a lot farther."

Calling it now, minaturized Sabatier methane reactor and BFR RCS-based thrusters, for carbon neutral rockets that run on water. (plus atmosphere Co2)

[CatastrophicFailure]

6 minutes ago, Canopus said:

doubt this would fare very well in actual traffic conditions.

That’s what they said about Teslas in the first place. 

Im still not convinced it’s all just a joke, but if there was anyone who could pull it off and make it work...

[Canopus]

3 minutes ago, CatastrophicFailure said:

That’s what they said about Teslas in the first place. 

And they weren‘t that wrong. I don‘t read much good about Tesla and its Cars.

Edited June 10, 2018 by Canopus

[CatastrophicFailure]

7 minutes ago, Canopus said:

And they weren‘t that wrong. I don‘t read much good about Tesla and its Cars.

My friend, I'm given to wonder if that's because it's what you choose to read. Respectfully, every time you comment on this thread it's always something negative.

Where I live, I see a dozen or more Tesla S's every day, that's saying something about a 500hp $100k electric supercar. Popular Mechanics just named the Model 3 Car of the Year, and it's already the best-selling midsized premium sedan in the US. I'll never own either one, I have no vested interest in the brand, but I can recognize something extraordinary even when it doesn't actually interest me that much. It seems to me most of Tesla's troubles are due to Musk's usual foible of promising a bit too much too soon. That, and a good solid helping of media bias.

If Tesla's issues really were that serious, they simply would not be selling like they are. Profitability for the company is expected later this year.

[magnemoe]

1 minute ago, CatastrophicFailure said:

My friend, I'm given to wonder if that's because it's what you choose to read. Respectfully, every time you comment on this thread it's always something negative.

Where I live, I see a dozen or more Tesla S's every day, that's saying something about a 500hp $100k electric supercar. Popular Mechanics just named the Model 3 Car of the Year, and it's already the best-selling midsized premium sedan in the US. I'll never own either one, I have no vested interest in the brand, but I can recognize something extraordinary even when it doesn't actually interest me that much. It seems to me most of Tesla's troubles are due to Musk's usual foible of promising a bit too much too soon. That, and a good solid helping of media bias.

If Tesla's issues really were that serious, they simply would not be selling like they are. Profitability for the company is expected later this year.

Here in Norway its lots of Teslas, think we have an huge faction of the total sale. 
Yes its an good reason, Norway has very high car taxes so an high end car will easy cost more than twice that in the US or Germany, however electric cars has no taxes at all, add other benefits like free parking and free pass on toll roads makes it extremely relevant as an high end car compared to say an Audi or BMW. 

Now Tesla has an long term problem then other car manufacturers with their insane volume start making high end electrical cars. Now Musk know this his main purpose with Tesla was to show that electrical cars could be cool and fun to drive and put more focus on them, mission accomplish. 

[Wjolcz]

1 hour ago, Canopus said:

Just feels like he‘s jumping over some steps, Like building an economic and reliable electric car, straight to jet equipped monstrosity. And seriously, while it sounds cool, what do rockets accomplish on a car that powerful brakes and sophisticated abs couldn‘t?

I don't know. Maybe sophisticated ABS doesn't do the job any more. Besides, I don't think friction of the tires only would be good enough. Maybe the tires simply explode at these kinds of acceleration/de-acceleration.

Or maybe he's just bored and wants a rocket car and the law doesn't forbid that.

Edited June 10, 2018 by Wjolcz

[tater]

1 hour ago, Canopus said:

And they weren‘t that wrong. I don‘t read much good about Tesla and its Cars.

Dunno what you are reading.

I see many every day, and I know several people who own them (2 people who own 2 (one has an S and an X, the other has an X and a 3), and a few more people who own one). They all love them.

They are incredibly fast, so for anyone interested in that, there's almost no choice, they're faster off the line than most sportscars even if the Tesla is towing something, lol. They're nice inside, and nice to drive. The only downside to them at all is range, so it limits you on long distance trips. For in town use, you're not going to drain it between charging it overnight in your garage.

[zolotiyeruki]

59 minutes ago, Wjolcz said:

I don't know. Maybe sophisticated ABS doesn't do the job any more. Besides, I don't think friction of the tires only would be good enough. Maybe the tires simply explode at these kinds of acceleration/de-acceleration.

Or maybe he's just bored and wants a rocket car and the law doesn't forbid that.

I think you're all thinking in the wrong direction.  I think the jets would point upwards, so that in emergency braking situations, they press the car downward in order to enable higher braking forces.

[NSEP]

27 minutes ago, zolotiyeruki said:

I think you're all thinking in the wrong direction.  I think the jets would point upwards, so that in emergency braking situations, they press the car downward in order to enable higher braking forces.

Or backwards?

I had this cool and stupid idea as a kid to have rocket engines at the back of a train to prevent accidents. But im not sure if i would sacrifice 100 necks for 1 life.

[Canopus]

33 minutes ago, zolotiyeruki said:

I think you're all thinking in the wrong direction.  I think the jets would point upwards, so that in emergency braking situations, they press the car downward in order to enable higher braking forces.

This i could imagine working.

[NSEP]

9 minutes ago, Canopus said:

This i could imagine working.

hmmm MaYbE ElOn Is NoT JoKiNg AfTeR ALL?????????///???//?/?////?

[StrandedonEarth]

1 hour ago, Canopus said:

This i could imagine working.

Not necessarily. On the surface, yes, but an overloaded tire will buckle in the middle (see "underinflated tire tread wear"), reducing the effective contact area. Increased downforce can also be hard on the tire (unless planned for like race cars) and can lead to tire (belt) separation and failure "down the road." Remember, it's not the actual friction that 'breaks' during a skid, but the rubber's shear strength (contact area is not a part of the friction equation, and if the rubber didn't shear it wouldn't leave black marks on the road), so contact area is important.

A large part of downforce generated on race cars is simply to counter the lift generated by the shape of the car.

Someone would have to do the math, but I think rocket thrust would be more effective as direct retro-thrust than increasing downforce.

Edited June 10, 2018 by StrandedonEarth

[Wjolcz]

400 pages and we're talking about cars. But with rocket thrusters. So I guess it's not that much of an offtop.

Yeah, I too think retrothrust would be the best and most efficient way to stop a car in this situation. Also, when on slippery road I would much rather have wheel brakes AND thrust that doesn't depend on friction to stop myself from falling off a cliff or just bumping the side of my car.

Edited June 11, 2018 by Wjolcz

[tater]

We’re jonesing for a launch, hence cars.

[zolotiyeruki]

2 hours ago, StrandedonEarth said:

Not necessarily. On the surface, yes, but an overloaded tire will buckle in the middle (see "underinflated tire tread wear"), reducing the effective contact area. Increased downforce can also be hard on the tire (unless planned for like race cars) and can lead to tire (belt) separation and failure "down the road." Remember, it's not the actual friction that 'breaks' during a skid, but the rubber's shear strength (contact area is not a part of the friction equation, and if the rubber didn't shear it wouldn't leave black marks on the road), so contact area is important.

A large part of downforce generated on race cars is simply to counter the lift generated by the shape of the car.

A lot depends on the road conditions.  Dry asphalt?  Yeah, you may be right.  A bit of water/ice/snow/slush, though, and having more downforce (and therefore traction) could make a big difference.

[Mad Rocket Scientist]

7 hours ago, Canopus said:

Just feels like he‘s jumping over some steps, Like building an economic and reliable electric car, straight to jet equipped monstrosity. And seriously, while it sounds cool, what do rockets accomplish on a car that powerful brakes and sophisticated abs couldn‘t?

Honestly I don't expect to see anything but twitter ramblings about rocket roadster until after the model 3 production is well sorted out.

Based on this:

It won't be just a braking boost, but a set of thrusters to help the car accelerate quicker, go faster, and turn faster. Based on some earlier things Elon said, the roadster v2 is probably limited in speed and handling by traction with the road through the tires, rather than power from the motors. This would also help overcome the advantage of lightness for handling in gas cars.

6 hours ago, Canopus said:

So nobody here sees any problem with this? Well i guess we‘ll see if any of this even get‘s beyond twitter post. I doubt this would fare very well in actual traffic conditions.

If you're talking about noise, Elon said this:

I agree that this system would be impractical and silly for the vast majority of driving, but I think that's true of any car that's this expensive and powerful.

Anyway, to avoid turning this into a Tesla Motors thread:

Does this mean using water carried along with the mission or mined from ice on Mars to capture CO2, or capturing water vapor (ice crystals?) from the martian atmosphere?

[cubinator]

1 minute ago, Mad Rocket Scientist said:

Does this mean using water carried along with the mission or mined from ice on Mars to capture CO2, or capturing water vapor (ice crystals?) from the martian atmosphere?

I think the ultimate goal would be to use water from Mars. But, you are going to already be carrying some water for drinking, washing, plants, etc. 

Anyway, it's good to know they are developing a fuel machine. I wonder whether the first people will stay two years or four. 

[Ultimate Steve]

11 minutes ago, Mad Rocket Scientist said:

Does this mean using water carried along with the mission or mined from ice on Mars to capture CO2, or capturing water vapor (ice crystals?) from the martian atmosphere? 

Probably using martian water. If you're going to carry the water all the way to Mars, it would probably be more practical to just bring more Methalox (besides the whole cryo storage thing).

[Mad Rocket Scientist]

1 minute ago, cubinator said:

I think the ultimate goal would be to use water from Mars. But, you are going to already be carrying some water for drinking, washing, plants, etc. 

Anyway, it's good to know they are developing a fuel machine. I wonder whether the first people will stay two years or four. 

The Case For Mars talked about using some feedstock hydrogen hauled from earth to make CH4 and H2O, then splitting the H2 off and recycling it through the process. It used 6 tons of hydrogen to make 108 tones of CH4-O2 propellant, and avoided needing ice mining the moment you arrive.