Super Heavy has splashed down in The Gulf of Mexico • Hacker News Board

Re: Super Heavy has splashed down in The Gulf of Mexico

#501

Post by dylan604 » Thu, Jun 06, 2024, 9:15 PM UTC

bee_rider wrote: post #492

dylan604 wrote: post #434

Earlier quoted context omitted.

The thing that tickles me is that it has to slow down to reach terminal velocity rather than the normal way of thinking about objects speeding up to reach terminal velocity.

I’m probably missing something important here, but isn’t this true of most things that de-orbit into an atmosphere?

not missing anything, but it's just one of those things about how fast orbital speeds are. yes, i know orbital speeds are around 17,000 mph. this is just another example of just how fast that is. a lot of people might be familiar with falling objects speeding up to get to terminal velocity which is kind of a speed limit for normal things. for de-orbiting spacecraft, this is just another milestone of slow speeds to achieve and not a limit of how fast it goes.

sometimes just looking at things from a different perspective makes me smile on the relative nature of "fast"

Re: Super Heavy has splashed down in The Gulf of Mexico

#502

Post by a_paddy » Thu, Jun 06, 2024, 9:17 PM UTC

dotnet00 wrote: post #396

BurningFrog wrote: post #393

Earlier quoted context omitted.

I'd be really surprised if they didn't have a GPS in the ship. Which should mean they know where it "landed".

They still would've been in position to put down a marker, since they had to be prepared for that before they knew they'd be able to maintain telemetry down to the water, and if they're already in position, it doesn't hurt to place the marker anyway.

And the coordinates of where it "landed" are less important when it's drifting in the middle of the ocean.

Re: Super Heavy has splashed down in The Gulf of Mexico

#503

Post by echoangle » Thu, Jun 06, 2024, 9:19 PM UTC

api wrote: post #120

delichon wrote: post #81

Watching pieces of the ship melt off, but then seeing it make a relatively controlled landing, is perversely confidence building. If it can survive that kind of damage on a control surface maybe it's a quite robust craft.

I’ve said for a while that we won’t be ready for the real space age until you can have a rusty pickup in space. What I mean by that is that we have it down well enough that the tech exceeds tolerances and can degrade gracefully. You see this in some sci-fi where there are rust bucket old ships that work.

I would compare it to Airplanes, and there are not a lot of rust-bucket airplanes, because just like in space, failures can lead to unavoidable death very quickly. That’s not comparable to a reliable pickup

Re: Super Heavy has splashed down in The Gulf of Mexico

#504

Post by magicalhippo » Thu, Jun 06, 2024, 9:20 PM UTC

notact wrote: post #217

pixl97 wrote: post #68

What the hell, half melted starship actually did the landing flip and hit the ocean slow!!! That was amazing!

Can someone explain why reentry must be so hellish? The energy gained during the rocket burn into orbit must be bled off during reentry, and that energy is enormous. However, why must reentry occur so quickly? It seems if the descent into the atmosphere was slower, the heat shield would be able to radiate the heat energy away more effectively, thus lowering skin temperatures, and significantly reducing the engineerin…

I tried what you said in the most realistic simulator we have, Kerbal Space Program, assuming like you that a gentler approach would be better. And I learned that no, that most certainly is not better.

What you need to protect is on the inside of the heat shield. Heat conduction is based on temperature difference and time[1] and the conduction of the material[2]. Since the heat shield tiles have a very low thermal conductivity, it takes a long time for significant heat to pass through.

Yes a more aggressive approach will lead to a greater temperature, but it'll also provide significantly greater drag, thus the the extreme temperatures only exist for a relatively short amount of time, and thus it doesn't have time to pass through the tiles and heat up the inside.

A very shallow approach has significantly less drag, and you spend significantly longer slowing down. The temperatures might be a fair bit less, but the much longer time spent decelerating means it has a chance to make it through the heat shield tiles.

It's not entirely unlike iron meteorites which can still be cold when landing, as they only spend a brief time in the atmosphere[3] and thus don't have time to heat up.

[1]: https://en.wikipedia.org/wiki/Heat_equation#Interpretation

[2]: https://en.wikipedia.org/wiki/Thermal_conductivity_and_resis...

[3]: https://earthscience.stackexchange.com/questions/127/what-te...

Re: Super Heavy has splashed down in The Gulf of Mexico

#505

Post by Denvercoder9 » Thu, Jun 06, 2024, 9:24 PM UTC

thehappypm wrote: post #484

PaulHoule wrote: post #366

Earlier quoted context omitted.

A positive way of framing it is that atmospheric recently is free. If the Earth didn’t have an atmosphere it would take just as big a velocity change to land as it does to get into orbit and getting to be orbit would be as hard as an interplanetary flight. It's worse than it sounds because the rocket equation has a logarithm in it... https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation double the Δv means you sq…

No atmosphere would be much easier. There's enough energy in a Tesla battery to for the Tesla to reach escape velocity. If you could simply drive at max acceleration (and the car didn't fall apart, and the tires continued to have grip, and a million other reasons why this is impossible) eventually you'd reach escape velocity and still have some percentage left. In a more realistic sense, a long railgun type system wo…

> There's enough energy in a Tesla battery to for the Tesla to reach escape velocity.

No, it's not even remotely close. A Model S weighs around 2000kg and has a battery of 100 kWh. That's √((100 kWh)/(1/2*2000kg)) = 600m/s of delta-v. Escape velocity for Earth is 11.2km/s, almost a factor 20 more.

Re: Super Heavy has splashed down in The Gulf of Mexico

#506

Post by inglor_cz » Thu, Jun 06, 2024, 9:33 PM UTC

kevstev wrote: post #230

themgt wrote: post #94

Earlier quoted context omitted.

That was seriously some of the most dramatic television I've ever watched. Video of Starship being melted/torn apart by supersonic plasma, the broadcast stream dying multiple times maybe due to ship destruction, then finally back online, peeking through the cracked camera to see the nearly destroyed grid fin STILL ACTUATING. The announcers laughing about the ship being "maybe held together by some nuts and bolts" and…

I have never rooted for a flap so hard, and likely never will. I am ready to buy flap merch. The energy of the SpaceX employees gave me goosebumps, this was great, it was hard not to get caught up in it- you know this is the culmination of years of hard work that is mostly theoretical until tests like these.

Life is really beautifully unpredictable. When I got up today (Central Europe, so several hours ahead of Texas), I never had an idea that a random steel flap is going to be my new superhero in mere hours.

Its tenacity in the face of hellfire was epic.

Re: Super Heavy has splashed down in The Gulf of Mexico

#507

Post by czl » Thu, Jun 06, 2024, 9:35 PM UTC

stctw wrote: post #406

amanaplanacanal wrote: post #391

Earlier quoted context omitted.

Firebombing whole cities in Europe and Japan is still a black mark in US history. It’s really hard for me to get “holier than thou” on other terror campaigns when I remember that.

It's easy to say that now. Have you lived through unrestricted, total warfare, where one side intends to conquer a continent or the world, invades without provocation, and won't stop until brought to submission through extreme force? The Allies did not initiate war and did not want war. How many of your country's people should you sacrifice to end a war of aggression started by the enemy? Should you not use the means…

> Allies did not initiate war and did not want war.

An argument made that WW2 was continuation of WW1 and that WW1 was wanted by British leadership who were locked in an arms race with Germany that they could not sustain much longer and wanted a war with Germany while they were ahead so the assassination that triggered WW1 was the pretext tobstart WW1. If you disagree please try to answer why leaders are regularly assassinated and that does not cause a world war.

Re: Super Heavy has splashed down in The Gulf of Mexico

#508

Post by bjelkeman-again » Thu, Jun 06, 2024, 9:35 PM UTC

tim333 wrote: post #371

somenameforme wrote: post #344

Earlier quoted context omitted.

The 'worst' thing about watching space launches on streams is that you simply cannot grasp how ridiculously huge these things are. Even if, like in the stream today, you see a water tower for some scale, the size discrepancies just make it so hard to intuit. Starship is 121 meters high. That's something taller than a football field, jetting off into space! I've only gotten to see a decommissioned Space Shuttle in per…

I've got the black and white arty photo as my lockscreen which gives you an idea https://cdn.mos.cms.futurecdn.net/E46BxzjjUkpthVBNE6k8mn-192...

My desktop. My login screen is two Falcon heavy side boosters landing.

Re: Super Heavy has splashed down in The Gulf of Mexico

#509

Post by resolutebat » Thu, Jun 06, 2024, 9:38 PM UTC

mlindner wrote: post #467

riffic wrote: post #457

for context which is often lacking in posts like this, this is what a Super Heavy is (I had to look it up lol because it's not really obvious from the title alone): https://en.wikipedia.org/wiki/SpaceX_Super_Heavy meta but it absolutely would not kill anyone to include some context in your submissions here.

There WAS more context, but some moderator of hacker news merged in the post with more context into this link that was posted first. That erased all the context. Also the significance is not Super Heavy landing in the Gulf of Mexico, but Starship landing in the Indian Ocean.

Both are very significant events, since previous tests didn't get even close to soft landing.

Re: Super Heavy has splashed down in The Gulf of Mexico

#510

Post by httpz » Thu, Jun 06, 2024, 9:40 PM UTC

somenameforme wrote: post #344

bearjaws wrote: post #3

The rate of descent is absolutely astonishing, 8km -> 1km in 20 seconds, then just hovers above the water. Absolutely incredible work by the SpaceX team. Living in central Florida I cannot wait for the new launch facility to come online. We're going to have lines of spectators into the space coast like we did for the shuttle. If any of you are heading to Disney World you should stop by the NASA Kennedy Visitor Comple…

The 'worst' thing about watching space launches on streams is that you simply cannot grasp how ridiculously huge these things are. Even if, like in the stream today, you see a water tower for some scale, the size discrepancies just make it so hard to intuit. Starship is 121 meters high. That's something taller than a football field, jetting off into space! I've only gotten to see a decommissioned Space Shuttle in per…

If you're in LA and want to see the first Falcon 9 that landed, you can see it displayed in front of Space X HQ.

https://maps.app.goo.gl/2LMvohTfwJ1Sq3o56