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Starship / Super Heavy

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Re: Starship / Super Heavy

#281

Post by mkl »

valuearb wrote: post #268
mkl wrote: post #244

Earlier quoted context omitted.

I'm not saying it would be easy, but I think it would be easier than Mercury. Even getting to Mercury is hard. I think getting off Venus from 50km up wouldn't be too bad. If you've got enough flotation to carry a research station or city or whatever, with water supply, food production, life support, etc., you can carry a fuelled up Starship and Super Heavy (if your base is smaller, use a smaller rocket [1]). Launchin…

A Starship/SuperHeavy combo weighs 11M pounds, that’s going to have to be one super large balloon you are living on.

That's tiny compared to a city though. This whole colonisation idea is predicated on super large balloons. Since breathable air is a lifting gas, it seems like the people would probably live inside them.

Re: Starship / Super Heavy

#282

Post by nickik »

christophilus wrote: post #247
nickik wrote: post #208

Earlier quoted context omitted.

Well, we actually have a large amount of companies trying to do it. Like 40-60 different companies. Not to mention government projects. Of all of those, only RocketLab has managed to do it, and their rocket is basically as tiny as you can build a orbital rocket. SpaceX did an orbital rocket bigger then RocketLab in 2008. RocketLab doesn't yet have real competition, despite many billions invested. SpaceX at the same t…

ULA is doing it, and seems to be a commercial success. I’m genuinely curious why ULA doesn’t get more publicity.

ULA is not new, its basically Boeing and Lockheed Martin getting together to form a monopoly. The rockets themselves have a lot of legacy going back 60 years. These rockets were developed for the US government and ULA itself has never created its own rocket.

I also didn't talk about China or Indian launch who are also doing it.

Re: Starship / Super Heavy

#283

Post by rrrrrrrrrrrryan »

rrrrrrrrrrrryan wrote: post #271
blackrock wrote: post #144

Earlier quoted context omitted.

How many G’s will passenger experience when the ship transitions from the belly flop to the suicide burn? That looks like an awful lot of G’s that this maneuver is pulling there.

The capsule containing passengers will separate during re-entry and land with parachutes. This suicide burn is just to try to recover the rocket to save money.

Edit: Disregard this, it's wrong entirely.

Re: Starship / Super Heavy

#284

Post by stjohnswarts »

heavenlyblue wrote: post #222
wolfram74 wrote: post #68

Earlier quoted context omitted.

Given most buildings are upwards of 90% air by volume, that's still quite dense.

Wanted to argue with you but apparently concrete is only 2.5g/cm3 so not that much different from water.

There have been ships made of concrete which I always found interesting. Ferrocement (I believe) is a form of boatcraft that can be done in your backyard without any special tools.

Re: Starship / Super Heavy

#285

Post by TylerE »

postalrat wrote: post #279
TylerE wrote: post #58

Earlier quoted context omitted.

I guess the counterargument is that as long as you bring it down in a "safe" area, you don't really need a 100% success rate. If you can reuse it, great, if not, well, it's a rocket.

The fuel used to attempt the landing the instead be used to launch.

That's true, but a suicide burn uses a _lot_ less propellant than you'd think. The atmosphere does most of the work.

Re: Starship / Super Heavy

#286

Post by Koiwai »

tenuousemphasis wrote: post #261
doomlaser wrote: post #49

Earlier quoted context omitted.

It oriented almost perfectly. I'm truly amazed at what SpaceX has accomplished so far. Just need to stick that landing a few dozen more times. It's quite a reorientation.

It actually oriented perfectly, but due to the flip, fuel pressure was lost leading an oxygen rich exhaust eating away the engine (becoming what's known as engine rich exhaust) before it was able to complete the landing burn. They should just have to fix the fuel pressure problem to have a complete success.

I'm very dumb so I'm asking: is "engine rich exhaust" a real term?

Re: Starship / Super Heavy

#287

Post by Koiwai »

MartinodF wrote: post #196
yalok wrote: post #179

Earlier quoted context omitted.

On landing video, I see only 2 engines turn on instead of 3 - why is that? Was one engine malfunctioning, or was it the result of low pressure?

The rocket weighs quite a bit less at the end, having used most of its fuel, so only two engines are needed to land. The engines cannot be throttled down more than ~50% (as all rocket engines), so a third one would add too much thrust. Falcon 9 does the same, relighting 3 engines (out of 9 total) for the boostback burn, 3 for the entry burn and then just 1 for landing.

Thanks for the explanation! it this also the reason why Raptor is (relatively compared to like F-1) small and BFR uses so many of them?

Re: Starship / Super Heavy

#288

Post by Koiwai »

fnord77 wrote: post #77
mabbo wrote: post #9

> The fully integrated Starship/Super Heavy launch vehicle will be approximately 400 feet tall and 30 feet in diameter. For reference, the Saturn V rocket from the Apollo program was 363 feet tall. It was 33 ft wide at the first stage, while Starship is 30 ft wide all the way to the top. It's just massive. And it's fully reusable. What a game changer.

considering this is over 50 years after Saturn V, I don't feel this is such a huge feat.

This is not true technic wise but true politics wise, or politically incorrect, you should not be downvoted.

Re: Starship / Super Heavy

#289

Post by jholman »

Koiwai wrote: post #286
tenuousemphasis wrote: post #261

Earlier quoted context omitted.

It actually oriented perfectly, but due to the flip, fuel pressure was lost leading an oxygen rich exhaust eating away the engine (becoming what's known as engine rich exhaust) before it was able to complete the landing burn. They should just have to fix the fuel pressure problem to have a complete success.

I'm very dumb so I'm asking: is "engine rich exhaust" a real term?

What do you mean by "real term"?

Real rocket science teams really use phrases like this, including this one. Is it a joke? Yeah, kind of. Is it what they would say if they had no sense of humour? No, probably not. Is it still a thing the experts actually say to actually talk about what's going on? Yeah, it is.

a few more examples:

"Rapid Unscheduled Disassembly" : explosive destruction of the rocket

"Lithobraking" : it's like aerobraking, but with less aero and more litho

Re: Starship / Super Heavy

#290

Post by iso947 »

dxdm wrote: post #197
iso947 wrote: post #186

Earlier quoted context omitted.

About that yes, but remember that a fully loaded starship in orbit can land on any solid surface in the solar system and return to earth (except for Venus) Starship’s usable volume is over 100 times that of an Apollo lunar lander.

I don't get it, how does that answer the question about the economics of lifting fuel into orbit? Could you elaborate your point?

To land the volume of one starship on the moon takes 3 or 4 launches of a fully reusable craft - so just the fuel.

To land that with Apollo would take 100 launches of a single use craft.

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