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Super Heavy has splashed down in The Gulf of Mexico

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

#441

Post by avmich »

vl wrote: post #376
avmich wrote: post #314

Earlier quoted context omitted.

> how many of those things are there? Apollo program flew once in 6 months. If we're to build a Moon base, we're going to have at least this frequency of flights - really, I'd prefer to have a great margin on top of that, because Moon is much harder than LEO, and we might need more resiliency to safely explore. Each flight to the Moon will likely need to involve 10-20 Starship flights (rough number) to LEO. So even i…

Mars launch window is every two years. It is very inefficient to launch at other times. As for moon, I'm surprised with the estimate you have provided. Apollo needed just one launch for each mission. Even if SpaceX will do orbital re-fueling, it's just two-three launches, why would you need more? BTW, the idea of getting heavy Starship to the moon and back is interesting, but at the end flying the vehicle optimized f…

> Even if SpaceX will do orbital re-fueling, it's just two-three launches, why would you need more?

Wikipedia says Starship weights 120 ton empty and 1320 ton fueled, plus 100 ton payload (approximate numbers). That means fuel weights 1200 ton. So to carry fuel to LEO to fuel up a Starship you need 1200 / 100 = 12 flights. You can change this number maybe 2 times into both directions, but I doubt you'll fuel Starship with just 2 or 3 flights of tankers. Would be glad to err here.

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

#442

Post by indoordin0saur »

hackernudes wrote: post #422
indoordin0saur wrote: post #357

Earlier quoted context omitted.

Ramsar, Iran has similar levels of background radiation as being on the surface of Mars. And people live completely healthy long lives there. Chronic low-level radiation isn't nearly as bad as we once thought. It's acute high-level doses or consuming radioactive substances that you really need to worry about. Mars really won't be bad at all with some easily implemented mitigation measures.

The commenter is talking about the 6 month trip to Mars in space, not on the surface.

On that, if you orient the ship so that the rear is pointed directly at the sun (trivial to do once you're coasting) you'll have a hundred feet of liquid fuel and other solid material which will block the primary source of radiation (the sun).

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

#443

Post by elsonrodriguez »

me_me_me wrote: post #212
elsonrodriguez wrote: post #199

Earlier quoted context omitted.

We will probably perform a human mission and return samples before a robot goes and picks up the Perseverance samples. We’ve been mars-capable since Apollo. It’s a matter of will, which is a political function of cost, which is falling rapidly.

> We’ve been mars-capable since Apollo. serious citation needed! you cant make shit up. Apollo and saturn5 were nowhere near getting humans to mars. Not even close. It got us to moon with bare minimum. A weekend trip vs 6 months trip. The scale up of needed resources is mind boggling. At every step. I mean pick any step and explain how Apollo could achieve it.

You can read up on Mars Direct for more info.

The gist of it is that the Saturn V has enough delta v to get to Mars, on the count of Mars having an atmosphere, which can be used for aerobraking.

Given the capability of reaching Mars with a Saturn V, the rest of the plan revolved around using Apollo hardware, with some modification, for both transport and habitats(re-use of empty stages featured prominently).

Ultimately even if we had hit some roadblock with martian soil or what have you, in an alternate timeline we could have at least sent uncrewed test flights to Mars and back.

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

#444

Post by avmich »

vl wrote: post #376
avmich wrote: post #314

Earlier quoted context omitted.

> how many of those things are there? Apollo program flew once in 6 months. If we're to build a Moon base, we're going to have at least this frequency of flights - really, I'd prefer to have a great margin on top of that, because Moon is much harder than LEO, and we might need more resiliency to safely explore. Each flight to the Moon will likely need to involve 10-20 Starship flights (rough number) to LEO. So even i…

Mars launch window is every two years. It is very inefficient to launch at other times. As for moon, I'm surprised with the estimate you have provided. Apollo needed just one launch for each mission. Even if SpaceX will do orbital re-fueling, it's just two-three launches, why would you need more? BTW, the idea of getting heavy Starship to the moon and back is interesting, but at the end flying the vehicle optimized f…

> My prediction that they quickly will go to specialized LEO-LMO vehicles with LEO re-fueling.

Two comments here. First, we assume now SpaceX is going to have Starship HLS - human landing system - which doesn't go back to Earth, doesn't have flaps or heat shield, and is going to be used between low Moon orbit (LMO) and Moon surface - maybe one roundtrip, maybe more. Yes, for each following roundtrip HLS needs to be refueled.

Second, Musk mentioned "Moon base Alpha" in his talk. Having a serious Moon base makes it possible to produce some of propellants there. Oxygen is plentiful in the form of oxides on the Moon, and by mass it's 2/3 - 3/4 of the propellant load of the Starship, so it might be useful to produce it on the Moon.

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

#445

Post by moskie »

indoordin0saur wrote: post #416
moskie wrote: post #405

Earlier quoted context omitted.

> given the very real concerns that there is a dangerous cult of personality surrounding Musk, seeing this footage presented this way is unsettling.

Seems like a very small-minded way to see things... But if it makes you feel any better, Musk is only one of many people working at SpaceX. You could see him as just a figurehead and you wouldn't too far from reality.

I could call you small minded for thinking only of advances in rocket technology, and ignoring the negative aspects of advancing Musk's power and influence. Should I?

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

#446

Post by dylan604 »

lsaferite wrote: post #394
idontwantthis wrote: post #118

Earlier quoted context omitted.

It looked like plasma got between the flap and the body. I wonder if that means something broke/melted to allow that, or if the design just allowed it accidentally.

It looked like the flap was starting to glow internally in the middle, right before the burn-through on the hinge point. I wonder if it maybe had a lost tile on the other side that evolved into the burn-through we saw in the video.

I imagine this is what happened to Columbia

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

#447

Post by avmich »

fwip wrote: post #436
avmich wrote: post #380

Earlier quoted context omitted.

> I'm saying there is no point whatsoever right now, at least no material or scientific purpose. "No point" here means "no reasonable goal". In this case reasonability is subjective - somebody sees obvious reasons why Mars colony could be useful for humanity, somebody doesn't. Pro arguments are science, learning how to live off another planet, certain insurance against planet-wide cataclysms, general progress in spac…

It's difficult to imagine any cataclysm that would result in the Earth being less habitable (even for us squishy humans) than Mars already is.

It's really a matter of imagination :) . I learned about the existence of the Institute of the Problems of Asteroid Hazards long time ago, which suggested to me it's not a black-and-white type of question.

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

#448

Post by rkagerer »

mathsmath wrote: post #360
cryptonector wrote: post #287

Earlier quoted context omitted.

Failure of the tanks would undoubtedly have been catastrophic. Partial failure of a flight control surface proved survivable.

It's also worth noting part of the craft flew (intentionally) without heat tiles, and another part with thinner tiles. They're gathering a ton of data to make it robust! Many of these engineers built Falcon 9, and I have a pretty high degree of confidence they'll shake out the issues. SpaceX operates very differently from traditional aerospace, so we'll likely see many more issues come up before Starship is human rat…

Two tiles were intentionally left out, in a non-critical area (the anticipated damage was still bad for re-usability, but tolerable for re-entry) and instrumented with sensors to collect data like just how hot it gets.

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

#449

Post by cletus »

Majromax wrote: post #193
cletus wrote: post #109

Earlier quoted context omitted.

If you think about this, it doesn't make a lot of sense because different satellites are going to sit in very different orbits. Geosynchronous satellites are an obvious case where satellites will collect into a limited number of orbits but they vary on what point of the Earth they sit over. Also getting to geostationary orbit takes a lot more fuel so the rocket has less room for payload than, say, low EArth orbit. I'…

> I'm not sure one rocket can launch a geostationary satellite above the Americas and above Europe in the same mission. Easily. Moving within an orbit is a matter of fine adjustment. For example, any stationkeeping that expands the orbit slightly will cause the satellite to "fall back" over time. Geostationary satellites are the best orbit for this, since every satellite in such an orbit essentially shares it with al…

I'm not sure this is true. if it were, there wouldn't be launch windows because any correction within a given orbit would be, as you call it, "a fine adjustment" yet we clearly do have launch windows.

Also if you're in a geostationary orbit to deliver one payload you have to leave that orbit to get to another geostationary orbit because there are other satellites in your way.

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

#450

Post by Zigurd »

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.

That doesn't work IRL. Space is insanely unforgiving. While Starship has a vastly better chance than STS had of achieving rapid reusability, you really can't launch with a rocket that isn't up to spec because adding robustness adds weight. Unlike a multi-stage expendable rocket, Starship uses all its fuel to get to orbit. To go to the moon or beyond, it requires refueling by several other Starships that also just get to orbit. If the payload spec can't be met you need even more refueling launches. If reusability isn't rapid, you need a starship for each refueling launch. If cost goals are not met, the cost difference vs expendable rockets shrinks. Everything has to go right.
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