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SpaceX launches Starship v3 rocket

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Re: SpaceX launches Starship v3 rocket

#271

Post by NetMageSCW »

erkt wrote: post #256
fooblaster wrote: post #182

Earlier quoted context omitted.

The hardest problem in the entire design had yet to be solved. Having a robust human rated tile system that can be rapidly turned around is a huge engineering challenge that kind of breaks the whole point of the design if it doesn't work. I wouldn't be surprised if they eventually give up and go back to a cheaper throw away second stage, or throw out the tile design completely and try for some evaporative cooling app…

I really hope to see the evaporative cooling make a comeback but it seems unnecessary when it’s returning to earth right now. It would also be interesting to see them do shallower dips into the atmosphere then pull back out and repeat. Like a skipping stone. Lots of expansion contraction, but might work better without tiles.

They did that during the return of Ship on this test flight.

Re: SpaceX launches Starship v3 rocket

#272

Post by NetMageSCW »

fooblaster wrote: post #210
oconnor663 wrote: post #209

Earlier quoted context omitted.

Bear in mind that a lot of what's happening to the tiles now is deliberate experiments to see how much weight they can shave off and how many failed tiles they can survive. Given that the vehicle is routinely surviving reentry at this point, it doesn't seem "hard" to make the tiles more robust by paying for it with added weight. The question is whether they'll have enough weight budget to pay for it? But at this poin…

"surviving reentry" and being reusable are two very different things, particularly if this is to become human rated.

Human rating is irrelevant to what they want to do, it is only a NASA rating - if NASA wants to ride they will have to come up with a rationale but private astronauts can fly on it.

Re: SpaceX launches Starship v3 rocket

#273

Post by NetMageSCW »

globalnode wrote: post #117
itsthecourier wrote: post #114

Earlier quoted context omitted.

why won't it ever work?

Even if it landed perfectly how is it going to be rapidly reusable with all those tiles breaking and needing repair? Then if that problem was magically engineered-away through some sort of materials science breakthrough, it still makes more sense to me to keep your big ships in a space staging area and your smaller ones as atmospheric gophers.

They’ve already demonstrated they can replace all the tiles in a couple of days - even if they continue to have some fall off it won’t be an issue.

Re: SpaceX launches Starship v3 rocket

#274

Post by thunderbird120 »

b112 wrote: post #132
throwaway85825 wrote: post #73

Earlier quoted context omitted.

The shuttle required long expensive refurbishment after each flight.

Just made me realise, this is just like the F-35. Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance. Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes. One was designed to be used in war, in desperate scenarios, with no ability to coddle it. The other, the F-35? Is desig…

>Its turn around time is ridiculous, it has to be maintained with specialized equipment/hangers, along with external contractor assistance.

>Compared to the Gripen, as an example, which can land on a freeway and be up in the air again in a few minutes.

I have no idea where people got the idea that the F-35 requires a major refit after each sortie or that it needs climate controlled hangars, but there's literally no truth to any of it.

The turnaround time for an F-35 after a mission in a wartime scenario isn't going to be much different from any other older fighter jet. Refuel, rearm, get back in the air.

One of the key requirements for the F-35 programs was to minimize extra care needed for the RAM (Radar Absorbent Material). Unlike older stealth aircraft the F-35's ram is "baked in" to the aircraft skin, rather than being a coating. The F-117 and B-2 require climate controlled hangars because their coatings are old and delicate, the F-22 doesn't, but needs regular touch-ups for its coating, the F-35 is just left sitting outside most of the time regardless of where it's operating, a desert, the arctic, a jungle, the deck of a ship, you just leave it out there. The only common maintenance done on the F-35's RAM is replacing a relatively small amount of special RAM tape which is usually used around the edges of the access panels which are opened for other types of maintenance.

Re: SpaceX launches Starship v3 rocket

#275

Post by NetMageSCW »

kibwen wrote: post #186
s1artibartfast wrote: post #177

Earlier quoted context omitted.

In short, the more stages the better to discard mass once it isnt necessary, and the larger to the better to improve the ratio of (ship+payload) to fuel. Here is a decent summary. https://gemini.google.com/share/121466b300c1

This is only true to an extent. Yes, a larger rocket means a better mass:payload ratio, but a larger rocket also means more mass in absolute terms, and more mass means more fuel, and more fuel means more mass, and more mass means more fuel, and more fuel means more mass, and so on. This is "the tyranny of the rocket equation", and it places an upper bound on the size of rockets that need to carry their own fuel for a…

No it doesn’t matter if the payload is full or not. If they succeed in full reuse, flying on a mostly empty Starship will be ten times cheaper than flying on an F9 and that means everything will switch eventually.

If a jumbo jet was ten times more efficient than a smaller plane, they would go everywhere. If a giant pickup truck got a 100MPG, why would you take a 30MPG economy sedan anywhere?

Re: SpaceX launches Starship v3 rocket

#276

Post by NetMageSCW »

djeastm wrote: post #211
clippy99 wrote: post #89

Earlier quoted context omitted.

SpaceX does an excellent job at videography. Sad that Nasa flew its Artemis mission with potato cameras.

SpaceX probably spends a lot of money on marketing/public relations creating great media. I'm guessing NASA's on a shoestring budget for that kind of thing.

One of SpaceX’s founding reasons was to promote STEM and they continue to do that with their video productions.

Re: SpaceX launches Starship v3 rocket

#277

Post by NetMageSCW »

EA wrote: post #68
SJMG wrote: post #39

Earlier quoted context omitted.

I'm concerned about the cracking clearly visible on the heat shield tiles. It doesn't bode well for rapid reusability.

The tiles ablate. The shuttle returned from every mission with missing tiles.

Starship’s tiles are not designed to ablate. They are intended to last multiple flights.

Re: SpaceX launches Starship v3 rocket

#278

Post by NetMageSCW »

SJMG wrote: post #39
Laremere wrote: post #15

Summary from my watch: - Launch roughly on time, after a scrub yesterday. (Sounds like the scrub was due to ground equipment, most notably the water system.) - Initial ascent was good, but then one engine on the booster went out. - Relight of the booster's engines after stage separation for the boost back burn failed. Engines did light again for a landing burn, but seems to have hit the water harder than expected and…

I'm concerned about the cracking clearly visible on the heat shield tiles. It doesn't bode well for rapid reusability.

That wasn’t cracking.

Re: SpaceX launches Starship v3 rocket

#279

Post by NetMageSCW »

SilverElfin wrote: post #61
stephc_int13 wrote: post #37

Earlier quoted context omitted.

The takeoff looked almost normal but I noticed a slight drift from vertical, likely because one of the engines was dead or dying. Overall the V3 is supposed to be an upgrade but actual progress is more or less stalling compared V2.

There is a slight tilt normally, but I agree it was more than usual.

Flight 12 flew a different flight path than previous test flights.

Re: SpaceX launches Starship v3 rocket

#280

Post by NetMageSCW »

syncsynchalt wrote: post #203
jordanb wrote: post #176

Earlier quoted context omitted.

The difference here is a matter of AV technology improvements in the last 40 years.

The difference is having high-bandwidth signal pointed up / away from the wall of plasma.

And having such a large craft that a hole in the plasma envelope exists above the craft that can reach Starlink.
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