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SpaceX test flight of Starship SN-5 [video]

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Re: SpaceX test flight of Starship SN-5 [video]

#301

Post by SEJeff »

martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

> - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it is the most advanced rocket engine ever made and I'm not aware of any upcoming engine that can compete with it.

I believe the Raptor is the first actually working full flow staged combustion engine. It is sort of a holy-grail of engine for liquid rockets. Tim Dodd has a lot more info on it here:

https://everydayastronaut.com/raptor-engine/

However please call it what it really is. It isn't a belly flop so much as it is a skydiver maneuver. Just like how a skydiver splays out their arms and legs to maintain stability and slow down a bit, starship will do the same. Also like a skydiver, it will upright itself before landing as a belly flop would almost guarantee a RUD.

Re: SpaceX test flight of Starship SN-5 [video]

#302

Post by AtlasBarfed »

fastball wrote: post #193
ncmncm wrote: post #158

Earlier quoted context omitted.

To get a sense of the difficulty, imagine sending a million people to the South Pole to set up a self-sustaining colony. That would be much more than 1000 times easier than establishing such a base on Mars.

I'm interested in living on Mars. I'm not interested in living in Antarctica.

Massive domes to act as greenhouses, melting a couple miles of ice cover. Fossils and untapped resources. Antarctica could be a lot of fun to colonize.

Re: SpaceX test flight of Starship SN-5 [video]

#303

Post by SEJeff »

apendleton wrote: post #232
paulsutter wrote: post #227

Earlier quoted context omitted.

In addition to being full-flow, Raptor runs on methane (CH4, the simplest hydrocarbon), which already exists many places in the solar system (including Mars), and is easier to manufacture than kerosene or liquid hydrogen. SpaceX developed an incredibly advanced simulator to make it happen: https://www.youtube.com/watch?v=vYA0f6R5KAI

Slight clarification: while there have been traces of methane detected on Mars, there's probably not enough to be able to easily use it as fuel. Methane is still beneficial for refueling on Mars, though, because you can make it in place out of water (which is plentiful on Mars as water ice) and CO2 (also plentiful, in the atmosphere) using the Sabatier process. So it remains the case that methane as fuel lets you avo…

Exactly. Elon has explicitly mentioned manufacturing metholox (the raptor engine fuel) using a really beefy ISRU factory. It would be feasible, but is still a lot of work required.

Re: SpaceX test flight of Starship SN-5 [video]

#304

Post by SEJeff »

jcun4128 wrote: post #275
nkoren wrote: post #273

Earlier quoted context omitted.

The Falcon Heavy uses 27 engines and has a perfect track record ,so they've got some credibility here.

Yeah looks like 3 for 3 so far. It seems like a big number... as opposed to just 5 (Saturn V). What is the rationale for more smaller engines(other than offset/greater forces/new R&D)?

Why only turn it up to 11 when you can turn it up to 31? See the Starship dial goes all the way to 31.

Re: SpaceX test flight of Starship SN-5 [video]

#305

Post by DannyB2 »

martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

Lettuce not forget Raptor runs on Oxygen and Methane. Both of which might be produced on Mars.

Re: SpaceX test flight of Starship SN-5 [video]

#306

Post by 0xffff2 »

h3rsko wrote: post #274
tjtrapp wrote: post #63

Earlier quoted context omitted.

We're hiring for Starship and Starlink software teams: https://grnh.se/080f65d02us It sounds like you're passionate about your work and that's an important quality. As gorgoiler points out, "Making a difference in the world is what counts." If you'd like to help, consider applying! :)

My dream is to work for spaceX, but I'm NY. Do you his have remote teams or a NY office?

I find it completely baffling that it's your dream to work for SpaceX but you're unwilling to relocate? I'm stuck in the bay area (which I absolutely despise) because of my job, but I get to write flight software for spacecraft so I deal with it.

Re: SpaceX test flight of Starship SN-5 [video]

#307

Post by 0xffff2 »

tjtrapp wrote: post #63
bfieidhbrjr wrote: post #55

Does anyone else get super depressed by this? I did some great work today. I coded something pretty cool and useful. I built a little deck to explain it. My coworkers loved it. My job security went up. I enjoyed it. The journey is the reward. But these guys are making rockets in tents. Should I be rethinking life? Because that's how it feels. I love it. I admire them. But it feels unobtainable. I want to make that ki…

We're hiring for Starship and Starlink software teams: https://grnh.se/080f65d02us It sounds like you're passionate about your work and that's an important quality. As gorgoiler points out, "Making a difference in the world is what counts." If you'd like to help, consider applying! :)

How's the work/life balance these days? Are 60-80 hour work weeks still the norm?

Re: SpaceX test flight of Starship SN-5 [video]

#308

Post by nickik »

napier wrote: post #247
martythemaniak wrote: post #205

I really love the out-in-the-open development process. It doesn't cost SpaceX anything, yet they attract lots of internet media where people set up streams, discuss progress etc. The next year should be pretty exciting as they develop things further. Starship has a number of big innovations, which are: - the raptor engine. This was developed behind closed doors and is sort of finished. We won't see much of it, but it…

> any upcoming engine that can compete with it. There's the criminally underfunded SABRE engine, an a air-hydrogen mix breathing-rocket hybrid design from Reaction Engines that rated to reach speeds of Mach 25 (roughly 35,000 miles per hour). As modelled, it's more efficient than any other current or proposed chemical propulsion technology, and the proposed single-stage runway launchable system would be capable of de…

SABRE engine is not really upcoming. It never even got close to production or prototype.

And the estimate cost of that vehicle were very optimistic with lots and lots of problems to overcome. A proposal like that from people who have never really done all that much is highly speculative.

The projected cost they could reach with that vehicle, is already beat by Falcon 9.

Elon Musk has even told the Royal Aeronautical Society that he thinks air-breathing engines are a bad idea. Massive complexity for not so much gain. Invest that money into better first stage engine, push threw the atmo quickly get out of it, and make optimal use of your second stage engine.

Its pretty save to say SpaceX will not invest in what is mostly a paper rocket with an engine that has only ever tested the cooling system.

Re: SpaceX test flight of Starship SN-5 [video]

#310

Post by nickik »

jcun4128 wrote: post #277
nine_k wrote: post #276

Earlier quoted context omitted.

Indeed, the N1 design [1] will finally be done right. [1]: https://en.wikipedia.org/wiki/N1_(rocket)#Block_A_first_stag...

The Raptor engines are more advanced than those NK-31's right? I mean by newer manufacturing but I remember seeing something about these Russian engines that were closed off in some factory somewhere/later(years) found and they were supposedly still more advanced/powerful(efficient?) than modern rockets.

You are right and by some measures they were. However current engines like Raptor, BE-4 and in some ways Marlin, will be in many way more advanced.
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