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Starship Flight 5: Launch and booster catch [video]

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Re: Starship Flight 5: Launch and booster catch [video]

#931

Post by Fin_Code »

abustamam wrote: post #923

This is truly an amazing feat! Congratulations to the SpaceX team. Can someone explain to me exactly WHY it's such a big deal though? Like subjectively I can see it's incredible but while watching the video there were enormous applauses at points I knew were a big deal but I lacked the understanding of physics to truly appreciate.

The current Falcon rocket always expends a stage and lands a stage. Starship will land both stages. Also Starship is far larger and in rocketry there is something called the square cube law that means bigger is better. So its far more efficient. That leads to far cheaper mass to orbit costs.

Re: Starship Flight 5: Launch and booster catch [video]

#933

Post by cubefox »

alecco wrote: post #33
themgt wrote: post #22

NSF video: https://x.com/nasaspaceflight/status/1845442658203734384 Truly incredible. A day for the history books.

> NSF is not affiliated with NASA, but the initials in the URL are used with permission from NASA.

They should just rename themselves to NSF Space Flight, or NSF for short.

Re: Starship Flight 5: Launch and booster catch [video]

#934

Post by caconym_ »

ninetyninenine wrote: post #909
caconym_ wrote: post #796

Earlier quoted context omitted.

The booster actually does have heat shielding behind the engine bells, to protect against aerodynamic heating on the return. In some of today's footage you can see it glowing yellow. However, Raptor 3 is supposed to obviate the need for this shielding.

Where did it glow yellow? What time in the video? The booster doesn’t travel fast enough to need heat shielding ever. It makes zero sense to use heat shielding behind the engine bells. Why? Think about it. If the booster renters the atmosphere engine bells first the engine bells would burn up BEFORE the air even touches the heat shield. If there are actually tiles there it’s just there to protect the booster from the…

You ought to do some basic research before making a post like this. Honestly might be the most baffling comment I've ever seen on HN---what kind of mindset does it take to have this kind of overriding confidence in one's own lay speculation?

The engine bells are made of different material than what's behind them (a material that has to directly withstand hot exhaust) and the aerodynamics of the ass end of the rocket are complex; some combination of these factors means this heating isn't an issue for the bells but is a concern for what's behind them. The booster does not re-enter from orbital velocity, but does come down engines first at supersonic speed. Stability in this orientation throughout the descent is a problem SpaceX solved with Falcon 9, and SH works the same way.

See the other reply to your comment for timestamped video of aerodynamic heating behind the engine bells.

Is it possible you're confusing the booster with the second stage (Starship)? They are not the same thing.

Re: Starship Flight 5: Launch and booster catch [video]

#935

Post by whimsicalism »

pfdietz wrote: post #879
sharlos201068 wrote: post #862

Earlier quoted context omitted.

Even the worst expected impacts of climate change will leave earth tremendously more habitable than anywhere else in the solar system.

Even a nuclear war would have that outcome. Even a KT boundary scale asteroid impact would have that outcome. The rest of the solar system is just hell.

There are plenty of imaginable events where being multiplanetary would help.

Re: Starship Flight 5: Launch and booster catch [video]

#936

Post by Faark »

stetrain wrote: post #423
ghc wrote: post #23

Nothing could have prepared me for how that catch looked. I was sure the rocket was careening into the tower at the last second before it straightened out. The control algorithms must be incredible for the landing system to work within those small tolerances.

Here’s a video from a farther vantage point that gives a better perspective on the landing process: https://x.com/shaunmmaguire/status/1845444890764644694

Wow, those pressure waves! Didn't see them yet, on all the close up footage. Thx for posting

Re: Starship Flight 5: Launch and booster catch [video]

#938

Post by margalabargala »

consumer451 wrote: post #915
mhandley wrote: post #877

Earlier quoted context omitted.

As to whether catching the booster adds risk - I'm not sure it does. First, to the extent the booster is out of position in the x (sideways) direction, the chopsticks can move to accomodate error. But actually I think this dimension is the easiest of the three, as the booster has plenty to time to null any error in this dimension. In the y direction (direction of travel towards the tower), the rails on the chopsticks…

I am really curious what the maximum wind speed allowed for a booster landing will be. Upon landing, it has a lot of windage and not nearly as much mass as during take-off. I have experience with docking large boats and it does seem to be a bit similar. In the case of boats, wind is a big deal, and the booster has nothing "below the waterline" to slow down the effects of wind.

I doubt this is an issue.

Not because wind wouldn't affect an empty booster; it certainly would.

But since the booster returns within 8 minutes of the launch, the weather in which a booster lands is restricted to the weather in which they will launch a rocket.

Re: Starship Flight 5: Launch and booster catch [video]

#939

Post by consumer451 »

margalabargala wrote: post #938
consumer451 wrote: post #915

Earlier quoted context omitted.

I am really curious what the maximum wind speed allowed for a booster landing will be. Upon landing, it has a lot of windage and not nearly as much mass as during take-off. I have experience with docking large boats and it does seem to be a bit similar. In the case of boats, wind is a big deal, and the booster has nothing "below the waterline" to slow down the effects of wind.

I doubt this is an issue. Not because wind wouldn't affect an empty booster; it certainly would. But since the booster returns within 8 minutes of the launch, the weather in which a booster lands is restricted to the weather in which they will launch a rocket.

But then wouldn't the limiting factor for launch be the maximum allowed wind for landing?

Re: Starship Flight 5: Launch and booster catch [video]

#940

Post by philipwhiuk »

UltraSane wrote: post #918

The contrast between SpaceX's success at creating reusable rockets and Tesla's failure at FSD is pretty stark.

To be honest FSD is way harder. The platform doesn't occasionally have a road closure sign or a new traffic light or a guy unloading his van or an emergency vehicle with its hazards on.

Don't get me wrong the engineering and physics are crazy ugly, but it's at least consistent within a range. Humans are messy, unpredictable, unreliable and chaotic.

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